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Messages - uniquorn

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1
atlantic side oct25-26
CAB extent

2
Developers Corner / Re: Test space
« on: Today at 09:34:16 PM »
with v103 overlay at 60%. Interesting effect with amsr2 moving over the stationary repeated missing frames.

3
Developers Corner / Re: Test space
« on: Today at 01:40:43 PM »
a quick look at ascat, some missing days, best viewed slow --

5
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 07:22:05 PM »
amsr2-awi-v103, atlantic side oct24-25. Sea ice crossing the shelf close to SZ.

6
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 03:28:53 PM »
Thanks SimonF92. Animation scope widened to include the 2 newer buoys 204763 and 204764
Looking forward to your animations

7
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 02:50:27 PM »
IABP buoy drift and surface temperature update.(11MB)

closer look at iabp204761 and 204762 in the Laptev (3.5MB)
click

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Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 12:46:16 PM »
IABP buoy drift and surface temperature update. A steady drift along the line from Chukchi to Fram since oct6 until recently. My buoy list needs updating since it doesn't appear to include 204672 above. (12MB is a bit large) edit: updating this updated below

Unrelated but also interesting is the amount of heat escaping from the Nth Greenland Coast. https://go.nasa.gov/2HxW0GH

amsr2 awi v103, oct14-24
click for animations.

polarview S1B

9
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 11:16:46 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.
20201023000000-OSPO-L4_GHRSST-SSTfnd-Geo_Polar_Blended_Night-GLOB-v02.0-fv01.0.nc
An excellent combination.

IABP raw data is available in the format shown below. The map shows the locations and the data can be looked up using the table

iabp204672 204762 is shown below. The default scales are large but you can create your own chart from the data.

10
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 24, 2020, 03:10:02 PM »
A closer look at refreeze not keeping up with dispersion in the Beaufort yesterday, amsr2 awi v103 oct12-23. Winds were not strong, just a little warmer.

Also moving the conversation about whoi itp121 from the melting season to this thread. Latest temperature/salinity profiles and drift path.
Temperature at 50m still high at over 2C.

itp121 shares a floe with ice mass balance buoy www.cryosphereinnovation.com/441910 currently maintaining thickness at ~2m.

11
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 24, 2020, 12:04:42 AM »
atlantic side oct22-23
wipneus' CAB extent

12
Arctic sea ice / Re: The caa-greenland mega crack
« on: October 23, 2020, 10:53:11 PM »
nth greenland oct16-23    https://go.nasa.gov/3jqDayn
Not that much open water, some of the darker coastal areas are fog over refreeze.

13
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 23, 2020, 04:18:24 PM »
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature and salinity, sep4-oct22  (8MB)
Combined these two ani's from the freezing season thread to make it easier to compare daily changes.

14
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 23, 2020, 03:40:46 PM »
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)
Ok, from your animation is it correct to say all the regions susceptible to warming from Atlantic Waters are already covered by ice or about to be covered? (exception Barents and Kara but we know those two seas are already lost to climate change)
It seems to me the anomalously warm Laptev and ESS areas are basically over the shallow shelf, which will have a record heat release (consistent with the record heat income from GAAC and the season in general). So no Atlantic warmth here to speak about.

The Laptev sea extent beyond the shelf (and so the heat anomaly, by the way). Intrusion of Atlantic waters are discernible on the salinity maps of the mercator. (P.S. : And acknoledging that the heat and salinity extent beyond the Laptev into the central bassin, even under the sea ice).
Yes, SST is more useful if we also show SSS
amsr2, awi dev v103 overlaid at 75% transparent onto mercator 0m ocean salinity, sep4-oct22  (7MB)
mercator label is just visible.
edit: It has often been proposed that the Atlantic waters would meet the Pacific incoming at some point. The delay in refreeze and perhaps some mixing from recent strong winds would seem to make that prospect more likely (according to the model). The Siberian shelf and the Chukchi plateau help to prevent it. (Shown on the 92m salinity map upthread)

15
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 23, 2020, 02:35:23 PM »
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)

16
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 21, 2020, 11:57:41 AM »
NSIDC ease-grid ice sea age update. The nearest clear day I found on Worldview for comparison in the Beaufort was oct8. https://go.nasa.gov/2IITyxk
click for animation.
edit: 2000-2020 animation here

17
Arctic sea ice / Re: The Rammb Slider Thread
« on: October 21, 2020, 11:23:10 AM »
Nice. Makes me wonder if heat loss would have been visible like that in previous years with a drier atmosphere.

