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Messages - Tealight

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1
Arctic sea ice / Re: The 2019 melting season
« on: May 16, 2019, 05:03:28 PM »
Now in mid-May, we are just over a month away from peak insulation. The time the northern hemisphere has it's greatest warming potential. Including Greenland, snow cover extent is still around 50% more than sea ice extent. From an overall albedo perspective this makes sea ice look less relevant than snow cover. At this time 2012 dived to record low snow extent in June and attacked the ice from all sides with continental heat to force widespread meltponding and eventual record low sea ice extent.

This year seems to have pretty average snow cover more in line with 2015 and 2016, but below 2017 and 2018.

2
Antarctica / Re: Sea Ice Extent around Antarctica
« on: May 15, 2019, 11:59:22 PM »
Nice analysis oren. As in my regional snow cover analysis some charts are very hard to read due to the high year to year variability. To me it looks like the Bellinghausen & Amundsen Sea have a downward trend for day 133 and day 365. The highs of the 2010s are the lows of the 1980s. The lines for day 166 to 274 are just to noisy to see anything.

Can make some 365 day charts showing decade averages? They have less noise and melt events don't have to fit into an exact month or specific day.

3
Antarctica / Re: Sea Ice Extent around Antarctica
« on: May 12, 2019, 06:03:23 PM »
Hi Rich, the current low sea ice extent is caused mostly by the Weddel Sea (see picture below). The Ross Sea is around average. I would say the cause is the current weather pattern. The circumpolar winds are very weak and plenty of mid latitude warmth reaches further south. Somewhere I read that the Antarctic Circumpolar Current is gradually moving south over the last few years, but I can't remember the source.

4
Arctic sea ice / Re: Albedo-Warming Potential
« on: May 05, 2019, 11:18:23 PM »
Thanks everyone. I can confirm it feels good to beat major international organisations like NASA, MetOffice and ecmwf.

Tealight, you derive AWP using sea ice area and then use this as a basis to calculate the energy available to reduce sea ice thickness ? How do you translate reduced thickness into resulting sea ice area and extent? A sea might have remaining ice piled up in one area  or spread out giving a higher extent value due to varying winds and currents?

Technically I keep track of two sea ice concentration values. One to calculate the melt (using SIC from previous years) and another calculated from thickness. The second one is the final model output. The additional thickness step makes the model more robust against flashes of low SIC like short term melt ponds.

For the Antarctic I used the following formula to get the best results:
SIC(%) = (Thickness(m)^1.3) / 0.0155

Thickness(m)   SIC value (%)
1.4   100
1.25   86
1   65
0.75   44
0.5   26
0.25   11
0   0

anything over 1.4m stays at 100% SIC.

5
Arctic sea ice / Re: Albedo-Warming Potential
« on: May 05, 2019, 08:27:26 PM »
Very popular here are the sea ice minimum and maximum polls guessing the correct sea ice extent in millions of square kilometer. A more scientific oriented version of it is the Sea Ice Prediction Network: https://www.arcus.org/sipn
This year was the second time they made a trial run to forecast the Antarctic summer minimum and I participated (as Nico Sun) with a forecast model derived from this Albedo-Warming Potential model. The underlying physics are the same. The major difference is that instead of accumulating an energy value in a grid cell, this energy is used to calculate the sea ice thickness loss. Additionally I added an outgoing infrared radiation variable to get an actual energy balance.

With the post season report released I can proudly claim victory not only in overall area values, but also on a regional scale with the lowest error over the entire 3 month forecasting period. This is in part thanks to the real world usefulness of the AWP model and in part due to the submission deadline of 1st December. Some other team's can only run their models at the beginning of every month and had to use October data for their model initialization. I attached the two most relevant figures, but recommend to read the whole report.

