Video follows.
The length of the melt season for Arctic sea ice is growing by several days each decade, and an earlier start to the melt season is allowing the Arctic Ocean to absorb enough additional solar radiation in some places to melt as much as four feet of the Arctic ice cap’s thickness, according to a new study by National Snow and Ice Data Center (NSIDC) and NASA researchers.
Arctic sea ice has been in sharp decline during the last four decades. The sea ice cover is shrinking and thinning, making scientists think an ice-free Arctic Ocean during the summer might be reached this century. The seven lowest September sea ice extents in the satellite record have all occurred in the past seven years.
“The Arctic is warming and this is causing the melt season to last longer,” said Julienne Stroeve, a senior scientist at NSIDC, Boulder and lead author of the new study, which has been accepted for publication in Geophysical Research Letters. “The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the ocean and increase ice melt during the summer, overall weakening the sea ice cover.”
To study the evolution of sea ice melt onset and freeze-up dates from 1979 to the present day, Stroeve’s team used passive microwave data from NASA’s Nimbus-7 Scanning Multichannel Microwave Radiometer, and the Special Sensor Microwave/Imager and the Special Sensor Microwave Imager and Sounder carried onboard Defense Meteorological Satellite Program spacecraft.
When ice and snow begin to melt, the presence of water causes spikes in the microwave radiation that the snow grains emit, which these sensors can detect. Once the melt season is in full force, the microwave emissivity of the ice and snow stabilizes, and it doesn’t change again until the onset of the freezing season causes another set of spikes. Scientists can measure the changes in the ice’s microwave emissivity using a formula developed by Thorsten Markus, co-author of the paper and chief of the Cryospheric Sciences Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md.
Results show that although the melt season is lengthening at both ends, with an earlier melt onset in the spring and a later freeze-up in the fall, the predominant phenomenon extending the melting is the later start of the freeze season. Some areas, such as the Beaufort and Chukchi Seas, are freezing up between six and 11 days later per decade. But while melt onset variations are smaller, the timing of the beginning of the melt season has a larger impact on the amount of solar radiation absorbed by the ocean, because its timing coincides with when the sun is higher and brighter in the Arctic sky.
Despite large regional variations in the beginning and end of the melt season, the Arctic melt season has lengthened on average by five days per decade from 1979 to 2013.
Still, weather makes the timing of the autumn freeze-up vary a lot from year to year.
“There is a trend for later freeze-up, but we can’t tell whether a particular year is going to have an earlier or later freeze-up,” Stroeve said. “There remains a lot of variability from year to year as to the exact timing of when the ice will reform, making it difficult for industry to plan when to stop operations in the Arctic.”
To measure changes in the amount of solar energy absorbed by the ice and ocean, the researchers looked at the evolution of sea surface temperatures and studied monthly surface albedo data (the amount of solar energy reflected by the ice and the ocean) together with the incoming solar radiation for the months of May through October. The albedo and sea surface temperature data the researchers used comes from the National Oceanic and Atmospheric Administration’s polar-orbiting satellites.
They found that the ice pack and ocean waters are absorbing more and more sunlight due both to an earlier opening of the waters and a darkening of the sea ice. The sea ice cover is becoming less reflective because it now mostly consists of thinner, younger ice, which is less reflective than the older ice that previously dominated the ice pack. Also, the young ice is flatter, allowing the dark melt ponds that form at the early stages of the melt season are able to spread more widely, further lowering its albedo.
The researchers calculated the increase in solar radiation absorbed by the ice and ocean for the period ranging from 2007 to 2011, which in some areas of the Arctic Ocean exceed 300 to 400 megajoules per square meter, or the amount of energy needed to thin the ice by an additional 3.1 to 4.2 feet (97 to 130 centimeters).
The increases in surface ocean temperatures, combined with a warming Arctic atmosphere due to climate change, explain the delayed freeze up in the fall.
