Support the Arctic Sea Ice Forum and Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Alison

Pages: [1]
1
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: October 16, 2019, 06:57:12 AM »
Juan,
thank you for your daily updates.  :)

2
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 13, 2019, 08:44:10 PM »
By the way, I still think that endless discussions on what charts that use extent & area are best to predict an ice-free Arctic are a waste of time because:-
- CO2 ppm is increasing at an accelerating rate (looks like will at 3 ppm per year this year)
- There is evidence that the Carbon Sinks are not doing so well, (recent post by AbruptSLR re the Southern Ocean & some work I did on carbon sinks c.f. emissions and CO" increases),
- Global Surface ar temps at record levels in an ENSO neutral year plus scary WMO report on recent trends.

BUT - I read the NSIDC talking about a hiatus in extent loss & I think it is WRONG.. Even though they emphasise caveats & the need to look at longer-term trends, it is God's gift to the denier industry.

So here is a 2nd post about it.
____________________________________________

By why stop with your so-called exaggerated years in one direction only?  If your are going to selectively discard data points, why not toss out the high years of 2000 and 2006 also?

Indeed, why not? So I googled to refresh my hazy memory of a Uni course on Mathematical Statistics to fin the standard methodology for identification of outliers. (That course was so long ago for analysis we did it by hand on mechanical machine Babbage would have recognised.)

It got wider - seems to be a big thing in machine learning (AI ?):-

https://machinelearningmastery.com/how-to-use-statistics-to-identify-outliers-in-data/
Machine Learning Mastery
How to Use Statistics to Identify Outliers in Data

Sometimes a dataset can contain extreme values that are outside the range of what is expected and unlike the other data. These are called outliers and often machine learning modeling and model skill in general can be improved by understanding and even removing these outlier values.

- An outlier is an unlikely observation in a dataset and may have one of many causes.
-Standard deviation can be used to identify outliers in Gaussian or Gaussian-like data.
- The interquartile range can be used to identify outliers in data regardless of the distribution.

I followed the recognised  interquartile range method using absolute deviations from the "expected" value from the linear regression used by NSIDC & me in these graphs

For NSIDC Extent it told me to dump an extra year, the very high extent value in 1996.

I did they same analysis or PIOMAS September volume, and it told me to dump 3 years, all very low values, 1981, 1982, and 2012.

The answers re all the same -
- there is barely any change from the linear regression with or without the "outlier years",
- there is no "hiatus" in the steady loss of Arctic Sea Ice extent as implied on the 3rd October  NSIDC analysis (https://nsidc.org/arcticseaicenews/)

Quote
Within the overall decline, it is notable that the most recent 13 years, from 2007 to 2019, have shown very little decline (Figure 3b). Both 2007 and 2012 were extreme low extent years, and variability has been high in this period. However, an earlier 13 year period, 1999 to 2012, shows a rate of decline that is more than double the overall rate in the satellite record. This illustrates the challenge of extracting a quantitative rate of decline in a highly variable system like sea ice, and the benefits of looking at decadal, and not year-to-year variations.

3
In regards to ice mass loss from Antarctic ice shelves, I provide the following information:

Sutterley, T. C., Markus, T., Neumann, T. A., van den Broeke, M., van Wessem, J. M., and Ligtenberg, S. R. M.: Antarctic ice shelf thickness change from multimission lidar mapping, The Cryosphere, 13, 1801–1817, https://doi.org/10.5194/tc-13-1801-2019, 2019.

https://www.the-cryosphere.net/13/1801/2019/

Abstract

We calculate rates of ice thickness change and bottom melt for ice shelves in West Antarctica and the Antarctic Peninsula from a combination of elevation measurements from NASA–CECS Antarctic ice mapping campaigns and NASA Operation IceBridge corrected for oceanic processes from measurements and models, surface velocity measurements from synthetic aperture radar, and high-resolution outputs from regional climate models. The ice thickness change rates are calculated in a Lagrangian reference frame to reduce the effects from advection of sharp vertical features, such as cracks and crevasses, that can saturate Eulerian-derived estimates. We use our method over different ice shelves in Antarctica, which vary in terms of size, repeat coverage from airborne altimetry, and dominant processes governing their recent changes. We find that the Larsen-C Ice Shelf is close to steady state over our observation period with spatial variations in ice thickness largely due to the flux divergence of the shelf. Firn and surface processes are responsible for some short-term variability in ice thickness of the Larsen-C Ice Shelf over the time period. The Wilkins Ice Shelf is sensitive to short-timescale coastal and upper-ocean processes, and basal melt is the dominant contributor to the ice thickness change over the period. At the Pine Island Ice Shelf in the critical region near the grounding zone, we find that ice shelf thickness change rates exceed 40 m yr−1, with the change dominated by strong submarine melting. Regions near the grounding zones of the Dotson and Crosson ice shelves are decreasing in thickness at rates greater than 40 m yr−1, also due to intense basal melt. NASA–CECS Antarctic ice mapping and NASA Operation IceBridge campaigns provide validation datasets for floating ice shelves at moderately high resolution when coregistered using Lagrangian methods.

&

E. Rignot et al. (Jul 2013), "Ice-Shelf Melting Around Antarctica", Science, Vol. 341, Issue 6143, pp. 266-270, DOI: 10.1126/science.1235798

https://science.sciencemag.org/content/341/6143/266.abstract

Major Meltdown
The ice shelves and floating ice tongues that surround Antarctica cover more than 1.5 million square kilometers—approximately the size of the entire Greenland Ice Sheet. Conventional wisdom has held that ice shelves around Antarctica lose mass mostly by iceberg calving, but recently it has become increasingly clear that melting by a warming ocean may also be important. Rignot et al. (p. 266, published 13 June) present detailed glaciological estimates of ice-shelf melting around the entire continent of Antarctica, which show that basal melting accounts for as much mass loss as does calving.