Full 2018-2019 post season report
http://www.climate.be/users/fmasson/SIPN-South_2018-2019_postseason.pdf

General SIPN south website
http://acecrc.org.au/sipn-south/


Sea Ice Loss Formula of the forecast model:

Ed = MJ_inlat,day x (1 - SIC) - MJ_out
z = Ed / Efusion

Ed = Melt energy per day
MJ_in = incoming solar radiation per m2
MJ_out = outgoing infrared emmision per m2
SIC = sea ice concentration
z = thickness loss in m
Efusion = Enthalpy of fusion per m3

6
Antarctica / Re: What's new in Antarctica ?
« on: May 04, 2019, 08:55:08 PM »
The visualization is great but I have some questions:
At what cross-section was the data measured? At the grounding line?
Is PIG really that wide? I thought it was 40km.
And some of the heights seem strange. Petermann, NG and even PIG could float with these heights.

The Grounding line isn't very smooth and changes constantly. I did just draw a line behind the glacier terminus where the bedrock is more or less a valley. Pretty much all of the west antarctic region is below sea level. You can't use below sea level as a definition, because then Pine Island and Thwaties are the same glacier.

Yes, Petermann, NG and PIG all float at the terminus. Do you think another thickness line would fit into the graphs? It's already quite crowded and the thickness data is even more unreliable / out of date.

PIG 40km is about right for the flat floating part, but not the whole valley which includes ice from the sides coming down.

7
Antarctica / Re: What's new in Antarctica ?
« on: May 04, 2019, 06:29:14 PM »
I made some Glacier size comparison charts featuring Greenland & Antarctic Glaciers. I hope it better visualizes how much ice is exposed to ocean water than a Bedrock map. The charts shows the dimensions of the glacier front. Where the x-axis is the glacier width and the y-axis is the glacier height.

https://cryospherecomputing.tk/Glacier-size

(same post as what's new in Greenland)

8
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: May 04, 2019, 06:28:40 PM »
I made some glacier size comparison charts featuring Greenland & Antarctic Glaciers. I hope it better visualizes how much ice is exposed to ocean water than a Bedrock map. The charts shows the dimensions of the glacier front. Where the x-axis is the glacier width and the y-axis is the glacier height.

https://cryospherecomputing.tk/Glacier-size

9
Antarctica / Re: Antarctic Icebergs
« on: May 03, 2019, 08:18:24 PM »
Now A68-A is just 5.5km away from the islands. I wonder if it's actually going to collide with the island itself. According to the Bedrock map the area is quite shallow, but it might be wrong. The small part that broke off early (A68-B) is currently in 40-50m deep waters.

10
Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: May 03, 2019, 11:29:48 AM »
Another month of low overall gain, but above average thickness.

Full size images and April animation at:
https://cryospherecomputing.tk/SIT

11
Arctic sea ice / Re: Albedo-Warming Potential
« on: May 03, 2019, 02:21:56 AM »
No surprise that we're tracking to get a similar anomaly in the Bering as last year, iirc last years ~250 mj/m2 was basically double any prior year.

Tealight, my understanding of the 'potential' part of AWP is that the calculation doesn't account for weather, correct? A cloudy season and a sunny season with similar extent would produce similar AWP numbers but would experience different actual warming?

You are right that it doesn't account for weather and doesn't calculate actual warming. The data presented here is just a model to rank years against each other instead of a daily or monthly minimum number. It also quantifies the actual surface albedo change in the Arctic. However, the underlying physics are good enough for real applications. Maybe I can give more information tomorrow.

12
Arctic sea ice / Re: Albedo-Warming Potential
« on: May 01, 2019, 01:05:08 AM »
Just in time before the May melt ponds start I created the regional anomaly charts. Just like last year almost all of the early accumulated AWP anomaly comes from the Bering Sea, but this year none of the regions is in the negative.

https://cryospherecomputing.tk/NRTawp

13
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 27, 2019, 07:04:48 PM »
Before working on all region graphs I created another section for the High Arctic. This one should be more useful for determining the record low in September. It only includes the following regions: Kara Sea, Laptev Sea, East Siberian Sea, Chukchi Sea, Beaufort Sea, Canadian Archipelago, Central Arctic.