18
Developers Corner / Re: Test space
« on: October 20, 2020, 10:59:42 PM »
IBCAO_v4_200m-sliced

19
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 20, 2020, 09:05:31 PM »
The 3-day forecast is finally going below freezing on the Russian side of the Arctic, although still far above normal: https://climatereanalyzer.org/wx/fcst_outlook/?dm_id=arc-lea&nday=3-day

Sometimes we have to be careful looking at temperature maps in areas of open water as the models will always forecast higher temperatures whilst that open water is there. As far as I understand it, if ice did indeed grow in some of that open water area, the models will show slightly colder temperatures than first predicted. As it happens though, it seems difficult at this point too see much refreeze from the main pack but hopefully we will see more evidence of coastal ice forming with winds blowing in from the landmasses.
There are some signs of light coastal refreeze along the esas. AMSR2 (awi v103) struggling to detect it consistently oct9-19, polarview S1 showing more detail on oct19.

20
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 20, 2020, 02:20:05 PM »
https://go.nasa.gov/3m5uQpn  oct15-20 with AWI AMSR2 v103 inset. The north greenland gap still recovering from the summer, sea ice still lifting off Ellesmere Island. Some Nares export.

21
Arctic sea ice / Re: The 2020 melting season
« on: October 20, 2020, 12:44:04 PM »
a closer look at itp121 drift, oct18-19

22
Arctic sea ice / Re: The 2020 melting season
« on: October 20, 2020, 11:10:45 AM »
A closer look at itp121 drift path. Small signs of inertial oscillation or tidal movement. It shares a floe with SIMB441910 (https://www.cryosphereinnovation.com/441910), thickness 210cm at deployment. (click for more data)

forum software behaving strangely today.

23
Arctic sea ice / Re: The 2020 melting season
« on: October 20, 2020, 12:50:10 AM »
itp121 has hardly moved. Temperature at 50m remains relatively high. Both temperature and salinity suggesting turbulence. Day 264-293.

24
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 19, 2020, 11:55:12 PM »
For what is worth (not much, admittedly), but the surface analysis of GFS (the GDAS) did not show a significant drop for SST during the week-end. <>
Raw surface temperatures and drift from iabp buoys over the last 5 days. Drift speed is the coloured path with scale at top left, temperature as text label. (Buoys in ice should be reporting ice surface temperatures. NA means they do not report surface temperature, some may be faulty.)
Click twice for full res. Large file.

25
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 18, 2020, 09:36:43 PM »
CAB extent update.
Atlantic side, oct8-18
added updated pixel count

26
Arctic sea ice / Re: The caa-greenland mega crack
« on: October 18, 2020, 12:35:06 AM »
CAA north coastal ice still restless. click for movement and full res.
https://go.nasa.gov/3lW02qZ

27
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 18, 2020, 12:17:30 AM »
CAB extent update.
Atlantic side, oct7-17
updated below

28
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 17, 2020, 12:55:53 AM »
updated below

29
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: October 16, 2020, 11:45:21 PM »
Just a hint of nares export over the last few days
https://go.nasa.gov/2H8Tu9A

30
Arctic sea ice / Re: What the Buoys are telling
« on: October 16, 2020, 09:07:22 PM »
something like splitting seasons at day265. Working on that

31
Developers Corner / Re: Test space
« on: October 16, 2020, 03:41:39 PM »
wake timing a bit quick -removed

32
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 15, 2020, 11:06:53 PM »
CAB extent update

33
Arctic sea ice / Re: What the Buoys are telling
« on: October 15, 2020, 10:48:20 PM »
A closer look at the Atlantic side temperatures at 80m depth. Max temp has been capped at -0.8C to show detail along the transpolar drift line. This means that some data is not shown fully at the Yermak plateau. I plan to look at that in more detail later.

34
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 15, 2020, 12:42:21 AM »
2020 again setting a new boundary for CAB refreeze (wipneus' CAB)
updated below

35
Arctic sea ice / Re: The 2020 melting season
« on: October 14, 2020, 11:12:31 PM »
@Oren, the static chart is a valuable addition to the analysis.

csv data as text file attached. conversion from day numbers/year may need checking.

36
Arctic sea ice / Re: The 2020 melting season
« on: October 14, 2020, 11:01:49 PM »
Beaufort 50m temperatures from whoi itp buoys, 2006-2020
edit: adjusted buoy sizes so newer year overlay is easier to identify
edit2: mp4 is smaller

37
Arctic sea ice / Re: What the Buoys are telling
« on: October 14, 2020, 10:12:41 PM »
overview of 50m temperature from whoi itp buoys, 2006-2020.

38
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 14, 2020, 03:29:34 PM »
Definitely some more refreeze outside the Lena delta.
Yes. Today may be the last day to check using corrected reflectance. Sea temperatures 50km from the coast were still just a touch cooler than the Lena river. Low cloud and fog a bit cooler.
Rainbow1 palette on viirs brightness temperature.
https://go.nasa.gov/374tZkp

39
Arctic sea ice / Re: MOSAiC news
« on: October 14, 2020, 01:28:33 PM »
T78 and T81 update.
T81 taking a long time to cool(thicken). There are some deployment notes for T78 but nothing for T81.