Abstract
We compare the volume flux divergence of Antarctic ice shelves in 2007 and 2008 with 1979 to 2010 surface accumulation and 2003 to 2008 thinning to determine their rates of melting and mass balance. Basal melt of 1325 ± 235 gigatons per year (Gt/year) exceeds a calving flux of 1089 ± 139 Gt/year, making ice-shelf melting the largest ablation process in Antarctica. The giant cold-cavity Ross, Filchner, and Ronne ice shelves covering two-thirds of the total ice-shelf area account for only 15% of net melting. Half of the meltwater comes from 10 small, warm-cavity Southeast Pacific ice shelves occupying 8% of the area. A similar high melt/area ratio is found for six East Antarctic ice shelves, implying undocumented strong ocean thermal forcing on their deep grounding lines.

4
The linked reference presents physical evidence that large amounts of intrapermafrost gas hydrates currently exist in a metastable state in the Arctic continental shelves, and that "… even minor temperature increases can be expected to trigger large-scale dissociation of intrapermafrost hydrates."  This potential source of GHG emissions has been ignored by consensus climate scientists, but represents a very significant climate change risk as the North Atlantic MOC has been pushing further and further into the Arctic Basin, and within a few decades time the introduction of this heat source to the seafloor of many key Arctic shelves may provide the 'minor temperature increases' that the authors (including Shakhova & Semiletov) warm many be sufficient to 'trigger large-scale dissociation of intrepermafrost hydrates.'

Evgeny Chuvilin, Dinara Davletshina, Valentina Ekimova, Boris Bukhanov, Natalia Shakhova  and Igor Semiletov (2019), "Role of Warming in Destabilization of Intrapermafrost Gas Hydrates in the Arctic Shelf: Experimental Modeling", Geosciences, 9, (10), 407; https://doi.org/10.3390/geosciences9100407

https://www.mdpi.com/2076-3263/9/10/407

Abstract: "Destabilization of intrapermafrost gas hydrates is one of the possible mechanisms responsible for methane emission in the Arctic shelf. Intrapermafrost gas hydrates may be coeval to permafrost: they originated during regression and subsequent cooling and freezing of sediments, which created favorable conditions for hydrate stability. Local pressure increase in freezing gas-saturated sediments maintained gas hydrate stability from depths of 200–250 meters or shallower. The gas hydrates that formed within shallow permafrost have survived till present in the metastable (relict) state. The metastable gas hydrates located above the present stability zone may dissociate in the case of permafrost degradation as it becomes warmer and more saline. The effect of temperature increase on frozen sand and silt containing metastable pore methane hydrate is studied experimentally to reconstruct the conditions for intrapermafrost gas hydrate dissociation. The experiments show that the dissociation process in hydrate-bearing frozen sediments exposed to warming begins and ends before the onset of pore ice melting. The critical temperature sufficient for gas hydrate dissociation varies from −3.0 to −0.3 °C and depends on lithology (particle size) and salinity of the host frozen sediments. Taking into account an almost gradientless temperature distribution during degradation of subsea permafrost, even minor temperature increases can be expected to trigger large-scale dissociation of intrapermafrost hydrates. The ensuing active methane emission from the Arctic shelf sediments poses risks of geohazard and negative environmental impacts."

5
Thank you very much for this overview and logic ASLR!

Another line of logic to remember when thinking about consensus science projections is as follows:

1. The IPCC explicitly states that their radiative forcing scenarios (e.g. RCP, etc.) do not include any representation of probability of occurrence, and yet consensus climate scientists typically assume for instance that RCP 8.5 is less likely to occur than forcing scenarios closer to RCP 6.0 because they assume RCP 8.5 represents the upper bound of forcing scenarios and that efforts like the Paris Agreement will increase the odds that a forcing scenario closer to RCP 6.0 will occur.  However, the two attached images show that ever since the Kyoto Protocol we have been exceeding RCP6.0 and following RCP 8.5.  This means to me that RCP 8.5 was not the upper bound scenario, as if mankind had not made the efforts associated with the Kyoto Protocol & similar measures, we would now be exceeding RCP 8.5.

2. The IPCC radiative forcing scenarios are determined by statistics associated with the peer reviewed literature available at the time that the family of forcing scenarios is developed.  Thus if the peer reviewed literature errs on the side of least drama, then so will the IPCC forcing scenarios.  Thus these scenarios to not represent a truly scientific determination of the likelihood of future radiative forcing, but rather they serve only as benchmarks for comparing different model projections (which is a valuable function).

3. Coming wars are not considered in the IPCC radiative forcing scenarios, but WWII indicates that wars generate a lot of carbon emissions.  With projections of 1.5 billion climate driven immigrants by 2050, the chances of future wars increase with each passing year.

4. The recent IPCC radiative forcing scenarios (RCP & SSP) assume that government policies with regard to climate change will be rational; and do not consider governmental behavior such as that exhibited by the Trump administration.

6
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: August 24, 2019, 11:53:56 AM »
JAXA ARCTIC SEA ICE EXTENT :- 4,412,266 km2(August 23, 2019)

Some extra stuff

Projections of the minimum
The first graph attached shows the range of projections to the minimum using the remaining melt in the last 10 years. The variation from the average of that melt ranges from + 27% (2016) to - 25% (2017), giving a range of projected minima from 3.62 to 3.94 million km2. The increases confidence in a prediction that despite current low daily extent loss, the 2019 minimum will be 2nd lowest in the satellite record.

The first table attached shows the daily melt in selected years from now to the average date of minimum.

Current position
The next table shows that despite slow daily extent losses, if extent losses now completely stopped, 2019 would be the 6th lowest minimum in the satellite record, and likely to be 4th by the end of the month, leaving 2007, 2016, and 2019 as the only years lower.

365 Day trailing Averages
The last graph shows that this continues to decline, and could easily at record lows by early 2020.   This can happen despite a minimum well above 2012. It is possible because that 2012 minimum was very short-term, extent recovering strongly and very quickly. A tortoise (2019) and the hare (2012) event. 

Another look in about a week's time, unless events (in the Arctic or closer to home) intervene.

7
A wider long-term view - I use to remind myself of ice volume vulnerability.

From the POMAS source:- http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/
Quote

It takes energy to melt sea ice. How much energy? The energy required to melt the 16,400 Km3 of ice that are lost every year (1979-2010 average) from April to September as part of the natural annual cycle is about 5 x 10^21 Joules, 50 times the annual U.S. energy consumption.