For the high Arctic 2012 still holds the record high followed by 2016 in second and 2007/2011 tied in third. The far higher average ice cover also significantly increases the gap to a completly ice-free state. On one hand the 2010s just reach 40% of the ice-free conditions compared to 61% for the whole Arctic. But on the other hand the 2010s absorb 32% more than the 1980s. For the whole Arctic it's just 15% more. So the last ten years really impacted the high latitudes more than the lower ones.

https://cryospherecomputing.tk/awp

Note: Before doing this recalculation I increased the ice albedo from 80% to 85% relative to ocean albedo. This is more in line with the values I measured from satellite images. The result is slighly lower absolute values, but hardly any change to anomaly values. The near-real time data will be updated tomorrow.

14
Antarctica / Re: What's new in Antarctica ?
« on: April 23, 2019, 01:49:47 AM »
The Antarctic Bedrock data was over 10 times harder to align than Greenland. There are hardly any landmarks, just plain white and with fast ice or ice shelfs you don't even know where the land begins. I had to use huge area images to align islands and then cut it down to individual glaciers. The bedrock resolution is just 1km/px as opposed to 0.15km/px for Greenland data.

https://cryospherecomputing.tk/Bedrock-Antarctica

15
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: April 22, 2019, 12:08:53 PM »
Did anybody say their favorite glacier isn't featured? No? Well here is all of Greenland Bedrock anyway.

https://cryospherecomputing.tk/Bedrock

16
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 21, 2019, 11:58:18 AM »
Oren I just finished summarizing the regional data. The Bering Sea and Beaufort Sea are already very close to icefree. If I do another central Arctic Graph for the pack ice region then they have to drop as well. In my view the Barents Sea is just like Greenland Sea, mostly for export of central Arctic Ice. The Bering Sea is too far south to affect the Central Arctic, at most it affects southern Chukchi Sea but not more. 2012 has shown that the Pacific side of the Arctic can get a huge melt even with a record bad Bering Sea melt.



17
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 20, 2019, 05:33:12 PM »
Two images to show the current massive regional differences. First a Peak Watt map showing maximum solar intensity at noon. It might be important to get the initial punch to turn snow into a melt pond. The high Arctic never receives this intensity and relies entirely on imported warmth.

For daily averaged energy values the Sea of Okhotsk, closely followed by Bering Sea currently absorbs over ten times more energy than the central Arctic.

Arctic mean: 6.1 MJ/m2

Sea of Okhotsk   18.711
Bering Sea   16.264
Hudson Bay   4.977
Baffin Bay   9.695
East Greenland Sea   8.159
Barents Sea   8.567
Kara Sea   2.753
Laptev Sea   2.387
East Siberian Sea   2.462
Chukchi Sea   3.255
Beaufort Sea   2.598
Canadian Archipelago   2.75
Central Arctic   1.601

18
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: April 20, 2019, 02:50:03 PM »
Just awesome Tealight!

May i suggest using a bigger font and a visual separation (thin line perhaps) between the glaciers and centring of the pics. Would make it even more beautiful imho.

Technically all pictures are centered (if you span the browser over two monitors) The Petermann Glacier has a different aspect ratio and the image overlay code needs a point zero which is set for the widest images. So all image overlays have to begin at the same position.

I try to add a visual separation, but the font is already quite big imo. After loading the webpage from the web and not locally I noticed it has a loading time. With 20MB it's already a decent size. Thus I probably create a separate page for Antarctic Glaciers.

Tealight...you should get an award for this work.

For this? It's just using some web templates, downloading other peoples work and aligning two images in a paint program. All in all two afternoons of work.

19
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: April 20, 2019, 11:37:05 AM »
New Bedrock overlay page for all of Greenlands major glaciers.

https://cryospherecomputing.tk/Bedrock

20
Greenland and Arctic Circle / Re: Bedrock overlay poll
« on: April 20, 2019, 11:34:33 AM »
Thanks everyone for voting. As I suspected both options have a use case. The problem with combining them was that the template for the image overlay slider and the template for the range slider both had "slider" in the name and interferred with another. I solved it by setting the opacity with a number input field and a button.

