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Messages - Tealight

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51
Permafrost / Re: Snow Cover changes on regional scale
« on: January 12, 2019, 03:06:32 PM »
We finish the Arctic regions with the mean extent over the whole year to see when each region starts to melt and at what rate. For example Alaska melt starts early at the end of April, but takes until the end of June. In contrast Eastern Siberia doesn't start until mid May, but also finishes at the end of June.

The 2000s and 2010s mean snow extents of Alaska and Eastern Canada show the magnitude of low spring snow cover or high autumn snow cover compared to the whole year.

52
Permafrost / Re: Snow Cover changes on regional scale
« on: January 11, 2019, 02:32:41 AM »
West Siberia varies more noticably from year, but has again an early summer low point around 2010-2012. October shows the typical long-term autumn increase in snow cover which we have observed in other regions. November only has a very small increase due to the large year to year variability.

53
Permafrost / Re: Snow Cover changes on regional scale
« on: January 11, 2019, 02:31:58 AM »
Today we continue with the Arctic region with Siberia. This post is about the Eastern and Central Siberia. The next one is exclusive to western Siberia. Check the region map in the first post for the exact boundaries.

Like the Arctic in Northern America early summer snow cover was lowest in the 2010-2012 region and increases for earlier years and later years. For eastern Siberia this is most pronounced in June and for Central Siberia in May.

Autumn Snow Cover shows no significant trend for eastern Siberia, possibly due to almost complete coverage by the end of October. Central Siberia experiences a slight increase in October and November snow cover.

54
Permafrost / Re: Snow Cover changes on regional scale
« on: January 09, 2019, 11:40:55 PM »
Eastern Canada doesn't have a downwards trend during Spring. Instead it's positive like in the autumn. The theory here is that eastern Canada receives so much more snowfall that it offsets any increased snow melt during spring. See the Northern Hemisphere snow cover thread for discussion, maps & graphs (around post 200).

snow cover trend per month
April: slight increase
May: clear increase
June: neutral
July: slight increase
Aug: None
Sep: clear increase (although at very low level)
Oct: clear increase
Nov: clear increase

55
Permafrost / Re: Snow Cover changes on regional scale
« on: January 09, 2019, 11:21:42 PM »
Today we continue with Canada. This post is about the Canadian Rockies and Central Canada. The next one is exclusive to eastern Canada. Check the region map in the first post for the exact boundaries.

For the Rockies May, June and October seem to have a consistent downward tend in snow cover over the last 20 years. The other months are very close to either the maximum extent or to the minimum extent. Only November has a very slightly positive trend in snow cover.

In Spring/Autum snow cover in Central Canada is highly variable from year to year. However October and November show a very clear upwards tend. So the data is confirming the theory that the higher atmospheric moisture from an increasingly ice free Arctic causes more snow cover in the autumn.

56
Permafrost / Re: Snow Cover changes on regional scale
« on: January 08, 2019, 02:37:53 PM »
The data is now available as a formatted Excel sheet through the Link in the first post. I try to post 2-3 regions every day until we covered all of them.

Today we continue the northern regions with northern Canada and Alaska. They feature a pattern I've seen in several northern regions. Early summer snow cover was lowest in the 2010-2012 region and increases moderately for earlier years and slightly later years.

57
Permafrost / Snow Cover changes on regional scale
« on: January 07, 2019, 01:25:37 AM »
I finished calculating regional snow extent data and will post my analysis here. The main snow cover thread doesn't quite fit for this detailed long term analysis. At the moment all data is still in one long list, but after formatting we can graph things like snow extent for region x in month y. I attached a map showing all regions and an example for Greenlands snow extent.

Eventually regional graphs should also get daily updates on my main snow cover webpage
https://sites.google.com/site/cryospherecomputing/snow-cover

Data Download (csv & formatted ExcelSheet)
https://github.com/NicoSun/CryosphereComputing/tree/master/ScienceData/Snow_Cover_Regional


58
Arctic sea ice / AMSR2 Snow & Ice Volume/Thickness
« on: January 03, 2019, 09:01:01 PM »
AMSR2 thickness and volume ties with 2013 and 2014 for the highest values.

Full size images + gif +netcdf at:
https://cryospherecomputing.tk/SIT

59
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 18, 2018, 10:50:05 PM »
Antarctic Sea Ice Area is now at record low, 60,000 km2 below 2016 and 2.72 SD below the mean. This is even slightly below the low estimate of my SIPN_south forecast which is already far lower than any other forecast. With compaction staying at record low too, I don't expect this year to slow down in area losses like 2016 which turned to above average compaction at this point.

more Area data and sea ice map on:
https://sites.google.com/site/cryospherecomputing/daily-data-antarctic


60
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: December 17, 2018, 01:22:59 AM »
I will try and boldly go where only Tealight has gone before.
...............
I think Tealight has got his timing for getting his project on the street just about right.