To melt the additional 280 km3 of sea ice, the amount we have have been losing on an annual basis based on PIOMAS calculations, it takes roughly 8.6 x 10^19 Joules .

Data from https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/basin_data.html tells us that on average the annual increase in Global Heat Content was about 1.13 x 10^22 joules (last 10 years, 0-2000 metres).

So every year the oceans' additional heat content is 130 times that used to melt the average permanent annual loss in Arctic Ice Volume, and more than twice the energy used for the entire melt from max to min.  Just as well ocean heat does not seem to be migrating North very quickly - but AWP in the Arctic was somewhat large this year - and the effect on SSTs has not gone away.

8
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: August 14, 2019, 07:18:06 PM »
Sorry, I obvious was not clear. I meant for the years 1999-2008 as well as the years 2009-2018.
The graphs are intentionally sparse of data to avoid too many trees when looking at the forest.
Also, this thread is the current season only, which is close to the end, and is often erratic. Projections / forecasts even more unreliable.

I occasionally go into longer-term mode, but go to the When will the Arctic be Ice-Free? thread where speculation is not only permitted but encouraged.

Also I am somewhat over-committed at the moment.

Sorry, but ....

9
Some consensus climate scientists like to focus on paleoclimate responses averaged over millenia to provide decision makers with a sense of comfort that Earth Systems will not change rapidly (on the order of decades) due to anthropogenic radiative forcing.  However, the linked article about new research on the nature of the last magnetic pole flip indicates that while this last flip ultimately took about 22,000 years to reach a new equilibrium, over that entire 22,000-year period very (incredibly) rapid fluctuations were occurring, and I suspect that our current socio-economic systems would not deal well with such fluctuations.

Title: "The last magnetic pole flip saw 22,000 years of weirdness"

https://arstechnica.com/science/2019/08/the-last-magnetic-pole-flip-saw-22000-years-of-weirdness/

Extract: "The records come from lavas in Chile and the islands of Tahiti, Guadeloupe, La Palma, and Maui. All of them have been studied previously for tracking the history of our magnetic field, as they host multiple lava flows that each provide a snapshot around the time of the reversal. But the method used to date these rocks—based on isotopes of the element argon, which gets trapped in crystals as they solidify—has been improved enough over the last few years that the rocks were worth revisiting to get more accurate dates for each flow. The new measurements come with error bars in the neighborhood of just ±5,000 years for 780,000-year-old lavas.

The new dates help lay out an interesting timeline. Although individual records in some places have seemed to record an incredibly rapid reversal of the poles, these lavas show a complex process playing out over something like 22,000 years."

10
Arctic sea ice / Re: The 2019 melting season
« on: August 11, 2019, 12:42:55 PM »
Any thoughts on why these two are so similar, or on what, if anything, it tells us about the rest of the season?

Really unexpected.

Same for Charctic, by the way.

Same reason for this one, I think.

11
Sun disappears over sub-Arctic Verkhoyansk district of Yakutia. Wildfires and CO held culprits:

Snippage:
Quote
There was no trace of light until after 8am local time over the Verkhoyansk district in the north of Yakutia.

Almost exactly a year ago - in July 2018  - there was another pitch black morning over three major areas of Yakutia, Eveno-Bytantaisky, Zhigansky and the same Verkhoyansky district.

Darkness which had a yellow tinge lasted for over three hours and was followed by drop in air temperature. 

The territory impacted by the gloom was larger than Italy.

This time weather experts thought the blackout was caused by smoke from wildfires mixing with heavy rain clouds, and they didn’t register change in temperature
<snip>
It was a high amount of carbon monoxide in the air that sped up and intensified the process of clouds formation, said chief specialist of Fobos weather station Yevgeny Tishkovets.

‘This situation can be compared to what is happening during cloud spiking which is done to cause rain. The cloud cover was as thick as it can possibly be,  add to this the wildfires smoke and precipitation. This is still, of course, rather approximate and we need to analyse what happened in a lot more details’, he said on Yakutia-24 TV channel.

The Fobos weather centre shared two maps, one showing extremely high amounts of carbon monoxide (7,19mg/m3 while the allowed maximum is 5mg/m3) in the air, and another one confirming very high level of cloudiness.

Currently heaviest wildfires are in the south of Yakutia, with smoke moving north.

More, with pictures, from that fount of weirdness, The Siberian Times (9 August)

12
Joëlle Gergis is a lead author for the upcoming AR6, and thus her linked article offers some insight on the leading-edge of consensus climate science thinking.  Unfortunately, even such 'leading-edge' consensus climate science underestimates the climate risks associated with such issues as: a) MICI-driven ice-climate feedbacks; b) potential changes in the stratospheric ozone layer, c) cascades of tipping points, leading to potential changes in climate state; and d) probable anthropogenic actions that could make global warming worse than expected.

Title: "The terrible truth of climate change", by Joëlle Gergis

https://www.themonthly.com.au/issue/2019/august/1566136800/jo-lle-gergis/terrible-truth-climate-change

Extract: "When the IPCC’s fifth assessment report was published in 2013, it estimated that such a doubling of CO2 was likely to produce warming within the range of 1.5 to 4.5°C as the Earth reaches a new equilibrium. However, preliminary estimates calculated from the latest global climate models (being used in the current IPCC assessment, due out in 2021) are far higher than with the previous generation of models. Early reports are predicting that a doubling of CO2 may in fact produce between 2.8 and 5.8°C of warming. Incredibly, at least eight of the latest models produced by leading research centres in the United States, the United Kingdom, Canada and France are showing climate sensitivity of 5°C or warmer.

When these results were first released at a climate modelling workshop in March this year, a flurry of panicked emails from my IPCC colleagues flooded my inbox. What if the models are right? Has the Earth already crossed some kind of tipping point? Are we experiencing abrupt climate change right now?

In 2017, we reached 1°C of warming above global pre-industrial conditions. According to the UN Environment Programme’s “Emissions Gap Report”, released in November 2018, current unconditional NDCs will see global average temperature rise by 2.9 to 3.4°C above pre-industrial levels by the end of this century.