The test pages are now removed and the overlays have an offical page:
https://cryospherecomputing.tk/Bedrock

21
Greenland and Arctic Circle / Bedrock overlay poll
« on: April 14, 2019, 03:40:48 AM »
I've often seen users asking about a glaciers bedrock elevation to estimate future retreat. Then some veteran users post a bedrock map, but it's still difficult to compare it to current satellite images. Therefore I want to build a bedrock overlay webpage for all major glaciers. However I'm not sure which of the two presentation styles is better.

You can vote for both options if you have no major preference.

Horizontal overlay
https://cryospherecomputing.tk/Test1

Full image Opacity
https://cryospherecomputing.tk/Test2

22
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 11, 2019, 12:11:44 AM »
Some feedback - not sure if you are aware but images don’t seem to load on mobile. When I hold down on the empty space and ask to open image though, it does show up on the next tab.

I still have to upload daily updated images to google drive and insert a shared link into the website. (I don't know yet how put them on the github server)

Oren had the exact same problems and it had something to do with his googleaccount. Can you try opening the webpage in incognito mode?

23
Arctic sea ice / Re: "Stupid" Questions :o
« on: April 10, 2019, 02:25:57 AM »
With the high (relative) levels of melting in the Arctic recently, the flooding that occurred in the NE USA, and the jet stream in that area..... I was wondering whether the water in the clouds came from the melting in the Arctic region, traveled South, then dropped it on the US?

It seems plausible in my head, but is that what happened?

The water generally comes from the warm & wet south, especially in spring. However without cold air from the Arctic the moisture wouldn't come down as heavily and cause flooding. The cold & dense air causes the warm & less dense air to rise, kind of like a mountain. As the warm air rises it cools, can't hold the moisture anymore and develops thick clouds & rain. On earth.nullschool.net I have often seen constant weather front change in the north eastern USA and south eastern Canada. A few days of warm & wet Atlantic air followed by cold air from the Arctic.

Good overview on wikipedia:
https://en.wikipedia.org/wiki/Cold_front

24
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 07, 2019, 10:37:28 PM »
Thanks for the patience and support everybody.

Here is the AWP NRT link:
https://cryospherecomputing.tk/NRTawp

By the way I added a website icon which should be displayed next to the page name in the tab. Right now it's some melting sea ice in Beaufort Sea (2016) at super low resolution. Maybe I make a logo in the future.

25
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 07, 2019, 12:11:26 AM »
The new near-real-time Albedo-Warming Potential script is programmed. If it updates tomorrow as intended I post the website link. The regional data has to wait until I structure the regional data from the previous 40 years.

26
Arctic sea ice / Re: Latest PIOMAS update (April 2019)
« on: April 04, 2019, 01:21:33 AM »
question to the specialists, theoretically i can calculate but there may be hidden traps for a layman, hence i thought to ask:

how much thicker must the ice be to keep the same volume while loosing > 1'000'000km2 in the 2 other dimensions. i assume extent and area won't produce the same result and since i'm not privy with the calculations, i ask that question.

trigger for the question is that each time after a month of steep losses i wonder how it can be that volume could keep level or even increase, is it realistic that the reminder at the same time would grow that much in thickness ?

after all the real area of thickness increase is relatively small, since i think that if the ice is melting at the periphery, there must be some significant range in the midle between the pole and the periphery where ice is melting, just not to zero, keeping thickness and another part where thickness is growing only a little, hence there is not much area left where ice would grow so much to compensate for all the losses.

so much my logics which may be wrong (apparently) and i want to know why i'm apparently erring.

In simple terms the ice that melts at the edge must be replaced by new ice in the centre. The major problem here is that everyone is only publishing average thickness values for the entire Arctic. The ice that was in Bering Sea and Guld of St Lawrence was probably just 10-20cm thick. So 20cm*1million km2 divided by 10 million km2 for the central Arctic gives you a thickness increase of only 2cm.

