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Messages - uniquorn

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1
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 03:03:07 PM »
Building on uniquorns nice code. (current date only)

2
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 01:56:51 PM »
Quote
Winter is finally here, Kotolny Island is really cold!
No it isn't. The quite moderate 10 day forecast is attached below. The icons indicate extent of cloud cover which affect radiative balance. The weather station reports 2m temperatures but those are relative to its elevation of 8m above sea level.

http://www.aps-polar.org/mv_html/j00001/2015-02/20150206_APS.htm congelation land-fast ice

While ECMWF and GFS assimilate this station in their regional forecasts (and CR in turn), it's not at all clear which hPa over the Laptev (925? boundary layer?) is most relevant to the cold experienced by open water (near-surface air is somewhat clamped to surface water temperature).

GFS is currently reporting air temperatures of -4.5, -4.7, -15.9 at the surface, 1000 hPa, 850 hPa respectively at UTC noon today. These bear no immediate relationship to highs or lows at Kotolny (-12. -7).
Quote
Can buoys in Laptev validate or improve on SST measurement
That 204672 buoy is in a good location but it does not currently appear in IADP's table!
https://iabp.apl.uw.edu/TABLES/ArcticTable.php

However 204761 and 204762 do: these are global drifters of type SVP-B, placed by AARI-USIABP (Russian Arctic and Antarctic Research Institute joint US Interagency Arctic Buoy Program). The former is at 75.23 114.88 on 10/25/2020 measuring water temperature at the bottom of the buoy at 0.96ºC. The latter is at 76.78 118.34 showing 1.68ºC.

It seems like 204763 and 204764 are also worthy of consideration. These are at 76.70 111.48 showing -1.68ºC and 79.90 121.38 seeing -0.80ºC. Uniq has picked these up in #538 below.

"These SVP (surface velocity drifters) were standardized in 1991 with small spherical hull, floats and large Holey-Sock drogues 15m below the surface. In 1993, drifters with barometer ports, called SVPB drifters measure sea surface currents, sea surface temperature baryometric pressure and lat/lon."

The hourly data is in .dat format which opens as tab-ready row & column in any text editor. It uses day number instead of dates: 299 is today Oct 25th. The most recent 557 readings from 204761 average 1.36ºC with a range of 0.58 to 4.08 ºC and stdev of 0.97, that is, the buoy has not seen any temperatures below zero and has mostly been around 1.4±1.0 ºC during its drift.
Quote
Do direct buoy measurements provide an independent check on the daily SST product from GHRSST?
More likely, the buoy data is assimilated into the product but that's unconfirmed.
Quote
Can radiative heat loss be determined from Worldview?
No. Clear weather allows that dramatic definition of heat loss leads via band 15 of Suomi VIIRS along the upper CAA. Note this is calculated from top-of-atmosphere in kelvin and is not suitable for determining overall blackbody heat loss:

"It does not provide an accurate temperature of either clouds nor the land surface, but it does show relative temperature differences which can be used to distinguish features both in clouds and in sea ice and open water over the polar regions during winter (in cloudless areas).... The sensor resolution is 375m, the imagery resolution is 250m, and the temporal resolution is daily."
Quote
How unusual is the current pattern of open water?
The image below calculates the frequency of open water at each position on Nov 1st for the seven years 2013-19 (this date in 2012 is not available from AMSR2_UHH). This gives the lightest gray for open water in all seven years, a slightly darker gray for open water in six of seven years and so on. The progression is fairly orderly Chukchi; the Laptev has mostly been frozen over. The pink shows areas that have never before been open on Nov 1st.

The base image is Smos-Smap ice thinness for Oct 23rd. It has an interesting green fringe of presumably nascent ice in the 2-3 cm thinness range. The interior ice thicker than 0.5m has been replaced with OsiSaf ice motion for the same date; the exterior open water has been removed to reveal the historical open water probabilities.

3
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 12:52:51 AM »
Here is the Oct 23rd situation. Panoply makes a quite decent no-click map out of GHRSST data with a little help from AMSR2_AWI, OsiSaf and Gimp. Click to see at full resolution of the data source. Note this is SSTfnd, not skin or subskin temperatures. The contour lines correspond to tick mark bins in the palette.

What this is saying is the open water is far too warm from the surface down to 10m depth to even be talking about ice forming without really cold air. Right now, the 2m air temperature at 85º on the 140th meridian connecting the NSI to the North Pole is -2ºC. Please remind me to make a new map when it is has been -35ºC for a couple weeks!

