Northern Hemisphere Snow and Ice Summer Retrenchment Thread 2012

darkman2

As we head toward summer the annual retreat of snow and ice across the Northern Hemisphere is well and truly underway. In fact I find alot of people are very surprised at just how dramatic the change is particularly by the height of summer and into August where away from the very highest mountain peaks in northern latitudes snow becomes a very rare commodity indeed even in those areas many might expect that not to be the case (Siberia for example). Not only does the snow and ice disappear almost completely outside of the most northerly polar region but mild air gets well up into the artic aswell and that's another interesting thing to observe. Those -10 850hpa temps become a distant memory in the late summer months. Just to find snow falling anywhere becomes a challenge.


An interesting place to observe is Svalbard, Norway which is a group of islands well to the north of Norway




Here are some webcams on the largest island of the archipelago to observe in the coming weeks.



Believe it or not snow will have gone from even here by the middle of May and the sea ice will be well on the way to disappearing.


Here are the dynamic charts updated daily for snow and ice extent in the Northern Hemisphere










And here is the extent of the cold air mass across polar regions today. Let's stick this image here and compare it at the height of summer!

MiNdGaM3

Both sea ice extent and sea ice area are the closest they've been to the long term mean since around 2010, and before that 2004.
A nice link for checking out the satellite imagery now that we have 24 hours sunlight. http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2012114.terra.4km

Nabber

How come the southern sea around the Kamchata peninsula freezes but the northern half doesn't?

MiNdGaM3

Nabber wrote: »

How come the southern sea around the Kamchata peninsula freezes but the northern half doesn't?

I think there is warm ocean current associated with a small scale gyre in the sea of Okhotsk that moves northward in that area called the "West Kamchatka Current". Seeing as it carries up warmer water from the southern tip of the peninsula, it probably plays a large role in keeping that area relatively ice free.
Conversely, a cold current on the western side of the sea of Okhotsk promotes colder waters further south and so extra sea ice from freezing and drifting from the north.

K_1

More ice for the time of year than any of the last 6 years:

Elmer Blooker

I'm amazed that Finland is still entirely snow covered as late as this, you would expect the southern half of the country to be snow free by now (like Sweden)
The winter was milder than normal in Scandinavia too.

dloob

I'm surprised it was such a good year for snow and ice.
I guess you get a skewed perspective here where we were stuck in wet mild Atlantic air while Europe froze.

darkman2

Some may have noticed the snow and ice are now melting on the webcam in the OP. Milder air has made it's way all the way up through Northern Russia into the Artic. And low pressure bringing strong winds only accelerates the melt. I think it should be watched over the next day or two. It's an interesting process that might surprise people in it's speed. Even at that latitude winter is over.

I also said to compare the OP 850hpa Northern Hemisphere temps over the summer. This is the situation now. As you can see the cold is receding fast.

Most of Spitzbergen does stay snow covered because it is high altitude. Low levels become typical of what we have in winter - during the summer.

MiNdGaM3

Also, Cryosphere Today is back up and running after nearly 3 weeks off.
http://arctic.atmos.uiuc.edu/cryosphere/

IJIS sea ice extent is back again also, after nearly 8 months off
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent_prev.htm

So plenty of source to keep up to date on the melt season this year.

K_1

MiNdGaM3 wrote: »

Also, Cryosphere Today is back up and running after nearly 3 weeks off.
http://arctic.atmos.uiuc.edu/cryosphere/

IJIS sea ice extent is back again also, after nearly 8 months off
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent_prev.htm

So plenty of source to keep up to date on the melt season this year.

The figures between those two sites and natice.noaa.gov/ims/ seem to contradict a bit, mainly on the max for this year.

MiNdGaM3

K_1 wrote: »

The figures between those two sites and natice.noaa.gov/ims/ seem to contradict a bit, mainly on the max for this year.

A number of different things can cause that. Some will use different satellite sensors, then use different algorithms to determine sea ice concentration, then use different measurements, such as area and extent, to plot the graphs with.

darkman2

Just bumping this for the webcam images of the snow melting at the very northern latitude in the OP.


Much warmer upper air temperatures at this stage across the artic regions.

MiNdGaM3

On Cryosphere Today we're currently lowest on record for sea ice area.
Sea ice extent is doing slightly better, about average for the last 5-6 years, but still well down on the long term mean.

K_1

MiNdGaM3 wrote: »

On Cryosphere Today we're currently lowest on record for sea ice area.
Sea ice extent is doing slightly better, about average for the last 5-6 years, but still well down on the long term mean.

And on National Ice Centre its nearly the highest in the last 6 or 8 years.

MiNdGaM3

Yep, extent doing slightly better.
Expect some big losses over the coming week though as Hudson Bay has some very warm air in place and the dipole anomaly is kicking into gear.

Here's my own extent graph, with 2007 in green and the long term average in yellow.

Supercell

First time i've ever watched midnight sun live, with added snow, pretty cool!!

K_1

Whats the difference between extent and area?!

MiNdGaM3

K_1 wrote: »

Whats the difference between extent and area?!

Extent considers any pixel that is covered by 15% (though occasionally 30%) sea ice or more as extent. So say a pixel is 1km2, if it is covered by 15% or more, it's counted as 1km of sea ice. If it's less than 15%, it's counted as just ocean.

Area uses the 15% cut-off (anything below 15% isn't counted, like extent), but then adds up the pixels above 15% based on their concentration.