Increasingly after my speaking events, I catch myself unexpectedly weeping in my hotel room or on flights home. Every now and then, the reality of what the science is saying manages to thaw the emotionally frozen part of myself I need to maintain to do my job.

Although the very foundation of human civilisation is at stake, the world is on track to seriously overshoot our UN targets. Worse still, global carbon emissions are still rising. In response, scientists are prioritising research on how the planet has responded during other warm periods in the Earth’s history."

13
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 04, 2019, 08:26:23 AM »
Total extent drop -93.6k, it is eating into the CAB now as well (-38.2k). Here is a diff with the previous day.

Bright red/blue: loss/gain of extent (crossing the 15% concentration limit). Light red/blue:  concentration change more than 7%. 

Click for the hi-res picture.

14
Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: August 03, 2019, 07:07:08 PM »
Does anyone measure the growth rate in Greenland mass loss?
Many many people do.

Google "GRACE-FO" & search "GRACE-FO" on this forum

GRACE-FO Data just started up again (up to May 2019). See example showing big variation between basins.

Will no doubt be part of Greenland Melt year-end (end is Aug 31 i.e. this month) reports later this yr (NSIDC & DMI).
GRACE-FO monthly data should be out up to August by end September.

But by golly I wish we had access to DMI monthly temp and precipitation data by drainage basins and SMB by drainage basins. That would be an impressive data set to analyse.

I've only got precip and temp data by months to end 2016 for all Greenland- from World Bank of all places.
________________________________________________
And now a whinge.
I have posted all I know about this on this thread, What's New in Greenland, and in Satellite News for months. Sometimes I think, "Why bloody bother".
__________________________________________
ps:
I agree with P-maker, quote below.
The world  -and a good few scientists - have leapt upon this three day shocker, and is already looking for the next big thing. I have been going on and on for what seems ages about it is the length of this event - since June 10th - that matters most.

I agree with P-maker, quote below, who expresses my similar feelings much better than I can
Quote
In my deepest soul, I am genuinely shocked that this kind of media/Twitter hysteria goes on for days without even the slightest bit of reflection. I know that out there, we have seasoned observers of Arctic reality 10, 20, even 60 years ago. None of those guys are allowed to chip in at the current pace of posting. It's about time to reflect a bit and consider what we have let ourselves into.

Please cool down for a minute and let the old folks contribute. This might add some perspective instead of more details, numbers and noise.

Cheers P

15
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 02:31:03 AM »
I have already simply proven the ice was already almost about to mass melt before the GAC.

So why isn't this accepted?


It is impossible to prove what would have happened in the absence of the GAC.  You, and several others have put forth compelling evidence that the ice was already in trouble before the GAC took over.

However, it is also impossible to ignore the huge drops in extent that occurred during the GAC.  Correlation does not equal causation, but that does not mean it should be ignored. 

Common sense would dictate that if you take a lot of crushed up ice and put it in a blender and shake it around, that will have an effect.  It is less clear to me that in 2012 the halocline was breached and warm waters mixed upwards.  If that had happened we might have seen a BOE.

In any event, what makes this season interesting is that we can compare what happens to the fragile ice in the absence of a GAC with what happened in 2012. 

Of course, if the weather changes again and brings strong storms into the arctic in the next couple of weeks, that will screw up our control. 

It is unfortunate, that we have to watch this experiment play out in real time on the only planet we have. 

16
Consequences / Re: Heatwaves
« on: July 29, 2019, 06:01:51 PM »
Here is a link to the Roy Scranton opinion piece. Thanks Vox,

https://www.technologyreview.com/s/613343/lessons-from-a-genocide-can-prepare-humanity-for-climate-apocalypse/

ps . There is a reference to " The arctic death spiral ". I always think of Jim Pettit's graph so named.

Had to fix Jims name, apologies .

17
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 29, 2019, 05:47:46 PM »
It has taken a lot of time and energy, successes and failures to build a library of spreadsheets and data sources. So it is a bit annoying to think people have to wade through a load of clutter to reach the data.

This is a data thread. So, please please please bring data or a new way of looking at the data (when discussion is great).
If not, bugger off.
____________________________________-
Meanwhile,

The Chukchi and the ESS continue to astonish. Observe how the graphs do not just deepen, they widen, with the profile switching from a V to a U shape. Big effect on AWP.

and even the Greenland Sea is instantly responding to no drift down the Fram.

18
Yet another positive ice-climate feedback mechanism that consensus climate science has previously underestimated; in that the linked research indicates that Alaskan tidewater glaciers are losing mass 100 times faster than previously assumed:

D. A. Sutherland et al. (Jul 2019), "Direct observations of submarine melt and subsurface geometry at a tidewater glacier", Science  26, Vol. 365, Issue 6451, pp. 369-374
DOI: 10.1126/science.aax3528

https://science.sciencemag.org/content/365/6451/369

Abstract
Ice loss from the world’s glaciers and ice sheets contributes to sea level rise, influences ocean circulation, and affects ecosystem productivity. Ongoing changes in glaciers and ice sheets are driven by submarine melting and iceberg calving from tidewater glacier margins. However, predictions of glacier change largely rest on unconstrained theory for submarine melting. Here, we use repeat multibeam sonar surveys to image a subsurface tidewater glacier face and document a time-variable, three-dimensional geometry linked to melting and calving patterns. Submarine melt rates are high across the entire ice face over both seasons surveyed and increase from spring to summer. The observed melt rates are up to two orders of magnitude greater than predicted by theory, challenging current simulations of ice loss from tidewater glaciers.

See also:

Title: "Alaskan glaciers melting 100 times faster than previously thought"

https://www.nationalgeographic.com/environment/2019/07/alaskan-glaciers-melting-faster-than-previously-thought/

19
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 11:52:06 PM »
I'll try cropping it first.
Thanks.

Voila! Side-by-side July 1-26, 5-day lagging median (left) vs. original (right).

Click to animate.

20
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 25, 2019, 09:25:43 AM »
Quote
You do know that there are no "sources" of cold?

Of course there are sources of cold. If I have a glass of warm water and I need a source of cold I just go get some ice and throw it in.
<Snippage>

OK, while creative, not really A Thing.