PIOMAS is really bad at getting the ice edge right, most of all soutwest Greenland which is pretty much never frozen. It's one of the reason why I developed the high resolution "AMSR2 Snow & Ice Volume". It's not as good for the very thick central Arctic, but much better for thin ice and defining an ice edge.

https://cryospherecomputing.tk/SIT

27
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 03, 2019, 01:45:58 AM »
Stumbled on to it while looking at your AMSR2 tab and I have to say it is absolutely beautiful in its presentation.

Please keep up the amazing work and cannot wait for the near real time data additions!

Thanks Viggy, it really means a lot to me. The presentation takes up about 75% of the time, but is also the most important part.

28
Arctic sea ice / Re: Albedo-Warming Potential
« on: April 03, 2019, 01:19:03 AM »
BAM! Two years have gone by without an update.

I finally have the processsing power and coding skills to take the AWP model to where I intended it to be. Instead of only calculating the anomaly of potentially absorbed solar radiation. I now calculate the raw accumulated values, the anomaly and a percentage of the current year to the maximum possible (complete Ice-free conditions). From the 1980s to 2010s this percentage has gone up from roughly 52% to 62%. Generally from August onwards the Arctic is 75% icefree and from September onwards the Arctic is 90% icefree.

Everything is now much better presented with interactive graphs and sliders to compare individual years. The regional data is already calculated, but needs even more work for proper presentation. Near-real time data for 2019 is in the works too.

Fancy new webpage:
https://cryospherecomputing.tk/awp

Still too short documentation of AWP model:
https://cryospherecomputing.tk/doc.


29
Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: April 03, 2019, 12:49:18 AM »
<snippage>Full size images and February animation at:
https://cryospherecomputing.tk/SIT
Thanks for this Tealight. I carelessly missed the February animation. Can I download it from somewhere?

Sorry, but to keep the update process simple I only create one gif file per month which always replaces the old one.

30
Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: April 02, 2019, 11:16:09 AM »
Only a moderate thickness increase and a complete volume stall in the second half of March, probably caused by the Bering Sea and Gulf of St Lawrence melt out.

Full size images and March animation at:
https://cryospherecomputing.tk/SIT

31
NOAA snow cover is finally showing heavy losses in western Canada. The southern Rockies however are still snow covered.

32
Arctic sea ice / Re: What's new in the Arctic ?
« on: March 29, 2019, 01:10:00 AM »
https://cryospherecomputing.tk/IceFreeDays

This site is just awesome! Very well done Tealight.

Thanks, there is still some more content in the works. Currently I'm working on a new version of my Albedo-Warming Potential model. My computation speed has improved significantly due to hardware and coding improvements.

The very first AWP version in 2016 would have needed over 1.5h for the entire 40 year dataset. With some coding improvement it came down to 30min last year and now with mutiprocessing (using all CPU cores) I'm down to 3min 52s!

edit: actually in 2016 with my old CPU it would have been more like 3h. 1.5h is on my new CPU without coding improvements.


What I'm seeing:  If you look at the Antarctic anomaly visualization, start the slider at 1979 and advance it year by year (my right arrow worked for me) at a steady pace.  I can't help seeing some kind of pattern, a rotation in the areas of more or less anomaly, that seems to persist over the entire data set.

Is this my imagination, or is there some serially correlated melt/freeze pattern that "rotates" around the continent...?  I have no idea ... just thought I'd share, since I've found viewing complex data can sometimes lead one to pick up patterns that might go missed.  Once upon a time I did some work in this area (the power of visual pattern recognition, with an eye to AI simulation). 

Curious!  Thanks.

Hmm, I don't a consistent pattern over the entire dataset but some years clearly show a rotation of the anomaly areas like 1987-1991 or 2007-2009.

