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Arctic sea ice / Re: 2017 sea ice area and extent data
« on: November 20, 2017, 04:51:19 PM »
Chukchi seen closing in somewhat over the next week by ESRL (AlaskaRegion5.gif) with considerable swings in temperature (inset, AlaskaRegion2.gif). It's hard to say though when the season will wind down here as the Bering Sea (south of the Strait) seems behind 2016. R.Thoman has the data:

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 20, 2017, 03:42:43 PM »
Do you know if that includes *freshwater* ice?
There's a comprehensive and quite readable discussion of every aspect of Arctic freshwater in Chapter 7 of the assessment. By freshwater, oceanographers don't mean drinking water fresh, merely how not-as-saline as 34.8 psu seawater. So 34.7 psu is already freshened by how much water would have to evaporate to bring it up to 34.8 psu. The surface freshwater anomaly extends cown a few tens of meters at most (first image).

First year ice is still quite salty -- not single ice crystals per se which are standard ice Ih with no inclusions -- but from extruded salt in brine channels that's still around. Thus the Russian 'Barneo' expedition this year had to melt snow to get their drinking water. By some accounts, a 2:3 mix of salt:fresh is utilizable by humans.

Below, some scattered snippets from Chapter 7. The attached figures are better viewed in the original.

Snow, Water, Ice and Permafrost in the Arctic (SWIPA) 2017
Arctic Monitoring and Assessment Program (AMAP), Oslo, 2017 [cutoff date mid-2016]

The Arctic water cycle is expected to continue to intensify during this century. Mean precipitation and daily precipitation extremes will increase over mid- and high latitudes, with implications for the management of water resources, flow of freshwater into the Arctic Ocean, changes in sea ice temperature, and amplification of regional warming (through reduced surface reflectivity caused by a shift from snow to more rain in the warmer seasons).
The areal reduction of old sea ice has consequences for mean sea-ice thickness, thickness distribution, and surface roughness of Arctic sea ice (Hansen et al., 2014; Renner et al., 2014; Landy et al., 2015). Reduced ice thickness is related to changes in the forcings, whereas changes in thickness distribution are directly related to the properties of the different ice classes present.

Younger sea ice has on average higher salinity than older ice, and this has various consequences, for example how much freshwater is transported with drfting ice and on habitat conditions for organisms living within the ice.

A shift from perennial sea ice to predominantly seasonal ice types will cause changes in the physical properties of the ice cover. These changes are mainly associated with the volume of brine trapped within the ice. In contrast to first-year ice, multi- year ice has undergone a summer melt season and in the process lost most of the brine trapped within.

The brine volume, which can be calculated as a function of salinity and temperature, determines the porosity of the ice, which controls many important properties of sea ice, such as its strength, thermal and dielectric properties, mass (chemical and gas) transport, and the development of melt ponds and surface albedo.

Salt and heat fluxes are affected by the increased presence of first-year sea ice. First-year ice growth rates are higher than for older ice types, which means more salt is released during autumn and winter ice growth. In summer, the higher melt rates for first- year ice increases freshwater input to the surface ocean, thereby increasing buoyancy flux and stratification. Gas exchange rates through sea ice are also changing: more saline ice means more active exchange processes because gas permeability is higher in more porous sea ice.

In contrast to the southern hemisphere, the configuration of continents in the northern hemisphere is such that they effectively capture moisture from the atmospheric storm tracks of the Westerlies and redirect in north-flowing drainage basins disproportionate quantities of freshwater into the Mediterranean configuration of the Arctic Ocean (Figure 7.1).

Hence, while the Arctic Ocean represents only 1% (in terms of volume) and 3% (in terms of surface area) of the global ocean, it collects over 11% of the global river discharge (Dai and Trenberth, 2002; Carmack et al. 2016). e Trade Winds also transport moisture from the Atlantic Ocean across the Isthmus of Panama to freshen the Pacific Ocean, and some of this freshened water eventually flows into the Arctic Ocean through Bering Strait. e resulting salt stratification or halocline (i.e. a freshened upper ocean and salinity increasing with depth) is the dominant characteristic of high-latitude seas in general and the Arctic Ocean in particular .

The freshwater budget of the Arctic Ocean is governed by the system’s key functions and processes: the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle and Pacific Ocean inflows;

The Arctic Ocean freshwater budget was recently updated by Haine et al. (2015) (Table 7.1). The distribution of freshwater within the Arctic Ocean is heterogeneous and controlled by circulation and water mass structure. The Arctic Ocean is made integral to the global ocean by the northern hemisphere thermohaline circulation which drives Pacific Water through Bering Strait into Canada Basin, and counter-flowing Atlantic Water through Fram Strait and across the Barents Sea into Nansen Basin.

Following Bluhm et al. (2015), it is useful to recognize four vertically-stacked circulation layers (Figure 7.5): (1) the wind- driven surface layer circulation that is characterized by the cyclonic Trans-Polar Dri from Siberia to Fram Strait and the anticyclonic Beaufort Gyre in southern Canada Basin; (2) the underlying circulation of waters that comprise the halocline complex, composed largely of Pacific Water and Atlantic Water that are modified during their passage over the Bering/ Chukchi and Barents/Siberian shelves, respectively; (3) the topographically-trapped Arctic Circumpolar Boundary Current that carries Atlantic Water cyclonically around the boundaries of the entire suite of basins; and (4) the very slow exchange of Arctic Ocean Deep Waters.

Within the basin domain two water mass assemblies are observed, the difference between them being the absence or presence of Pacific Water sandwiched between Arctic Surface Waters above and the Atlantic Water complex below; the boundary between these domains forms the Atlantic/Pacific halocline front.
But the distribution of freshwater within the Arctic Ocean is not uniform, and salinities range from about 35 where Atlantic Water enters the basin to near zero adjacent to river mouths and along the coast (Carmack et al., 2016). is huge range in salinity, the main parameter that determines density stratification in high-latitude oceans, affects almost every aspect of circulation and mixing within the Arctic Ocean.

Relative to a reference salinity of 34.8, about 101,000 km3 of freshwater are stored in the Arctic Ocean (this is an estimate of the 2000–2010 annual average volume by Haine et al., 2015; Table 7.1). The largest freshwater reservoir exists in the Amerasian Basin, specifically in the Beaufort Gyre where about 23,500 km3 freshwater are stored and the accumulated freshwater anomaly diluting the upper ocean above the 34.8 isohaline surface is about 20 m thick. In the Eurasian Basin, typical liquid freshwater thicknesses are 5–10 m.

Freshwater in the solid phase as sea ice is another important reservoir in the Arctic. About 14,300 km3 of freshwater are stored in sea ice (2000–2010 average from Haine et al., 2015). e largest sea ice volumes are north of the Canadian Arctic Archipelago and Greenland and across the pole, where the ice is still relatively thick (Kwok et al., 2009).

The seasonal freeze-thaw cycle acts to exchange freshwater between the liquid and solid phases. Its amplitude is about 13,400 km3 (averaged over the decade of the 2000s; Haine et al., 2015), close to the annual average freshwater volume stored in sea ice. Sea-ice formation in winter occurs throughout the Arctic Ocean but the prevailing currents tend to export ice frozen over the Eurasian shelves toward the central Arctic and the Trans-Polar Drift (Figure 7.5).

Under current climate conditions only about 35% of the sea ice present at the end of winter, when the ice volume peaks survives the summer to become multiyear ice. Of the remaining 65%, most melts within the Arctic although some is exported south.

Kwok and Rothrock (2009) reported submarine and satellite data that show the average end-of-melt season ice thickness was 3.02 m in 1958–1976 but just 1.43 m in 2003–2007. Because both ice extent and ice thickness are declining, sea-ice volume is also declining.

Currently, the Arctic Ocean is freshening (Haine et al., 2015), warming (Polyakov et al., 2012), losing sea ice (Stroeve et al., 2012), and its ice cover is changing properties and moving faster (Kwok et al., 2013).

Arctic sea ice / Re: Latest PIOMAS update (November mid monthly update)
« on: November 19, 2017, 10:14:26 PM »
Here is November sea ice thickness from RASM-ESRL, including ten days of forecast. Again, we don't know how this was initialized back in mid-August nor how to compare it numerically to Piomas but do have some idea how the RASM-ESRL model adds thickness to existing ice and how it freezes open water (which is rapidly shrinking in the Chukchi and even pushing into the Barents towards the end, much more so than on the same date in 2016).

Arctic sea ice / Re: 2017 sea ice area and extent data
« on: November 19, 2017, 04:04:33 PM »
really like your graph.  However, the 2000's average is getting a little long in the tooth as a "current" baseline.  It would be nice to have a more recent aggregated average  can't do a 2010's average yet, maybe you can add in a dashed line for the previous 10 years average.
Or simply do all possible rolling 30 (or 20) year baselines, each as a frame of an animation, to show the sensitivity/robustness to choice of baseline. (This sounds like a lot of work but actually it isn't.)

The first animation below shows the average number of days of open water (based on UH AMSR2 6.25 km) from the September minimum until 18 Nov 17. There is a surprisingly large area that has never had open water during this time frame (gold) as well as substantial areas that never have had ice (blue). The contoured frames have 18 levels. The second animation shows open water vs ice (of any non-zero concentration) over this same time frame.

'Seasonally open' is too often left vague but often seems to refers to summer (or perhaps better, to 91 days of peak insolation centered on the June solstice) when reflection of sunlight becomes oceanic absorption of its heat.

However 'seasonally open' is perhaps more important in the fall because it can modulate radiative heat loss from the ocean and delay formation of a thermal blanket of snow, thus affecting thickening of ice and pre-conditioning of the following melt season. Because Arctic Amplification is primarily a fall and winter phenomenon, observed melt season trends are downstream (and even noisier because of highly variable spring and summer weather).

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 19, 2017, 03:50:53 PM »
For a comprehensive summary of 2017, if a 288 page document can be called a summary, there is a quite decent report at the link below. The cover picture of the ice edge, a fraction of which is shown below, tells the story in brief.

Snow, Water, Ice and Permafrost in the Arctic (SWIPA) 2017
Arctic Monitoring and Assessment Programme (AMAP), Oslo, 2017

Arctic temperatures are rising faster than the global average. The Arctic was warmer from 2011 to 2015 than at any time since instrumental records began in around 1900, and has been warming more than twice as rapidly as the world as a whole for the past 50 years. January 2016 in the Arctic was 5°C warmer than the 1981–2010 average for the region, a full 2°C higher than the previous record set in 2008, and monthly mean temperatures in October through December 2016 were 6°C higher than average for these months. Sea temperatures are also increasing, both near the surface and in deeper water.

Except for the coldest northern regions of the Arctic Ocean, the average number of days with sea ice cover in the Arctic declined at a rate of 10–20 days per decade over the period 1979–2013, with some areas seeing much larger declines. Warm winds during the autumn of 2016 substantially delayed the formation of sea ice.

The area and duration of snow cover are decreasing. Snow cover has continued to decline in the Arctic, with its annual duration decreasing by 2–4 days per decade. In recent years, June snow area in the North American and Eurasian Arctic has typically been about 50% below values observed before 2000.

Permafrost warming continues. Near-surface permafrost in the High Arctic and other very cold areas has warmed by more than 0.5°C since 2007–2009, and the layer of the ground that thaws in summer has deepened in most areas where permafrost is monitored.

Freshwater storage in the Arctic Ocean has increased. Compared with the 1980–2000 average, the volume of freshwater in the upper layer of the Arctic Ocean has increased by 8,000 cubic kilometers, or more than 11%.  is volume equals the combined annual discharge of the Amazon and Ganges rivers, and could—if it escapes the confines of the Arctic Ocean—affect circulation in the Nordic Seas and the North Atlantic.

Arctic climate trends affect carbon storage and emissions. New estimates indicate that Arctic soils hold about 50% of the world’s soil carbon. While thawing permafrost is expected to contribute significantly to future greenhouse gas emissions, the amount released over the past 60 years has been relatively small.

The impacts of Arctic changes reach beyond the Arctic. In addition to the Arctic’s role in global sea-level rise and greenhouse gas emissions, the changes underway appear to be affecting weather patterns in lower latitudes, even influencing Southeast Asian monsoons.

Warming trends will continue. Models project that autumn and winter temperatures in the Arctic will increase to 4–5°C above late 20th century values before mid-century, under either a medium or high greenhouse gas concentration scenario. This is twice the increase projected for the Northern Hemisphere.  These increases are locked into the climate system by past emissions and ocean heat storage, and would still occur even if the world were to make drastic near-term cuts in emissions.

Arctic sea ice / Re: 2017 sea ice area and extent data
« on: November 17, 2017, 11:03:46 PM »
The years pinch together in Dec because after it's all frozen over, it's frozen all over. It's good to keep in mind what geographic region 'extent' refers to. Nothing wrong with using the whole Northern Hemisphere (or NH minus Great Lakes) but any definition beyond the Arctic Ocean proper swamps out what is going on there. Which is unfortunate since most of the knock-on effects (eg low albedo during insolation season) initiate there.

The boundaries taken below exclude the Bering Sea, CAA, the Fram and Nares Strait exports, and the Barents south of Novaya Zemlya's tip. It's more accurate to use open water in the much higher resolution UH AMSR2 sea ice concentration than some of the extent sources.  In the region shown, open water has been on a slight increase (suggesting AO extent is slightly decreasing). That's not attributable to melt or bulk ice pack motion but to compaction and export.

These latter considerations complicate monitoring of the freezing season progress per se. In terms of developing anomalies, it's probably better to follow ice thickness growth at RASM-ESRL or Piomas, in addition to snow thickness, snow/ice surface temperature, and open sea water temperatures in the Chukchi and north Svalbard areas (which show no sign of closing over). These could get tossed in with Arctic Amplification but that is usually taken as the overlying atmospheric anomaly relative to global mean temperature. long history to intermediate water warming.

Permafrost / Re: Modelling permafrost carbon feedback
« on: November 17, 2017, 04:31:23 PM »
Nice talk. Fig.1 from the article mentioned above is shown below. Unfortunately its chronology appears to be flawed.

Permafrost thawing as a possible source of abrupt carbon release at the onset of the Bølling/Allerød
Peter Köhler, Gregor Knorr & Edouard Bard
Nature Comm 2014 open source 27 follow-up cites

One of the most abrupt and yet unexplained past rises in atmospheric CO2 (>10 p.p.m.v. in two centuries) occurred in quasi-synchrony with abrupt northern hemispheric warming into the Bølling/Allerød, ~14,600 years ago.

We suggest, in line with observations of atmospheric CH4 and terrigenous biomarkers, that thawing permafrost in high northern latitudes could have been the source of carbon, possibly with contribution from flooding of the Siberian continental shelf during meltwater pulse 1A. Our findings highlight the potential of the permafrost carbon reservoir to modulate abrupt climate changes via greenhouse-gas feedbacks.

Changes in the global carbon cycle during the last deglaciation are so far not completely understood. However, based on the data and model-based interpretation, the emerging picture indicates that the rise in atmospheric CO2 of ~45 p.p.m.v. during the first half of the deglaciation (~1 p.p.m.v. per century) was probably fuelled by the release of old, 13C- and 14C-depleted deep ocean carbon.

Atmospheric CH4 rose by 150 p.p.b.v. between 18.5 and 14.6 kyr BP and then by the same amount again, but within centuries, around the onset of the B/A. The changes in both greenhouse gases (GHG) imply that a ratio of both changes ΔCH4/ΔCO2 is a factor of five larger around 14.6 kyr BP than during the previous four millennia.