“If air and ocean temperatures are similar, the ocean is not going to lose heat to the atmosphere as fast as it would when the differences are greater,” said Linette Boisvert, co-author of the paper and a cryospheric scientist at Goddard. “In the last years, the upper ocean heat content is much higher than it used to be, so it’s going to take a longer time to cool off and for freeze up to begin.”
==============================================================
I tend to take research done by Ms. Stroeve with a grain of skepticism, since she allows her work to be aided by political activists at Greenpeace.
This photo was taken on 09/11/2012:
Source: Greenpeace
But politics aside, more importantly, no evidence seems to be visible in common sea ice graphs like this one. In fact, the melt season started later than usual this year, according to NSIDC’s Arctic Sea Ice Extent Graph.
They did some CYA for that:
“There is a trend for later freeze-up, but we can’t tell whether a particular year is going to have an earlier or later freeze-up,”
National Snow & Ice Data Center (NSIDC) – click to view at source
Granted, the report mentions it to be mostly a regional effect, While there likely is some truth in the report, what isn’t explored is whether the cause of this change is part of a natural cycle, a natural cycle enhanced by some AGW effects, or purely an artifact of AGW.
Their claim…
The increases in surface ocean temperatures, combined with a warming Arctic atmosphere due to climate change, explain the delayed freeze up in the fall.
…reads like something Greenpeace would write, providing no other possibility. One thing I tend to notice about Earthly geological and atmospheric processes is that they tend to act on timespans than exceed human lifetimes, sometimes being orders of magnitudes longer. In the case of Arctic sea ice, a record going back to 1979 is shorter than that and only represent a fraction of what may be a natural cycle. Making claims that they know exactly what the cause is might very well bite them in a few years or few decades.
Tom in Denver says:
April 1, 2014 at 10:35 am
A quick look at the Southern Hemisphere Sea Ice Area shows an increase in sea ice since 1979. The global net change in sea ice is pretty much a wash. It’s hard to call this global warming when one hemisphere is showing sea ice growth and one is showing a reduction. Perhaps it would be more accurate to call it “Hemispherical warming”
=============
It’s all to promote that new film – Deviancy or Variancy or Variation or some such.
Obviously.
Shows how the power of Hollywood moves ice nearly eleven thousand miles – just to promote a celluloid saga!
Auto
Sounds like the affects of the PDO warm cycle to me.
Anthony Watts says:
April 1, 2014 at 11:46 am
People want this website to disappear,
============
The Weblog Awards
Best Group or Community Weblog: Watts Up With That?
Weblog of the Year: Watts Up With That?
😀
REPLY: SOME people – A
TheLastDemocrat says:
April 1, 2014 at 11:08 am
—-
That’s OK, Winnie the Pooh already found the North Pole, we don’t need you to locate it again.
Per my last.
Sorry – leapt before any research!
[Please pass my Nobble Prize now – thanks]
It’s none of those, but – if you care – quite close to the first named; right initial, and the letters are similar (more so at the front).
Going back to read the rest of the thread, now.
Auto.
Jimbo says:
April 1, 2014 at 11:28 am
Wasn’t there enough time to include 2013? Maybe 2013 would have messed up their nice, neat story line.
Guess what? The paper, submitted on Dec. 4, 2013, included the 2013 melt season. You just didn’t bother to check, right?
Maybe you’ll be happier with another GRL paper in press by that group that discusses the difficulties of forecasting summer Arctic ice extent.
Predicting September Sea Ice Ensemble Skill of the Search Sea Ice Outlook 2008–2013
Abstract
Since 2008, the SEARCH Sea Ice Outlook has solicited predictions of September sea ice extent from the Arctic research community. Individuals and teams employ a variety of modeling, statistical and heuristic approaches to make these predictions. Viewed as monthly ensembles each with one or two dozen individual predictions, they display a bimodal pattern of success. In years when observed ice extent is near its trend, the median predictions tend to be accurate. In years when the observed extent is anomalous, the median and most individual predictions are less accurate. Statistical analysis suggests that year-to-year variability, rather than methods, dominate the variation in ensemble prediction success. Furthermore, ensemble predictions do not improve as the season evolves. We consider the role of initial ice, atmosphere and ocean conditions, and summer storms and weather in contributing to the challenge of sea ice prediction.