40
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 14, 2020, 01:06:31 PM »
Tidally Forced Lee Waves Drive Turbulent Mixing Along the Arctic Ocean Margins
Ilker Fer, Zoé Koenig, Igor E. Kozlov, Marek Ostrowski, Tom P. Rippeth,, Laurie Padman, Anthony Bosse, Eivind Kolås
First published: 06 August 2020

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL088083

Quote
Abstract

In the Arctic Ocean, limited measurements indicate that the strongest mixing below the atmospherically forced surface mixed layer occurs where tidal currents are strong. However, mechanisms of energy conversion from tides to turbulence and the overall contribution of tidally driven mixing to Arctic Ocean state are poorly understood. We present measurements from the shelf north of Svalbard that show abrupt isopycnal vertical displacements of 10–50 m and intense dissipation associated with cross‐isobath diurnal tidal currents of ∼0.15 m s−1. Energy from the barotropic tide accumulated in a trapped baroclinic lee wave during maximum downslope flow and was released around slack water. During a 6‐hr turbulent event, high‐frequency internal waves were present, the full 300‐m depth water column became turbulent, dissipation rates increased by a factor of 100, and turbulent heat flux averaged 15 W m−2 compared with the background rate of 1 W m−2.

41
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 13, 2020, 11:31:10 PM »
It's time to go to night vision using worldview terra modis viirs brightness temperature band 15 (night or day) https://go.nasa.gov/2FpoLVd
Today's image showing the effect of wind driven drift on the Atlantic front (awi amsr2 v103 from yesterday inset)

Quote
The VIIRS Brightness Temperature, Band I5 Night layer is the brightness temperature, measured in Kelvin (K), calculated from the top-of-the-atmosphere radiances. 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 over clear land. It can be used to distinguish land, sea ice, and open water over the polar regions during winter (in cloudless areas).

The VIIRS Brightness Temperature layer is calculated from VIIRS Calibrated Radiances (VNP02) and is available from the joint NASA/NOAA Suomi National Polar orbiting Partnership (Suomi NPP) satellite. The sensor resolution is 375m, the imagery resolution is 250m, and the temporal resolution is daily.

Only one Polarview S1B of the area today.

It's also worth looking at relatively cloud free sea ice north of the CAA today. High winds are forecast for this area too over the next couple of days.      https://go.nasa.gov/3dAMzSN

42
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 12, 2020, 11:33:01 AM »
Thanks for the SMOS post. As we suspected, all that MYI exported to the Beaufort tail has nearly melted out, and will give no resilience against next year's melting season.
It effectively amounts to open water except energy to refreeze further area is closer to zero.
For practical purposes Beaufort sea is free of MYI facing the refreeze season

It will be interesting to see what the NSIDC ice age update looks like. Here is a polarview S1A of the stalwart MYI floe at the centre of the amsr2 inset (awi v103). It's looking somewhat rounded, so has probably not had an easy time during the melting season.   ~300km2, maybe it will show up on cryosat2 if it doesn't drift too quickly.
Quote
CryoSat-2 will achieve improved spatial resolution of 250 m in the along-track direction using the Synthetic Aperture technique.
https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/cryosat/overview

43
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 11, 2020, 11:02:23 PM »
Just a hint of coastal refreeze in parts of the Lena delta on worldview. Quite a change from sep23. (click for ani)

polarview, oct10

Oddly enough, further north it still looks like melt season.

44
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 11, 2020, 08:23:00 PM »
No data for 2012 but 2020 is about to test the boundary set by 2018 for slow refreeze in the CAB.

45
Thanks SimonF92. I'm hoping this will give me a better look at the Nares Strait eventually.

46
Arctic sea ice / Re: What the Buoys are telling
« on: October 08, 2020, 07:10:06 PM »
iabp drift update with surface temperatures (where available) roughly every 3hrs, oct3-8
click twice and scroll
edit: some reported temperatures look questionable

47
Arctic sea ice / Re: The 2020 melting season
« on: October 08, 2020, 12:34:38 PM »
Nice, the DOS or (power)shell solution is quick if you don't need to bind the lat/lon to the list. It's interesting that 2020 salinity, which may be a signature of pacific water, is a closest match with 2012. It could just be coincidence.

Rough location overlay

48
Arctic sea ice / Re: MOSAiC news
« on: October 07, 2020, 11:32:37 PM »
from https://twitter.com/seaice_de



Quote
Lead openings and deformation caused by the wind shear are rather abrupt events than continuous processes.

49
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 07, 2020, 12:12:59 PM »
A quick look in more detail at refreeze in the Beaufort/southern CAB. The v103 presentation shows some nice detail suggesting a weather front passing over the area.
v103, sep30-oct6

comparison of UHH and v103, oct4 (click for correct resolution)

polarview S1A of the same area, oct6 (click twice for full res)

50
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 07, 2020, 12:48:31 AM »
There is still a massive amount of oceanic heat
Agreed.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct5

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