From the University of Washington
From research stations drifting on ice floes to high-tech aircraft radar, scientists have been tracking the depth of snow that accumulates on Arctic sea ice for almost a century. Now that people are more concerned than ever about what is happening at the poles, research led by the University of Washington and NASA confirms that snow has thinned significantly in the Arctic, particularly on sea ice in western waters near Alaska.
A new study, accepted for publication in the Journal of Geophysical Research: Oceans, a publication of the American Geophysical Union, combines data collected by ice buoys and NASA aircraft with historic data from ice floes staffed by Soviet scientists from the late 1950s through the early 1990s to track changes over decades.
Historically, Soviets on drifting sea ice used meter sticks and handwritten logs to record snow depth. Today, researchers on the ground use an automated probe similar to a ski pole to verify the accuracy of airborne measurements.
“When you stab it into the ground, the basket move up, and it records the distance between the magnet and the end of the probe,” said first author Melinda Webster, a UW graduate student in oceanography. “You can take a lot of measurements very quickly. It’s a pretty big difference from the Soviet field stations.”
Webster verified the accuracy of airborne data taken during a March 15, 2012 NASA flight over the sea ice near Barrow, Alaska. The following day Webster followed the same track in minus 30-degree temperatures while stabbing through the snow every two to three steps.
The authors compared data from NASA airborne surveys, collected between 2009 and 2013, with U.S. Army Corps of Engineers buoys frozen into the sea ice, and earlier data from Soviet drifting ice stations in 1937 and from 1954 through 1991. Results showed that snowpack has thinned from 14 inches to 9 inches (35 cm to 22 cm) in the western Arctic, and from 13 inches to 6 inches (33 cm to 14.5 cm) in the Beaufort and Chukchi seas, west and north of Alaska.
That’s a decline in the western Arctic of about a third, and snowpack in the Beaufort and Chukchi seas less than half as thick in spring in recent years compared to the average Soviet-era records for that time of year.
“Knowing exactly the error between the airborne and the ground measurements, we’re able to say with confidence, Yes, the snow is decreasing in the Beaufort and Chukchi seas,” said co-author Ignatius Rigor, an oceanographer at the UW’s Applied Physics Laboratory.
The authors speculate the reason for the thinner snow, especially in the Beaufort and Chukchi seas, may be that the surface freeze-up is happening later in the fall so the year’s heaviest snowfalls, in September and October, mostly fall into the open ocean.
What thinner snow will mean for the ice is not certain. Deeper snow actually shields ice from cold air, so a thinner blanket may allow the ice to grow thicker during the winter. On the other hand, thinner snow cover may allow the ice to melt earlier in the springtime.
Thinner snow has other effects, Webster said, for animals that use the snow to make dens, and for low-light microscopic plants that grow underneath the sea ice and form the base of the Arctic food web.
The new results support a 15-year-old UW-led study in which Russian and American scientists first analyzed the historic Arctic Ocean snow measurements. That paper detected a slight decline in spring snow depth that the authors believed, even then, was due to a shorter ice-covered season.
“This confirms and extends the results of that earlier work, showing that we continue to see thinning snow on the Arctic sea ice,” said Rigor, who was also a co-author on the earlier paper.
The recent fieldwork was part of NASA’s Operation IceBridge program, which is using aircraft to track changes while NASA prepares to launch a new ice-monitoring satellite in 2017. The team conducted research flights in spring 2012 as part of a larger program to monitor changes in the Arctic.
The research was supported by NASA and the U.S. Interagency Arctic Buoy Program. Co-authors are Son Nghiem at NASA’s Jet Propulsion Laboratory, Nathan Kurtz at NASA’s Goddard Space Flight Center, Sinead Farrell at the University of Maryland, Don Perovich at the federal Cold Regions Research and Engineering Laboratory and Matthew Sturm at the University of Alaska Fairbanks.
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Data break around 1980…? China, methinks
Changing precipitation patterns, that’s all. A regional effect.
I would like to see this compared with the Antarctic.
“dbstealey says:
August 13, 2014 at 9:33 am
Changing precipitation patterns, that’s all. A regional effect.”
############
note that skeptics merely assert claims. no data. no analysis. just assertion.
no uncertainty. no doubt. no acknowledgement that they might be wrong.
no critical assessment of prior work. no citations.
read climate science. say no and throw up a reason
For a second there, I thought Mosher was describing climate alarmists.