Late fall temperatures seen by the Polarstern:
https://www.awi.de/fileadmin/user_upload/MET/PolarsternCoursePlot/psobsedat.html


20201023000000-OSPO-L4_GHRSST-SSTfnd-Geo_Polar_Blended_Night-GLOB-v02.0-fv01.0.nc

4
The rest / Re: SpaceX
« on: October 23, 2020, 02:46:56 PM »
—- Lunar Starship mockup?
Quote
Austin Barnard (@austinbarnard45)10/22/20, 12:41 PM
NASA Artemis Moon lander anyone?
https://twitter.com/austinbarnard45/status/1319318065872556035
Austin Barnard: Yes this is real,
Austin Barnard: No this is not for flight, my best guess is this will be a mock up lunar variant for the starship presentation.
#Artemis

More photos:
https://twitter.com/austinbarnard45/status/1319387277748019201

https://twitter.com/superclusterhq/status/1319387578026676224

5
Find me another single month that is split at 500mb in the NH as I have shown repeatedly and I would reconsider this stat as a measure of anything.  feel free to adjust the scale, it may be not what I am imagining.

pointing at a massive average of the geopotential heights is not yet useful, and when it becomes apparent that annual or even seasonal averages are split at 500mb, I'm not confident we will retain the capacity to observe it.

The Earth is still round.. Is that the test?

Is splitting at 500mb a useful test?  It's a valid question.

6
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 20, 2020, 12:17:58 AM »
Quote
Effect of storms and high winds on freeze open water?
Whatever the actual effects, we are quite limited by available observables in terms of validation. As with the 2012 GAAC controversy, there is no control on what would have happened without the GAAC.

Consequently even if we had seen SST change here, attribution to the storm is problematic. Here the highest winds and swells did not hit the ice pack head on which has been required for major damage in the past. OsiSaf is showing a distinct anti-cyclonic rotation but has no motion coverage of open water (but see CMEMS).

The first image below maps out where it is currently cold enough to bring surface sea water to -1.8ºC. This would have to persist a very long time without wind to actually freeze anything. Here GFS nullschool doesn't offer SST contouring so it has to be done from a screenshot with wind turned off in Gimp GMIC, then labelled multiple times with green circle site data. A lot of the 'upper half' of the Arctic Ocean is just not cold enough yet.

The slide show looks at entrained Pacific Ocean moisture intrusion via total cloud water (TCW) which is determinable from satellite. The height of the cloud deck above the water surface is not available but presumably low; this property had to be measured during the Mosaic expedition.

This event brought in a gale force jet, matching the maximum the Polarstern encountered during its year. Moist low clouds can completely offset blackbody cooling of the surface but not evaporative, convective, conductive or mixing effects which potentially could be much larger.

Following moist intrusions into the Arctic using SHEBA observations in a Lagrangian perspective
S. Mubashshir Ali  Felix Pithan  19 June 2020
https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.3859 free full

"Warm and moist air masses are transported into the Arctic from lower latitudes throughout the year. Especially in winter, such moist intrusions (MIs) can trigger cloud formation and surface warming. While a typical cloudy state of the Arctic winter boundary layer has been linked to the advection of moist air masses, direct observations of the transformation from moist midlatitude to dry Arctic air are lacking.

Moist intrusions are usually triggered by an anticyclonic blocking‐like feature to the east and a low‐pressure system to the west and also linked to Rossby wave‐breaking events (Liu and Barnes, 2015). MIs cause strong downward long‐wave radiation due to a high localised concentration of water vapor which can lead to anomalous surface warming over land or sea ice."

7
Arctic sea ice / Re: Latest PIOMAS update (Oktober, mid-monthly update)
« on: October 18, 2020, 07:14:14 PM »
Some people have good use for the updated regional data files.

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz

8
Arctic sea ice / Re: Latest PIOMAS update (Oktober, mid-monthly update)
« on: October 18, 2020, 07:11:44 PM »
The Fram volume export graph. Looks are a bit different this time  after upgrading the plotting software (matplotlib), probably needs a bit of tweaking.

9
Arctic sea ice / Re: Latest PIOMAS update (Oktober, mid-monthly update)
« on: October 18, 2020, 07:02:21 PM »
Here are the volume and volume-anomaly graphs.