33
Arctic sea ice / Re: What's new in the Arctic ?
« on: March 28, 2019, 02:17:41 PM »
New Sea Ice comparison tool showing the number of Ice Free Days in a year and the anomaly compared to the long term baseline of 1979-2018.

https://cryospherecomputing.tk/IceFreeDays

34
That is AMAZING and thank you! One question. Could you make a map comparing 2018 minus 1998 in terms of anomalies? (or a year - year comp tool)? This would be very helpful for comparing yearly shifts vs normals. I am comparing 1998 and 2018 and the 20 year change is astonishing in many regions -- parts of Canada have two to three months of extra snowcover vs. 20 years ago, while parts of the Arctic have become almost entirely ice free!

A year to year comparison tool would be nice, but it isn't something I can create easily. All the calculations would need to be done in javascript of which I have almost zero knowledge of. The current year comparison with the slider is just template code added together. It took maybe a reasonable 2-3 hour to create the site, far below the required few days to learn the basics of javascript.

I attached your requested 2018 - 1998 map.

35
All hail HTML, CSS, Javascript and the W3.CSS template creators.

I managed to combine a beautiful slider with an image slideshow. Now I have the tools to easily compare years against each other. The images are updated in the same place to a new year for easy comparison instead of putting all images into a huge grid like on my old website.

These news are posted here due to the first content using this are the Snow Covered Days maps.

https://cryospherecomputing.tk/Snow-Cover

36
Arctic sea ice / Re: The 2019 melting season
« on: March 12, 2019, 06:36:30 PM »
Thanks to all who tested the website. In the future just pm me to keep the thread clean.

37
Arctic sea ice / Re: The 2019 melting season
« on: March 12, 2019, 02:37:40 AM »
A short off topic announcement & question. (It will help you following sea ice melt in the future)

I'm trying to get off googlesites to get more presentation freedom and created a webpage with github pages and a proper address saluting to the glorios pacific atoll of Tokelau.  :D

https://cryospherecomputing.tk/

Currently it's just a generic template with links to the images on googledrive thrown into. None of the buttons should do anything. Does anybody have problems accessing the website or seeing any of the images?

Attached is an image of all Tokelau islands (stuck next to each other) and how the website should look like on a 1080p monitor.

38
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: March 10, 2019, 06:47:44 PM »
As many of you know the DMI moved all their Greenland data products to the Polar Portal website (http://polarportal.dk/en/greenland/surface-conditions/)

I emailed them about the missing accumulated SMB map and their reply was that it isn't as popular as the anomaly map and therefore unlikely to make it over to PolarPortal. I find it dissapointing, but to brighten up my day I found their monthly raw data is freely available for research purposes. (currently Jan 1980 to Aug 2017)

So I think I produce the accumulated SMB maps myself all the way back to 1980 and create some long term SMB graphs (whole year Sep-Aug) and only the melt season (Jun-Aug). Is there anything you would like to see that's possible to create with monthly surface mass balance data?

39
Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: March 07, 2019, 02:12:18 PM »
Only moderate increases in the AMSR2 Snow & Ice Volume. The St. Lawrence and Sea of Okhotsk ice
is too thin affect the overal numbers much.

Full size images and February animation at:
https://cryospherecomputing.tk/SIT

40
With the latest cold outbreak into the USA, North American Snow Extent is back to over two standard deviations above the long term mean. The time is running out to get a low albedo spring for an early sea ice melt.

41
Permafrost / Re: Snow Cover changes on regional scale
« on: March 05, 2019, 11:31:22 AM »
As promised here is the detailed 10 year mean snow extent, though for Tibet it's still quite noisy. The only smooth period is mid to late summer showing a decline in snow cover. The Tibet region includes the glaciated Himalayas, so snow extent never reaches zero.

42
Permafrost / Re: Snow Cover changes on regional scale
« on: March 05, 2019, 11:10:10 AM »
Tealight did you compute R2 for those trends? Some of them don't look like they have very strong correlation.

I just added a linear trendline in excel to get any quick impression from the noisy data. Some months have R2 almost 0 and some as high as 0.6.  We are analysing a highly weather dependent variable so I don't expect high R2 values to begin with. That's why climate scientists use 10 to 30 year averages.