Radiocarbon calibration uncertainties during the last deglaciation: Insights from new floating tree-ring chronologies
Florian Adolphi et al

Radiocarbon dating is the most commonly used chronological tool in archaeological and environmental sciences dealing with the past 50,000 years, making the radiocarbon calibration curve one of the most important records in paleosciences.

For the past 12,560 years, the radiocarbon calibration curve is constrained by high quality tree-ring data. Prior to this, however, its uncertainties increase rapidly due to the absence of suitable tree-ring 14C data. Here, we present new high-resolution 14C measurements from 3 floating tree-ring chronologies from the last deglaciation.

By using combined information from the current radiocarbon calibration curve and ice core 10Be records, we are able to absolutely date these chronologies at high confidence. We show that our data imply large 14C-age variations during the Bølling chronozone (Greenland Interstadial 1e) – a period that is currently characterized by a long 14C-age plateau in the most recent IntCal13 calibration record. We demonstrate that this lack of structure in IntCal13 may currently lead to erroneous calibrated ages by up to 500 years.

The resulting 14C records are in broad agreement with IntCal13 and its underlying raw datasets, even though we find significant differences to the Tahiti corals by Durand 2013. Independent of their exact absolute age, the tree-ring 14C records indicate substantial 14C-age variations between 14,000 and 14,700 cal BP e a period that is currently characterized by a long 14C age plateau in IntCal13.

We demonstrate that the lack of these variations in IntCal13 can lead to erroneous age calibration by up to 500 years during the onset of the Bølling chronozone around 14,700 cal BP. On the other hand, the 14C-age variations indicated by our floating tree-ring chronologies, can aid in obtaining a higher accuracy and precision of calibrated 14C ages during this period, which is currently also limited by the long age plateau in IntCal13.

Given that the Tahiti coral record also disagrees with most other 14C datasets at that time, we suggest that it is more likely that reservoir/archive specific effects in the coral data are the cause for the offset between both datasets. Consequently, this would contradict the conclusions of Köhler 2014 who inferred a release of old carbon from permafrost thawing as the reason for the rapid decline in delta14C seen in the coral record around 14,600 cal BP.

The forum / Re: Trackers in iframes
« on: November 17, 2017, 12:09:13 AM »
this is already going over my head, I just unchecked a couple of boxes
Why did i ever let go of my 1980 Honda Civic wagon, what was I thinking??? No tracking, no hacking, no engine warning lights -- that car practically drove itself.

"They" say some millennials actually want to be tracked, profiled and targeted with ads. It seems the more you shop, the more you save.

our new "smart" thermostat, the Ecobee4 ...It's way cool!

-Touch screen. wifi enabled, connects to internet to retrieve current weather and weather forecast
-can be controlled remotely with Android phone app
-comes with an extra room sensor to monitor temp in other rooms (the thermostat can be set to an average temp)
-sensor can sense occupancy so it can heat the house according to what her particular rooms are empty or occupied
-has Amazon Alexa assistant built in so we can access all that stuff with voice control, it can play music, news, and all that cool stuff
-will integrate with and allow us to voice control smart wifi dimmer switches for the lights
-it pays attention to outside temps and adjusts according to the seasons when adjust room temp (i.e., in winter it will start heating sooner to have the temp 67 by 6pm, whereas in summer time it would take less time to get up to temp by 6pm)
-and lots of other cool stuff I'm still learning about
- They claim it reduces the average home heating bill by 23%!It's usually sells for $249, but last week was on sale for 209, plus I found a $40 off $200 coupon for Lowe's .com.  Combined with a $50 Oregon Energy Trust rebate, it came in at just under $120!

The forum / Re: Trackers in iframes
« on: November 16, 2017, 06:26:16 PM »
budmantis  Today at 12:40:46 PM
Didn't knowingly insert that, very annoying! How do I get rid of it?

It's inserted in every opening post. I'll see if I can get rid of it as admin.
Hmmm, can you take a screenshot of what this looked like?

In every opening post? That sounds like the keepers of our "free" forum software took a dive. Disturbing if they took an unannounced payment, did not notify administrators, and did not make a spyware "feature" opt-in. Ethically unacceptable. It could affect thousands of other sites.

Here is another possible instance of someone unintentionally pasting in a tracker:

Permafrost / Re: Arctic Methane Release
« on: November 16, 2017, 03:19:54 PM »
The graphic below (which expands upon a click) summarizes the effects of glaciation in the Arctic Ocean basin. It shows the most recently discovered glacial trough, the De Long, along with many others, summarizing work over many years by M Jakobsson and co-workers.

These troughs cut across the edge of the continental shelf and deposit sediment fans in the deep. The ESAS (resp. Beringia at low sea stand) is quite unusual in that its continental shelf edge was little affected by glaciers during the Pleistocene (because it received insufficient snowfall).

Since sediment fans provide an important organic substrates for archaeal methanogens, little methane is expected along the ESAS which largely lacks them and, while landslides could occur, there is no risk of a 'clathrate gun' for the ESAS. The real risk comes from vast near-shore deposits of free methane gas sitting under a deteriorating permafrost cap, as documented by Semiletov and Shakhova.

"... abundant CH4, including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on assumption... metal oxide reduction appears to be the dominant geochemical environment affecting shallow sediment; there is no evidence for upward diffusing CH4. These results strongly suggest that gas hydrates do not occur on any of our depth transect [cores] spread across the continental slope in this region of the Arctic Ocean. This directly conflicts with ideas in multiple publications" Ouch! CM Miller et al 2017

Note the MacKenzie River is surprisingly not associated with a major trough or fan; the main feature in the CAA passes just east of Banks Island. Likewise, Petermann Glacier is not a dominant feature; it appears to have been block by a much larger glacier passing south through the Nares Strait.

These troughs today play an important role in oceanic circulation (ie mixing of incoming warm Atlantic Waters), notably in the Barents Sea and east of Svalbard.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 15, 2017, 06:52:54 PM »
does IMB 2017B count?
Not if it wasn't used in producing the 2m Tropical Tidbits temperature model map. If independent, it  has some interest in terms of a reality check (validation point) for the later, though one point per 9 million sq km is rather sparse. Whatever, 2m is not what the snow/ice surface is experiencing which is 0.1m or better, Teff.

Improving the effective temperature estimation over sea ice using low frequency microwave radiometer data and Arctic buoys  10 Nov 17 EUMET OSISAF

Looking at the polarview Svalbard anomaly map that has made numerous appearances here, note that the area for which it is defined makes little sense today to the south, as even in mid-February these days ice doesn't get at all close to that boundary. However the areal definition does fairly well in excluding Fram ice yet including the Yarmak Plateau that is important to bringing Atlantic Water up from depth.

Open water in the Chukchi is following the bathymetry fairly well (as expected for Bering Sea waters), including a protrusion into the Chukchi Borderlands. However west of Herald Canyon, the influence is non-evident (eg in the ESAS west of Wrangel).

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 14, 2017, 11:50:24 PM »
You mean this TPW?
Yes! Surprising that it display, original size is 1000 x 470

Turns out they offer quite a few specialized views, though not either pole. I found the netCDF files but they are not in the Geo2D format that would allow re-projection in Panoply with a more attractive palette (though Zack seems to have found a way of doing this.) It would be feasibly to string together multiple days, though they set everything at 100ms delay and then use multiples of first and last rather than setting ms properly. archive front page

Consequences / Re: Places becoming less livable
« on: November 14, 2017, 05:34:53 PM »
The Willamette Valley in Oregon had this very same problem as Delhi with field burning when I lived there. Some 160 golf course rye seed growers would get a slightly better return on investment according to a 40-year old study from the local ag college by torching the stubble, so never mind the health toll on the other 3,000,000 valley residents. It was called Freedom to Farm.

Rural interests were greatly favored then and now by legislator allocation which was historically property-owner based. Eventually they smoked out the freeway causing an epic multi-vehicle pileup and lost support. Very similar to household plastic trash smoldering in a backyard barrel which was also legal until very recently.

Punjab, at least they are growing food there. I have no idea whether it is just a traditional practice without a agronomic basis (soil nitrogen will largely volatilize and waft away, not stay as ready fertilizer), whether it is just slightly cheaper than discing, whether markets exist for stubble (they do), whether it is just stubborn regional flexing of political muscle, whether soil pests are actually reduced, or whether it would be far cheaper simply to accept reduced yield and import (more) wheat from the US.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 14, 2017, 04:32:37 PM »
is GOFS an improvement, otherwise what's the point?
Good question. Ditto for RASM-ESRL which seems to offer a third version of similar products (below). But that could be asked as well for UH and UB SMOS. Hamburg has coordinated salinity polarizability with Cryosat thickness; Bremen with another soil satellite SMAP. Maybe the two could get together and offer one optimal product?

sea temperatures at surface and depth matter
The air temperature at 2m can be quite cold relative to the sea water freezing point yet the re-analyzer temperature anomaly can still be a pronounced orange, especially for a 30 year base period that misses out on more recent Arctic Amplification (which is largely a fall and winter phenomenon).

Actually the temperatures of physical interest to the freeze season are those directly observable of the water and snow/ice surfaces themselves, not modeled meteorological 2m, though the three strongly influence each other.

Seductive computer graphics in many instances have gotten far ahead of actual data accuracy. Only a handful of products, such as UH SMOS, contain error analysis maps in their netCDF bundle. It is not rocket science, using 3rd party ImageJ 3D surface plugins, to drape say ice thickness over its error bump map, both as time series.

Note some open water north of the Bering Strait is still 3ºC above the freezing point. Given wind mixing (shown), thin dry air has a lot of work to do before stable frazil ice can form. Meanwhile upwelling net longwave cooling (provided by ESRL in Arctic11.gif, Arctic23.gif, and Arctic14.gif) is another consideration.

For all their shortcomings, we are probably better off using coupled radiative water-ice-snow-air-precip-cloud forecast models, which quantitatively integrate all the considerations, than intuiting off a single parameter such as a transient air mass. navigate to Coupled --> Surface Fluxes

There are no active temperature gauges today in the Arctic Ocean itself, only a handful on the periphery and one daily sonde at Ny-Ålesund. This would be like producing a high resolution daily 2m temperature map of Europe using only station data from North Africa, Ireland and Finland, lol.

water vapor intrusions can have very significant impacts
Yes indeed, seems like last season had a number of notable and persistent events. Anybody recall the link to that very fine TPW web graphic? It showed counter-rotating water vapor trails sometimes rising up into the North Atlantic and beyond, bring warm vapor from the Caribbean.

Winter storms have been analyzed by L Boisvert and coworkers, including in several AGU2017 abstracts, notably:

GC43J-07: Increasing frequency and duration of Arctic winter warming events open source
RM Graham et al

During the last three winter seasons, extreme warming events were observed over sea ice in the central Arctic Ocean. Each of these warming events were associated with temperatures close to or above 0°C, which lasted for between 1 and 3 days. Typically temperatures in the Arctic at this time of year are below −30°C. Here we study past temperature observations in the Arctic to investigate how common winter warming events are. We use temperature observations from expeditions such as Fram (1893–1896) and manned Soviet North Pole drifting ice stations from 1937 to 1991. These historic temperature records show that winter warming events have been observed over most of the Arctic Ocean.

Despite a thin network of observation sites, winter time temperatures above −5°C were directly observed approximately once every 3 years in the central Arctic Ocean between 1954 and 2010. Winter warming events are associated with storm systems originating in either the Atlantic or Pacific Oceans. Twice as many warming events originate from the Atlantic Ocean compared with the Pacific. These storms often penetrate across the North Pole. While observations of winter warming events date back to 1896, we find an increasing number of winter warming events in recent years.

Record low Arctic sea ice extents were observed during the last three winter seasons (March). During each of these winters, near-surface air temperatures close to 0°C were observed, in situ, over sea ice in the central Arctic. Recent media reports and scientific studies suggest that such winter warming events were unprecedented for the Arctic. Here we use in situ winter (December–March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter warming events are.

Despite a limited observational network, temperatures exceeding −5°C were measured in situ during more than 30% of winters from 1954 to 2010, by either North Pole drifting stations or ocean buoys. Correlation coefficients between the atmospheric reanalysis, ERA-Interim, and these in-situ temperature records are shown to be on the order of 0.90.

This suggests that ERA-Interim is a suitable tool for studying Arctic winter warming events. Using the ERA-Interim record (1979–2016), we show that the North Pole typically experiences 10 warming events (T2m > −10°C) per winter, compared with only five in the Pacific Central Arctic (PCA).

C21B-1119: Winter Arctic sea ice growth: current variability and projections for the coming decades

C33C-1215: Rainy Days in the New Arctic: A Comprehensive Look at Precipitation from 8 Reanalysis

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 14, 2017, 12:43:43 PM »
Quite a change ... one of our long-time resources for sea ice thickness has been replaced. The ice is markedly thinner in the new products; whether it is any more accurate is questionable. Still, the forecasts give some idea what is coming.

The animations show the Beaufort barely closing over, the Chukchi and Svalbard remaining open and some moderate Fram export, to 20 Nov.

As of 30 Sept 2017, ACNFS will be replaced by the Global Ocean Forecast System (GOFS 3.1). Daily Arctic and Antarctic ice products are available from the GOFS 3.1web page. The ACNFS webpage will remain in service for historical purposes but will not be updated with real-time ice forecast products.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 13, 2017, 10:33:59 PM »
on the Chukchi front, refreezing is actually the slowest in years. while the Svalbard front is actually receding poleward.
That's right, Oren. It appears primarily attributable to influxes of Bering Sea and Atlantic Waters that are too warm, given their immense heat capacity relative to the freezing capacity of cold air in conjunction with net upwelling radiative energy flux loss. (Ice pack bulk motion, compaction and dispersion need to be factored in but have been fairly minimal.)

The 3.125 km resolution of UH AMSR2 sea ice concentration (previous post) does a better job at picking out open water than far coarser satellite data used elsewhere for the less intuitive extent/area graphs, especially as coastal complexity comes into play. However those have the longer history necessary to pull trends from natural variability. In my view, picking connected open water in this region is more appropriate than ad hoc regional definitions of Beaufort vs Chukchi vs East Siberian seas.

The UH SMOS sea ice thickness product below uses a quite different approach that is complementary to AMSR2 sea ice concentration. At the very margins of the ice pack where new ice is in the initial stages of formation, SMOS provides the opportunity to apply a specific thickness and brine content cutoff for what is to be considered as defining the effective ice edge. As depicted in the second animation, the thickness, salinity and snow surface temperatures have slightly different edges.

The freezing point of sea water at 34 psu salinity is -1.8ºC which corresponds to 271.35 on the kelvin scale shown. (While not considered politically correct today, ºK was used for the first 149 years for this scale, including by Kelvin himself.) Bulk ice salinity increases towards the edges and markedly so for ice age due to progressive brine exclusion.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 13, 2017, 05:42:13 PM »
Below is an update on Arctic Ocean open water from the 10 Sept minimum (fixed black outline) until 12 Nov with relative areas of ice-free regions for later dates (inset bar graph), with emphasis on the Chukchi-Beaufort and north Svalbard. Interior green represents 100% sea ice concentration in the UH AMSR2 assessment; there is little else this time of year except on the periphery.

