Arctic lakes have been freezing up later in the year and thawing earlier, creating a winter ice season about 24 days shorter than it was in 1950, a University of Waterloo study has found. But, I don’t think they are paying attention to cycles like the PDO. And, in 1992, Mt. Pinatubo’s eruption had global effects on lowering temperature, making their start point a cherry pick.
Dramatic thinning of Arctic lake ice cuts winter ice season by 24 days
Arctic lakes have been freezing up later in the year and thawing earlier, creating a winter ice season about 24 days shorter than it was in 1950, a University of Waterloo study has found.
Researcher Claude Duguay stands on the cracked ice of an Arctic lake
(Credit: Claude Duguay/University of Waterloo) Download image
The research, sponsored by the European Space Agency (ESA) and published in The Cryosphere, also reveals that climate change has dramatically affected the thickness of lake ice at the coldest point in the season: In 2011, Arctic lake ice was up to 38 centimetres thinner than it was in 1950.
“We’ve found that the thickness of the ice has decreased tremendously in response to climate warming in the region,” said lead author Cristina Surdu, a PhD student of Professor Claude Duguay in Waterloo’s Department of Geography and Environmental Management. “When we saw the actual numbers we were shocked at how dramatic the change has been. It’s basically more than a foot of ice by the end of winter.”
The study of more than 400 lakes of the North Slope of Alaska, is the first time researchers have been able to document the magnitude of lake-ice changes in the region over such a long period of time.
“Prior to starting our analysis, we were expecting to find a decline in ice thickness and grounded ice based on our examination of temperature and precipitation records of the past five decades from the Barrow meteorological station,” said Surdu “At the end of the analysis, when looking at trend analysis results, we were stunned to observe such a dramatic ice decline during a period of only 20 years.”
The research team used satellite radar imagery from ESA to determine that 62 per cent of the lakes in the region froze to the bottom in 1992. By 2011, only 26 per cent of lakes froze down to the bed, or bottom of the lake. Overall, there was a 22 per cent reduction in what the researchers call “grounded ice” from 1992 to 2011.
Researchers were able to tell the difference between a fully frozen lake and one that had not completely frozen to the bottom, because satellite radar signals behave very differently, depending on presence or absence of water underneath the ice.
Graph showing the reduction in grounded ice between 1992 and 2011
(Credit: Planetary Visions / University of Waterloo, Canada / ESA) Download image.
Radar signals are absorbed into the sediment under the lake when it is frozen to the bottom. However, when there is water under the ice with bubbles, the beam bounces back strongly towards the radar system. Therefore, lakes that are completely frozen show up on satellite images as very dark while those that are not frozen to the lake bed are bright.
Researchers used the Canadian Lake Ice Model (CLIMo) to determine ice cover and lake ice thickness for those years before 1991, when satellite images are not available.
The model simulations show that lakes in the region froze almost six days later and broke up about 18 days earlier in the winter of 2011 compared to the winter of 1950. Shorter ice-cover seasons may lead to shifts in lake algal productivity as well as thawing of permafrost under lake beds.
“The changes in ice and the shortened winter affect Northern communities that depend on ice roads to transport goods,” said Surdu. “The dramatic changes in lake ice may also contribute to further warming of the entire region because open water on lakes contribute to warmer air temperatures, albeit to a lesser extent than open sea water.”
The ice regimes of shallow lakes were documented using radar images from ESA’s ERS-1 and -2 satellites. More information on the ESA is available online.
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So if there is water under the ice that simply does not contain bubbles, or if there are bubbles within the ice itself, how does this play out?
I see no particular reason that bubbles should necessarily be present in such water in the first place or, even if they are present, why they should disappear to radar imaging when the water freezes to the bottom of the lake, presumably with these echogenic bubbles now still present within the ice.
What am I missing?
Lake ice season is obviously different than sea ice extent.
Using Cryosphere data, I get a pretty flat line for max and min ice dates, with an average of 254.21 and 66.67 days respectively (about 12 Sep and 8 Mar).
I STD Dev is 9.96 for max, and 6.83 for min.
The melt season is getting slightly longer, with the max date arriving earlier by 0.0401 days per year. Ice max is also shortening, at 0.0453 days per year. This works out to the melt season arriving about 1/2 day earlier, every 1000 years.
This is confirmed by counting the total melt days per year. On average, ice decreases 187.89 days per year, and increases 177.36 days per year. The trend for the melt days is 0.0052 days per year increase. 3 years have been less 1 std Dev of 10.5 for melt season length, and 3 years have been above this. Only 1 year has been outside 2 std Dev, and that was 1997, which had nearly 220 melt days.
somehow the corrupt station data is melting ice at the bottom of lakes.
of course forget the fact that we see confirming evidence in the loss of permafrost.
Arctic amplification is real.. regardless of the cause. When the planet warmed in the 20-40s
we saw the same thing with retreat of ice at the NP. When the globe warms it does not warm uniformly. The arctic warms more. The warming we’ve seen there over the past few decades has consequences:
1. generally less ice
2. ground ice at the bottoms of lakes declining
3. permafrost declines
4. species migration northward at 3 times the normal rates.
11 meters in elevation per decade and 16km in latitude per decade.
Simple fact. plants and animals dont migrate because of “biased” surface stations. Their migration is driven by changes in the climate.