43
Permafrost / Re: Snow Cover changes on regional scale
« on: March 04, 2019, 12:47:47 PM »
The final regions are Tibet and the mountain ranges north of it. (I named the region Central Asian Mountains)

Tibet months with trends:
March to May: increase
June to February: decrease

Central Asia Mountain months with trends:
October - February: increase
May: decrease

Tibet goes completly against the general trend with increases in spring snow cover and decreases for most of the year including autumn and winter. A more detailed look follows tomorrow with daily values of 10 year averages. The mountains north to it follow the general trends with increased autumn-winter snow cover and decreased spring snow cover.


44
Permafrost / Re: Snow Cover changes on regional scale
« on: March 04, 2019, 12:34:56 PM »
It's time to finish the project with the last four mid-latitude regions in Asia. This post is for the low elevation Central Asia and East Asia.

Central Asia months with trends:
Oct: increase
Nov: increase
Dec: increase
Jan decrease
Feb: increase
Apr: decrease

East Asia months with trends:
Oct-Mar: increase

Both regions show the typical autumn-winter increase in snow extent. In spring central asia shows decrease and east asia shows no trends.

45
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: February 25, 2019, 11:41:59 PM »
The higher snow extent this year should make the snow melt faster because it is spread out more. This is a simple energy transfer law of Volume to SurfaceArea ratio that effects everything.

Meanwhile in the UK we have the warmest February on record. The last two weeks were constant strong southern wind and today we reached 20°C in Wales and even 15°C in northern Scotland which has a similar latitude to northern Quebec or central Hudson Bay. I already bought some ice cream this year to cool down during late winter.

46
Arctic sea ice / Re: Guess the date of the max
« on: February 21, 2019, 11:49:06 PM »
Anyway I am going for the 15th March as recommended by my ouija board. After all, this is a science-oriented forum.

The 11th - 15th March category is almost completly empty in your graph. The average is just there because other years are earlier and later.

I voted 1-5th of March, but I feel it might be even earlier. Currently we have very high extent in the southern most regions of Sea of Okhotsk and around Newfoundland which melt early. The only region with significant growth potential is the Bering Sea.

47
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: February 21, 2019, 11:29:53 PM »
The NOAA North American snow extent is now over two standard deviations above average, in Asia about one above and in Europe well below average. However in spring we could still see a crash like in 2012.

https://sites.google.com/site/cryospherecomputing/snow-cover

48
Antarctica / Re: Antarctic Icebergs
« on: February 20, 2019, 10:45:37 PM »
A small part of A68A completly disintegrated instead of breaking off in one piece. Previous images are in the "Rift in Larsen C" topic which really isn't fitting anymore.

https://forum.arctic-sea-ice.net/index.php/topic,1175.msg186956.html#msg186956

49
Antarctica / Re: What's new in Antarctica ?
« on: February 13, 2019, 11:20:42 PM »
A few islands near the northern tip of the antarctic peninsular lose snow cover - while the rest remain white - why?. In the 2001 image it looks as if sea ice is still surrounding the greenish island. It does not look as if the loss of Larsen B ice shelf has changed anything. Snow beginning to re-appear in the 2019-02-12 pic. Images cut from arctic.io

The islands are east of the Antarctic Peninsular, which means they are sheltered from the wet westerly winds and receive little snow fall compared to islands west of the peninsular. They are also in a good position to receive warm and dry from Foehn wind. Together with the fairly northern latitude is enough to keep the low elevation coastal regions from getting glaciated and become snow free in summer. But since they are so close to Antarctica snow can fall any time of the year. It really depends on the weather.

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Arctic sea ice / Re: PIOMAS vs CryoSat
« on: February 12, 2019, 10:58:59 AM »
Well this region has been very cold this winter, but we can only guess if this has translated into extra thickness. From Lebedev ice growth formula we know that sea ice over 2m grows very slowly no matter how cold the air is.

All I know for sure is that my AMSR2 thickness is high as well, but it is definitely affected by snow.

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