The second animation compares 12 Nov 17 to the same date in 2013-2016. The magenta line shows the union of open water for these five years; 2012 data is not available at UH until the first of January. The multiplier relative to the low year 2013 and relative to five year mean are also provided.

year   rel 2013   rel mean
2017   1.88   1.27
2016   1.53   1.04
2015   1.32   0.90
2014   1.64   1.11
2013   1.00   0.68

Permafrost / Re: Arctic Methane Release
« on: November 13, 2017, 06:01:31 AM »
My reading of S&S is that they see the over-pressurized free methane gas, never mind the hydrates, as by far the greater problem that faces us.
That's correct, Terry. Semiletov estimates the methane hydrates as less than 5% of total ESAS methane; because of this, Shakhova can say the decay timeline of the hydrate stability zone is completely irrelevant because there's already enough free methane gas to catastrophically affect global climate, should even a fraction of it reach the atmosphere.

In view of this, why do people keep bringing up off-site clathrate studies that have zero relevance to ESAS methane release over a 0-20 year time frame?

According to S&S, there do not exist any published studies to date showing ESAS methane hydrates even occurs, whereas we're real sure that methane is currently being released in volume. That methane, from triple isotope studies, is a waste product of archaeal decomposition of buried organic matter. It is not geothermal methane nor destabilized clathrate.

It would be more interesting to chase down the observational basis for S&S's estimate of pressurized free methane volume reserves. Is there really as much down there as they say? How is it distributed relative to the coastline, riverine sediment inputs, and shelf break? Would it really matter if the estimate were 50% too high (or too low)?

And how much pressure has built up under the (deteriorating) permafrost lid and what is its connectivity? That greatly affects the fraction of escaping methane that can reach the atmosphere because slow occasional bubbles have a very different fate -- dissolving into seawater -- from vigorously fountaining methane.

I'm not sure why people keeping throwing in off-ESAS studies of sulfate oxidizing bacteria breaking down the methane before it even leaves the sediment. Obviously that isn't happening to a sufficient extent here. The methane may be rising too rapidly or the sulfate supply was just not there or has been exhausted.

Along the ESAS shelf break, SWERUS core traverses showed MnO and FeO, rather than sulfate, were serving as the terminal oxidants. Landslides there won't matter since the methane is already exhausted.

The ESAS, especially the near-coastal regions rich in methanogenic sediment, is exceedingly shallow, much of it less than 10 m deep. Again, it's baffling why people keep referring to deep sea methane studies or inconsequential shelf areas like the Beaufort with very different histories. Sure, those bubbles will get swept aside by currents and dissolve in sea water, eventually getting metabolized before Henry's Law kicks in.

That isn't the case for over-pressurized methane in shallow water because high volume hotspot vents physically entrain seawater, bringing the methane rapidly near and to the surface where it can equilibrate with (ie raise) the currently low partial pressure of atmospheric methane.

In the interview, Shakhova says "a fraction" will inevitably reach the atmosphere, not specifying that fraction other than to say given the immense estimated methane reserves, its pressure, the erosion of permafrost lid, and beyond-linear rate of hotspot development, that this fraction is all that it would take to seriously disrupt global climate.

S&S have laid out plausible concerns based on decades of observational data. How events will actually play out in the near future depends on the numbers. For those, far more sonar surveys are needed, both of vent activity and subsurface structural changes. The ESAS is so vast and the season so short that it's time-consuming to sample its area with line surveys, much less repeat them to establish a time series.

However -- and this is the whole point of the 2017 NatComm paper -- they have been able to conduct repeat transects and repeat drill cores to a limited extent. Those don't indicate the worst case scenario (a massive one-time blowout) but support decadal-scale accelerating emissions that come close enough in effects.

It won't work to simply monitor atmospheric methane increase (though that's the final arbiter) because it's a lagging indicator for deterioration of the ESAS permafrost lid. As such, it wouldn't give enough time to 'make room' whereas better data might (see #482).

Permafrost / Re: Arctic Methane Release
« on: November 06, 2017, 06:42:56 PM »
Wait, what? tell me exactly where Hansen says this ?
No idea. That would have been a decade prior to the first actual data from Oden's traverses of the ESAS shelf edge. There is little methane to be found there any more. Warm water along the edge of the ESAS continental shelf could not trigger substantial methane release if it's not there to begin with. There's only so far you can go with models not grounded on observational data.

Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH4) in sediments as gas hydrate and free gas. Although release of this CH4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint  SWERUS-C3 expedition. The cores come from depth transects across the slope and ... north of Wrangel Island and the New Siberian Islands. ...

These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH4, including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on assumption.

Lots of other interesting stuff in that same special issue of The Cryosphere with potential relevance to ESAS methane:

Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

Global sea level rise during the last deglacial flooded the Siberian continental shelf in the Arctic Ocean. Sediment cores, radiocarbon dating, and microfossils show that the regional sea level in the Arctic rose rapidly from about 12 500 to 10 700 years ago. Regional sea level history on the Siberian shelf differs from the global deglacial sea level rise perhaps due to regional vertical adjustment resulting from the growth and decay of ice sheets.

Post-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records

The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.

Ice-shelf damming in the glacial Arctic Ocean: dynamical regimes of a basin-covering kilometre-thick ice shelf

Recent data suggest that a 1 km thick ice shelf extended over the glacial Arctic Ocean during MIS 6, about 140 000 years ago. Here, we theoretically analyse the development and equilibrium features of such an ice shelf. The ice shelf was effectively dammed by the Fram Strait and the mean ice-shelf thickness was controlled primarily by the horizontally integrated mass balance. Our results can aid in resolving some outstanding questions of the state of the glacial Arctic Ocean.

The De Long Trough: a newly discovered glacial trough on the East Siberian continental margin

Ice sheets extending over parts of the East Siberian continental shelf have been proposed for the last glacial period and during the larger Pleistocene glaciations. The sparse data available over this sector of the Arctic Ocean have left the timing, extent and even existence of these ice sheets largely unresolved.

Here we present new geophysical mapping and sediment coring data from the East Siberian shelf and slope collected during the 2014 SWERUS-C3 expedition. Sub-bottom profiles reveal a set of glacial landforms that include grounding zone formations along the outer continental shelf, seaward of which lies a  >  65 m thick sequence of glacio-genic debris flows.

The glacial landforms are interpreted to lie at the seaward end of a glacial trough – the first to be reported on the East Siberian margin, here referred to as the De Long Trough because of its location due north of the De Long Islands. Stratigraphy and dating of sediment cores show that a drape of acoustically laminated sediments covering the glacial deposits is older than ∼ 50 cal kyr BP.

This provides direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum and most likely occurred during the Saalian, Marine Isotope Stage 6.

Permafrost / Re: Arctic Methane Release
« on: November 06, 2017, 05:03:52 PM »
Assuming it's bad, getting worse and becoming significant soon: what to do?
That's a good question.

Better data: not nearly enough research resources are currently being allocated to the ESAS. This wouldn't affect outcome but would at least box in timing and magnitude better.

Shakhova makes a case for methane escape growing 'exponentially' rather than linearly. That could be a figure of speech or the solution to a differential equation: 'the rate of increase in methane release proportional to the current rate of methane release'.

Linear increases from slow thermal permafrost degradation could possibly be accommodated. However if the very establishment of a minor escape route leads to its physical enlargement to a major hotspot, and vigorous hotspot venting leads to explosive fountaining of regional pressurized gas stores, then the rate of methane release feeds on itself (by enlargement of the vent and conduit connectivity) and so goes up faster than linearly.

On the figure of speech side, Shakhova might just mean a whole lot more hotspots than last time they were out there. This might suggest permafrost degradation is crossing some kind of threshold across an ever-broader area. We may just happen to be here at an unfortunate one-off bad time in the late Holocene, perhaps compressed or partially brought on by anthropogenic warming.

Either way, modeling is delusional. It's all about the history and heterogeneity, for which sufficient detail will never be available. Nobody even has a talik count. Show me the scour map. Faults can be visualized at cm scale at km depth? Monitoring is all you can do.

Hope: there are a lot of steps between methane deep in the mud and methane in the greenhouse stratosphere, maybe some of them will slow or limit release to a rate that the atmosphere can accommodate.

Even in shallow water, only a fraction of the methane in bubbles actually reaches the atmosphere. That fraction rapidly increases with entrainment during rapid voluminous releases. The atmospheric half-life is fairly short, provided stratospheric hydroxyl radical supply is not overwhelmed.

Make room: reduce gratuitous greenhouse gas emissions as much as possible as soon as possible. That would include all the usual suspects such as coal and fugitive methane emissions.

The biggest single benefit with overnight effect and least societal inconvenience comes from cutting beef-belch methane (and its production-associated emissions). But banning beef because of emissions would about as popular as banning football because of concussions.


There don't seem to be any remotely plausible geo-engineering options. Some of them seem so stupid, like laying down a giant tarp over a third of the Arctic Ocean, they aren't worth discussing. Drill and flare to CO2? How many decades have we been doing that without depleting Texas -- the ESAS is 3x the size. How much did Shell blow on just one Beaufort platform, five billion? Is there a single connected reservoir or a hundred thousand?


Because IPCC dug themselves into such a hole with the slow CO2 narrative, they are in no position to pivot to methane. Methane is seen as a threat all right ... to their credibility. So 'policy-makers' will mainly hear methane being dissed, not that they would do anything if better informed.

Threat-proportionate action is not underway with CO2 today; even less will be done about methane as it touches two sacred western industries. Nothing can be done about ESAS methane emissions; it is wait-and-see how soon, how bad they'll get. We're not on track to make adequate headroom to accommodate even decadal-scale rapid release.

Permafrost / Re: Arctic Methane Release
« on: November 06, 2017, 04:03:07 PM »
I strongly recommend reading and re-reading the April 2017 Shakhova & Semiletov interview and going through the nine pictures in the NatComm paper until you get it. A lot of people posting here simply do not grasp the basic 1,2,3 of what's been observed nor the whats and whys S&S are proposing.

After assimilating the nine pictures, perhaps then opinionate on whether it is right or wrong or too soon to say. More work is needed, it always is; however the nine pictures in the NatComm paper show where it's headed: additional bubble and drill core-calibrated, repeat sonar surveys.

Essentially all observational data on the East Siberian shelf methane derives from field work by S&S and colleagues. Do you understand what that means? It means people pontificating on ESAS methane need to base off S&S data. Very few do. It means models have to be calibrated with S&S data. Very few are.

The vast majority of ESAS secondary coverage falls into psychological categories such as projection, competition, ignorance, misunderstanding, denial, and panic. Very little commentary is data-driven.

Cubicle-based, lower-latitude authorities seem to think the ESAS consists of a vast submerged tundra, with featureless even layers of permafrost and clathrates at depth warmed from below by a uniform geothermal gradient, extending out to the edge of the continental shelf under a unchanging near-frozen placid sea.

Inconveniently, the East Siberian shelf and its sedimentary drape are very heterogenous structurally because of a long complicated history of interaction with adjacent permafrost land, enormous sediment-laden rivers and paleo-rivers, ocean waters that advance and retreat with glacial cycles, with land exposed to very cold air at low stands, complicated by a 53m sill at the Bering Strait and a 1 km thick ice shelf at the last glacial maximum and thermokarst processes that still proceed even when permafrost is submerged.

Because submerged permafrost does not form a homogeneous lid, degradation of lid quality begins long before it thaws uniformly to its full thickness. Multiple escape routes have already developed in inhomogeneous regions such thawed or never-frozen taliks, thermokarst, glacial scours, pockmarks, convective salt fingering, groundwater intrusion, and geological faults. Not only that, the limited number of revisited escape routes are getting worse, fast. For the large volume of over-pressurized free methane gas that is already sitting there.

S&S are primarily concerned with this heterogeneity and its consequences. That's a good start in those nine pictures in the NatComm paper. There's more though: the special journal issue on the Oden's research and the 2018 papers now visible as AGU17 abstracts: special issue of The Cryosphere Semiletov Semiletov Semiletov Weidner Jakobsson

Arctic sea ice / Re: Arctic Image of the Day
« on: November 04, 2017, 02:53:18 PM »
Here is the ultimate polar bear picture from Svalbard by Marcus Westberg, part of a quite interesting article on the fjord change there. It loses impact upon size reduction so it needs a click to display properly.

Believe the flowers in front of the bear are purple saxifrage (Saxifraga oppositifolia); the whitish ones don't seem to be Dryas octopetala but most photos of them that I found were just labelled 'wildflowers'. The Svalbard flora web page lists 108 dicots; Cardamine bellidifolia seems a possibility.

Svalbard was totally ice-covered during the Weichselian ice age which ended around 10 000 years ago, so almost all the species would have come in subsequently from Greenland, Canada, Scandinavia and Russia.

Arctic sea ice / Re: 2017 sea ice area and extent data
« on: November 04, 2017, 10:35:33 AM »
The two supplemental images below show predicted ice and snow thickness in a discrete palette just for Nov 12th with ice with 10 cm freeboard (ie 1m thick) highlighted. At issue is the ability to support an insulating snow blanket. Snowdrifts are below the resolution of the data but may be thick enough in places in the central Arctic Ocean to somewhat inhibit ice thickening, provide it wasn't rained upon or wetted by waves.

Arctic sea ice / Re: 2017 sea ice area and extent data
« on: November 03, 2017, 11:33:21 PM »
Here is the open water extent since the 10 Sep 17 minimum (stationary black outline, 100% ice concentration in faint green) from UH AMSR2/Gimp, followed by the thickness/extent forecast out to Nov 12th per ESRL/Panoply/Gimp.

According to this, the Beaufort will have an ice cover by mid-November whereas the Chukchi will largely remain open and Atlantic Waters will still dominate north of Svalbard. There's some indication that Fram export may pick up mid-month.

Consequences / Re: Hurricane season 2017
« on: October 27, 2017, 06:41:58 PM »
that's Corruption with a capital C
You think? But, but their newly hired PR chief in NYC says contract was all done in good faith.

As was everything before the hurricane: closing 200 schools, cutting off the power for 3 hours a night in rural areas to avoid overtime, not replacing hundreds of PREPA workers who retired abruptly to get their pension activated, and bleeding maintainance via a huge new slush fund dished out to upper management.

"Puerto Rico has a history of dolling out shady government contracts and questionable deals with various private entities.

The island’s officials filed for bankruptcy in May and recently closed nearly 200 schools to save $7 million, while simultaneously issuing 107 consulting contracts since January to questionable recipients, according to a report in September from The Daily Caller News Foundation’s Ethan Barton.

Puerto Rico spent $256 billion in federal funds from 1990 through 2009, but only collected $74 billion in tax revenue. The U.S. territory is required to prioritize payments to creditors unless the funds go to essential services.

About $4.7 million in consulting contracts went to companies with ties to government officials, more than $800,000 of which were public relations groups. Consulting contracts totaling nearly $389,000 were awarded to the marketing firm KOI Americas, which is owned by Edwin Miranda, a friend of former Puerto Rico Gov. Luis Fortuño.

“The contract was done in good faith with PREPA (Puerto Rico Electric Power Authority)” and “speaks for itself,” Whitefish spokesman Ken Luce told MSNBC in an interview, adding later: “There’s nothing there.” (Reporting by Susan Heavey; Editing by Chizu Nomiyama

he story of PREPA is the story of Puerto Rico. The utility, created by a New Deal governor in 1941, powered rapid industrialisation in the 1970s as American pharmaceutical and other firms flocked to the island to take advantage of federal tax benefits. By offering stable, well-paid jobs to electrical workers, PREPA helped create a Puerto Rican middle class, says José Caraballo Cueto, an economist at the University of Puerto Rico. The boom was short-lived. When the federal government peeled back the tax perks in 1996, factories started leaving and PREPA began losing customers.
Declining revenues were exacerbated by political patronage, corruption and inefficiency. Municipalities and government agencies do not pay for electricity in Puerto Rico. Successive governments spent tens of millions of dollars evaluating solar and natural-gas projects in order to wean PREPA off its dependence on oil, but did next to nothing. Less than 3% of the island’s energy came from renewables.