10
Arctic sea ice / Re: Latest PIOMAS update (Oktober, mid-monthly update)
« on: October 18, 2020, 06:59:10 PM »
PIOMAS has updated the gridded thickness data upto day 289 (15th or 16th of Oktober). Volume calculated from thickness on that day was 4.91 [1000 km3]. That is the second lowest value for day 289. The difference with the lowest (2012) is very small though.

Here is the animation for Oktober 2020 sofar.

11
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 15, 2020, 05:41:55 PM »
I think it is worth remembering we are living on Earth not Mars... We have a layer of gas above ours heads which is not transparent to IR. Even in the old, dark, dry Arctic of the past it was impossible to radiate an infinite amount of heat to space. There is always an upper limit. A temperature inversion in the low layer, even in Siberia in the 1880s could not have been greater to ~ -25°C. At some point, even in an absolutely dark and dry Arctic a point of equilibrium will be reached. And on top of that amount of heat lost to space is not primarily a function of the temperature at surface, it is not the case, definitively. The temperature at surface is not totally decorrelated from the heat lost to space of course. But there is an atmosphere above surface, in the end. It is Earth here, not Mars... Heat has to go trough the atmosphere before, and there is on the road CO2, CH4, H2O in every states possible, etc... And now that Arctic is providing a lot of heat and moisture, we are seeing a new state where there is a layer of clouds and moisture in the low layers which is isolating the surface, with temperature between 0 and -5°C at 2 meters versus -20°C to -30°C at 2 meters in the case there is no clouds.
Holy mother of Einstein, it is Earth here, not Mars !
The picture which follows is the forecast for Saturday for a given model. It is the minimum for the temperature of brilliance in infrared (10.8 microns) for the all day. Scale is from blue for the warmest (~0°C) to white (~ -40°C) going trough the brown / beige / I don't know which color (-10°C to -20°C). There is also the isolign for the surface temperature of -2°C to roughly approximate the edge of sea ice (more or less, we all see what the shape of sea ice currently). Over Beaufort, yes we are radiating at 0°C (blue color) and we are losing heat to space. But over Chukchi, ESS, Laptev, Kara, Barents, we have a layer of clouds as thick as the troposphere. And the temperature of brilliance is -20°C to -40°C. The temperature of brilliance is more directly correlated to heat lost to space than surface temperature. This really means, this really means, that during the storm, we are not going to radiate heat toward space at ~0°C from the ocean. We are going to radiate heat at -20°C or -30°C or -40°C. And there is a factor 1.5 to 2 between the radiation from a black body at 0°C and a black body at -30°C or something. The heat stirred by the storm is heat at ~0°C, the heat lost to space is heat at -30°C, and there is a ratio of 1.5 to 2 between the two... I made the same map but with the mean of the IR temperature from Friday to Thurday. The ice sheet is high and dry, radiating at -30°C and isolating the ocean at 0°C below. The Beaufort is, yes, a good heat sink fully radiating toward space. But for the siberian side, the clouds are here as the ice sheet, isolating the surface below. Even with a mean over 5 days, almost all the siberian side is forecasted to be isolated.

12
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 15, 2020, 03:41:17 PM »
...
There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts.

Not sure how that works.

Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space. It is not going to lead to more sea ice decline, since in the following days darkness is an almost infinite sink of heat excess until next Spring. So this weekend is going to lead to less heat stored beneath.

Where in the preceding paragraph am I wrong?

The Arctic in winter is not an infinite heat sink. Definitively NOT. There is a thing names moisture and another names cloud which is in play,

http://ogimet.com/cgi-bin/gsynres?ind=20069&decoded=yes&ndays=50&ano=2020&mes=10&day=15&hora=12

and there is also the fact that heat builds up in summmer in Arctic, and the heat transported from the tropics - a region where the bilan is strongly positive - etc. Arctic in winter is not an infinite heat sink. And never was one by the way. It is not a proof, but just look at the correlation between Nh and T at Ostrov Vize here for example :

http://ogimet.com/cgi-bin/gsynres?ind=20069&decoded=yes&ndays=50&ano=2012&mes=1&day=15&hora=12

13
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 15, 2020, 10:50:59 AM »
This is the second mentioning of "shoaling" in recent days, see also A-Teams post above:

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed ...

I understand shoaling to mean what happens to waves as the approach shallower water (shoals) . According to Wikipedia shoaling happens when depth is less than half the wavelength.