We all know now about Mosh (English major ect), but thats OK.
Confirms the decrease in specific humidity in other articles we’ve talked about here.
http://wattsupwiththat.com/2013/03/06/nasa-satellite-data-shows-a-decline-in-water-vapor/
Steven Mosher says:
note that skeptics merely assert claims. no data… &etc.
The Arctic is a region. As I said, Steven, I would like to see this compared with the Antarctic. More data would be good. The article reports on a regional Arctic effect. But thanx for not putting the usual quote marks around skeptic…
The article reports that it’s minus 30º there. So this can’t cause disappearing Arctic ice due to ‘global warming’ — which is always and everywhere the implication by the climate alarmist promoters.
Regional weather changes. Always. The Sahara desert was green savannah only a few thousand years ago. The Gobi desert hardly existed a few centuries ago. Now it is threatening Beijing; it’s only 60 miles away, moving toward the city, and growing.
That’s the difference between skeptics and alarmists. The skeptics’ default position is natural climate variability. The null hypothesis. But alarmists see a ‘fingerprint of AGW’ in everything. Proving it has been their stumbling block. There is almost no evidence of AGW, and this Arctic weather pattern is no exception.
Steven Mosher says:
August 13, 2014 at 9:38 am
———————————-
I like how one random comment on a blog is a blanket representation of all skeptics. Imagine if that were true about all online comments!
But but but…we get more snow in warmer years!
Positive feedback ( for both accumulating or declining )
When ice is accumulating, more snow depth is available, which protects from melting.
When ice is declining, less snow depth, exposure to sunshine increases melting.
Apply feedback to natural variability and significant changes ensue.
Thinner snow, really? Maybe they should take more measurements in more places on more occasions. On April 15th of this year I flew over about 2000 miles of Arctic, including the Greenland Icecap from Kulusuk to Nuuk, Baffin Bay, Baffin Island and Hudson Bay exiting near Churchill, Manitoba, on a very clear day I might add. I was astounded not only by the sea ice extent in Baffin Bay and Hudson Bay but by the evident snow depth everywhere. Yeah, I know you can’t measure snow depth from the air, but I’ve been an avid skier for 46 years, skiing some pretty deep stuff in the San Juans and the Wasatch Range, and I have developed a pretty good eye for looking at land features from above and below and determining whether there was a lot of snow or just thin cover. What I saw was thick, not thin.
“Yes, we know that the Arctic sea ice is recovering, but the really important measure is the snow pack on top of it and that’s in a worse decline than we thought”
A virtual beer to the first person who finds a serious comment / headline to that effect….
dbstealey says:
August 13, 2014 at 9:51 am
“default position is natural climate variability”
…
When one explanation is used to explain everything, it explains nothing.
The authors speculate the reason for the thinner snow, especially in the Beaufort and Chukchi seas, may be that the surface freeze-up is happening later in the fall so the year’s heaviest snowfalls, in September and October, mostly fall into the open ocean.
====
Which makes the most sense….
Snow season has been moving up for several decades…..earlier in the fall…and later in the spring
Fall has been increasing
Still the same amount almost….just falling earlier in the year…..and melting earlier in the spring
The block of time is the same
There seems to be an influence of prevailing official thought to relate the change to AGW that precludes thorough and unbiased science.
Snow deposition and depth is a critical part of glacier formation and influences the thickness of ice layers in ice core studies. I worked with and discussed at length this issue with Fritz Koerner,
http://www.igsoc.org/news/fritzkoerner/
a glaciologist who cored in Antarctica, as well as on Baffin and Ellesmere Islands.
A major factor in the final snow level is the amount and direction of the wind. It not only determines the distribution as it falls but also redistributes the snow after it falls. You can also have a phenomenon called scouring in which the wind blowing the snow across the surface can remove previous snowfall layers. This becomes particular corrosive after the snow forms larger granules, firn
http://www.britannica.com/EBchecked/topic/208027/firn
during the transition to ice.
Wind patterns are critical, but were ignored until NASA finally identified them as a factor in 2007.
http://www.nasa.gov/vision/earth/lookingatearth/quikscat-20071001.html
People studying Arctic climate and environment have known for years that wind patterns are critical in ice and snow formation and that they are as much a cause of changing ice conditions as temperatures. They are a major part of this changing snow pattern as well.
