Northern Hemisphere Winter 2020-2021 Snowcover / Misc Obs

[gerontocrat]

And here is the snow map

The places where snow stubbornly resists melt are Central Northern Canada and Central to Eastern Northern Siberia. I am willing to believe the temp forecasts in the post above - so the snow is doomed, I say, doomed.

[Comradez]

According to Cryosphere Computing, NH snow extent anomaly is now (5/2/21) at --0.223 million km^2.

NH sea ice extent anomaly is now (5/2/21) at -0.135 million km^2.

Combined NH extent anomaly (let's call it the NH albedo extent anomaly) is now -0.358 million km^2.

If I recall correctly, previous discussions on this forum have concluded that, by May 1st there starts to be a strong correlation between snow extent anomaly on land and eventual arctic sea ice minimum in September.  If that is the case, then signs are currenting pointing to a slightly below average (but nowhere near record-breaking) eventual September sea ice minimum this year. 

[gerontocrat]

https://ccin.ca/ccw/snow/current

May is when most of the melt is supposed to happen

North America
Snow Cover Extent (SCE) still falling quickly, well inside the SD+1 boundary
Snow Water Equivalent (SWE) stalling a bit, above the SD+1 boundary

Eurasia
Snow Cover Extent (SCE) reducing at averge speed, now inside the SD+1 boundary
Snow Water Equivalent (SWE) falling quickly. Still above the SD+1 boundary by a bit. If it falls to inside that boundary, it will be the first time since last October when snowfall had barely started.

Once gain, very much above average Snow Water Equivalent (SWE) in winter does not prevent snow melt and SCE reduction.

click images to enlarge

[Aluminium]

Snow anomaly decreased by more than 1000000 km² in 1 day. It was -55268 km².

[Comradez]

Yep, I was just about to comment on that, Aluminium!  The snow melt is catching up with 2020 in Eurasia, and it is slightly head of 2020 still in Quebec. 

[gerontocrat]

I like Nico Sun's graph - 7th May

click to enlarge

[gerontocrat]

May should be the big snow melt month, So far Eurasia looks more impressive

A little gif to show progress

click to start - runs 5 times

[Shared Humanity]

I like Nico Sun's graph - 7th May

click to enlarge

Fantastic graph. Would love to see something similar with SWE.

[gerontocrat]

I like Nico Sun's graph - 7th May

click to enlarge

Fantastic graph. Would love to see something similar with SWE.

Wouldn't we all.

Find a data source he can use and it is quite possible Nico Sun would do it.
But I can't find the source where Environment Canada get their data from or anywhere else that provides a simple daily download facility.

[Comradez]

Asia is down way more today.  The Siberian melt is picking up steam.

According to Cryosphere Computing, NH snow extent anomaly is now (5/8/21) at -1.363 million km^2.

NH sea ice extent anomaly is now (5/8/21) at -0.312 million km^2.

Combined NH extent anomaly (let's call it the NH albedo extent anomaly) is now -1.675 million km^2.

[Comradez]

Asia snow extent falling off a cliff. 

According to Cryosphere Computing, NH snow extent anomaly is now (5/11/21) at -2.015 million km^2.

NH sea ice extent anomaly is now (5/11/21) at -0.297 million km^2.

Combined NH extent anomaly (let's call it the NH albedo extent anomaly) is now -2.312 million km^2.

[gerontocrat]

Problems with riding 2 horses

EDIT:   latest Nico Sun graph increases difference on anomalies in Snow Cover Extent between Nico & Environment Canada

We have two data sets on snow cover extent.
-Environment Canada
- Analysis by Nico Sun.

Environment Canada uses an average of the years 1998/99 through 2011/12
Nico Sun uses an average of 2000 to 2019.

They use different data sources and processing.

Environment Canada

Data are derived from the operational global snow depth analysis run at the Canadian Meteorological Centre, Environment and Climate Change Canada Canada, since 1998. The CMC analysis is based on optimal interpolation of real-time climate station snow depth observations merged with background information from a simple snow model, as described in Brasnett (1999). This snapshot is a contribution to the Global Cryosphere Watch (GCW) programme of the World Meteorological Organization. (Brasnett, B. 1999. A global analysis of snow depth for numerical weather prediction, Journal of Applied Meteorology 38:726-740.)

Nico Sun uses the NOAA / NSIDC analyses.

Nico Sun shows a Snow Cover Extent (SCE) anomaly  of minus 2 million Km2.
Environment Canada gives no numerical figure but the graphs show SCE at or or little bit above average.