Other meanings are "becoming shallower" and also when aquatic organisms group together (e.g. a shoal of herring).

So how does that fint into the bigger picture of an open ocean as Aslan seems to talk about, and what is meant by a phrase like "shoaling of the Atlantic Waters" as in the paper quoted by A-Team?

Err I am not really good at speaking english. AW are below the halocline. With waves, mixing weakens the halocline and allow heat transfer from the AW. For me shoaling means that AW are "less deep" and nearer to surface, with increased heat flux.

For the baroclinicity, I have added the vorticity (blue, positive, and red negative) and T'w in black. We can see that near the surface, the strong inversion is associated with the gradient in wind speed. This also creates shear and then vorticity. We have, as usual, shear zone and vorticity to the left and right to the LLJ, but near the surface there is also vorticity associated with the shear zone at the interface between sea ice and open ocean. But the max of vorticity over sea ice in the lowest 500 meters is really linked to the interface between sea ice and open ocean, it is not linked to the shear due to the deceleration of wind speed.

14
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 15, 2020, 09:09:55 AM »
On top of all the retroaction already described, there is also the fact that an open ocean generate less friction, and the lack of an inversion increase even more the wind speed at surface. This is visible for the storm of Friday and Saturday. The low level jet brings stronger winds at surface over open ocean than sea ice. The cross section is from south to north, trough the low level jet for Saturday at 12Z. Higher wind speed reached the surface open ocean.

P.S. ; One important point... For the map, it is wind speed at 500m, not surface. There is two LLJs, one over sea ice and one over open ocean, but strong winds at 10m are only found over open ocean.

15
Developers Corner / Re: Test space
« on: October 03, 2020, 12:29:23 PM »
VISHOP file

17
Arctic sea ice / Re: Latest PIOMAS update (September 2020)
« on: September 03, 2020, 06:47:42 PM »
Latest thickness map compared with recent years and their differences.

18
Arctic sea ice / Re: Latest PIOMAS update (September 2020)
« on: September 03, 2020, 06:42:48 PM »
Fram volume export graph.

19
Arctic sea ice / Re: Latest PIOMAS update (September 2020)
« on: September 03, 2020, 06:41:47 PM »
Volume and volume-anomaly graphs.

20
Arctic sea ice / Re: Latest PIOMAS update (September 2020)
« on: September 03, 2020, 06:39:21 PM »
PIOMAS has updated the gridded thickness data to day 244 (31 August or first of September). Volume calculated from thickness was 4.31 [1000 km3] which is third lowest for that day (behind 2012 and 2019).

Here is the August animation.

21
Some people have good use for the updated regional data files.

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz

22
Updated Fram volume export graph.

23
Updated volume and volume-anomaly graphs.

24
PIOMAS gridded thickness data was updated to day 228 (15/16 August). Calculated volume on that day is 5.14 [1000km3], which means a third lowest place before 2012 and 2019.

Here is the animation for August thus far.

25
Developers Corner / Re: Sentinel-Hub custom rendering settings
« on: August 18, 2020, 10:49:49 AM »
Im working on a large project at the moment (Scottish snow, not Arctic stuff), but heres the mask im using;

easy distinction between clouds and ice/snow

https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=81.2492016395353&lng=-70.00167832709849&zoom=11&preset=CUSTOM&layers=B01,B02,B03&maxcc=100&gain=1.0&gamma=1.0&time=2020-01-01%7C2020-07-01&atmFilter=&showDates=false&evalscript=cmV0dXJuIFtCMDEqMi41LEIwNCoyLjUsQjExKjIuNV0%3D


You can separate ice (yellow) from clouds (white) in python with;

img = cv2.imread(directory + filename)
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
lower_range = np.array([22, 93, 0])
upper_range = np.array([45, 255, 255])
mask = cv2.inRange(hsv, lower_range, upper_range)

'mask' then becomes cloud-corrected ice, with caveats


26
Arctic sea ice / Re: The caa-greenland mega crack
« on: August 16, 2020, 07:41:41 PM »
A brief peek through the clouds of the eddies north of Ellesmere Island.
Click to run

27
Arctic sea ice / Re: The 2020 melting season
« on: August 09, 2020, 09:33:10 PM »
This remarkable freeze/melt cycle has been unfortunate but perhaps inevitable, putting us literally in uncharted waters with regards to massive climate change impacts.