You don't really have "sources of cold" any more than you have "sources of vaccuum".  What "cold" indicates is a difference in enthalpy - net heat content components of a system, and thanks to the laws of thermodynamics heat will attempt to equilibrate across it - thus your ice cubes melting. 

There wasn't any "cold source" here, just the heat of varying levels being redistributed.

This does bring me to a point which I feel people have been overlooking.  It unfortunately is one for which we probably have the least instrumentation for - net enthalpy of the Arctic ocean and surrounding seas.

*This* will be the key factor in the tipping point.

Insolation year over year is virtually constant.  How much heat is retained or lost is a factor of our GHG levels and import from outside the Arctic during the refreeze.  There is in fact a calculable maximum possible loss which can be determined via calculation of black body radiation per square meter.  That can go up, but only if the temperature of the atmosphere goes up.

Further, once you have ice, and then snow cover, the rate of heat flow out of the ocean goes down again. Temperature drops and decreases the flow out of the atmosphere - or the heat source changes by way of the thermal gradient driving more import of heat into the arctic via broad scale convective atmospheric circulation from lower latitudes.  When that happens - as we've been starting to see, possibly as far back as the 1990s - the imported heat replaces the losses which normally would come out of the ocean, and enthalpy increases. 

So it has been for several years also that I've started becoming a much closer student of winter refreeze and weather conditions, and to a lesser degree have been trying to better understand the changing dynamics of current and salinity.  I have a very long way to go.

These I think more than summer melt are the real players - behind the scenes, pulling the levers of the secondary stuff we focus a lot of our attention on.

So again, when a BoE occurs, a great deal else will need to have happened to make it possible.  The net sum of those changes will already be driving, have been driving climate changes which are not reversible without our finding a way to dump petajoules of heat out of the ecosystem. 

The state of the ice will be a side effect of that, and while no doubt a BoE will help dump more heat into an already overwhelmed system, it will be stacking it on top of an already monumental pile.  Absent of this any BoE is simply an anomaly which the system would swallow and then rapidly return to where it was previously. 

In a small way, that is *exactly* what we saw in 2012.  We were all convinced in 2013 that the End Was Nigh, and there were lots of scary moments which ended in... a bounce back.  The heat content of the system at the time is exactly why that happened.  If the area loss was the key to tipping the system over, that should have done it, but it didn't.  To be clear, I'm not trying to minimize the cascading effect of 2012, which was huge, but rather to put it into what I think is correct context.  In that regard, I think if we want to understand the most key drivers behind 2019, we need to go well past 2012, probably at least another decade, possibly two in order to find the build up which led us to where we are now.

So right now you are witnessing the history of previous winters playing out.  There is excitement, driven in part by weather, much as in 2012, but again, now as then I think it is the heat the system started with in May that is the hidden power behind what is playing out now.

(Edit:  Looking for papers on Arctic Ocean heat content, I found this, which helps partially illustrate where I was trying to take my point.

https://advances.sciencemag.org/content/4/8/eaat6773

)

21
Sig


That's one hell of a graph. I've never seen anything that shows the rebound years so vividly.


Terry

22
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 22, 2019, 10:35:15 PM »
<various snippages>
I did not say that a BOE is a huge danger. On the contrary, I think I made it abundantly clear that I think a BOE is a non-event.

The ongoing loss of Arctic Ice is not a BOE, and it is the ongoing and continuing loss of Arctic Ice that is already having dangerous effects and will only get worse as more ice is loss. Irregardless of an eventual BOE.
On this, I have to say I'm in concord with binntho.  For all of our wrangling over what is an entirely symbolic metric threshold (1000km3 of ice), it is an effect, rather than a cause.

That cause - general heating of the Arctic climate - is already generating cascading failures in the biome and through teleconnections wreaking havoc all across the northern hemisphere.  One need go no further than news of massive animal die offs, massive floods, crushing heat waves, and images of half of Siberia under wood smoke to validate this.

This will no doubt scale with time, but reaching the specific above mentioned threshold will not mark nor prompt any abrupt transition that isn't already well underway, nor already having pronounced effects on the world.

The rest of it - the personal charges of denialism et. al. - are value judgements, and are really out of place here.

Gentle sentients, can we please return to the discussion of science rather than tearing at each other?

23
Northernmost Alaska.
Quote
Rick Thoman (@AlaskaWx) 7/21/19, 9:43 PM
The Chukchi Sea offshore of Utqiaġvik has been largely #seaice free since early June and July is sure to have 0% ice coverage. The change in July extent since the 1990s is astounding. Sunday PM photo courtesy @IARC_Alaska. #akwx #Arctic
https://twitter.com/alaskawx/status/1153118308083703808

24
Consequences / Re: Climate change, the ocean, agriculture, and FOOD
« on: July 22, 2019, 09:16:24 PM »
.. that is rather similar to 'weeds' that are regularly mown .. Dandilions will soon become prostrate in leaf and flower .. I always use this example when I am assured plants have no memory or intelligence . b.c.

25
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 19, 2019, 01:44:15 PM »
An average melt won’t break records - just like an average 2012 wouldn’t have from here. It takes something exceptional to break records - with seven years of additional CO2 and heat, that something may not need to be quite as exceptional as 2012 - but still exceptional, IMO.
When just an average of the last 10 years melt from now would produce a 2nd lowest extent (and area) it does tell you the ice is in a pretty bad state.

It will only need area loss from now to be above average by 9% to produce a new record area low.

If volume loss from 30 June to minimum is merely average, volume will be lowest in the satellite record by a whopping 10%.

When things look dodgy even in a year that is not exceptional, you know the ice is not looking in good shape..

26
Arctic sea ice / Re: The 2019 melting season
« on: July 18, 2019, 09:54:16 PM »
The storage of heat in the basin proper via the Chukchi pathway is a big concern (some research has pointed to that fact recently). Eventually that heat will build up and disrupt the halocline and years like this, where summer SSTs have soared, aren't helping.

That is why the freezing season might even be more interesting than the melting season. The past 2-3 years saw a big change in the behaviour of the Bering/Chukchi. If they become like the Barents then one of these years the attack of the CAB will start one month earlier than usual and that might be enough to kill it...