I would go for Nico's analysis except Environment Canada has graphs on Snow Water equivalent (i.e. snow mass).

Graphs attached to illustrate the difference.

click to enlarge

[Comradez]

Heh, there's no way NH snow cover extent is merely around average or even slightly above average.  2021's snow melt is starting to put recent years' snow melt to shame, and I have a hard time believing that snowmelt in the late 1990s used to be even faster. 

According to Cryosphere Computing, NH snow extent anomaly is now (5/12/21) at -2.698 million km^2.

NH sea ice extent anomaly is now (5/11/21) at -0.291 million km^2.

Combined NH extent anomaly (let's call it the NH albedo extent anomaly) is now -2.989 million km^2.

[Aluminium]

2020/2021 comparison is similar for both sources. 2021 is well ahead of 2020 currently on both continents and both metrics.

[gerontocrat]

https://ccin.ca/ccw/snow/current
Data from Environment Canada on NH snowfall & melt.

North America
SCE reducing - just below +1SD boundary
SWE stalled, and now well above the +1SD boundary

Eurasia
SCE stalled and even ticked upwards, just above the +1SD boundary,
SWE reducing, but at well above the +1SD boundary.

i.e. no rush to finish snowfall melt this year.

click images to enlarge

[gerontocrat]

There has developed a significant inconsistency between snow cover extent (SCE) from Nico Sun and from Environment Canada

Nico shows recent strong snow cover extent (SCE) reduction in Europe, Asia and North America.

Environment Canada shows a recent small uptick and small downtick in SCE, and in North America a recent slow reduction in SCE that has now stalled.

https://cryospherecomputing.tk/
https://ccin.ca/ccw/snow/current

click images to enlarge

[kassy]

Could be different baselines. The latter is based on deviation from 1998 and 1999 years;

Figure 2: These plots show time series (updated daily) of snow cover extent (million km2) over (a) Northern Hemisphere land areas (excluding Greenland), (b) North America, and (c) Eurasia. Snow cover is assumed to be present in grid cells where the daily snow depth in the CMC analysis is at least 2 cm. The time series average and range between ±1 standard deviation (calculated for 1998/99 to 2011/12) shows how current conditions compare to historical variability.

Nico´s is from NOAA NSIDC data which is from 1979 and on.

Snow cover extent provided by the Rutgers University Global Snow Laboratory (GSL) is available from 1967–2021 for the North America + Greenland, Northern Hemisphere, Eurasia, and North America. All anomalies are relative to the 1981–2010 average.

https://www.ncdc.noaa.gov/snow-and-ice/extent/

[The Walrus]

The North American stall is not surprising considering the recent snowfalls in the Rockies.

[gerontocrat]

Could be different baselines. The latter is based on deviation from 1998 and 1999 years;

Baselines is not the point, though the difference between the 1981-2010 and 1998/99-2020/11 averages should be able to tell us something about the long-term trend in snowfall extent.

What I was showing is that snow cover extent is currently reducing fast according to Nico's analysis and slow to zero reduction according to Environment Canada.

[oren]

I never did trust Environment Canada much. Their constant purples in the Himalayas are very suspect and their methodological transparency is less than desirable.
In any case Nico=NSIDC as Kassy points out.

[gerontocrat]

I never did trust Environment Canada much. Their constant purples in the Himalayas are very suspect and their methodological transparency is less than desirable.
In any case Nico=NSIDC as Kassy points out.

If NSIDC or NOAA or ? produced a data set of Snow Water Equivalent compatible with the NSIDC SCE data that NICO uses I would go down on my knees and beg, grovel and humiliate myself to persuade NICO to do the same with SWE as he does with SCE.

Then I would happily consign Environment Canada to history.

But so far can't find a source of data.

[oren]

Continuing with my layman criticism, I've always wondered what their source was of snow thickness / water equivalence. I once tried to verify their thickness maps against measurements in specific weather stations, but the maps are barely readable and the measurements variable, and eventually the effort didn't provide results.
I understand why you report their numbers (and thanks for that along with thanks for many other of your posts), but I'm not surprised if the sources don't agree.

[kassy]

grid cells where the daily snow depth in the CMC analysis is at least 2 cm.

Maybe there was some area that dropped under 2cm but got some fresh snow recently?

[gerontocrat]

Snow Cover from Tealight's https://cryospherecomputing.tk/

Asia, especially, from early May to now (almost) finished the snowmelt season with a flourish.