PREPA is responsible for $9bn of Puerto Rico’s $73bn of debt. As PREPA and other agencies borrowed billions of dollars from international creditors (and from each other, a practice some have compared to a Ponzi scheme), the utility started skimping on maintenance. In 2014 an austerity law prompted hundreds of experienced employees to retire and claim their pensions before cuts took effect. They were never replaced. The result, according to Synapse’s report, was generator failures, blackout rates four times higher than other American utilities, rising consumer costs, environmental violations and an increasing numbers of worker injuries and fatalities. A three-day blackout in 2016 caused by a fire at the Aguirre plant foreshadowed the darkness and economic standstill Hurricane Maria would bring. “We took the risk and we are paying the price,” says Mr Torres, peering at his poster.

The reconstruction has begun in an unusual fashion. Puerto Rico has hired a tiny Montana-based contracting company called Whitefish Energy to oversee grid restoration. Normally, states and municipalities contact a “mutual aid network” that can quickly mobilise thousands of repairmen. “But Puerto Rico never said ‘Hey, we need crews’,” says Mike Hyland of the American Public Power Association (APPA), which represents 1,100 utilities. Mr Rosselló originally claimed he could not get in touch with the APPA, and then later explained that he began negotiating with Whitefish before Hurricane Maria. The company had responded to a request for repair work after Hurricane Irma, and it appeared to be Puerto Rico’s cheapest option. José Roman of the Puerto Rican Energy Commission, an independent body created in 2014 to regulate and monitor PREPA, confirmed that no official bidding process took place. “The government was in emergency mode,” he said.

“It wasn’t like all the big guys were jumping up and down to go to a bankrupt island,” said Ken Luce, a Hill & Knowlton spokesman hired by Whitefish a week ago. The company, which has two full-time employees, began as a joint-venture in 2015 with a Brazilian company called Comtrafo to build a transformer plant in Montana, a project that has since sputtered out."

Edit: The contract was taken down off the web at 11:00 am Friday; however thousands of people of people downloaded the document or still have its tab open. Note 'document-cloud' only serves the pages a browser is displaying. To see more, you must scroll down and wait for that portion to load. The pdf too is an image that does not allow text searching.

Andrew Freeman has a careful account:

"By comparison, minimum wage in Puerto Rico is $7.25 an hour. According to, the average salary for a journeyman electrical lineman is $39.03 per hour in the continental U.S. However, a journeyman lineman on Whitefish Energy's Puerto Rico project will earn $277.88 per hour."

"UTIER, the electrical workers' union of Puerto Rico, expressed alarm at those rates, tweeting: "We need support and help, but under these conditions it is impossible and questionable. Who allowed this?""

Consequences / Re: Hurricane season 2017
« on: October 27, 2017, 01:56:36 AM »
Ok, I get it, crony capitalism. FEMA to pay 100% of whitefish's preposterous invoices. Such as $1000 reimbursement for per each leg of air travel to Miami rather than $119 actual ticket cost. That is, it is like the hourly labor charges: Whitefish gets reimbursed at that rate, not the worker bees.

Given that PREPA was deep in bankruptcy prior to the hurricane and that management had long been looting the grid maintainance budget, other potential contractors were apprehensive about ever getting paid.

However Colonnetta's private equity firm could be certain in fronting the money to Techmanski that they would be repaid many times over because they could be certain of backing by Zinke, FEMA political appts, and the Trump admin.

Whitefish Energy was founded in 2015 by Andy Techmanski. In 2016, a 51% stake in the company was sold to Comtrafo S.A, an authentic Brazilian company that wanted to set up a transformer assembly plant in MT.

Whitefish had two employees when the hurricane struck; their primary investor, HBC Investments aka Joe Colonnetta, a Dallas based investor and major Trump donor  to the Trump's election campaign, the Trump Victory PAC and other GOP candidates.[wikipedia].

Colonnetta contributed $20,000 to the Trump Victory PAC during the general election, $2,700 to Trump’s primary election campaign (then the maximum amount permitted), $2,700 to Trump’s general election campaign (also the maximum), and a total of $30,700 to the Republican National Committee in 2016 alone.

Colonnetta’s wife, Kimberly, is no stranger to Republican politics either; shortly after Trump’s victory, she gave $33,400 to the Republican National Committee, the maximum contribution permitted for party committees in 2016.

The Colonnettas’ contributions to the Republican Party precede the Trump administration. For example, in October 2011, Joe Colonnetta contributed $30,000 to the RNC; in 2008, he gave $26,200 to the RNC and $28,500 to the McCain Victory Committee. During both years, Kimberly Colonnetta also contributed thousands to various Republican campaigns. [Daily Beast]

An Army Corps spokesman said its restoration work was now being closely coordinated with PREPA, but the relationship among PREPA, Whitefish and the Federal Emergency Management Agency remains in flux. FEMA, which has committed to cover 100 percent of the grid repair costs, has not yet received reimbursement requests from PREPA for work by Whitefish and other contractors, a FEMA spokesman said.

The oversight board has the authority to reject contracts such as the $300 million contract PREPA struck with Whitefish Energy. An emergency manager can play a larger role in vetting contracts. Many members of Congress have expressed concern about the contract. House Minority Leader Nancy Pelosi, D-Calif., urged inspectors general to investigate it.

PREPA, a bankrupt, publicly owned utility with $9 billion in debt, faced deep-rooted problems even before Maria ravaged the island.

Puerto Rico's federal oversight board was created by Congress to oversee the restructuring process of the island's $70 billion debt load. It rejected a proposed settlement on PREPA's $9 billion in debt, and the power monopoly filed for bankruptcy in July.

Here is the full contract: it appears that SSNs are used rather than a business EIN because Whitefish is located at the Techmanski's lakeside home and has no brick and mortar business.

FEMA has denied it ever saw, much less reviewed or approved the contract:

Arctic sea ice / Re: 2017 sea ice area and extent data
« on: October 26, 2017, 10:32:24 AM »
Here is the regional breakdown from @zlabe. Note these are presented relative to two standard deviations of extents spanning a thirty year period, 1981-2010. These std devs vary quite markedly with the season. All the regions are at or below 2 for late October 2017, there is no anomaly or 'recovery' this year in the statistically significant sense. The early decades of Old Arctic of course weight down the statistics but are necessary to provide sufficient data.

Some of the 'seas' like the Chukchi get assigned somewhat arbitrary boundaries; temperatures in that sea are also unpredictably influenced by inflows through the Bering Strait (per decades of mooring data).

Consequences / Re: Hurricane season 2017
« on: October 25, 2017, 01:20:01 AM »
Says here upper management looted the Puerto Rican national electric company starting in 2014, diverting almost all the maintenance money to a slush fund ...

4. PREPA’s non‐labor operations budgets are poorly allocated

A major component of PREPA’s operational spending lands in Administrative and General
(A&G)  functional  area,  and  that  spending  in  this  area  has  increased  in  recent  years  for
unexplained causes. A review of PREPA’s records shows that PREPA spent the astonishing
figure of  $165 million in  A&G in  FY2016,  of  which  $134 million fell into  an undescribed
discretionary fund
. To give this figure context, PREPA spent the equivalent of more than a
third of its entire capital budget on discretionary A&G spending. 

Problematically, PREPA describes that it is “an inefficient bureaucracy” that is “overly staffed
with  non‐value  added  administrative  personnel,”  and  that  “the  executive  directorate  and
executive  team  is  oversized.”13  It  is  difficult  for  us  to  overstate  how  concerning  this  is.
Moreover, we have absolutely no further information about what, exactly, PREPA spent these
funds on...

Wow, these are decent hourly wages by Puerto Rican standards, all going to outside contractors as if they didn't have enough of their own idled lineman standing by: $2840 a day plus $412 per diem food and lodging. That adds up when the crew is standing around waiting for a broken crane and material to arrive.

The two-person Montana company Whitefish [owned by a Brazilian company] from Secretary Zinke's home town was awarded a $300 million dollar no-bid contract over the phone. One of the two employees thre is just the spokesperson. Whitefish could be paid as much as $300 million for up to two years of work.

Under the contract, the hourly rate was set at $330 for a site supervisor, and at $228 for a “journeyman lineman.” The cost for subcontractors, which make up the bulk of Whitefish’s workforce, is $462 per hour for a supervisor and $319.04 for a lineman. Whitefish also charges nightly accommodation fees of $332 per worker and almost $80 per day for food

Permafrost / Re: Arctic Methane Release
« on: October 24, 2017, 11:44:17 AM »
Terry, I'm doing the same, revisiting the whole matter now that they've got more of their voluminous field data out into papers. So far, Cid_Yama's analysis up-forum has been spot-on.

Those words are my encapsulation of what Shakhova says in the N Breeze interview. Given a non-native speaker of English, with verbosely articulated concepts and awkwardly written scientific prose -- yet doing very important research in a very remote area -- I felt a short and pithy summary was worthwhile. The raw transcript or youtube can be consulted when there's any question what was actually said. 

People have wondered aloud why the most recent paper sat in peer review at NatComm for 11 months. Actually it is a minor miracle something still so jumbled ever got published, ie how awful was the paper when first submitted? And what took so long for 2014 field work to get written up? Actually long delays are not at all unusual and so-so communications skills are very common among scientists. Just read the AGU17 abstracts.

Here are the relevant sections. I read them as saying the methane hydrate objection is a double red herring. Clathrates are in fact present, contrary to trolling from the CO2 side, but irrelevant to the discussion, contrary to follow-on trolling. Bring me another rock.

With or without hydrates, there's an undisputed huge volume of over-pressurized methane gas under the permafrost seal that will bubble up the first narrow escape route that opens up and blowout with further seal failure. With a million disintegrating corks in a million bottles of champagne, what could possibly go wrong. The well blowouts clip from the paper makes the case for pressure containment (bottom).

I find this very troubling, that this GHSZ stability zone keeps getting brought up when it's both wrong and irrelevant. Especially by scientists who know better. It raises all sorts of red flags for me about motivations. Research should be discussed strictly on its merits.

Dr. Shakhova: We use an analogy where we compare the East Siberian Arctic Shelf to a bottle of champagne. So the gas produces within this bottle and it keeps accumulating as long as the cork serves as an impermeable lid.

This lid is subsea permafrost. Before it was just permafrost [on land] but after it was submerged it became subsea permafrost and served to preserve an increasing amount of gas produced from its release to the ocean and atmosphere above. While this lid is impermeable, there is nothing to worry about.

But when this lid loses its integrity, this is when we start worrying. This is where the methane is releasing and the amounts of methane currently releasing makes us think it will increase as a result of the disintegration of this permafrost body.

Nick Breeze: In relation to the ESAS, how do you know these hydrates are there and that they are a potential threat?

Dr. Shakhova: The importance of hydrates involvement in methane emissions is overestimated. The hydrate is just one form of possible reservoirs, in which pre-formed methane could be preserved in the seabed if there are proper pressure/temperature conditions; it is just the layer of hydrates composes just few hundred of meters – this is a very small fraction compared to thousands of meters of underlying gas-charged sediments in the ESAS.

Dr. Semiletov added that the 5 billion tonnes of methane that is currently in the Earth’s atmosphere represents about one percent of the frozen methane hydrate store in the East Siberian Arctic Shelf. He finishes emphasising  “…but we believe the hydrate pool is only a tiny fraction of the total.”

Dr. Shakhova: The second point is that the hydrates are not all of the gaseous pool that is preserved in this huge reservoir. This huge area is 2 million square kilometres. The depth of this sedimentary drape is a few kilometres, up to 20 kilometres at places. Generally speaking, it makes no difference if gas releases from decaying hydrates or from other free-gas deposits, because in the latter, gas also has accumulated for a long time without changing the volume of the reservoir; for that reason, gas became over pressurised too.

Unlike hydrates, this gas is preserved free; it is a pre-formed gas, ready to go. Over pressured, accumulated, looking for the pathway to go upwards.

The point Shakhova and Semiletov are making is that the question of whether there are methane hydrates present beneath the permafrost is really not important. The estimated amount of hydrates, 1500 billion tonnes, is actually only a tiny proportion of the actual pressurised methane store beneath the gas hydrate stability zone.

Dr. Shakhova: The third point is that the hydrates, despite disbelief from some scientists, have already been found in the ESAS. We know from personal communication that the South Korean expedition was accomplished in 2016 and they sampled the hydrates. I believe, this data will be published soon. However, hydrates could only be sampled if they remain stable. After hydrates are destabilised, we can only sample gas releasing from these decaying deposits.

In our observations, we have accumulated the evidence that this gas front is propagating in the sediments. To me as a scientist, these points are enough to be convinced that methane release in the ESAS is related to disintegrationof subsea permafrost and associated destabilisation of seabed deposits whether it is hydrates or free gas accumulations.

The NatComm paper describes a drilling gas blowout that fountained up 10 meters over sea level:

Numerous gas blowouts followed by long-lasting gas flow have been reported from permafrost areas disturbed by exploratory drilling in Siberia, both on-land and offshore. Such gas blowouts were reported from shallow permafrost-related gas-hydrate accumulations at depths of only a few tens of metres, starting from 20 m depth.

Offshore, a particularly powerful gas discharge erupting from a well drilled through the subsea permafrost was documented in the Pechora Sea shelf; a gas–water fountain originating from 50 m beneath the sediment surface in 64 m-deep water reached 10 m above the ship. Echo sounding carried out at the drilling site 10 days after this event revealed an underwater fountain ∼10 m in diameter, with a height ∼40 m above the sea floor (ref 56)

Permafrost / Re: Arctic Methane Release
« on: October 23, 2017, 11:10:14 PM »
Trolls can post without getting refuted as in the melt season. They often arrive in pairs
Or threesomes, adopting various levels of obviousness, some holing up in sleeper cell posts until the signal is given. They've been gotten wrist-slaps in the past for 2020 divinations but these same disruptors have been tolerated for years and years. Garbage is better intercepted en route before the forums are defaced.

In terms of Arctic methane, the situation is even worse: S&S get non-stop harassment, the trolls being influential scientists from the CO2 community rather than the ignoramuses we get here.

Look at the ASI blog, it's totally out of control, I never go there any more. The disrupters have moved on now to the forums, probing them to see if anyone is moderating. The agenda this week is to build a fake consensus that it's all a long long ways off, check back in five years time if then.

What becomes of the average joe trying to follow the issue and maybe get to the next level of understanding? It's not a climate change resource for them any more, too confusing.

The 'Recent Post' section most days, just angry people venting about politics. Hmmm, maybe someone could start a forum called Angry People Venting About Politics and all the conspiracies could be consolidated there. Some of these people had been really strong contributors.

Over time I've watched the better posters, one after the other, leave the site permanently to go off on their own, just to get a moderated environment. Which just scatters the effort thinner than ever. But I'm thinking about doing that too; I'm tired of these same trolls chasing me around from one forum to another. Too bad, there's a LOT of good people here.

Is Neven really not coming back until next May?