That's probably how it will go down. The changes in the Chukchi and Barents/Kara in the long run are the lynchpins because they allow shoaling of warm Pacific and Atlantic waters. Once they warm and shoal enough, they will be able to attack from the bottom and eliminate summer sea ice earlier and earlier in those regions (with variability, of course). Add in a bad weather year and that will likely prove the tipping point. 2016 was probably 2 weeks away from having a remnant rump ice pack similar to how it will look in the future.

27
Consequences / Re: Hurricane Season 2019
« on: July 10, 2019, 08:06:53 PM »
Parts of New Orleans Are Flooded. Worse Is on the Way.
A brewing storm surge could elevate the Mississippi River to 20 feet above sea level—as high as the levees that protect the city.
Henry GrabarJuly 10, 2019 12:23 PM
Quote
There was quite a lot of water in the streets of New Orleans on Wednesday morning, thanks to intense thunderstorms that prompted the National Weather Service to issue a “Flash Flood Emergency” warning. Parts of the city received nearly a foot of rain before noon, turning neighborhoods that rarely flood into canoe routes.

Those scenes offer a preview of what’s to come later in the week, when a tropical depression is projected to turn into Hurricane Barry and make landfall on the Louisiana coast as a Category 1, dropping as much as 2 feet of rain in some parts of the state.

New Orleans has long had a problem with rainfall flooding, since much of the city sits just above sea level, and a good part of it sits below. Enormous pumps were a big part of the city’s $14.6 billion storm protection upgrade after Hurricane Katrina hit in 2005, and their struggles are a subject of citywide scrutiny every time it rains. Topographically, New Orleans is often likened to a bowl, but it’s more like a waffle, with pockets of low ground that fill up with just a few inches of rain.

A rain forecast like Barry’s is never welcome news in New Orleans. But what makes this storm particularly ominous is that it comes at a time when the Mississippi River in New Orleans is just below flood stage, an unusual and unprecedented development this late in the year. As I wrote in June, the river—swollen by a record year of rainfall in the Midwest—has never been so high, so long. A few feet of rain and a midsized storm surge are projected to bring the river to a height it hasn’t hit in more than 90 years, reaching the top of the levees. Another foot would cause river water to crash into the neighborhoods below. Katrina hit when the river was running at 3 feet; it currently sits at 16 feet.
...
The levees top out around 20 feet; storm surge on the Mississippi is projected at 20 feet. If the forecast stands, at least some water will overtop the levees along the banks of the river.
https://slate.com/business/2019/07/new-orleans-is-flooded-in-some-neighborhoods-and-a-storm-surge-is-coming.html
Photos, tweets and a flood graph at the link.

28
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 10, 2019, 07:18:10 PM »
- Extent loss on this day 182 k, 92 k more than the average loss on this day of 92 k.

92+92=182?

consider how many numbers (data) the man is turning over each day for our all benefit,
such hints can be made a bit more friendly in my opinion.

29
For these polls, I make my choice when they open, and don't change it.  It's supposed to be a prediction.  So I picked "Between 2.75 and 3.25" and I'm standing pat.

30
My best achievement on this forum ever was the email that I, Mr. nobody, wrote Dr. Zhang in 2017, explaining that PIOMAS numbers were eagerly awaited by all, and perhaps they could release the data twice a month. He wrote back sure, they'll try to do a mid-month update. And ever since, they did. I guess no one ever thought to ask...

31
Arctic sea ice / Re: The 2019 melting season
« on: July 04, 2019, 09:09:24 PM »
That is not a real chart of july 3rd. It would mean a BOE within two weeks.

this is:https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_nic.png
The truth is somewhere between in this case I think.

We know there is a substantial amount of MYI spread out in that "thin" area shown.  Over the winter, it was divided, and divided again, with spaces between filled in with ice which now is rapidly being converted to soup... that's what the consistent 100K+ drops in area are telling me, especially when coupled with far more modest drops and occasional increases in extent.

It certainly isn't going to flatline in a BoE, but I'm expecting CAPIE to make a hole in the floor.  It could lead to this paradoxical outcome... 2nd - 4th lowest annual extent while having lowest annual area.

32
Science / Re: 2019 Mauna Loa CO2 levels
« on: July 04, 2019, 04:34:19 AM »
Apocalypse For Real has a posting about rate of CO2 increases on his blog. Well worth a look.

http://www.megiddo666.apocalypse4real-globalmethanetracking.com


"The change from 210 to 280 ppm (emerging from the last ice age to beginning of the Industrial Revolution) took 15,900 years.
The change from 280 ppm to 350 ppm (reached in 1987, when the international community and energy industry unequivocally knew that emissions were going to cause a problem for human society) took only 202 years.
The last 60 ppm increase (350 to 410 ppm) has only taken 32 years. This has never happened in 800,000 years. In fact, in the ice core data there is no record of a 10 ppm increase in 39 years - until human emissions impacts in the 1900's.
Global CO2 concentrations have never increased by 10 ppm in 47 months. There is no comparison in 800,000 years of ice core data. Nothing in paleo-climate proxies. Only in models with polynomial, or exponential, curves.

We are in uncharted "terror incognita" (pun intended)."

33
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 26, 2019, 12:28:03 PM »
Jaxa AMSR2 Arctic sea ice volume calculated by Wipneus
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf

34
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 25, 2019, 09:13:56 AM »
JAXA ARCTIC EXTENT :-  9,597,909 km2(June 24, 2019)

- Extent is 5th 6th lowest in the satellite record.
- Extent loss on this day 61 k, 16 k less than the average loss on this day of 77 k.
- Extent loss from maximum 4,673 k, 134 k (3.0 %) greater than the average of 4,539 k loss from maximum by this day,
- On average 45.9% of the melting season done, with 81 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.26 million km2, 4th lowest in the satellite record, and 1.08 million km2 above the 2012 low of 3.18 million km2.
Looking at the last 5 years average remaining melt gives a result of 4.36 million km2, 6th lowest, and 1.18 million km2 above 2012.