For example, say we have 4 pixels, each representing 10km, with sea ice concentrations as follows: pixel 1= 90%, pixel 2= 50%, pixel 3 = 20% and pixel 4= 10%.
For sea ice extent which uses 15%, pixels 1,2 and 3 will be counted (>15%) as completely covered in ice, giving an extent of 30km2.
For extent which uses 30%, only pixel 1 and 2 will be counted (>30%) giving an extent of 20km2.
While for area, 4 isn't counted as it's below 15%, but pixels 1,2 and 3, are added by their concentration giving 16km2. i.e., 9km2(90% of 10km2) + 5km2 (50% of 10km2) + 2km2 (20% of 10km2).
Hope that makes sense!

Danno

Long term averages are recovering...

MiNdGaM3

Danno wrote: »

Long term averages are recovering...

Haven't seen that graph before. Have you any more details? The averages used? Whether it's 15 or 30% extent? What they used for the data pre-79?

Seems a bit odd that it shows the anomaly as higher than at any point since the 70s, when every other data set showed it just reaching average...

EDIT: Actually, based on the Met Office page, this might explain it.

08/MARCH/2011. The switch of satellite source data at the start of 2009 introduced a discontinuity in the fields of sea ice in both the Arctic and Antarctic.

03/DECEMBER/2010. The SSM/I satellite that was used to provide the data for the sea ice analysis in HadISST suffered a significant degradation in performance through January and February 2009. The problem affected HadISST fields from January 2009 and probably causes an underestimate of ice extent and concentration. It also affected sea surface temperatures in sea ice areas because the SSTs are estimated from the sea ice concentration (see Rayner et al. 2003). As of 3rd December 2010 we have reprocessed the data from January 2009 to the present using a different sea ice data source. This is an improvement on the previous situation, but users should still note that the switch of data source at the start of 2009 might introduce a discontinuity into the record.

darkman2

The situation as of the 17th of June. Very little snow left anywhere at this stage away from the highest mountain peaks and ice retreating rapidly now.

K_1

Getting ominously close to lowest in recent years for this time now,after coming off a high that was higher than any recent years in March.

K_1

On the other end, ice building up rapidly and snow starting to build up in New Zealand and the Andes, One spot in South Africa too.



Slightly higher than the long term mean.

Redsunset

http://stevengoddard.wordpress.com/spectacularly-poor-climate-science-at-nasa/

Interesting stuff. Just stick it in here. Scroll down to get to Arctic ice bit but all worth a read.

MiNdGaM3

redsunset wrote: »

http://stevengoddard.wordpress.com/spectacularly-poor-climate-science-at-nasa/

Interesting stuff. Just stick it in here. Scroll down to get to Arctic ice bit but all worth a read.

With regards the Arctic ice stuff, that's a little old ain't it? There have been numerous scientific predictions, from numerous scientists at NASA, with the consensus being for an ice free Arctic not arriving for another few decades yet.

I think it's best just to stick with the data, rather than blog attacks on scientists.

Redsunset

I'm focusing on the old news papers. Plenty of ice melt pre industrial revolution.

MiNdGaM3

redsunset wrote: »

I'm focusing on the old news papers. Plenty of ice melt pre industrial revolution.

Ah, ok, though I wouldn't quite consider the early 20th century pre-industrial!

The Arctic warming, especially in the 40s is quite well known I thought? If there was any attempted cover up (as Goddard appear to believe) it's been quite a failure!
JSTOR has some great old articles of the Arctic and sea ice, with a few even discussing fears of the ice spreading further south, as well as the areas of reduced sea ice being noted.

Here's a quote from a letter from 1881 Titled "The Recent Advance of the Polar Ice in the Greenland and Spitzbergen Sea.", showing their fears of what may happen if the sea ice keeps spreading as it had been.

This winter the ice may spread still further, unless the winds prevail from the south to raise the temperature, drive the iee north and eat into it along its southern edge.
If the winter winds are northerly, we may expect to meet with the ice in the spring, approaching the Faroe Islands on the west, and find it down on the coast of Norway on the east

Redsunset

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," said Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data.


http://www.jpl.nasa.gov/m/news/index.cfm?release=2012-217

Sponge Bob

Redsunset wrote: »

. With the last one happening in 1889, this event is right on time,"

Followed by a hard hard winter and "Bumper crop of snow began arriving--snowing furiously, like twilight, two feet on the ground this morning"

Followed (same link) by

Every man engaged in shoveling snow off buildings; church fell in, some houses collapsed and families had to move out

Sounds awful! A more technical observation here which may be of interest.

MiNdGaM3

I don't know if anyone has been following the Arctic sea ice situation, but it's looking pretty dire.
Sea ice area was already at record lows for the last 6 weeks, with extent second lowest on record on most sites up until a few days ago. But a very unusual storm (<965hPa) has done some huge damage to the sea ice over the last 4 days.
Here's an animation of the sea ice concentration from the 4th to the 9th.



Sea ice extent is now lowest on record for the time of year by about 50k on the IJIS/JAXA site here, and on most other graphs which you can view here

But sea ice area is faring much worse. The current figure is now over half a million square km below the previous low at this time of year, and also less than 300,000km2 off the all time low, which wasn't set until September 10th last year.
So with just 300k required to lose, and a month of melt likely left and the last 10 days averaging a 100k loss, things look quite bad.

On top of that, the latest snow cover extent values are in now.
April, May, June and July 2012 were the 4th, 2nd, 1st and 1st lowest snow cover extent on record for the northern hemisphere respectively.
http://climate.rutgers.edu/snowcover/table_rankings.php?ui_set=1

Redsunset

Yes impressive.

Ice Impacts of a Rare Arctic Summer Storm


http://dotearth.blogs.nytimes.com/2012/08/08/a-closer-look-at-ice-impacts-of-a-rare-arctic-summer-storm/?smid=tw-share