Permafrost / Re: Arctic Methane Release
« on: October 23, 2017, 09:34:11 PM »
WAIS could make a significant contribution to methane emissions into the atmosphere give a sufficient abrupt collapse scenario.
I for one have relied on your most excellent coverage and assessment of this contingency over the years. I should have mentioned above that Barents methane release may have mostly happened already, that Greenland methane is improbable any time soon, that Laptev methane release is ongoing too, that the Beaufort shelf is too small to concern us (though interesting things have gone on there), and that the ESAS permafrost is degrading rapidly and perhaps transitioning shortly from near-term threat to outright existential problem.

The rate of degradation of the sub-sea permafrost is somewhat lost in the overly complex Fig.2 and its widely scattered caption in the NatComm Shakhova paper. Where they re-drilled previous boreholes, the ice-bonded permafrost table (IBPT) had dropped 4.5 meters, much much farther than hypothesized in next millennium models. open access

The IBPT positions observed in 1982–1983 at sites 301, 303, 304 and 305 were at 3.3–4.2 m, 5.8–7 m, 8.3–8.6 m and 16–16.8 m b.s.l., correspondingly (Table 1). In 2012–2013, the IBPT positions were identified at 8.6 m, 11.4 m, 12.8 m, and 19.3 m b.s.l. at sites 4D-14 (former 301), 4D-13 (former 303), 3D-14 (former 304), and 2D-13 (former 305), correspondingly. IBPT deepening during the last 31–32 years varied from 9.3 to 18.3 cm year−1 with a mean rate of 14±3.1 cm (mean±s.e.m.) per year during the last 31–32 years.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 23, 2017, 08:51:46 PM »
You've confused rapid fall extent onset, which is a bad thing for ice future because it holds the ocean heat in, with volume growth which puts more of a burden on the next melt season but is disfavored by heat-retaining water under a skin of ice.

Which melt season is driven by future weather that you (and everyone else) have not the slightest clue about, a la 2007 and 2012. Watch that 30 year sea ice age video of Tschudi's -- it's all right there.

When will the Bering Strait and Chukchi freeze over this year, relative to 2016? No one has the slightest idea. That date has nothing whatsoever to do with whole-ocean trend mumbo-jumbo.

Oren is on point. (Note attached on-topic data supporting views.)  It's the dog walking on its two hind legs: we applaud not so much that the air cold enough for volume recovery but that is cold and dark enough to have open water freezing in late October. How much the ice will thicken over the winter depends quantitatively on HOW cold the air is, not merely that it is cold (below -1.8ºC).

This is the freeze forum, one of our rare science areas. We have dedicated forums for extent, area and volume trend-trackers. Please delete off-topic, unsupported speculation and move it somewhere appropriate.

Permafrost / Re: Arctic Methane Release
« on: October 23, 2017, 05:25:17 PM »
Terry: Methane requires extensive explanations ... wondered if the pockmarked floor of Hudson Bay methane pockets that erupted when the ice sheet withdrew and when  ice cleared  seasonally.
I'm looking forward to reviewing the whole ESAS methane business, where it stands as of 2017, one line at a time, starting from the beginning. The freeze season forum is getting trolled pretty bad; fall visitation is down 90%, not worth the effort.

Reading that last Shakhova interview is really harrowing, especially since she's been hearing the objections and misunderstandings for years but sees no reasoning there that to alter outcome expectations. People here can't conceptualize the vast Siberian permafrost lands nor how scientifically familiar the Russians are with them after some centuries. The ESAS alone is 3x the size of Texas or France.

The poster child for post-glacial methane rebound is more Barents Sea. I don't know if Hudson Bay has had the organic-rich sediment inflows that are needed for biotic methane, nor the erosion of the permafrost periphery, nor if the Canadian shield there holds much natural gas.

Sediments in the ESAS can be 20 km thick. Shakhova has shifted from thermal over to biotic methane after the isotope study. Says stable clathrates have been found by South Koreans despite shallow water but are an incidental component, all that matters is total capped reservoir (truly vast) and escape rates (not linear in time, instead accelerating). (plus googScholar 'Alun Hubbard methane')

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 23, 2017, 02:52:11 PM »
most probably places the <1 mkm2 event beyond 2020.
The same rubbish every fall, catastrophism after low years, recovery chatter after upticks. What could possibly serve as a scientific basis for a 4+ year weather-ocean-ice forecast? In some ways, 2007 was the most disturbing year to date; neither it nor 2012 were foreseen or foreseeable.

Very few of our registrants seem to take any substantive interest in the 2017/18 freezing season, the topic of this forum. Sharing of ungrounded speculation and personal hunches is very boring. Maybe we should just shut it down and come back in May. Visitation levels don't justify the effort.

SMOS 3.1 thin ice thickness is an interesting way to track the season though. If ice doesn't thicken much during the winter (as expected from Arctic amplification), there's that much less to melt during the melt season. Thinner ice also responds very differently to wind dispersion and export.

The first animation compares newly formed ice from 2012-2017 for the 21st of October; there's quite a bit of variability. The still image shows the same years side by side. The bottom animation computes the six year average for this date and flickers 2017 over it.

Whole Arctic trend-lining is far less informative than regional trend-lining, itself little done on our forums even though wipneus posts the necessary data. 2D maps take regional trend-lining to its end state, the resolution of the data. As there's no physical basis for drawing 'Beaufort' or 'Chukchi' boundaries etc, maps can show what is going on free of nomenclatural bias. To first order, that is latitudinal freeze-up about the cold pole (rather than the north pole).

SMOS in a sense integrates all the heat fluxes between atmosphere, newly forming ice and ocean. Since the weather has been so uneventful for so long, bottom growth prediction for older ice will have fewer problems than in past years. The interest right now is the date of final freeze-over, which is going rather slowly in the Beaufort-Chukchi-ESAS regions and unremarkably above Svalbard.

The freeze season settles down more into straight thermodynamics after freeze-over, though low clouds remain important for net heat loss. I've inquired about getting near-real time cloud synaptic state; for now we can only get at those indirectly (but quantitatively) through RASM-ESRL energy fluxes.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 22, 2017, 05:26:35 PM »
my predictions were perfect
Preposterous. Without some idea of what the weather is going to do a few months to a year out, it's just numerology trending off hindcasts. No one had or has the slightest idea where the weather is going, least of all you.

The basic idea in measuring 'forecast skill' is assigning a baseline score of 0.00 to physics-free continuation. Thus I can predict with very high confidence that the weather in Tucson AZ will be sunny on 22 Oct 2025 but the skill there is 0.00 because it's been like that for centuries.

To get a grasp on just how incredibly complicated it is to make real predictions, try reading this article on k-means synoptic states over the Beaufort-Chukchi. The cloud component alone is extremely difficult yet is very important all year long to sea ice extent and thickness for seasonally different reasons.

Can you share with us where you got the necessary data for this summer?  Cloudsat is essential for prediction but it broke a reaction wheel on June 4th and went into standby mode, not sending any more data down. The problems with Cloudsat and Calypso data are all but intractable even when they are operational; no one here has ever made any headway with the CSU data repository.

The best that can be hoped for is some rules of thumb will emerge that provide some after-the-fact understanding:

Synoptic Conditions, Clouds, and Sea Ice Melt Onset in the Beaufort and Chukchi Seasonal Ice Zone
Z Liu, A Schweiger APL UW

Cloud response to synoptic conditions over the Beaufort and Chukchi seasonal ice zone is examined. Four synoptic states with distinct thermodynamic and dynamic signatures are identified using ERA- Interim reanalysis data from 2000 to 2014.

CloudSat and CALIPSO observations suggest control of clouds by synoptic states. Warm continental air advection is associated with the fewest low-level clouds, while cold air advection generates the most low-level clouds. Low-level clouds are related to lower-tropospheric stability and both are regulated by synoptic conditions.

High-level clouds are associated with humidity and vertical motions in the upper atmosphere. Observed cloud vertical and spatial variability is reproduced well in ERA-Interim, but winter low-level cloud fraction is overestimated. This suggests that synoptic conditions constrain the spatial extent of clouds through the atmospheric structure, while the parameterizations for cloud microphysics and boundary layer physics are critical for the life cycle of clouds in numerical models. Sea ice melt onset is related to synoptic conditions.

Melt onsets occur more frequently and earlier with warm air advection. Synoptic conditions with the highest temperatures and precipitable water are most favorable for melt onsets even though fewer low-level clouds are associated with these conditions.

[Already by 2014, it had been shown] synoptic patterns better explain the variability of sea ice than climate indices such as the Arctic Oscillation, the North Atlantic Oscillation and the Arctic dipole.
These are in effect rudimentary synoptic patterns: for example the daily AO index is constructed by projecting the daily 1000mb height anomalies poleward of 20°N onto its loading pattern, the leading mode of Empirical Orthogonal Function (basis states) of monthly mean 1000mb height during 1979-2000 period.

Meanwhile, back to ESRL's modest but already ambitious day 10 forecasts and whether they're useful for winter ice thickness growth (which we need for melt season preconditioning). There was a computer mishap resulting in no data for Oct 20th affecting all three archive sections. [This got fixed by the 23rd.] This happened previously on Sept 12th. REB_plots had a glitch on the 16th and so on. To enumerate these, just look down file list for size anomalies.

There's no going back, so the practical impact will be a small but permanent gaps in the initial state time series. That is no different from UH AMSR2 and all the other product archives. In the animations up-forum, the gaps are filled with a duplicate frame from the day before (or if multi-day, from above and below). It is feasible to interpolate within Panoply but with the ice edge moving and so forth, the accuracy is problematic whereas a stalled frame conveys the notion of missing data.

Permafrost / Re: Arctic Methane Release
« on: October 22, 2017, 01:33:59 PM »
Here's a start on listing the endless objections to ESAS methane, mostly taken from the 2017 Shakhova interview. It all bears an uncanny resemblance to a dysfunctional corporate leadership game called "bring me another rock".

The permafrost seal didn't have time to melt
The permafrost seal is melting but the time scale is millennia away
The permafrost seal melted during the Eemian and earlier inter-glacials
The taliks all froze after Holocene inundation
There are no mechanisms that could damage the permafrost layer
The migration routes for the methane are fairly minor so the volume is insignificant
The minor migration routes aren't degrading further into hotspots
The hotspots will soon deplete their underground reservoirs
The geological faults do not bypass the permafrost seal
The ice scours do superficial damage to subsurface permafrost
There's no methane down there
There's no methane left down there
The release of methane can't be proven to be accelerating
There wasn't any methane released during the Eemian
The previously accumulated methane was all released during the Eemian
There wasn't any build-up of methane during the Pleistocene
There's no massive groundwater incursion of freshwater
There's no coastal permafrost erosion of any significance in Siberia
Thermokarst only develops on land
The six rivers sediment does not lead to biogenic methane
The Holocene has been going on too long and peaked at 5 kyr
The shelf was all flooded at 11 kyr
There won't be wind disruption of ocean stratification until the ice is gone in 2050
The sunshine doesn't penetrate 10 m of clear water to warm the upper shelf
There are important lessons for shallow shelf from deep oceanic clathrate
The armchair models don't need observational calibration
There aren't any inter-glacial methane pulses found in Greenland ice cores
The methane gets consumed in bottom sediments
The bubbles lose their methane before reaching the surface
The bubbles dissolve in the water and are quickly consumed
The consumption of methane by bacteria leads to offsetting algal blooms
The methane doesn't reach the atmosphere
The methane reaching the atmosphere is quickly broken down
The half-life is too short for methane to have any effect
The only time scales that matter are 2100 and multi-millennial
The equivalence multiplier we should use for methane is 20
There'll always be enough hydroxyl radical

Permafrost / Re: Arctic Methane Release
« on: October 22, 2017, 12:43:28 PM »
I worked through all 530 AGU abstracts mentioning methane and found two more of interest. The underwater geology of Arctic Ocean continental shelf has a rich and complicated history mostly unfamiliar to mid-latitude climate scientists, leading to poorly-grounded objections to ESAS methane release that have to be tediously explained over and over.

The four N Shakhova papers from 2017 are all open access. The abstracts really don't capture what the best of what's in the articles; often the internal discussion provides much better background and explanations of the significance. Comments and questions of peer-reviewers are also available and instructive.

The April 2017 interview with Shakhova briefly summarizes responses to many asinine objections raised up over the years by CO2-oriented scientists who perceive methane as mainly a threat to the primacy of their preferred narrative. It's probably worth pulling together more detailed responses from these recent articles as well as excellent material scattered up-forum. open access open access open access open

OS43B-02: Relict thermokarst carbon source kept stable within gas hydrate stability zone of the South Kara Sea
A Portnov et al

Substantial shallow sources of carbon can exist in the South Kara Sea shelf, extending offshore from the permafrost areas of Yamal Peninsula and the Polar Ural coast. Our study presents new evidence for >250 buried relict thermokarst units. These amalgamated thawing wedges formed in the uppermost permafrost of the past and are still recognizable in today’s non-permafrost areas. Part of these potential carbon reservoirs are kept stable within the South Kara Sea gas hydrate stability zone (GHSZ).

We utilize an extensive 2D high-resolution seismic dataset, collected in the South Kara Sea in 2005-2006 by Marine Arctic Geological Expedition (MAGE), to map distinctive U-shaped units that are acoustically transparent. These units appear all over the study area in water depths 50-250 m. Created by thermal erosion into Cretaceous-Paleogene bedrock, they are buried under the younger glacio-marine deposits and reach hundreds of meters wide and up to 100 meters thick.

They show the characteristics of relict thermokarst, generated during ancient episodes of sea level regression of the South Kara Sea. These thermokarst units are generally limited by the Upper Regional Unconformity, which is an erosional horizon created by several glaciation events during the Pleistocene.

On land, permafrost is known to sequester large volumes of carbon, half of which is concentrated within thermokarst structures. Based on modern thermokarst analogues we demonstrate with our study that a significant amount of organic carbon can be stored under the Kara Sea.

To assess the stability of these shallow carbon reservoirs we carried out GHSZ modeling, constrained by geochemical analyses, temperature measurements and precise bathymetry. This revealed a significant potential for a GHSZ in water depths >225 m. The relict thermokarst carbon storage system is stable under today’s extremely low bottom water temperatures ~ -1.7 °C that allows for buried GHSZ, located tens of meters below the seabed.

Noteworthy, vast parts of GHSZ do not expose on the seafloor, since both upper and lower GHSZ boundaries occur clearly sub-seafloor. Our findings show that under the deepest regions of the South Kara Sea, large areas of relict thermokarst may presently exist within the GHSZ of unique configuration, and therefore provide substantial methane source for gas hydrate.

B21C-1973: Methane fluxes from intense bubbling seep sites: Mapping and Quantification from the seafloor up to the atmosphere
J Greinert

Despite the ever increasing number of seep sites being discovered in shelf and continental slope areas, sites where dissolved or free gas fluxes at the seafloor fuel a significant sea surface gas flux into the atmosphere are rare. Here, we report on multi-year studies from a very active seep site in the Dutch North Sea that has been revisited several times since 2009, with large-scale surveys including multi-beam based bubble mapping, CTD water column sampling, direct ROV observations, sub-seafloor free gas mapping and CRDS-based sea surface flux and atmospheric measurements.

More than 800 individual flares in five main clusters were recorded and first approximations yield 280L of CH4 per minute being released from the seafloor in the entire area. These fluxes created sea surface anomalies even in the strongly stratified water column during the summer period.

Atmospheric concentrations increased by almost 1ppm above the strongest flare cluster in 42m water depth. Currently ongoing studies that aim at merging single-beam and multi-beam echosounder data on a meter scale will verify if the previously calculated seafloor gas flux estimates are correct, or if even higher fluxes occurred that explain the significant increase in the atmosphere. Spatial bubble dissolution modeling will be applied to calculate if the newly determined fluxes can support the measured sea surface concentrations and if ocean-atmosphere equilibration supports the observed atmospheric increase.