Other Stuff

Until the weekend GFS showing  temperature anomalies at +0.9 to +1.9 degrees celsius. During this time the images suggest high +ve anomalies in central and eastern Siberia, with contrasting and sometimes strong -ve anomalies for most of the time on land and coastal sea by and in the Beaufort/CAA and Western Siberia, and in contrast again mostly +ve anomaly over most of the Arctic Ocean.

Over the weekend the picture changes somewhat. By Monday the CAA gets warmer, NW Canada and Alaska get a lot colder, and on the Russian side warmth moves west into areas bordering the Laptev and Kara, while the ESS area switches from strong warmth to a cold snap. However, over the Arctic Ocean itself there is a modest +ve  temp anomaly. Overall the Arctic temp anomaly stays well below 1 degree celsius.

A complicated picture.

We are now entering the period of maximum daily extent loss that lasts until mid or late July and then very gradually declines.
Apart from 2 days, over the last 3 weeks and more extent loss has been below or well below average.
_____________________________________________________________________
The volume data for June should be available by late next week. It will be interesting to see what has happened to volume and perhaps more importantly, thickness during this month.

35
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 24, 2019, 05:51:47 AM »
Pragma, thank you.  But all the credit has to go to the NSIDC, they can be obtained here:

http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/

I think they are amazing too, and I am glad to bring them before this forum if they have not previously around.
They are great, so thanks NSIDC for this work and also, thanks Pagophilus for let us (me?) know about this graphs!  :)
(I think I saw them before, but I didn't remember...)
______________________________

[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.
 
June 23rd, 2019:
     9,658,561 km2, a drop of -69,506 km2.
     2019 is 5th lowest on record.
     (2012 highlighted).

36
At least the US House of Representative realizes that we are already in a 'Climate Crisis':

House Select Committee on the Climate Crisis

https://climatecrisis.house.gov/

37
Notice anything unusual in this year data in the attached plot of Greenland Surface Ice Melt Extent Area thru the second week of June 2019?

38
The first linked reference indicates the relatively unique relationship between the African rift valley and the West Antarctic Rift, WAR, established about 180 million years ago as Gondwana (Pangaea) split apart (see first and second images).

http://www.luomus.fi/en/largest-lava-eruptions-earth

Caption for the second image: " Schematic cross-section of the Karoo continental flood basalt province c. 180 million years ago. 1) Mantle melts extensively and the 2) melts intrude the lithosphere (=crust + brittle upper mantle), where they form large magma chambers and mix with it. 3) The contaminated melts proceed upwards and 4) erupt from shield volcanoes or fissures. 5) Some rare melts do not assimilate lithosphere and preserve the original mantle-derived geochemical signature. Image: Luomus / Jussi Heinonen"

Quote: "Our latest findings indicate that the enormous melt generation was caused by at least two processes: 1) Gondwana supercontinent functioned like a "lid on a cooking pot" and prevented the cooling of the sublithospheric mantle. High amount of accumulated heat caused more efficient melting of the mantle (Heinonen et al., 2010). 2) Some portions of the sublithospheric mantle were relatively Fe-rich and melted more efficiently than ambient mantle materials. Such portions were formed by mixing with ancient parts of oceanic crust that sank in to the mantle at subduction zones (Heinonen et al., 2013, 2014)."

Furthermore, the second linked reference shows how the sub-lithospheric interconnection between Africa's rift valley and WAR may have changed with some interconnection possibly being maintained via mantle plumes, such as beneath the Erebus volcano (see the third and fourth images).  Thus as the WAIS loses ice mass, we may witness changes in mantle dynamics as far away as Central Africa and South America:

Philip J. Heron (19 November 2018), "Mantle plumes and mantle dynamics in the Wilson cycle",
Geological Society, London, Special Publications, 470, https://doi.org/10.1144/SP470.18

https://sp.lyellcollection.org/content/early/2018/11/16/SP470.18

Caption for third image: "A cartoon of a simple supercontinent, the starting point for this review. Step 1, a supercontinent is amassed through a super-downwelling. Step 2, subduction then forms on the margins of the continent, generating sub-continental plumes due to mantle return flow and warming of the mantle through continental insulation (step 3). Step 4, the continental plumes facilitate the dispersal of the supercontinent."

Edit, see also Replies #: 101, 102, 103, 113, 115, 117, 147, 167, 168, 170, 172, 178, 442, 900 & 1,149.

39
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 06, 2019, 06:09:36 AM »
I made an analysis today, with the drops from June 4th to June 13th. It is interesting, because 2012 drops an average of 125.5K km2 on these 9 days, while the leader [2016] only drops 28.18K km2.

The result: 2016 continues to be the lowest on record on June 13th, but 2012 changes from being the 12th lowest on record, to become the 2nd lowest.

More interesting, 2019 needs to drop an average of 47.2 K km2, to become the lowest on record on June 13th. Will it happen? Today’s drop of 44 K km2 is only 3.2K km2 lower of what it is needed.

I think that 2019 can be the lowest on record on June 13th. Any bets?   8)


Edit: The true is that I am concerned. Not a smile at all.

40
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: June 05, 2019, 10:27:48 PM »
I think we all see the same thing here: The loss flatlines and even seems to drop. Which may very well be indicative of a real state change and not a statistical fluke. I think it may very well be the former, but the datapoints are too few to statistically validate any change in trends.

I think the  loss flatlines (in the case of the Arctic) because total winter extent vs loss is reaching a hard limit - zero - as to how much ice is left over at the end of the melting season.

We have seen a decline in melt season total loss of extent and volume, but that remaining volume is (1) harder to reach and increasingly (2) isn't replaced during the refreeze.

The sun reaches the 80N at the same time, and has the same effect, but there is less ice at lower latitudes.

My instinct now is to watch the winter numbers more closely than summer's, as that's were I think the real harbingers to our first BoE will show up.

41
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 05, 2019, 10:14:38 PM »
I explain it that way:
The August/Sept/Oct (ASO) (minimum) decrease from the 1980s to the 2010s is larger than the decrease of the other months. Therefore the anomalies from the average in ASO are larger at the beginning (positive spikes) and at the end (negative spikes) of this time series than in the centre of the graph. Around 2000 these anomalies are not so prominent, as they represent more or less the average of the whole data pack.