It’s easy to forget, as the post-BOE forum properly notes, that once upon a time the Barents, Baltic, Bering, Baffin. Chukchi, and Kara hosted millions of sq km of year-round ice. (And that not so long ago, 1000 m thick ice gouged the Lomonosov ridgetop.) On 08 Aug 2020, 38% of the remaining ice (the Arctic Ocean basin, was open water. Vast areas of tundra are free of reflecting snow as well. We’re already well into BOE in most respects.

What’s going on at the moment is baffling, notably between Greenland and the north pole. It’s clear we don’t really understand the current physical state of the ice. Thus even if surface weather were predictable three days out, where things will end up by mid-October still remains up in the air.

However we do have a good grip on some of the pre-conditioning events that have brought the ice to its current state:

-1- The melt season really began in the previous freeze season, even earlier. Vast areas of surprisingly thin 0.3m ice remained in the Laptev when the Polarstern moored on Oct 4th. That and a slow start to freeze-up are documented by thousands of km of ship thickness transects with no graduating SYI floes thick enough to stand on for Mosaic. (T Krumpen http://dx.doi.org/10.5194/tc-14-2173-2020)

-2- The TransPolar Drift over winter, as accurately imaged in Ascat time series, bore little resemblance to recent years in two key respects: months of very rapid Fram-ward displacement and extensional engagement of ice to the pole and beyond. Often the ice drift is just circumpolar.

-3- The whole icepack does not rotate CW with the TPD but rather participation is demarcated by immense  curvilinear leads, newly visualized in a dockside posting by L Kaleschke and enhanced on the Mosaic forum by directional convolution. These fracture lines, coincidentally or causally, approximately delimit the puzzling openings to the pole above Morris Jesup. A lot of MYI ice between Greenland and the pole was fractured by lead formation.

-4- Missing this year was any significant CW rotational movement of thick ice out of the western CAB. While this ice has never moved further than a half gyre in the last ten years of tracking, commonly a strip of CAB ice moves to inevitable melt in the warmer open seas of the Chukchi (which might be called internal export).

-5- Export out the Fram was robust during the TPD, pushing everything ahead of a 500 km east-west line through the initial position of the PS to oblivion in the Greenland Sea. Behind this line, newly formed Laptev ice filled the growing open water gap to shore. However, since mid-May, export out the Fram, SV-FJL gap, Bering Strait, CAA garlic press and Nares have all been inconsequential (and will remain so, too little time is left).

-6- A record heat wave off Ellesmere in mid July coupled with persistent easterly winds melted vulnerable matrix ice joining floes, enabling churning of offshore ice into residual rubble. The observed movement to the west is not unusual but it was far more narrowly restricted to the CAA coast in past events. The main CAB ice pack, being no longer attached to coastal land or ocean bottom, might be set adrift to elsewhere by persistent winds from the south. We’ve not yet seen that game-changer.

-7- The Pacific-side cyclone centered on July 27th hit like a tornado at 75º/-160º decimating the ice, on Sentinel-1 and WorldView, making clear that error-prone thickness and area/extent whole-ocean numbers don’t capture key issues such as ice mechanical strength, internal pressure or response to stress.

Both the Chukchi and slow-melting Beaufort were pre-conditioned by dispersion for flash lateral and bottom melt after the storm; note insolation today at 75º surprisingly is still 64% the strength the week centered on solstice (4th image below) but has to get through clouds and escape low angle surface reflection.

Are these independent events or somehow consequent to a single master change (such as breakdown trend of equatorial heat gradient as manifested in the jet stream)? Yes to a certain extent but this view has to be distinguished from the slot machine model put forward by Csnavywx in #4662.

That is, the multi-decadal downward trend of ice has created a set-up for which a coincidental confluence of bad weather events over a single freeze/melt cycle sequentially sum to an ice disaster. Even bland weather from here to October may suffice for a seriously below-trend outcome. Regardless of how the season turns out, as @Zlabe notes, fractional BOE has gone on all summer.

The files below expand or animate with a click. File names explain the topic addressed. I thank uniquorn for valuable discussions. Clouds are removed by setting a sequential five day AMR2 stack to 'darken only' in gimp.

28
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 07, 2020, 09:02:23 AM »
Uni Hamburg AMSR2 2012 sea ice concentration is only available from first of August. Here is an animation of the first six days  with 2020 and 2012 side by side.

29
Arctic sea ice / Re: Latest PIOMAS update (August 2020)
« on: August 04, 2020, 10:23:39 AM »
Thickness map compared with previous year and their differences.