In any case, the clear spatial correlation between seafloor gas release, sea surface and atmospheric anomalies prove that the methane emanating from the seafloor is the source of the increased atmospheric CH4 concentration. Optical studies show that massive and constant gas release is needed to have such an effect. This study can be used as an ideal case study for comparison to other high intensity seeps and their potential for having local effects on CH4 budgets.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 20, 2017, 04:51:05 PM »
Thanks. You are talking about ice and snow thicknesses?

Salinity, compressive strength, sea water temperature, the three melts, and two precips are not to be found in REB. None of these are attributed within RASM_ESRL. Their model might be able to derive some from others but salinity, water temperature and so on must be external inputs. From where though, there might be something better out there that could be stubbed in.

The REB files overlap do considerably in name. And they do provide start-stop ranges. However they provide 40 animation frames, the first of which I've been taking as t00 whereas RASM_ESRL provide only 9.

So I'm not sure what you mean by same as every 4th bit of data is the same. That would only use up 4x9 = 36 (sometimes 4x8 = 36) of the 40, suggesting the initial (or final?) state is missing in RASM_ESRL. Or rather, the latter uses intervals, n times has n-1 intervals but what does this mean in tangible terms for observational validation or animation frames, very little.

It seems better just to use REB whenever possible since they didn't see the merge app as applicable to RASM_ESRL intervals. But REB doesn't have the data to generate all the forecast animations that RASM_ESRL can. No way am I going to interpolate four 6hr frames out of one 24 hour to complete the file set in REB.

NaNs, float etc seem to be non-issues suppressed by Panoply and have no impact on visualizations or grepped csv coming out of ncdump.

It appears that not nearly enough information is provided in RASM_ESRL and together to draw all the REB plots. That's unfortunate, those files might have been provided so users could correct the many inept products provided in REB plots, make omitted ones, compare to other observational sources, run an alternative model, or compare to competitive products like ECMWF. 

NOAA states this project is experimental. Fair enough but in its 3rd year, it's time to pull things together, maybe lay on some documentation and make the five minute fixes. It's true though that they didn't need to provide a public archive at all, much less the most thorough one around providing comprehensive Arctic forecasts. Expired forecasts have such limited interest that the real value may lie in archival initial states (or their reanalysis), which need attending to before letting this go on as unattended robo-ware.

Going around the web to the netCDF data sources we commonly use for forum graphics, I see a tremendous range in quality from zero (take this map and shove it), outdated (defective variable treatment disabling Geo2D), inadequately commented files, okay, and fantastic. In the instances where I know the authors, there's been a perfect correlation of open sourcing effort with the quality of their journal publications.

Data is not open source accessible in my view if it can't be viewed and manipulated without purchasing proprietary software, working in terminal mode, or emailing a deceased author. Site users and journal readers should have the capacity in most instances to reproduce major graphics.

I see a goodly number of totally incompetent graphical products, both in archives and after peer review. That is the real purpose of posting netCDF files -- the next person who comes along might have the skills to fix the graphic, re-project or re-palette it, delete over-writing  layers, test it for accuracy, or combine it in novel ways with other data sources. There is no purpose to climate science if it is not communicated.

In every collaborative project I've worked on, everyone including myself had moved on and lost all interest long before the draft worked its way through the publication process. We all knew what was in the data, making derivative charts from it was considered a total bore, the only thing worse being a remake six months later. Here again it's in everyone's interest to have a proper archive.

Other scientific communities with even bigger data sets, such as genomics, laid down the law fifteen years ago (GenBank) and enforce it via conditions in the grant (both govt and foundation). There was a lot of initial resistance to sharing, people acted like they somehow 'owned' the data even though the public had bought and paid for every scrap of it with the understanding they could see it.

Nobody has to share: just click the 'Don't Accept' option on the grant application, do the work at home, pay for it out of your non-salaried savings, and post on your facebook page to sidestep journal data requirements. If you don't go that route, then an adequate open archive is, scientifically speaking, obligatory. And it's especially important in the case of climate change.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 19, 2017, 10:54:01 PM »
Here are 27 days of sea water salinity from RASM-ESRL for October. As noticed before, each ten day forecast series begins at hour 24 rather than hour 00, the initial state. (Some even start at hour 48, skipping the first two days.) The odd boundary on the Svalbard side apparently results from a lack of data (or maybe it's off-scale on the high side).

There's ample room in a netCDF file for an explanation of the satellite (or oceanographic) source of the data but there is none. It's not clear what salinity under the ice pack means in terms of depth. The salinity range is also mistakenly set, showing large negative salinities.

Indeed, the whole file system of this project is seriously mis-configured. File names for a given product are all the same; they're supposed to be inseparably concatenated with their date. The daily RASM-ESRL archive is presented as nine separate files but these in effect just represent an animatable time sequence. They could have been folded into a single file with each time an animation frame (and there's a simple command line for doing just that).

This project reminds me of an autonomous 18-wheeler driving without incident from NY to LA but continuing on, only to plunge off the Santa Monica pier. That is, is anyone really driving this project, who is using it without reporting the flat tires, and how long can it run on fumes without  interventional refueling?

Whatever, it's interesting to watch salinity evolve along the Alaskan and East Siberian coasts. Salinity lowers the freezing point of sea water somewhat but here it is not determinative because though the remaining open water is fresher, its temperature (and that of the air above) are warmer.

SMOS provides bulk ice salinity of the ice pack surface which is more or less directly observable from its dielectric. As sea ice ages, it extrudes its brine which lowers its perceived bulk salinity here.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 19, 2017, 06:37:53 PM »
Right. ESRL is primarily interested in making forecasts whereas we are primarily interested in archival initial state time series because short-term predictions have such a limited shelf life. The idea here was to finish scrolling through all their precipitation products to see which are worth scripting (Panoply --> ImageMagick --> cloud --> forum) into hindcasts + today + forecast time series.

The ESRL web site presents this one well enough, though too large to display well here. It might be of heads-up interest should more moisture-laden storm sweeps north from the Caribbean again this fall. However ice thickening takes place on a much slower time scale, so daily comings and goings of the insulating blanket of snow are of less interest than mean snowpack.

While it's hard to see the thermal relevance of blowing ankle-deep snow to bottom ice formation rates, maybe it will be knee-deep by late winter and suppress early melt pond formation through reflectance.

There being little purpose in simply replicating daily changes in NOAA's web site, the question becomes where we can 'add value'. Among the many opportunities explored in previous posts (eg SMOS-ESRL thin ice hybrids), are combined time series across the three ESRL (and other) archives.

These can be seasonal: the forecast below combines an open water property with a sea ice measure, namely temperature. That product diminishes in utility along with residual exposed water later in the fall. Salinity is another option; it mixes SMOS bulk ice salinity with that of ESRL open water. That too is seasonal since UH SMOS availability is melt-limited.

Note the Chukchi north of the Bering Strait is still far too warm for ice to form. That stayed open to mid-December last year. The map also shows a pronounced intrusion of warm surface water in the Yermak Plateau area north of Svalbard. Spurious open water is shown around CAA islands which are very difficult to get at accurately with gridded data (UH AMSR3 3.125 km is a better option there).

Technical note: these are easy to make since 'not sea ice' on the sea ice layer provides a pixel-perfect cut-out allowing any open water characteristic to show through. As long as the data sources are both available to Panoply as netCDF files, Gimp will receive the maps in perfect co-registration with compatible and operable palette legends. This readily scales to times series via tile 'n' slice.

Permafrost / Re: Arctic Methane Release
« on: October 19, 2017, 01:25:43 PM »
One aspect of this which is not GAU (geology as usual), raised by both S&S and separately by Wadhams, concerns anthropogenic warming of Arctic Ocean water at the depth of the continental shelf, ie at the interface with submerged permafrost. This could provide an accelerant to loss of impermeable gas cap, not so much by plain thermal diffusion as by cryo-geological mechanisms described by S&S.

Recall here that about a third of this ocean, especially on the Siberian side, is very shallow, well within range of wind, wave and tidal turbulent mixing. Early and persistent seasonal loss of ice cover  attributable to anthropogenic Arctic amplification allows enhanced solar heat adsorption and provides much longer fetches for wind to mix up stratification.

Wadhams sees a significant difference between submerged permafrost meeting sea water near the latter's freezing point of -1.8ºC vs contacting sea water above its own melting temperature which is more like 0ºC (since permafrost ice is freshwater ice formed on land). Consequently, geology-as-usual may be going off the trolley tracks. In this view, the late timing within the Holocene cycle is being seriously supplemented by man-made effects.

IP Semiletov is a co-author on 3 papers at AGU17. I did not see abstracts for N Shakhova; her four 2017 papers are listed below.

PP51B-1069: Deglacial remobilization of permafrost carbon to sediments along the East Siberian Arctic Seas
J Martens et al

Current climate change is expected to thaw large quantities of permafrost carbon (PF-C) and expose it to degradation which emits greenhouse gases (i.e. CO2 and CH4). Warming causes a gradual deepening of the seasonally thawed active layer surface of permafrost soils, but also the abrupt collapse of deeper Ice Complex Deposits (ICD), especially along Siberian coastlines. It was recently hypothesized that past warming already induced large-scale permafrost degradation after the last glacial, which ultimately amplified climate forcing. We here assess the mobilization of PF-C to East Siberian Arctic Sea sediments during these warming periods.

We perform source apportionment using bulk carbon isotopes  together with terrestrial biomarkers (CuO-derived lignin phenols) as indicators for PF-C transfer. We apply these techniques to sediment cores  from the Chukchi Sea and the southern Lomonosov Ridge.

We found that PF-C fluxes during the Bølling-Allerød warming (14.7 to 12.7 cal ka BP), the Younger Dryas cooling (12.7 to 11.7 cal ka BP) and the early Holocene warming (until 11 cal ka BP) were overall higher than mid and late Holocene fluxes. In the Chukchi Sea, PF-C burial was 2x higher during the deglaciation (7.2 g m-2 a-1) than in the mid and late Holocene (3.6 g m-2 a-1), and ICD were the dominant source of PF-C (79.1%). Smaller fractions originated from the active layer (9.1%) and marine sources (11.7%).

We conclude that thermo-erosion of ICD released large amounts of PF-C to the Chukchi Sea, likely driven by climate warming and the deglacial sea level rise. This contrasts to earlier analyses of Laptev Sea sediments where active layer material from river transport dominated the carbon flux.

Preliminary data on lignin phenol concentrations of Lomonosov Ridge sediments suggest that the postglacial remobilization of PF-C was one order of magnitude higher (10x) than during both the preceding glacial and the subsequent Holocene. We will apply source apportionments between coastal erosion of ICD and river export of active layer material for the outer East Siberian Arctic Seas.

Our findings demonstrate remobilization of PF-C during past warming events and suggest that current climate change might cause a similar cascade of permafrost destabilization and, thus, accelerate climate warming.

PP54A-03: Late Holocene sea ice conditions in Herald Canyon, Chukchi Sea
C Pearce et al

Sea ice in the Arctic Ocean has been in steady decline in recent decades and, based on satellite data, the retreat is most pronounced in the Chukchi and Beaufort seas. Historical observations suggest that the recent changes were unprecedented during the last 150 years, but for a longer time perspective, we rely on the geological record. For this study, we analyzed sediment samples from two piston cores from Herald Canyon in the Chukchi Sea, collected during the 2014 SWERUS-C3 Arctic Ocean Expedition.

The Herald Canyon is a local depression across the Chukchi Shelf, and acts as one of the main pathways for Pacific Water to the Arctic Ocean after entering through the narrow and shallow Bering Strait. The study site lies at the modern-day seasonal sea ice minimum edge, and is thus an ideal location for the reconstruction of past sea ice variability.

Both sediment cores contain late Holocene deposits characterized by high sediment accumulation rates (100-300 cm/kyr). Core 2-PC1 from the shallow canyon flank (57 m water depth) is 8 meter long and extends back to 4200 cal yrs BP, while the upper 3 meters of Core 4-PC1 from the central canyon (120 mwd) cover the last ~3000 years. The chronologies of the cores are based on radiocarbon dates and the 3.6 ka Aniakchak CFE II tephra, which is used as an absolute age marker to calculate the marine radiocarbon reservoir age.

Analysis of biomarkers for sea ice and surface water productivity indicate stable sea ice conditions throughout the entire late Holocene, ending with an abrupt increase of phytoplankton sterols in the very top of both sediment sequences. The shift is accompanied by a sudden increase in coarse sediments (> 125 µm) and a minor change in δ13Corg.

We interpret this transition in the top sediments as a community turnover in primary producers from sea ice to open water biota. Most importantly, our results indicate that the ongoing rapid ice retreat in the Chukchi Sea of recent decades was unprecedented during the last 4000 years.

PP54A-02: The Deglacial to Holocene Paleoceanography of Bering Strait: Results From the SWERUS-C3 Program (Invited)
M Jakobsson

The multi-disciplinary SWERUS-C3 Program was carried out on a two-leg 90-day long expedition in 2014 with Swedish icebreaker Oden. One component of the expedition consisted of geophysical mapping and coring of Herald Canyon, located on the Chukchi Sea shelf north of the Bering Strait in the western Arctic Ocean.

Herald Canyon is strategically placed to capture the history of the Pacific-Arctic Ocean connection and related changes in Arctic Ocean paleoceanography.

We provide a new age constraint of 11 cal ka BP on sediments from the uppermost slope for the initial flooding of the Bering Land Bridge and reestablishment of the Pacific-Arctic Ocean connection following the last glaciation. This age corresponds to meltwater pulse 1b (MWP1b) known as a post-Younger Dryas warming in many sea level and paleoclimate records.

High late Holocene sedimentation rates in Herald Canyon permitted paleo-ceanographic reconstructions of ocean circulation and sea ice cover at centennial scales throughout the late Holocene. Evidence suggests varying influence from inflowing Pacific water into the western Arctic Ocean including some evidence for quasi-cyclic variability in several paleoceanographic parameters,  such as micro-paleontological assemblages, isotope geochemistry and sediment physical properties.

U13B-13: Implementation of an acoustic-based methane flux estimation methodology in the Eastern Siberian Arctic Sea
EF Weidner et al

Quantifying methane flux originating from marine seep systems in climatically sensitive regions is of critically importance for current and future climate studies. Yet, the methane contribution from these systems has been difficult to estimate given the broad spatial scale of the ocean and the heterogeneity of seep activity.

One such region is the Eastern Siberian Arctic Sea (ESAS), where bubble release into the shallow water column (<40 meters average depth) facilitates transport of methane to the atmosphere without oxidation. Quantifying the current seep methane flux from the ESAS is necessary to understand not only the total ocean methane budget, but also to provide baseline estimates against which future climate-induced changes can be measured.

At the 2016 AGU fall meeting, we presented a new acoustic-based flux methodology using a calibrated broadband split-beam echosounder. The broad (14-24 kHz) bandwidth provides a vertical resolution of 10 cm, making possible the identification of single bubbles. After calibration using 64 mm copper sphere of known backscatter, the acoustic backscatter of individual bubbles is measured and compared to analytical models to estimate bubble radius. Additionally, bubbles are precisely located and traced upwards through the water column to estimate rise velocity. The combination of radius and rise velocity allows for gas flux estimation.