Thanks for helping out  :)   I would say its a year too late. Not only did we have major arguments here about albedo, but I also need to take a long break from Climate Science research. It's not so much of a time issue, but I need all my concentration and analysis power for my day job.

Anyway, the Near-Real-Time AWP page (soon daily updated) is coming along, but I'm not sure on the main graph. It's supposed to compare major Regions of the world. Canada and the USA are each large enough to put them into the same category as Europe, but the southern USA has almost never snow cover (see atached map) and is more similar in latitude to northern Africa. So for now I have excluded the two southern US regions. Apart from high altitude Tibet all other regions extent to around 35 degrees south.

I think I make at least 4 regional graphs. One for European subregions, one for Asia and one or two for North America. 8 regions might be a little too cluttered. Then it will be one graph for Canada + Alaska and one graph for US Pacific, US Rockies, US Mid-West and US North East

https://sites.google.com/site/cryospherecomputing/awp/awp-northern-hemisphere


61
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: December 16, 2018, 12:56:06 AM »
The time has come  :)

After a few hours of coding and 1.5h of calculation the AWP and AWP_anomaly data for the Northern Hemisphere is ready to be explored. For eastern Canada, the most discussed Region here I already made two charts of the mean anomaly for April and May.

We have:
21 years * 365 days * 24 Regions * 2 variables = 367,920 values

That will take some time to get through and find all interesting parts. I hope some forum members can explore it too. The data is available as usual on Google Drive and now also on Github.

Google Drive:
https://drive.google.com/drive/u/1/folders/1MiBVuMjoG-TRBsJhwPiChJYF5lKlaaxC
Github:
https://github.com/NicoSun/CryosphereComputing/tree/master/ScienceData/Northern_Hemisphere_AWP

62
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: December 14, 2018, 01:49:08 PM »
I'm almost finished with my Northern Hemisphere AWP model, hopefully done this weekend. The most important part left is coding the calculations for each individual region and then the daily updates can start.

A proper documentation, long term graphs and other visulization will follow soon after.

In the regional breakdown it's impossible to create exact regions for each individuals preferences. So I chose my regions by considering geographic regions and international borders. (apart from mid latitude Asia, no one there is interested in it anyway)


63
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 12, 2018, 08:34:19 PM »
In any case, the graphs posted by Tealight (though they do not show very many years) suggest that the rate of melt we're now seeing is at least unusual if not unprecedented. I still haven't seen anyone give an answer to gerontocrat's question about whether we're witnessing a bigger change in the last few years, to bring cause this decline in Antarctic sea ice extent, or whether this is just an anomaly. The rate of melt occurring now may seems like an important piece of evidence to be considered.

Generally Antarctic sea ice is more variable from year to year, but doesn't have a clear trend like the Arctic. As far as I know it is more sensitive to weather patterns as the Arctic because it isn't constraint by continents on all sides, only one in the middle. In the last two years we got weather favoring low sea ice and with the addition of greenhouse gases it looks like an extreme warming. My cumulative albedo warming maps look completely different from year to year and I don't see a clear trend. This year will most likely end up in second place so the top 3 years in accumulated solar energy are the last 3 years.

https://sites.google.com/site/cryospherecomputing/awp/Antarctic-Overview

On my compaction graphs I only show record high and record low years (apart from recent years). The middle contains over 30 years zig-zagging around the mean. For this time of the year sea ice compaction is unprecedented. The second lowest compaction value for 11th December is 60.7% in 2010. Is the graph with two standard deviations any better?


64
Arctic sea ice / Re: Latest PIOMAS update (November mid-monthly update)
« on: December 03, 2018, 02:12:10 AM »
The November coldness seems have had an impact on the ice. Both thickness and volume increased way above previous years.

Full size images + gif +November netcdf at:
https://sites.google.com/site/cryospherecomputing/amsr2-sea-ice-volume

65
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: November 29, 2018, 08:19:01 PM »
I also think the actual average map is of interest, as it can show which specific points and areas tend to be more or less snow-covered.

Ok here is a map of the 2000-2017 mean snow coverage. Do you like the colorbar better with inconsistent ticks of 90 days & last one of 95 instead of the three 100 day ticks?

Full size at:
https://drive.google.com/drive/u/1/folders/19b4bnBcnv7Ho3nbmjubMnwVJy2tkP1F7

66
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: November 28, 2018, 12:59:06 AM »
I calculated how long in each year (2000-2017) a gridcell is covered by snow or ice. The presentation is quite bad with google sites so I recommend viewing the images in the google drive folder or even better download the netcdf file and choose the visualization yourself.