30
Arctic sea ice / Re: Latest PIOMAS update (August 2020)
« on: August 04, 2020, 10:08:20 AM »
Fram volume export graph.

31
Arctic sea ice / Re: Latest PIOMAS update (August 2020)
« on: August 04, 2020, 10:05:52 AM »
The volume and volume-anomaly graphs.

32
Arctic sea ice / Re: Latest PIOMAS update (August 2020)
« on: August 04, 2020, 09:56:26 AM »
PIOMAS gridded thickness data is updated to day 213 (31Jul/1Aug). The (calculated) volume on that day was 6.52 [1000km3], second lowest (behind 2019).

Here is the animation.

33
Arctic sea ice / Re: The 2020 melting season
« on: July 30, 2020, 01:07:41 PM »
As it appears (to my non-expert eyes) that clouds cause artifacts in the concentration products, the big question in my mind is whether they cause high-concentration streaks, or whether they cause low concentration streaks... Can some kind soul superimpose (and synchronize) the cyclone and the concentration images and prove it one way or the other?
p.s. Of course it's also possible the storm causes actual concentration changes that appear to be in its shape. Would love an expert opinion.

Another version, to add to uniquorns great work.

(Large file warning!)

34
Sorry for the delay, some trouble with the download caused a corrupted file (uice, the ice velocity data).

Here are the updated volume and volume-anomaly graphs. Worth a click for size.

35
PIOMAS has upgraded the gridded thickness data to day 197 (15 /16 July). Volume on day 197 was 9.04 [1000km3], which means an annual fourth lowest place for that day.

Fasten seat belts, here is the animation of July so far. Might need a click.

36
Arctic sea ice / Re: The caa-greenland mega crack
« on: July 15, 2020, 12:54:38 AM »
For uniquorn, these are all the images that were available.

Second is just east of Nansen sound.  Lots of areas breaking up the CAA

Both need clicks.

37
The rest / Re: SpaceX
« on: July 08, 2020, 03:07:23 PM »
—- Starlink (+ Blacksky sats) launch today!
Quote
SpaceX (@SpaceX) 7/7/20, 6:06 PM
Falcon 9 is vertical on LC-39A ahead of our tenth Starlink mission, targeted for [today] at 11:59 a.m. EDT. Vehicle and payload look good; weather is 60% favorable → spacex.com/launches
https://twitter.com/spacex/status/1280624175590240256

SpaceX’s next batch of Starlink satellites back on the launch pad
July 7, 2020 Stephen Clark
https://spaceflightnow.com/2020/07/07/spacexs-next-batch-of-starlink-satellites-back-on-the-launch-pad/

Edit:
Quote
SpaceX (@SpaceX) 7/8/20, 11:01 AM
T-1 hour until Falcon 9 launches its tenth Starlink mission; team is monitoring weather conditions. Webcast will go live ~15 minutes before liftoff spacex.com/launches

SpaceX (@SpaceX) 7/8/20, 11:48 AM
Standing down from today’s mission due to weather; proceeding through the countdown until T-1 minute for data collection. Will announce a new target launch date once confirmed on the Range
https://twitter.com/spacex/status/1280891612088823808


——  Next customer launch targeting July 14th
Quote
Nathan Barker (@NASA_Nerd) 7/7/20, 1:55 PM
Before Falcon 9 and Starlink even gets off the ground, the next Falcon 9 launch hazard advisory is on the Range for July 14th. This advisory is covering a period from 4:55 pm EDT to 9:47 pm EDT. This launch will carry KMilSatCom 1 for the South Korean Military.
https://twitter.com/nasa_nerd/status/1280560997237997568

—- Starship
Quote
Michael Baylor (@nextspaceflight) 7/7/20, 6:07 PM
New road closures in Boca Chica! Starship SN5 static fire testing starts July 10. Then, the notice starting July 13 through July 15 says SN5 150 meter launch! Surely too soon? Windows are daily from 8 am to 5 pm local.
cameroncounty.us/spacex/
https://twitter.com/nextspaceflight/status/1280624400694341632

—-
SpaceX Super Heavy ‘high bay’ construction begins in South Texas
SpaceX began assembling the first building dedicated to Starship's Super Heavy booster on July 7th.
https://www.teslarati.com/spacex-starship-super-heavy-high-bay-construction/amp/


—-  NASA & SpaceX
Congress may allow NASA to launch Europa Clipper on a Falcon Heavy
New budget also offers some hope for Human Landing System.
Eric Berger
Quote
One of the big questions in recent years has been how NASA will get its multi-billion-dollar Europa Clipper mission to Jupiter's moon. In the past, Congress has said this must go on NASA's Space Launch System rocket, but this came with downsides. For one, the SLS rocket likely will cost NASA at least $1.5 billion more than a commercial rocket. Also, because it takes so long to build the large rocket, it's unlikely an SLS would be available for the Clipper before 2026.