Here, we follow up with the completed implementation of this methodology applied to the Herald Canyon region of the western ESAS. From the 68 recognized seeps, bubble radii and rise velocity were computed for more than 550 individual bubbles. The range of bubble radii, 1-6 mm, is comparable to those published by other investigators, while the radius dependent rise velocities are consistent with published models. Methane flux for the Herald Canyon region was estimated by extrapolation from individual seep flux values.

1. Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea
I Leifer, D Chernykh, N Shakhova… open access

Sonar surveys provide an effective mechanism for mapping seabed methane flux
emissions, with Arctic submerged permafrost seepage having great potential to significantly
affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes ... seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.

On a century timescale, methane (CH4) is the next most important anthropogenic greenhouse gas after CO2. However, on a decadal timescale comparable to its atmospheric lifetime, CH4 is more important to the atmospheric radiative balance than CO2 (Forster 2007; Fig. 2.21

ESAS seepage is on a dramatically larger scale with∼ 30 000 plumes manually identified in just two transects. Seepage densities up to ∼ 3000 seep bubble plumes per km2 were found transecting
a single hotspot. Based on the hotspot size (18 400 km2), an order of magnitude estimate suggests 60 million seep plumes for the hotspot alone.

2. The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis
CJ Sapart, N Shakhova, I Semiletov, J Jansen… open access

CH4 concentration and triple isotope composition were analyzed on gas extracted from sediment and water sampled at numerous locations on the shallow ESAS from 2007 to 2013. We find high concentrations (up to 500 µM) of CH4 in the pore water of the partially thawed subsea permafrost of this region.

For all sediment cores, both hydrogen and carbon isotope data reveal the predominant occurrence of CH4 that is not of thermogenic origin as it has long been thought, but resultant from microbial CH4 formation. At some locations, meltwater from buried meteoric ice and/or old organic matter preserved in the subsea permafrost were used as substrates.

Radiocarbon data demonstrate that the CH4 present in the ESAS sediment is of Pleistocene age or older... Our sediment data suggest that at locations where bubble plumes have been observed, CH4 can escape anaerobic oxidation in the surface sediment.

3. Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf
N Shakhova, I Semiletov, O Gustafsson… open access

Here we present results of the first comprehensive scientific re-drilling to show that subsea permafrost in the near-shore zone of the ESAS has a downward movement of the ice-bonded permafrost table of ∼14 cm year−1 over the past 31–32 years. Our data reveal polygonal thermokarst patterns on the seafloor and gas-migration associated with submerged taliks, ice scouring and pockmarks.

4. Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea
AN Charkin, MR van der Loeff, NE Shakhova 2017 open access

It has been suggested that increasing terrestrial water discharge to the Arctic Ocean
may partly occur as submarine groundwater discharge (SGD), yet there are no direct
observations of this phenomenon in the Arctic shelf seas... Another possible mechanism for preventing taliks from freezing and/or preventing talik formation could be groundwater flow through coastal sediments, especially in the areas underlain by faults

Arctic sea ice / Re: Latest PIOMAS update (October, mid month update)
« on: October 19, 2017, 12:08:43 AM »
AGU17 Search “piomas”

GC43J-04 PIOMAS-20C: Variability of Arctic sea ice thickness and volume over the 20th Century.
Axel J B Schweiger UW-APL

Changes in Arctic sea ice are a fingerprint of natural and anthropogenic climate change. The dominant signal in sea ice variability from 1979 to the present is the reduction of sea ice extent, area and thickness. Prior to 1979, the state of our knowledge about sea ice variability is limited to information about sea ice extent and concentration assembled mostly from shipping logs and very little is known about the variability of sea ice thickness and total sea ice volume.

Here we use the Panarctic Ice and Ocean Modelling and Assimilation system (PIOMAS) to generate a sea ice reanalysis from 1900 to 2010 (PIOMAS-20C). PIOMAS-20C is generated by forcing PIOMAS with atmospheric reanalysis data from the ERA-20C project. We present initial results that include validation of atmospheric forcing parameters over sea ice from the ERA20C project and sea ice thickness from PIOMAS-20C.

The PIOMAS-20C sea ice thickness is generally in good agreement with available observations before and after 1979. We specifically investigate patterns of sea ice thickness and volume variability in the early 20th century and compare them with changes over the more recent period.

C33C-1205 Seasonal evolution of the Arctic marginal ice zone and its power-law obeying floe size distribution
Jinlun Zhang  UW-APL

A thickness, floe size, and enthalpy distribution (TFED) sea ice model, implemented numerically into the Pan-arctic Ice–Ocean Modeling and Assimilation System (PIOMAS), is used to investigate the seasonal evolution of the Arctic marginal ice zone (MIZ) and its floe size distribution.

The TFED sea ice model, by coupling the Zhang et al. [2015] sea ice floe size distribution (FSD) theory with the Thorndike et al. [1975] ice thickness distribution (ITD) theory, simulates 12-category FSD and ITD explicitly and jointly. A range of ice thickness and floe size observations were used for model calibration and validation. The model creates FSDs that generally obey a power law or upper truncated power law, as observed by satellites and aerial surveys.

In this study, we will examine the role of ice fragmentation and lateral melting in altering FSDs in the Arctic MIZ. We will also investigate how changes in FSD impact the seasonal evolution of the MIZ by modifying the thermodynamic processes.

C21B-1119 Winter Arctic sea ice growth: current variability and projections for the coming decades
Alek Petty

Arctic sea ice increases in both extent and thickness during the cold winter months (~October to May). Winter sea ice growth is an important factor controlling ocean ventilation and winter water/deep water formation, as well as determining the state and vulnerability of the sea ice pack before the melt season begins. Key questions for the Arctic community thus include: (i) what is the current magnitude and variability of winter Arctic sea ice growth and (ii) how might this change in a warming Arctic climate?

To address (i), our current best guess of pan-Arctic sea ice thickness, and thus volume, comes from satellite altimetry observations, e.g. from ESA's CryoSat-2 satellite. A significant source of uncertainty in these data come from poor knowledge of the overlying snow depth.

Here we present new estimates of winter sea ice thickness from CryoSat-2 using snow depths from a simple snow model forced by reanalyses and satellite-derived ice drift estimates, combined with snow depth estimates from NASA's Operation IceBridge.

To address (ii), we use data from the Community Earth System Model's Large Ensemble Project, to explore sea ice volume and growth variability, and how this variability might change over the coming decades. We compare and contrast the model simulations to observations and the PIOMAS ice-ocean model (over recent years/decades). The combination of model and observational analysis provide novel insight into Arctic sea ice volume variability

C33B-1201 The Impact of Moisture Intrusions from Lower Latitudes on Arctic Net Surface Radiative Fluxes and Sea Ice Growth in Fall and Winter
Bradley M Hegyi

The fall and winter seasons mark an important period in the evolution of Arctic sea ice, where energy is transferred away from the surface to facilitate the cooling of the surface and the growth of Arctic sea ice extent and thickness.

Climatologically, these seasons are characterized by distinct periods of increased and reduced surface cooling and sea ice growth. Periods of reduced sea ice growth and surface cooling are associated with cloudy conditions and the transport of warm and moist air from lower latitudes, termed moisture intrusions.

In the research presented, we explore the regional and Arctic-wide impact of moisture intrusions on the surface net radiative fluxes and sea ice growth for each fall and winter season from 2000/01-2015/16, utilizing MERRA2 reanalysis data, PIOMAS sea ice thickness data, and daily CERES radiative flux data.

Consistent with previous studies, we find that positive anomalies in downwelling longwave surface flux are associated with increased temperature and water vapor content in the atmospheric column contained within the moisture intrusions.

Interestingly, there are periods of increased downwelling LW flux anomalies that persist for one week or longer (i.e. longer than synoptic timescales) that are associated with persistent poleward flux of warm, moist air from lower latitudes. These persistent anomalies significantly reduce the regional growth of Arctic sea ice, and may in part explain the inter-annual variability of fall and winter Arctic sea ice growth.

C21D-1144: Anomalous circulation in the Pacific sector of the Arctic Ocean in July-December 2008
Gleb Panteleev

Variability of the mean summer-fall ocean state in the Pacific Sector of the Arctic Ocean (PSAO) is studied using a dynamically constrained synthesis (4Dvar) of historical in situ observations collected during 1972 to 2008. Specifically, the oceanic response to the cyclonic (1989-1996) and anticyclonic (1972-1978, 1997-2006) phases o f the Arctic Ocean Oscillation (AOO) is assessed for the purpose of quantitatively comparing the 2008 circulation pattern that followed the 2007 ice cover minimum.

It is shown that the PSAO circulation during July-December of 2008 was characterized by a pronounced negative Sea Surface Height (SSH) anomaly along theEurasian shelf break, which caused a significant decline of the transport in the Atlantic Water (AW) inflow region into the PSAO and increased the sea level difference between the Bering and Chukchi Seas. This anomaly could be one of the reasons for the observed amplification of the Bering Strait transport carrying fresh Pacific Waters into the PSAO.

Lagrangian analysis of the optimized solution suggests that the freshwater (FW) accumulation in the Beaufort Gyre has a negligible contribution from the East Siberian Sea and is likely caused by the enhanced FW export from the region north of the Canadian Archipelago/Greenland.The inverse modeling results are confirmed by validation against independent altimetry observations and in situ velocity data from NABOS moorings. It is also shown that presented results are in significantly better agreement with the data than the output of the PIOMAS model run utilized as a first guess solution for the 4dVar analysis.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 18, 2017, 11:31:33 PM »
Speaking of snow depth, here is another ESRL product, snowdepthchange.gif from their web page or archival REB_plots. It is somewhat peculiar in that D0 is not provided, only the D5 forecast. Thus the animation is of these day fives -- 15 Sep to 22 Oct -- rather than the presumably more accurate initial states.

Still, it gives an idea how rapidly snow depth changes from day to day as well as the expected prevailing wind. The final frame averages these out, even though the palette is not really designed to support this.

This time of year, when thermal insulation not solar insolation is the issue for the rate of bottom ice growth induced by frigid surface air, the relevant property of snow is its conductivity.

Is it still, as often assumed, a uniform basin-wide porous medium with a large immobilized air component (like a foam pad) after being blown around for weeks, possibly getting dunked, rained on, and soaked with sea spray? If so, is the current ankle-deep mean snowpack enough to seriously inhibit bottom growth, relative to not-so-cold prevailing mean air temperatures?

That's hard to say directly with no buoys, no ships, and no one out there but satellites can measure bulk properties. The scale though is not commensurate with that of snow features, though Sentinel-1 comes fairly close.;jsessionid=CE14DA1FFAEF3D6FD98ABAD517B04B81.enterprise-15000

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 18, 2017, 09:12:41 PM »
unique event which will take place in Davos, Switzerland
I am skipping both Bilderberg and Davos this year in favor of a staycation. ;) 

The abstracts below speak to common themes on the forum; it's hard to say which will emerge as game-changers vs incremental improvements vs never-to-be-seen-agains.

C21G-1188: Estimation of Melt Ponds over Arctic Sea Ice using MODIS Surface Reflectance Data
Y Ding et al

Melt ponds over Arctic sea ice is one of the main factors affecting variability of surface albedo, increasing absorption of solar radiation and further melting of snow and ice. In recent years, a large number of melt ponds have been observed during the melt season in Arctic. Moreover, some studies have suggested that late spring to mid summer melt ponds information promises to improve the prediction skill of seasonal Arctic sea ice minimum.

In the study, we extract the melt pond fraction over Arctic sea ice since 2000 using three bands MODIS weekly surface reflectance data by considering the difference of spectral reflectance in ponds, ice and open water. The preliminary comparison shows our derived Arctic-wide melt ponds are in good agreement with that derived by the University of Hamburg, especially at the pond distribution. We analyze seasonal evolution, inter-annual variability and trend of the melt ponds, as well as the changes of onset and re-freezing.

The melt pond fraction shows an asymmetrical growth and decay pattern. The observed melt ponds fraction is almost 25% in early May and increases rapidly in June and July with a high fraction of more than 40% in the east of Greenland and Beaufort Sea. A significant increasing trend in the melt pond fraction is observed for the period of 2000-2017.

C21G-1179: A Novel Approach To Retrieve Arctic Sea Ice Thickness For Prediction And Analysis
L Brucker et al

In spite of October-November Arctic-sea-ice-volume loss exceeding 7000 km3 in the decade following ICESat launch, most global ocean reanalysis systems are not able to reproduce such a drastic decline.

Knowledge of the sea ice properties and its thickness distribution is critical to our understanding of polar ocean processes and the role of the polar regions in the Earth's climate system. Existing large-scale sea ice thickness datasets are derived from freeboard observations made by different satellite altimeters (radar and lidar). These datasets are significantly different due to the remote sensing technique and spacecraft orbit, and they are limited in time. These differences increase the difficulty of using such data for sea ice initialization and assimilation, and increase the challenge for studying sea ice processes and interactions with the ocean and atmosphere.

For the first time, we were able to reproduce the Arctic sea ice thickness field at 10 km resolution with success for fall, winter, and spring (April/May depending on melt conditions) from passive microwave data. Our results reveal the same patterns of thickness distribution in the Arctic basin and peripheral seas as CryoSat-2, and the majority of the retrievals are within 0.5 m of CryoSat-2. The range of CryoSat-2 ice thickness is correctly retrieved, including in the upper range (3-5 m). The amplitude is well reproduced too, as the distribution of differences is centered on 0 m (no bias).

Some underestimations are visible between islands of the Canadian Archipelago, but due to the size of the field of view our confidence will always be lower in this region where there is land contamination. An initial comparison of the AMSR2 ice thickness with IceBridge airborne products in different sectors (Beaufort sea, central Arctic) demonstrates the quality of the retrievals.

We will also quantify the prediction and nowcast gain obtained from assimilating these new retrievals. We carried-out the integration of 36 members of coupled NASA Goddard Earth Observing System Model, version 5 (GEOS-5) to enable the implementation of an Ensemble Kalman Smoother (EnKS) over the period September 2012 - January 2013. Assimilating our retrievals improves the nowcast of ice volume, the forecast and the retrospective forecast.

C11D-06: Regional Arctic sea-ice prediction: A direct comparison of potential versus operational seasonal forecast skill
M Bushuk et al

Seasonal predictions of Arctic sea ice on regional spatial scales are a pressing need for a broad group of stakeholders, however, most forecast skill assessments to date have focused on pan-Arctic sea-ice extent (SIE). In this work, we present a direct comparison of potential and operational seasonal prediction skill for regional Arctic SIE. This assessment is based on two complementary suites of seasonal prediction ensemble experiments performed with a global coupled climate model.

First, we assess the operational prediction skill for de-trended regional SIE using a suite of retrospective initialized seasonal forecasts spanning 1980-2017. These retrospective forecasts are found to skillfully predict regional winter SIE at lead times of 3-11 months and regional summer SIE at lead times of 1-4 months, owing partially to subsurface ocean temperature and sea-ice thickness initial conditions, respectively. Second, we present a suite of perfect model predictability experiments with start dates spanning the calendar year, which are used to quantity the potential regional prediction skill of this system.

These perfect model experiments reveal that regional Arctic SIE is potentially predictable at lead times beyond 12 months in many regions, substantially longer than the current operational skill of this system. Both the retrospective forecasts and perfect model experiments display a spring prediction skill barrier for regional summer SIE forecasts, indicating a fundamental predictability limit for summer regional predictions. The skill gap identified in this work indicates a promising potential for future improvements in regional SIE predictions.