In other words, the LIA was real. It used to be colder. Now its warmer. and the arctic warms more generally speaking. during the MWP the Vikings were glad of this
In this short press release we find “dramatically affected”, “decreased tremendously”, “shocked”, “dramatic”, “stunned” and again “dramatic”. I hope the paper addresses variation in the depth of water before freeze up, the timing and depth of snow over early ice and the actual dates of the opening and closing of winter roads each year. I also want to see a graph of the annual met records and their modelled ice thickness for the entire time period. A further question relates to the use of Barrow data- is it representative? real or upjusted?
corrigendum:
max date arriving earlier by 0.0401 days per year
Should be
min date arriving earlier by 0.0401 days per year
The dates of the ice max and ice min are both arriving slightly earlier. The ice max date is coming just slightly earler than ice min, enlarging the melt season by 1/2 day per 1000 years.
In other words, there has been no significant change in sea ice extent melt season, over the record.
In fact, the length of the melt season has been remarkably constant.
Why did they only report on the small area shown.
Jimbo says:
February 4, 2014 at 9:32 am
Why near Barrow?
Yes, Jimbo, you recognize both are rhetorical questions.
Don’t tell mosh, but the answer probably is…….
The correlation doesn’t hold for other the vast other areas along the Canadian Arctic coastline.
Another computer model – about as accurate as the global warming models.
You are correct.
There is actually a very simple way to test the validity of one of their claims. Are there any fish in those lakes? If there are no fish then the lake could have frozen to the bottom. If there are fish, the lake cannot have frozen to the bottom, at least not in the lifetime of that population of fish (when they were either introduced or initially migrated into the region – potentially thousands of years).
According to the Alaska Department of Fish and Game: North Slope Management Area – “The state’s third largest lake, Teshekpuk Lake, is found here on the coastal plan, as are hundreds of smaller lakes. Most of these lakes are inaccessible by road and too shallow to support fish populations, but there are dozens of lakes that contain lake trout, Arctic char, Arctic grayling, and burbot.” The key phrase in this statement is “too shallow to support fish” – if it is too shallow to support fish it is most likely to have frozen to the bottom.
As far as their claim that the winter ice season is 24 days shorter than it was in 1950, this is simply a case of laziness. To paraphrase a comment an older limnologist friend of mine expressed – ‘Students today don’t want to do the footwork of going out and collecting samples and data and are far too willing to stay warm and comfortable at home working with computers and models.’
1998 and 2010 were El Niño years. Warm. Move along, nothing to see here…
Looks like they left out last winter (2012-2013) which one of the coldest in many years.
It’s worse than we thought! Early climate alarmism at work, they too made assumptions in a straight line.
Sound familiar? LOL.
So dark lakes are frozen to the bottom, and bright lakes have water under the ice.
Now where is the data on how the water depth in those lakes has changed. Did the frozen stiff lakes have the same water level they had before, or have the bright lakes got more water in them, than they had before.
Enquiring minds, want to know.
Oh boy, imagine if this happened today? We must accept the reality of climate change in Antarctica.
[Apologies if I have made any typing errors as it is from an image.]
It is 83 F this afternoon at my house in SW Florida. Just wanted y’all to know the only ice I am thinking about is how much more I need in my beverage. Why anyone would want a colder world is beyond me.
Cool – the ice is melting earlier and refreezing later.
Means that there is more time to go fishing!
Seems to be at odds with Mackenzie River area ice bridge opening and closing date data
http://www.dot.gov.nt.ca/_live/pages/wpPages/Open_Close_Dates_Ice_Bridges.aspx
The graphs of the arctic melt season.
[IMG]http://i62.tinypic.com/20uae79.jpg[/IMG]
Ok, lets try this….
http://oi62.tinypic.com/20uae79.jpg
Dave –
Apologies, I applied the stats to the wrong column. My entry above should read as follows:
The historical average for the Yukon River breakup is May 8th, with a standard deviation of 5.1 days.
The breakup date for 2013 was May 15th, that is, about 1 and 1/2 standard deviations above the 118 year mean. In the 24 years since 1990, only three times has the breakup occurred later than the historical mean, three times at the mean (on May 8th), and 18 times earlier than the historical mean. On the whole, the last quarter century speaks to relative warmth.
On the other hand, only ten times in the 118 year record has the ice broken after May 15th.
*******
Kids, don’t let what happened to me, happen to you. Don’t play with moving averages at home.
Anyone else paying attention to great lakes ice? Haven’t seen anything like it in my lifetime.
http://iceweb1.cis.ec.gc.ca/Prod20/page2.xhtml?CanID=11080&lang=en
Looking at the Yukon breakup at Dawson City, the earliest occur between 28 April (1940) and 3rd May (1926). In the 1930s warm perid there were 6 years in this range, averaging May 2. In the 2000s warm period there were 7 years, averaging April 30, 2 days earlier. Upstream, the population of Whitehorse went from about 1000 people in the 1940s to 25,000 in the oughts. For the period from 1971 to 2000 the average Dec temperature in whitehorse was -14.9 degrees C, with the average high -10.6 and the average low – 19.1. In 1944 these temps were – 11, -7 and -14. In 2009 they were -13, -9 and -16. Could it be that there has been no real warming in the Yukon and the growth of Whitehorse has warmed the Yukon enough to move the breakup 2 days earlier? Since global warming is manifested most strongly at high latitudes and in the winter, this would not suggest much warming since the late 1930s.
Was this study necessary to “prove” the ice has shrunk since 1992? We have satellites for that. Common sense tells you the ice on arctic lakes would follow a similar pattern. The problem for the warmistas, as usual, is their failure to understand/recognize that this all happens in a pattern. The arctic ice will follow earth temperatures when it cools as well.
File this under the history of global warming. Check the lakes out now!!