Because the spacecraft may be ready to launch as early as 2024, and storing it would lead to increased costs, NASA's Jet Propulsion Laboratory has studied alternative launch vehicles. Among the most promising is a Falcon Heavy booster with a kick stage.

In the House legislation, Congress says NASA "shall use the Space Launch System, if available, as the launch vehicles for the Jupiter Europa missions," and plan for an orbiter launch no later than 2025. Because few people at NASA expect an SLS vehicle to be available in 2025, this is a pretty big deal.

It remains to be seen how the US Senate will act—the biggest proponent of the SLS rocket, Alabama's Richard Shelby, chairs the Senate Appropriations subcommittee. …
https://arstechnica.com/science/2020/07/house-budget-for-nasa-frees-europa-clipper-from-sls-rocket/

—-
Excellent review of information from the web conference yesterday.  NASA admits they paid closer attention to SpaceX and its “new” approach, compared to the well known and trusted Boeing.
Quote
Thomas Burghardt (@TGMetsFan98) 7/7/20, 8:34 PM
Today, NASA released the final results of the Starliner OFT investigation. Now, Boeing teams will move to implement 80 recommendations ahead of OFT-2 later this year and crewed flight in 2021.

Quote
NASA and Boeing Complete Starliner Orbital Flight Test Investigation
https://www.nasaspaceflight.com/2020/07/nasa-boeing-complete-oft-investigation/
https://twitter.com/tgmetsfan98/status/1280661557614166017

Edit:  Here is a link to the audio briefing, which starts about five minutes in.
NASA Live: NASA Review of December 2019 Boeing Starliner Orbital Flight Test (July 7, 2020)
➡️https://www.youtube.com/watch?v=hsB1ZWrGero

38
Changes from June 15.

Laptev ... -64%
Hudson ... -58%
Baffin ... -46%
CAA ... -45%
Kara ... -44%
ESS ... -41%
Chukchi ... -34%
Barents ... -34%
Greenland ... -21%
CAB ... -15%
Beaufort ... -14%

39
Arctic sea ice / Re: Latest PIOMAS update (July 2020)
« on: July 04, 2020, 11:24:43 AM »
The thickness map for day 182, compared with previous years and their difference. All need a click for size.

40
Arctic sea ice / Re: Latest PIOMAS update (July 2020)
« on: July 04, 2020, 10:41:55 AM »
Volume and volume-anomaly graphs. Click for size.

41
Arctic sea ice / Re: Latest PIOMAS update (July 2020)
« on: July 04, 2020, 10:29:26 AM »
PIOMAS has updated the gridded thickness data. Last day (day 182, 30th June or 1st July) the calculated volume was 12.53 [1000km3], which is the fourth lowest for day 182.

Here is the animated thickness map, which seems to start only after a click.

42
Arctic sea ice / Re: The 2020 melting season
« on: June 30, 2020, 12:44:06 AM »
Some ridiculous soundings coming out of YLT and WEU (Alert and Eureka) the past couple of days. Below is an example from this morning at YLT. Aside from the lack of column moisture (due to crushing subsidence from the ridge) and near-surface inversion due to melt, this looks similar to subtropical soundings. Note the tropopause all the way up around 250mb and freezing level at 700mb (>3000m). Peak of +15C just a couple of hundred meters up.

43
Some people have good use for the updated regional data files.

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz

44
Updated Fram volume export graph.

45
Arctic sea ice / Re: The 2020 melting season
« on: June 13, 2020, 12:33:32 AM »
The 12z models and 00z EURO the 12z euro isn't out yet have backed off considerably with the dipole in the long range.

Instead of setting up a full or 3/4 dipole the models slide the Eurasian vortex over the pole/Atlantic side and merge it with the GIS vortex which won't budge.

This keeps the torching over the Pacific half.

It's not a good pattern by any means but it definitely is much better than the entire CAB getting the roast.