C21G-1190: Assessing surface radiative fluxes and developing surface turbulent heat fluxes over Arctic sea ice
M Song et al

In this study, we have developed a new satellite-based surface heat and moisture flux data set over the ice-covered ocean in the Arctic using a recently developed flux algorithm based on the theory of maximum entropy production (MEP model). First, the accuracy and uncertainty associated with surface radiative fluxes and temperature for three available satellite products are evaluated against the assembled in-situ data.

The three satellite products are the Surface Radiation Budget project (SRB), the International Satellite Cloud Climatology Project (ISCCP), and the Extended AVHRR Polar Pathfinder version-2 (APP-x).

Our comparisons suggest that 1) in terms of the overall bias, root mean square error, and correlation, the net surface radiative flux of ISCCP is closer to in-situ observations than that of SRB and APP-x; 2) in terms of the bias by local times, it is not very clear which satellite product is superior to others; and 3) in terms of inter-annual variability of the bias, the net surface radiative flux of ISCCP is more accurate than that of SRB and APP-x. Based on the above comparison, we use the ISCCP surface radiative fluxes as input values for the MEP model to calculate surface turbulent heat fluxes over Arctic sea ice.

C21G-1184: Improving Arctic sea ice edge forecasts by assimilating high resolution VIIRS sea ice concentration data into the U.S. Navy’s ice forecast system
OM Smedstad et al

This study presents the improvement in ice edge error within the U.S. Navy’s operational sea ice forecast system gained by assimilating the high horizontal resolution visible/infrared satellite-derived VIIRS ice concentration products. A series of hindcast studies are performed for the period of 1 January – 31 December 2016 using Global Ocean Forecast System (GOFS 3.1), a 1/12° HYbrid Coordinate Ocean Model (HYCOM) that is two-way coupled to the Community Ice CodE (CICE) in a daily update cycle with the Navy Coupled Ocean Data Assimilation (NCODA).

Comparisons using the VIIRS ice concentration products (< 1km resolution) show lower ice edge location errors than the current system, which assimilates near real-time passive microwave data from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSMIS) and the Advanced Microwave Scanning Radiometer (AMSR2) ice concentration products (25 and 12.5km resolution, respectively).

The daily ice edge locations from the model simulations are compared against independent observed ice edge locations. Results from the Pan-Arctic and regional areas along with seasonal time scales will be presented. A previous study using the Arctic Cap Nowcast/Forecast System (ACNFS), a 1/12° coupled HYCOM/CICE/NCODA for the Northern Hemisphere only, has shown that by assimilating the VIIRS (along with SSMIS and AMSR2) ice concentration products reduced the ice edge location errors by 25% in the pan-Arctic region for the same year-long time period.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 18, 2017, 12:15:22 PM »
Here are those same three RASM-ESRL precipitation forecasts at 24 hour intervals out to Oct 24th. A moderate amount of rain-on-snow is foreseen for a small area north of Svalbard. Snow depth is moderate, at most 0.25m, and quite uneven in providing thermal insulation after wind-blown drifting is considered (2nd image),

Arctic sea ice / Re: The 2017/2018 freezing season
« on: October 18, 2017, 09:46:40 AM »
It's that time of year again, when thousands of abstracts for AGU meeting become available. Hardly anyone discloses results, posters aren't available for poster sessions, talks won't be videoed, their powerpoints won't be archived, and already-published articles won't be linked.

Still, AGU17 does allow a look ahead to the coming year of journal articles. A name search can show what a particular scientist has been up to; for example Neven asked upforum what J Stroeve is doing, she is on three of the abstracts.

Snow on Arctic sea ice is an active topic. Like ice thickness and clouds, it is very difficult to characterize basin-wide, in part because depth alone doesn't capture its insulating properties in freeze season: it's blown into windrows, it may be dunked in sea water on a floe with negative freeboard, or be rained upon and refreeze. Still, it looks like some better products than what we have now may be in the pipeline.

C23E-08: Merging observations and reanalysis data to improve estimates of snow depth on Arctic sea ice
NT Kurtz et al

Snow is an important controlling factor in the heat and radiation balance of the Arctic sea ice pack. Knowledge of snow on sea ice is also required for retrievals of sea ice thickness from airborne and spaceborne altimeters, and is presently the largest source of uncertainty in the conversion of freeboard to sea ice thickness from these altimetry data.

Multiple sources of observational snow depth data exist such as those from the Operation IceBridge (OIB) snow radar, passive microwave satellites, and ice mass balance buoys. However, these observational data sources are limited in spatial and/or temporal extent, which makes their usage impractical when used for basin-wide sea ice thickness retrievals in a standalone fashion.

We show how the use of snow depth observations from the OIB snow radar can be used as a primary means to improve basin-scale snow depth results from a simple snow model forced by reanalyses and satellite-derived ice drift estimates. We also show how different observational data sets impact the snow depth estimates, and how best to incorporate data sets of differing temporal and spatial scales to provide snow thickness estimates of consistent quality over the entire sea ice growth season. Particular focus is given to the new 2017 OIB data set which included new flights into the eastern Arctic sector where interesting differences were seen between the first year and multiyear ice areas.

C32B-02: Snow accumulation on Arctic sea ice: is it a matter of how much or when?
M Webster  et al

Snow on sea ice plays an important, yet sometimes opposing role in sea ice mass balance depending on the season. In autumn and winter, snow reduces the heat exchange from the ocean to the atmosphere, reducing sea ice growth. In spring and summer, snow shields sea ice from solar radiation, delaying sea ice surface melt. Changes in snow depth and distribution in any season therefore directly affect the mass balance of Arctic sea ice.

In the western Arctic, a decreasing trend in spring snow depth distribution has been observed and attributed to the combined effect of peak snowfall rates in autumn and the coincident delay in sea ice freeze-up. Here, we present an in-depth analysis on the relationship between snow accumulation and the timing of sea ice freeze-up across all Arctic regions.

A newly developed two-layer snow model is forced with eight reanalysis precipitation products to: (1) identify the seasonal distribution of snowfall accumulation for different regions, (2) highlight which regions are most sensitive to the timing of sea ice freeze-up with regard to snow accumulation, and (3) show, if precipitation were to increase, which regions would be most susceptible to thicker snow covers. We also utilize a comprehensive sensitivity study to better understand the factors most important in controlling winter/spring snow depths, and to explore what could happen to snow depth on sea ice in a warming Arctic climate.

C33C-1215: Rainy Days in the New Arctic: A Comprehensive Look at Precipitation from 8 Reanalysis
L Boisvert  et al

Precipitation in the Arctic plays an important role in the fresh water budget, and is the primary control of snow accumulation on sea ice. However, Arctic precipitation from reanalysis is highly uncertain due to differences in the atmospheric physics and use of data assimilation and sea ice concentrations across the different products. More specifically, yearly cumulative precipitation in some regions can vary by 100-150 mm across reanalyses. This creates problems for those modeling snow depth on sea ice, specifically for use in deriving sea ice thickness from satellite altimetry.

In recent years, this new Arctic has become warmer and wetter, and evaporation from the ice-free ocean has been increasing, which leads to the question: is more precipitation falling and is more of this precipitation rain? This could pose a big problem for model and remote sensing applications and studies those modeling snow accumulation because rain events will can melt the existing snow pack, reduce surface albedo, and modify the ocean-to-atmosphere heat flux via snow densification.

In this work we compare precipitation (both snow and rain) from 8 different reanalysis: MERRA, MERRA2, NCEP-R1, NCEP-R2, ERA-Interim, ERA-5, ASR and JRA-55. We examine the annual, seasonal, and regional differences and compare with buoy data to assess discrepancies between products during observed snowfall and rainfall events. Magnitudes and frequencies of these precipitation events are evaluated, as well as the “residual drizzle” between reanalyzes. Lastly, we will look at whether the frequency and magnitude of “rainy days” in the Arctic have been changing over recent decades.

C21B-1122: Synoptic weather conditions, clouds, and sea ice in the Beaufort and Chukchi Seasonal Ice Zone
Z Liu et al

The connections between synoptic conditions and clouds and sea ice over the Beaufort and Chukchi Seasonal Ice Zone are examined. Four synoptic states with distinct thermodynamic and dynamic spatial and vertical signatures are identified using a k-means classification algorithm and the ERA-Interim reanalysis data from 1979 to 2014.

The combined CloudSat and Calipso cloud observations suggest control of clouds by synoptic states. Warm continental air advection is associated with the fewest low-level clouds, cold air advection under low pressure generates the most low-level clouds. Low-level cloud fractions are related to lower-tropospheric stability and both are regulated by synoptic conditions. Observed cloud vertical and spatial variability is reproduced well in ERA-Interim, but winter low-level cloud fraction is overestimated.

Sea ice melt onset is related to synoptic conditions. Melt onsets occur more frequently and earlier with warm air advection states. The warm continental air advection state with the highest temperature is the most favorable for melt onsets even though fewer low-level clouds are associated with this state. The other warm advection state is cloudier but colder.

In the Beaufort and Chukchi Seasonal Ice Zone, the much higher temperature and total column water of the warm continental air advection state compensate the smaller cloud longwave radiative fluxes due to the smaller low-level cloud fraction. In addition, the higher shortwave radiative fluxes and turbulent fluxes to the surface are also favorable for sea ice melt onset.

C21G-1186: There goes the sea ice: following Arctic sea ice parcels and their properties.
MA Tschudi et al

Arctic sea ice distribution has changed considerably over the last couple of decades. Sea ice extent record minimums have been observed in recent years, the distribution of ice age now heavily favors younger ice, and sea ice is likely thinning. This new state of the Arctic sea ice cover has several impacts, including effects on marine life, feedback on the warming of the ocean and atmosphere, and on the future evolution of the ice pack.

The shift in the state of the ice cover, from a pack dominated by older ice, to the current state of a pack with mostly young ice, impacts specific properties of the ice pack, and consequently the pack’s response to the changing Arctic climate. For example, younger ice typically contains more numerous melt ponds during the melt season, resulting in a lower albedo. First-year ice is typically thinner and more fragile than multi-year ice, making it more susceptible to dynamic and thermodynamic forcing.

To investigate the response of the ice pack to climate forcing during summertime melt, we have developed a database that tracks individual Arctic sea ice parcels along with associated properties as these parcels advect during the summer. Our database tracks parcels in the Beaufort Sea, from 1985 – present, along with variables such as ice surface temperature, albedo, ice concentration, and convergence.

We are using this database to deduce how these thousands of tracked parcels fare during summer melt, i.e. what fraction of the parcels advect through the Beaufort, and what fraction melts out? The tracked variables describe the thermodynamic and dynamic forcing on these parcels during their journey. The attached image (it’s not) shows the ice surface temperature of all parcels (right) that advected through the Beaufort Sea region (left) in 2014.

C33C-1210: Towards development of an operational snow-on-sea-ice product
GE Liston et al

While changes in the spatial extent of sea ice have been routinely monitored since the 1970s, less is known about how the thickness of the ice cover has changed. While estimates of ice thickness across the Arctic Ocean have become available over the past 20 years based on data from ERS-1/2, Envisat, ICESat, CryoSat-2 satellites and Operation IceBridge aircraft campaigns, the variety of these different measurement approaches, sensor technologies and spatial coverage present formidable challenges. Key among these is that measurement techniques do not measure ice thickness directly – retrievals also require snow depth and density.

Towards that end, a sophisticated snow accumulation model is tested in a Lagrangian framework to map daily snow depths across the Arctic sea ice cover using atmospheric reanalysis data as input. Accuracy of the snow accumulation is assessed through comparison with Operation IceBridge data and ice mass balance buoys (IMBs). Impacts on ice thickness retrievals are further discussed.

Permafrost / Re: Arctic Methane Release
« on: October 17, 2017, 11:40:28 PM »
Searching for 'methane' at AGU17 abstracts gets you 530 abstracts, some of more interest than others.

Arctic sea ice / Re: What the Buoys are telling
« on: October 17, 2017, 08:57:41 PM »
Sounds good but when and how many?

AGU17 C21B-1120: Autonomous Ice Mass Balance Buoys for Seasonal Sea Ice
JD Whitlock et al abstract search tool

The ice mass-balance represents the integration of all surface and ocean heat fluxes and attributing the impact of these forcing fluxes on the ice cover can be accomplished by increasing temporal and spatial measurements. Mass balance information can be used to understand the ongoing changes in the Arctic sea ice cover and to improve predictions of future ice conditions.

Thinner seasonal ice in the Arctic necessitates the deployment of Autonomous Ice Mass Balance buoys (IMB’s) capable of long-term in situ data collection in both ice and open ocean. Seasonal IMB’s (SIMB’s) are free floating IMB’s that allow data collection in thick ice, thin ice, during times of transition, and even open water.

The newest generation of SIMB aims to increase the number of reliable IMB’s in the Arctic by leveraging inexpensive commercial-grade instrumentation when combined with specially developed monitoring hardware. Monitoring tasks are handled by a custom, expandable data logger that provides low-cost flexibility for integrating a large range of instrumentation.

The SIMB features ultrasonic sensors for direct measurement of both snow depth and ice thickness and a digital temperature chain (DTC) for temperature measurements every 2cm through both snow and ice. Air temperature and pressure, along with GPS data complete the Arctic picture. Additionally, the new SIMB is more compact to maximize deployment opportunities from multiple types of platforms.

Greenland and Arctic Circle / Re: What's new in Greenland?
« on: October 17, 2017, 03:11:29 PM »
Nice, T-lite! If you have that gif in a linear grayscale palette, it would be easy to make 3D surfaces of the trough. The newer over older below shows that depths at the calving front and preceding trough are now substantially shallower than in version 2.

Also adding below the best overall geoid I could locate for Greenland and the Arctic Ocean. Seems like there should be an interactive version or global geolocated netCDF and indeed finally located the former. visualization service

Consequences / Re: Hurricane season 2017
« on: October 17, 2017, 02:23:04 PM »
This storm really moved along fast on Nullschool and seems to have dissipated without any discernible impacts foreseen for the Arctic Ocean (which however will see consistent but moderate  winds sweeping from Svalbard clear across to the Bering Strait).

J Masters at WeatherUnderground has a good account of Ophelia and its significance:

Europe may see an increase in strong ex-hurricanes in the future

Ophelia’s ascension to Category 3 status and subsequent impact on Ireland just 12 hours after becoming an ex-hurricane was made possible, in large part, by unusually warm ocean temperatures that were 1 – 2°C (1.8 – 3.6°F) above average. As the planet continues to warm due to the effects of human-caused global warming, we should expect to see more hurricanes maintaining their strength far to the north, allowing them to draw very close to Europe.

According to a 2014 study led by University of Wisconsin hurricane scientist Jim Kossin, "The poleward migration of the location of tropical cyclone maximum intensity", there has already been a “pronounced poleward migration in the average latitude at which tropical cyclones have achieved their lifetime-maximum intensity over the past 30 years. The poleward trends are evident in the global historical data in both the Northern and the Southern hemispheres, with rates of 53 and 62 kilometres per decade, respectively.” paywalled

The scientists hypothesized that this poleward shift could be linked to the expansion of tropics poleward that has long been predicted as a likely consequence of human-caused global warming. They noted that so far, though, the poleward trend observed in the Atlantic tropical cyclone database has been small.

Ophelia was an “off the charts” storm

One other way we know that Ophelia was an extremely unusual storm is that is broke some of the graphical displays we use to view the forecast. The National Hurricane Center graphical forecasts of the storm’s track had to be truncated east of 0° longitude (the Greenwich Prime Meridian), since they never planned for the possibility that an Atlantic hurricane or its identifiable remnants could make it so far to the northeast.

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