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Author Topic: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs  (Read 10014 times)

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #150 on: November 08, 2018, 08:43:53 AM »
Finally: another thing to note!

Here is the SWE map as of 7/1/2018. The areas in red (300-400MM of accumulated SWE as of 7/1) survived the summer and are the toe-holds for re-glaciation (as evidenced by what has happened this autumn).

The threshold for summer coverage may be slightly higher further south, but I think this may be a good gauge for 2019's expansion (or not) on 2018's accumulation of anomalies. Any areas in red as of 7/1/2019 are probably likely to retain full coverage for the full year. Just something to keep in mind in seven more months...!


Niall Dollard

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #151 on: November 08, 2018, 10:05:08 AM »
An inventory and analysis of the glaciers and snow fields in the Torngat mountains of northern Labrador.

https://www.igsoc.org/journal/60/223/t13j195.html

Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #152 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.

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #153 on: November 10, 2018, 04:15:23 PM »
An inventory and analysis of the glaciers and snow fields in the Torngat mountains of northern Labrador.

https://www.igsoc.org/journal/60/223/t13j195.html

That is a very informative piece of research. Thank you.

"More recently, in a pilot study of change detection on a
subset of the 96 largest Torngat glaciers, Brown and others
(2012) documented a 9% decrease in ice area between
2005 and 2008 using glacier outlines mapped from SPOT5
(Satellite Pour l’Observation de la Terre) imagery (2008) and
this study (2005). The recent reduction of glacier ice in the
Torngat Mountains was interpreted as a response to both
higher summer air temperatures and a multi-decadal decline
in winter precipitation (Brown and others, 2012). A full
analysis of change detection over the past 60 years for all
glaciers and ice masses in the Torngat Mountains, including
field surveys, is currently in progress."

gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #154 on: November 10, 2018, 05:24:08 PM »
And that study tells us that we are not currently talking about a lot ..

Quote
In 2005, 195 ice masses existed in the Torngat Mountains,
covering a total area of 24.51  +/-1.80 km2. The size
distribution is highly skewed to smaller ice masses, with
almost a third smaller than 0.05 km2 and only eight larger
than 0.5 km2 (Fig. 5). The 30 largest ice masses made up
almost 50% of the total ice area, whereas the 30 smallest ice
masses covered only 2.8% of the total area. The median ice
mass area was 0.07 km2 (range 0.01–1.26 km2), and the
median ice mass length was 0.33 km (range 0.04–2 km). In
total, 49 ice masses were longer than 0.5 km, 8 longer than
1.0 km and 15 shorter than 0.1 km. Ice masses in the Torngat
Mountains span slightly more than 1° of latitude (58.6–
59.9° N; 170 km) and occur within 50 km of the Labrador
Sea (Table 1; Fig. 1). Ice masses more commonly occur in
the fretted mountain region (68%; 80% of ice area) adjacent
to the Labrador Sea (Table 1). For the most part, ice mass
forms are evenly distributed across the region, except for
summit ice masses that predominantly occur inland and
farther north.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #155 on: November 10, 2018, 05:29:01 PM »
And that study tells us that we are not currently talking about a lot ..

Quote
In 2005, 195 ice masses existed in the Torngat Mountains,
covering a total area of 24.51  +/-1.80 km2. The size
distribution is highly skewed to smaller ice masses, with
almost a third smaller than 0.05 km2 and only eight larger
than 0.5 km2 (Fig. 5). The 30 largest ice masses made up
almost 50% of the total ice area, whereas the 30 smallest ice
masses covered only 2.8% of the total area. The median ice
mass area was 0.07 km2 (range 0.01–1.26 km2), and the
median ice mass length was 0.33 km (range 0.04–2 km). In
total, 49 ice masses were longer than 0.5 km, 8 longer than
1.0 km and 15 shorter than 0.1 km. Ice masses in the Torngat
Mountains span slightly more than 1° of latitude (58.6–
59.9° N; 170 km) and occur within 50 km of the Labrador
Sea (Table 1; Fig. 1). Ice masses more commonly occur in
the fretted mountain region (68%; 80% of ice area) adjacent
to the Labrador Sea (Table 1). For the most part, ice mass
forms are evenly distributed across the region, except for
summit ice masses that predominantly occur inland and
farther north.
The study also ended in 2012 which was (IMO) the inflection point re: moisture feedbacks / +albedo compensating for -sea ice. They all end around that time. Another ten years of data will be very telling, assuming we are still collecting data in 2028 and things haven't gone off the deep end by then.

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #156 on: November 10, 2018, 06:05:43 PM »
The study also ended in 2012 which was (IMO) the inflection point re: moisture feedbacks / +albedo compensating for -sea ice. They all end around that time. Another ten years of data will be very telling, assuming we are still collecting data in 2028 and things haven't gone off the deep end by then.

You are correct and the study only looked at the largest 96 ice masses. The smaller ice masses, a total of 99 were ignored in this study. However, I would like to allay your concerns that further study may not occur. A more thorough study of all of the ice masses is now underway.

"A full analysis of change detection over the past 60 years for all glaciers and ice masses in the Torngat Mountains, including field surveys, is currently in progress."

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #157 on: November 10, 2018, 07:49:21 PM »
Tealight, maybe a stupid question. But why is Greenland white ? Is there no data about it, or did nothing changed, or.......

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #158 on: November 10, 2018, 08:42:13 PM »
Since you cut off the legend, I have no idea what this map is measuring...above or below the mean of what?