This kind of thing is what will keep 2020 from passing 2012 in the end.

We'll see

Yep, we've seen this time and again in the last 8-9 years. It's a pattern and I think part of the reason for this strong +PV tendency has been due to a marked increase in low-level baroclinicity and eddy kinetic energy as the mid-high lats warm faster in summer than the basin proper. It is providing a transient negative feedback by preferentially favoring storms over the basin during the summer months (on the cold side of the jet). This retards melt and slows down the year-to-year summer progression. Of course, eventually the warming signal will overwhelm this, but it may take another 20 years to do so (the occasional year like 2016 nonwithstanding). Eventually, increasing warming over land will cause the warm conveyor belts on these storms to start doing enough damage to offset the shielding effect and destroy ice cover anyways. We may end up seeing a fairly long period of not much change -- followed by a quick transient period to sea-ice free, followed by decoupling of the troposphere from the stratosphere in the autumn and subsequent large hits to winter ice volume recoveries. Nakamura et. al's BoE experiments suggested as such a few years back.

And I suspect 2007 and whatever future year(s) this happens will be seen as the turning points.

If you're looking for ocean-driven signals as well, simply look at the trend of shoaling along the Atlantic-inflow stream and heat content storage coming from the Chukchi. They're pointing to the 2040s as well. Incidentally, this is around the same time aragonite undersaturation in the Arctic begins to show up, too (aragonite undersaturation starts in the 2030s around Antarctica). Full-on ecosystem disruption seems pretty ripe around that time.

46

If one were to zoom in with a powerful enough microscope, they would see that the ice and the brine are discrete entities.

In liquid state, sea water is H2O molecules bound by hydrogen bonds (intermolecular bonds) with salt ions (Na+ and Cl-) dissolved in solution.

During the freezing process, the salt ions and some of the H2O molecules are separated from the rest of the H2O molecules. The crystal lattice of ice is composed of only H2O molecules bound together by intermolecular bonds. Consider this lattice to be similar to a house which is held together with wood and screws.

The brine exists in the spaces within the lattice, but is not part of the lattice itself. The brine is like a sofa inside a house. It fits inside the house, but it is not a component of the ice house and does not impact the strength (heat) required to dismantle the ice house.

As you indicate, the brine does exit the ice lattice over time... by escaping through the spaces in the lattice. Most of the brine exits within a year of ice formation.

The lattice portion of the ice house is the same in the Arctic as the ice in your freezer and melts at the same temperature.

As one who in my chemistry career used salt-ice baths to achieve lower than 0ºC temperatures I wish to correct the physical chemistry referred to in this post.

When water freezes into ice, the hydrogen bonds make a hexagonally shaped network of molecules inherent to the structure of ice.
When a solute is added to water the ordering of the solvent molecules is disrupted. This means that more energy must be removed from the solution in order to freeze it.
When salt is added to water, the resulting ions in the water disrupt the usual network of hydrogen bonds made upon freezing. As a result, the freezing point of the solution is lower than it is for the pure solvent. This is termed freezing point depression.  As the ice warms up the network of hydrogen bonds (referred to above as the lattice) requires less energy to be broken up so the melting point is lower.
Because the solubility of the salt decreases with temperature some of the salt is rejected, forming brine pockets.  These brine pockets get eliminated over time but some salt remains in the ice disrupting the structure. In multiyear ice the salt content will ultimately reach the solubility of the lowest temperature the ice has reached so in thick MYI you'd expect lower salinity at the top vs. the bottom.

Here's an amusing video illustrating the difference in melting between saline and pure water ice.


47
Arctic sea ice / Re: The 2020 melting season
« on: June 05, 2020, 08:56:06 AM »
Thick ice is rotating into Beaufort, so Amundsen may clear but my guess is the CAA coast needs to clear before Beaufort will. IF that means that Pacific waters are moving east into ESS then the ice there will weaken and cause losses as it moves north.

ice thickness and sssalinity courtesy of Hycom.

48
Arctic sea ice / Re: Latest PIOMAS update (June 2020)
« on: June 03, 2020, 11:10:57 AM »
Thickness map for day 152, compared with previous yeas and their diff's. Click for size.

50
Arctic sea ice / Re: Latest PIOMAS update (June 2020)
« on: June 03, 2020, 11:03:12 AM »
A large amount of ice crossed the imaginary line in the Fram Straight in the beginning of May.

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