42
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 05, 2019, 12:55:19 PM »
.. hi .. Gerontocrat .. I would appeal for 2016 to remain .. it is still the front runner for the next month . 2018 on the other hand .. :) . b.c.
I am keeping 2016 on graph Arc4.
The change is to the daily change graph Arc2. Adding any more years makes it look a total mess.

43
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 05, 2019, 06:20:20 AM »
Thank you so much for what you do Juan!  The last thing I do every night before I go to bed is check for your post.  If It gets difficult for you to post the numbers we all understand. 

Thank you again for your great contributions to this forum!


44
Arctic sea ice / Re: The 2019 melting season
« on: June 04, 2019, 01:50:55 PM »
Dr. Jeff Masters (Wunderground-Cat6) is referencing Neven's ASIF ...

Well, let me return the favour.  ;)

Here's the most pertinent quote:

Quote
The latest GFS model forecast suggests that the Arctic high will drift to a location a few hundred miles north of Alaska by mid-June and remain strong. This position and strength is characteristic of the Arctic dipole anomaly, which features unusually high pressure over the Arctic Ocean north of North America and unusually low pressure over northeastern Eurasia. This pattern brings in warm southerly winds along the shores of the East Siberian and Chukchi seas, which favors strong ice melt in these sectors and pushes the ice away from the coast, leaving open water. The pressure pattern also causes loss of Arctic sea ice due to winds that transport of ice out of the Arctic Ocean and into the North Atlantic through Fram Strait, to the east of Greenland.

Indeed, and ECMWF shows the same. Three more days of 1035 hPa over the Beaufort, and then lows are coming into play as well. We'll see what that does to ice colour, especially on the Siberian side.

45
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 04, 2019, 06:55:50 AM »
In case Juan can't make it tonight (JAXA was very late in posting):

[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

June 3rd, 2019:
     10,558,744 km2, a drop of -34,927 km2.
     2019 is 2nd lowest on record.

46
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 03:39:59 PM »
gerontocrat and Juan

keep doing what you do...it is why I visit this thread daily.

47
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 10:53:32 AM »
A book-keeper's response (Be humble, Gero, be humble)

Someone posted that without my postings, there would be no thread.
NOT TRUE. I've only been around for a couple of years on this forum.
Many have exhausted themselves putting info on this thread before myself and Juan, and many more will do so in the future.

The title of the thread is "2019 sea ice area and extent data", not "When will the Arctic Go Ice-Free".

My guess on the latter is a BOE before 2030 - but mainly based on volume declining much faster than area, leading to a tipping point when average thickness is low enough for a massive area loss. But that discussion belongs on the other threads.

I believe a BOE this year is in the realms of vanishing probabilities. History does give us the limits of melting from now to minimum.
- The maximum is about 23% above (the 10 year) average - in 2012 - but from a starting extent nearly 0.8 million km2 above 2019's extent as of now. Even this would give a minimum of 2.45 million km2, hardly a BOE.
- The next highest melt from now was in 2007, +9.5% above average, giving a minimum of 3.3 million km2, just above the 2012 record low of 3.18 million km2.
- The 5 previous years melt from now were all below average.
- Temperatures, though above average and over the entire Arctic Ocean, are not hugely so.
-And, yesterday Tealight updated his May volume stuff on https://cryospherecomputing.tk/SIT.html Volume about 3rd lowest, average thickness up at 1.8 meters.

So, what is my guess for the immediate future. Melt will continue, at average, or maybe a bit above. One or more seas (e.g. the Chukchi) will accelerate their change from ice deserts (with occasional open water periods) to open water seas (with occasional icy periods).

Armageddon will be postponed for another year, though a second lowest minimum is on the cards.

2012
2012 did its first collapse in JAXA extent from the 5th to the 13th June. On the 5th I will change graph Arc2 to show the 2012 daily change and dump 2016.
_____________________________________________________
The book-keeper returns to his quill pen and Kalamazoo ledger

And that's all I am going to say about that

48
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 09:59:58 AM »
JAXA ARCTIC EXTENT :- 10,671,125 km2(June 1, 2019)

- Extent is 2nd lowest in the satellite record, 266 k > 2016, 150 k < 2018.
- Extent loss on this day 98  k, 43 k more than the average loss of 55 k on this day.
- Extent loss from maximum 3,600 k, 455 k (14.5%) greater than the average of 3,145k loss from maximum by this day,
- On average 31.8% of the melting season done, with 104 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.94 million km2, 2nd lowest in the satellite record, and 0.76 million km2 above the 2012 low of 3.18 million km2.

Looking at the last 5 years average remaining melt only gives a result of 4.18 million km2, 4th lowest, and 1.01 million km2 above the record low of 2012.

On 22nd April, 2016 started its 2 months as the front runner with steep declines in extent.  To become lowest again, 2019 will have to match or exceed the above average extent losses of 2016 from now until at least mid-late June. For that reason I have removed 2018 daily change and replaced it with 2016 data on graph Arc2.

 Later this week that will be replaced with 2012 as it becomes the front runner (see next post).

Other Stuff

GFS shows temperature anomalies varying from +1.7 to +2.9. The sheer persistence of above average temperatures across most of the Arctic that has existed for a good while, should reinforce that 2019 will be a continuation of the 2010's decadal decline in sea ice extent and area.

However, at the moment little reason to suppose sea ice extent loss will be at much above average in the immediate future, despite the high extent loss on this day.
_________________________________________________________
ps: This year GFS has not seem to me be be "running hot". On the data I use, temperatures and precipitation, it seems to be pretty good at least to 5 days out. Last year it did seem to me to run hot, especially towards the end of the forecast period of 10 days.

pps: As the June poll is underway, I have promoted the projections table Arc1 to the top of the attachments.

49
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 09:19:10 AM »
Don't know much about keeping boos but I am very thankful for Gerantocrats excellet bookkeeping and look forward to his posts every day!

50
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 07:09:34 AM »

It seems like gerontocrat's daily projection that ice losses will not exceed historical averages belongs in the melting season thread where that point of view can be debated.

This is the bookeeper thread, not the analysis thread.

Without gerontocrat's contribution to this thread, it wouldn't exist.

Pages: [1]