NetCDF & Images:
https://drive.google.com/drive/u/1/folders/1QCM9lVx6tg0QGQXgK8NBZmKkYHLQN940

Website:
https://sites.google.com/site/cryospherecomputing/analysis/snow-covered-days

67
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: November 25, 2018, 09:39:49 PM »
A small preview to show that albedo doesn't matter in winter. Currently Greenland absorbs the same amount of energy as the Northern Atlantic (none). Without a coastmask there is just a big empty void on the map.

1st image: absorbed solar radiation
2nd Image: absorbed solar radiation anomaly

68
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: November 10, 2018, 02:28:26 PM »
Hereby I officially launch the Northern Hemisphere Snow Cover page on CryosphereComputing. The automated update works for the images and from tomorrow the 10day gifs should update as well.

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

The navigation sidebar was already overflowing, so I changed it to a top bar to keep things clean.

69
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: November 04, 2018, 02:03:34 PM »
Hi Northern Hemisphere Snow Cover fans,

I'm still in the process of building my Albedo Warming model for the whole Northern Hemisphere. It's probably ready before Christmas.

So far I manged to get the NOAA data into a usable format and encoded the continents as subregions. What's still missing is a pixel area correction.

Since I got the snow extent data already I will then publish daily snow extent graphs as well. What do you think about the following graph combining all continents & sea ice into one graph? It's definitely different to any other product out there, but I'm not sure if it has too much colour on it. Changing them and the transparancy is of course no problem.

Edit: In the first picture the shaded regions are 1 standard deviation



70
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 23, 2018, 04:33:16 PM »
I so wish Tealight aka Nico Sun did estimates of FDDs for the Arctic Ocean as a whole, or even better sea by sea as he does for Albedo warming potential. All I want for Xmas is a....

I think he wants it as well, but he has only a limited amount of time and if he does a new gridded FDD analysis it will be a full FDD map of the Arctic and not just a few new graphs.

Currently he is busy with a daily & year-round combined Albedo Warming Potential for Land & Ocean (see map below)

The data is only available since 1997 and he doesn't have a regional breakdown yet for this projection.

71
Arctic sea ice / Re: Latest PIOMAS update (September mid-monthly update)
« on: October 04, 2018, 12:55:42 AM »
On my AMSR2 thickness model Sea Ice Volume didn't change in September (fairly typical behavior) Only the distribution shifted from the Eurasian-Pacific side towards Canada and Greenland.

https://sites.google.com/site/cryospherecomputing/amsr2-sea-ice-volume


72
Arctic sea ice / Re: Latest PIOMAS update (September)
« on: September 04, 2018, 12:52:38 PM »
Am I misinterpreting the Worldview of the ESS ice? Looks way thinner than PIOMAS August 31 suggests.

PIOMAS is quite low resolution so the ice-free areas average out with the last remaining thick floes. My AMSR2 derived Volume model is more detailed and shows gaps in the ESS arm.

https://sites.google.com/site/cryospherecomputing/amsr2-sea-ice-volume

73
Permafrost / Re: Northern Hemisphere snow cover
« on: July 27, 2018, 03:13:21 AM »
I'm working on a simple (non-gridded) version of my AWP anomaly model for the Northern Hemisphere land cover in order to quantify the effect of the increased snow extent we had the last few springs. There will still be a continental breakdown of Eurasia, North America and Greenland because the Latitude changes differently on each for the same snow extent values.

What's definitely clear is that the most important months are May and June. The autumn does hardly matter because the solar intensity is too low. Overall there is of course a strong warming trend. 2017 causes a drop in the 5 year moving average, and 2018 doesn't make up for it. (until June)

Maybe I finish it sometime in August and will post a better description and analysis on my website.
https://sites.google.com/site/cryospherecomputing/awp

All snow extent data is from Rutgers University:
https://climate.rutgers.edu/snowcover/table_area.php?ui_set=2

Here are some preliminary Graphs for the whole Northern Hemisphere.

74
Any way of telling how thick they are from the freeboard ?

sidd
Yes by measuring the shadow...requires calculating the elevation-angle of the Sun at the time of the acquisition.

I did some measurements and currently the southern branch and it's tabular icebergs have 68.8m freeboard. For comparison during the record low in August 2015 the freeboard was 125m.

75
Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: June 12, 2018, 01:21:54 AM »
here is a version comparison of the 2016 minimum

76
Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: June 12, 2018, 12:57:16 AM »
Very late update this month. I lost all my Cryosphere data due to some problems with new computer hardware and had to recover everything. Most of the stuff I created in the last two month was lost. Daily images & NETCDF files for the thickness data should be available soon.