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #159 on: November 10, 2018, 08:52:09 PM »
It's snow and ice extent anomaly.

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #160 on: November 10, 2018, 08:58:07 PM »
And i think something like volume. Why else would it have the different colors, light and dark blue.

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #161 on: November 10, 2018, 09:00:30 PM »
OK. I'll hazard a guess. White areas are then areas where snow is present where it is normally present at this time.

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #162 on: November 10, 2018, 09:02:13 PM »
And i think something like volume. Why else would it have the different colors, light and dark blue.

Where did you get the chart from? Attach with the legend and a link to the site and we can have a worthwhile discussion.

oren

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #163 on: November 10, 2018, 09:20:14 PM »
Thank you Tealight. Awesome. I especially liked the animation.
To those asking, my guess is the blue shows more snow extent than climatology, and the red means less extent.
This can't show volume as the database (NOAA?) has no information on thickness.

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #164 on: November 10, 2018, 09:57:48 PM »
Shared Humanity, almost on top of this page, the last post from Tealight. There is a link to the site.

Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #165 on: November 10, 2018, 10:27:42 PM »
Thank you Tealight. Awesome. I especially liked the animation.
To those asking, my guess is the blue shows more snow extent than climatology, and the red means less extent.
This can't show volume as the database (NOAA?) has no information on thickness.

That's correct. I wanted to include a colormap for the snow cover anomaly map, but I didn't manage to put it on the map (in the Atlantic Ocean). By default matplotlib only allows the colormap on the side which would cut a huge part of the actual map away. This would greatly distord the data compared to the normal extent map.

At the moment I can only change the description in the bottom right corner. Maybe red: below climatology, blue: above climatology, white: same as climatology

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #166 on: November 11, 2018, 03:41:39 AM »
Shared Humanity, almost on top of this page, the last post from Tealight. There is a link to the site.

Thanks

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #167 on: November 11, 2018, 05:19:33 AM »
Now i see, it's the same as with sea ice extent/area. Like 50 % of the land is covered with snow. The 10 day animation shows plenty of red further south in the US, and more dark blue further to the north. Would that not create some kind of contrast ? A warming south, and i don't know cooling, but at least a faster with snow covered north.

Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #168 on: November 11, 2018, 11:33:00 AM »
I have changed the description to match the colorbar in descriptive words. Is it any clearer? The deepest red and blue are +-100% departure from the climatology, not the +-50% on my sea ice area. It's because the snow extent data can only be 0 or 100%, nothing in between. With a +-50% colormap it would look too extreme.


The second attachment shows the actual colorbar and where it's supposed to be.

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #169 on: November 13, 2018, 03:59:30 AM »
Looks like North America might be making a run for another record month. The SWE departure is even more impressive.


bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #170 on: November 13, 2018, 06:25:06 AM »
We are so screwed


bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #171 on: November 13, 2018, 05:22:27 PM »
o boy



who could have ever seen something like this happening



whatever will we do

Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #172 on: November 13, 2018, 06:10:19 PM »
I changed my normal snow cover map to include daily change. Now red indicates snow cover loss from the pervious day and blue indicates snow cover gain. I feel this change makes it a bit more informative than before.

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #173 on: November 13, 2018, 07:17:04 PM »
He bbr, do you know how they calculate that snow water equivalent ? last year there was some 400 to 500 km3 of snow water extra than average. How much snow is that, is it like 1/10 of a m3 melt water for 1 m3 of snow. Or is it like 50 % ........?

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #174 on: November 13, 2018, 07:37:10 PM »
He bbr, do you know how they calculate that snow water equivalent ? last year there was some 400 to 500 km3 of snow water extra than average. How much snow is that, is it like 1/10 of a m3 melt water for 1 m3 of snow. Or is it like 50 % ........?
I have no idea. I consider 1KM^3 of SWE to be the same equivalent to 1KM^3 of sea ice but I could be wrong.

Alexander555

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #175 on: November 13, 2018, 08:08:14 PM »
They are talking about snow water. That's after the snow melted i would think . For normal snow it's like 10%, old snow 50 %, ice 100 %. So how much snow was there extra, 500 km3 represents a layer of 5 million km2 a meter thick at 10 %.

Red

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #176 on: November 13, 2018, 08:36:43 PM »
Snow water equivalent (SWE) is the depth of water that would result if the snow mass melted completely.

From the perspective of water resources, flood prediction, and engineering, the most important observation (and one not taken by most weather observers) is the "Snow Water Equivalent of Total Snow Depth". This measurement is very important as it represents the amount of water contained in the total snowpack that is available to melt and run off when temperatures rise. Thus it can be used to forecast future water supplies and assess the potential for flooding. It can also be converted to weight per area. This number is critical for monitoring the weight of snow on roofs. For example, if there are 10 inches of old packed snow on the ground, this may contain 3.0" of water content which equates to nearly 15 pounds per square foot if uniformly distributed on the ground and roofs.

https://madis-data.noaa.gov/snow_measurements.html

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #177 on: November 14, 2018, 08:13:15 AM »
This is very frightening. I would imagine we will see a very severe outcome as this heat comes up against the snowfall about to fall across the Northeast (several events over next ten days per 00z EURO). This is D10 water temp vs. same time 2017. The Gulf Stream bulge got worse tonight. I would say it may be unprecedented for time of year.


bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #178 on: Today at 07:30:02 PM »
^map is wrong -- the EURO apparently has a bias where it creates a crazed Gulf Stream each and every run.

Also: first snow of the season now falling in NYC with a few inches expected! Very, very early.