Another factor associated with ice formation, changing wind patterns, and ocean currents is the horizontal transportation of heat, but there is a change in vertical movement of heat as it moves through the ice from the much warmer ocean below to heat the air. A change in water temperature would change the amount of snow melt on the surface. A diagram of the energy balance through arctic sea ice is included in this article I wrote about the claims of thinning sea ice.
http://drtimball.com/2013/thinning-arctic-ice-more-al-gore-aided-and-abetted-misinformation/
Measuring snow depth is very difficult any where because of wind, during and after deposition. It also says nothing about the type of snow and the water content. The fur traders identified “small snow” as the type that falls when conditions are very cold. The size of snowflakes and therefore depth of fall varies with temperature. On average warm snow requires 25.4 cm to produce the same water equivalence as 30 cm of “small snow”. The change in water content and depth of snow measured are somewhat commensurate with the warming from 1980 to 2000, especially when combined with the changing wind patterns.
The data is actually quite variable from yr to year. A straight line through the data is only one possibility. There are a couple of other possibilities that look equally valid. 1) A slight increase from about 1950-1970 followed by a decrease thereafter. 2) Pretty much ZERO change from about 1950-1980 followed by a decrease thereafter, which more closely matches earths warming profile. If it is one of these two then it quite possibly is just another example of things going in 30-60 yr cycles.
Mosh,
It might easily be said of warmists: “note that warmists merely assert claims. model output. biased analysis. just assertion. no uncertainty. no doubt. no acknowledgement that they might be wrong. unbalanced assessment of contradictory work. only favorable citations.”
But it would be unproductive and unkind. Where does lobbing these kinds of grenades into a conversation get anybody except ticked off?
Steven Mosher says:
August 13, 2014 at 9:38 am
Alarmists don’t have a scientific leg upon which to stand. There is zero evidence is support of CACA & all the evidence in the world is against it.
Edward Richardson says:
dbstealey says: “default position is natural climate variability”
…
When one explanation is used to explain everything, it explains nothing.
I don’t think you understand “default position”. It is not an explanation, it is a starting point.
To Edward Richardson
Look in the mirror lately. CAGW activist have been singing the same song for 20 years.
Note the ” so a thinner blanket may allow the ice to grow thicker during the winter”, preparing the reason why there has been no death spiral and the ice may increase in the near future..
The CO2 warmed the air which made the ice thinner and now the pesky lack of snow means the ice has got thicker again.
dbstealey says:
August 13, 2014 at 10:19 am
“it is a starting point.”
No, natural variability is not the starting point. “I don’t know” or “I wonder why” is the starting point.
Climate Weenie says: ” Apply feedback to natural variability and significant changes ensue.”
Please allow me to quote ….”merely assert claims. no data. no analysis. just assertion. no uncertainty. no doubt. no acknowledgement that they might be wrong. no critical assessment of prior work. no citations.”
Weenie – you have just declared feedback as the knob available to amplify response to your heart’s content.
But conservation of energy is the basis of all systems theory – where does the law of conservation of energy fit into your assertion? Show us how you get the particular “loop gain” of your purported feedback system to argue an amplified response at the poles.
Consider the energy balance at the edge of the ice sheet for a unit-retreat of ice cover. Energy must be conserved over the stages of this increment-amplified-further-increment that you assert due to incoming sunlight.
Have you noticed there is ice at the poles? By some odd dint of fate, it just happens to be the parts of the globe where the incident power from the sun is smallest. Hmmm.
Could this be because of diminishing cos-theta (reducing incoming solar power) as we head pole ward?
Looking at the edge of the ice sheet, a retreat of ice cover at one cos-theta will lead to a change in surface area at a lower cos-theta. The incoming solar energy available to melt ice is therefore diminishing as the edge of the ice sheet retreats.
From this, I would conclude that the feedback must be negative. And this comes from conservation of energy as cos-theta falls.
But feel free to argue that this diminishing energy input is amplified as the ice retreats. Please explain the physics at the edge of the ice sheet.
MattN says:
August 13, 2014 at 9:53 am
But but but…we get more snow in warmer years!
That was my thought. The planet is cooling.
Snow what? Climate changes,but thanks to the sun we actually have one. so, lighten & smarten up and get a job.