While I was rewriting several parts I also refined the algorithm slightly. Now the volume crash in late summer isn't as extreme. The graphs looks a bit smoother, but it will be more noticeable on the map showing local thickness. (I haven't shown late summer maps yet so it doesn't tell you anything  ;D)

Anyway here are is the May data:



77
Arctic sea ice / AMSR2 Snow & Ice Volume/Thickness
« on: March 04, 2018, 12:53:45 PM »
A few people already know the ADS/JAXA sea ice thickness and melt concentration product. It is derived from various AMSR2 scanning frequencies.

The melt concentration makes it hard to estimate the sea ice volume, because you can't just read out all individual cell values and calculate the sum. To overcome this issue I developed a melt algorithm which estimates thinning based on the melt concentration percentage and the number of days it occurred. The algorithm also estimates freezing of open water from the melt concentration.

My calculated Sea Ice Volume & Thickness:
https://cryospherecomputing.tk/SIT






Anyone interested in the details can look at my short documentation.
https://sites.google.com/site/cryospherecomputing/documentation/amsr2-sea-ice-volume-algorithm

Due to the JavaScript download-site from ADS I can't set up daily updates, but I'm able to download a whole month of sea ice thickness products and get rid of unwanted files and decompress the right ones for processing. With these scripts I can update it every month with a few minutes work.

The AMSR2 thickness isn't as accurate as PIOMAS for actual sea ice thickness. It's definitely affected by melt pond refreezing in August, which almost cancels out further volume losses and thickness increase is rather slow in October-November. As indicated with 2017 it counts snow cover as additional sea ice volume like CryoSat did.

If ones aware of these artefacts it's still a very useful tool to judge current sea ice conditions. Refreezing melt ponds mean a quick end to the melting season and additional snow has to melt in spring before the sea ice melts.

Further it has a higher spatial resolution (10km) than PIOMAS and a higher temporal resolution for the entire Arctic than CryoSat.

Attached is a comparison to PIOMAS

ADS Raw Data visualization:
https://ads.nipr.ac.jp/vishop/#/monitor




78
Arctic sea ice / Re: Albedo-Warming Potential
« on: March 24, 2017, 11:25:44 PM »
I prepared the daily updates of my AWP model for this melting season. In April I have some more time for polishing and might update all regional graphs as well. Until then you can follow the bright colour spectacle on:

https://sites.google.com/site/cryospherecomputing/warming-potential/graphs


79
Arctic sea ice / Albedo-Warming Potential
« on: September 27, 2016, 09:29:22 AM »
The Albedo-Warming Potential is an attempt to quantify the additional warming from a lower ice cover at the poles. At the moment these calculations don't include cloud cover, therefore it is called "Warming Potential" and not actual warming. However, over six-month weather tends to average out and warm areas correlate well with low ice extend in September. The basis of all calculations is a self-developed global surface radiation model and NSIDC Sea Ice Concentration data.
It is in essence a much better version of my “Quantifying albedo effect / Rating daily area values” topic. In order to present the results better I created my own website and only use links on the forum. If I update my calculations all changes will be applied to this first post too and not scattered across several posts. 

Link to my website CryosphereComputing:
https://cryospherecomputing.tk/awp.html

former website
https://sites.google.com/site/cryospherecomputing/warming-potential


The following images are all cumulative results from the last day of the melt season. The end of the astronomical summer to be precise. For daily Animations click on the link below the year. All daily values are also available on my website.

All anomalies are calculated against the 2007-2016 sea ice concentration average.
Red indicates lower albedo and above average warming.
Blue indicates higher albedo and below average warming.
One extra day of peak insulation on open ocean is about 20 MJ/m2.
One extra month of peak insulation on open ocean is about 600 MJ/m2.

2007
Daily Animation



2008
Daily Animation


2009
Daily Animation


2010
Daily Animation


2011
Daily Animation



2012
Daily Animation





2013
Daily Animation



2014
Daily Animation



2015
Daily Animation



2016
Daily Animation



Pan Arctic Graphs:




Regional graphs:

https://sites.google.com/site/cryospherecomputing/warming-potential/regional-graphs


Global surface radiation model details:
The model calculates the incoming solar energy per day per m2 for all latitudes between 40N and 90N (0.2 degree steps). Considered are solar zenith angles, the atmospheric reduction (Air mass), Projection effect and water albedo for every 15min interval. If a grid cell has 55% ice concentration, then it is treated as a water area 55% the size of the grid cell.


NSIDC Sea Ice Concentration details:
   Ice concentration average: 2007-2016
   Pole hole ice concentration is calculated from a 2-pixel wide ring around the hole
   Lake ice is ignored to reduce noise
   Pixel Area corrected
   warming potential for each individual pixel (max. 0.44-pixels off from pixel center)

NSIDC Data
Cavalieri, D., C. Parkinson, P. Gloersen, and H. J. Zwally. 1996, updated yearly. Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 1. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.http://dx.doi.org/10.5067/8GQ8LZQVL0VL.

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