The IPCC said that the Arctic was freezing up in the 1970′s. The graph below is from the 1990 IPCC report, and shows Arctic sea ice satellite data which is conveniently omitted from NSIDC graphs that start at the 1979 peak.
http://stevengoddard.wordpress.com/2013/10/30/smoking-gun-that-the-temperature-record-is-fraudulent/#more-97626
==========
In the case of Arctic sea ice, a record going back to 1979 is shorter than that and only represent a fraction of what may be a natural cycle.
If the first IPCC report has ice record going back to 1974 with ’74 being low the 1979 information is a true cherry pick. We should not use it.
Point taken about the short record though.
Craig C says:
April 1, 2014 at 11:32 am
The polar ice melts when the sun comes up, freezes when it goes down. How much remains depends on wind and currents. 35 years is not anywhere near enough time to discern climatic patterns, not even enough to predict weather.
====
Craig, I, like the Met Office can predict weather based on less than 35 years’ records. I did it at school from – I think – 9 years old. “Tomorrow will be much like today.” Beat the Met office nowadays.
Whether we are successful – aye, there’s the crunch!
http://nsidc.org/news/press/2014_seasonalseaice_PR.html
Ice is easy to predict when it follows our trend line……. and not easy to predict when it doesn’t
ROTFLMAO
Julienne “Captain Obvious” Stroeve says:
“
The lengthening of the ice melt is increasing the ice melt? Aye, aye, Captain!
From the article above:
OK.
So, let’s look at two pieces of Arctic Ocean, separated by only a few kilometers so each receives the same solar radiation over the 24 hours of a typical “perfectly clear” day in late August through late October when Arctic sea ice is actually at its lowest point: That lowest point actually coming just slightly before the equinox most years – and has been constant since data began – around 15 – 22 September.
Oh by the way, at this same time of year that the Arctic ice edge at approximately latitude 80-81 north, the Antarctic sea ice is at its maximum at latitude 58-59 south, and is receiving 5X the solar radiation that the little bit of Arctic ice is ….
But she will tell she us doesn’t want to study the amount of energy being reflected by the ever-increasing Antarctic sea ice extents, because that “little” increase in Antarctic sea ice extents (only 1/2 the size of Greenland last October!) doesn’t fit her story and her agenda.
Having prejudiced you, now let’s look at these same two square meters of ocean: one covered by sea ice, one is open ocean.
1. Which gains more heat from the sun during those few hours when the sun is above the horizon?
2. Which loses more heat to the air and to space by evaporation, long wave radiation, convection, conduction every hour of every day?
Well, yes, the open Arctic ocean does absorb more solar energy. But not that much more actually1 See, the sun in late August and early September is actually very, very low to the horizon, even at noon. And, with the equinox rapidly approaching, the sun is below the horizon between 11 and 12 hours a day during this time. Also, because the sun is so rarely above 10 degrees above the horizon, its weak rays struggle to get through an air mass between 7 and 28 TIMES the air mass at the equator when that sun IS actually above the horizon. Worse, at these low solar elevation angles, the suns rays DO reflect from the water with an albedo (direct radiation) of between 0.20 to 0.38. A far, far greater albedo than the often-claimed Wikipedia value of 0.065 for open ocean.) Worse, from her standpoint that is, these albedo and air mass calculations are NOT based on long-winded theory and impossible-to-verify computer models but on “simple” geometry and solar physics.
Now, against a measured open-ocean albedo of 0.25 to 0.38 at low solar elevation angles, consider that Judith Curry measured the “dirty” summer arctic ice albedo each day between May and September during her SHEBA experiments up there on the ice. Lowest measured arctic sea ice albedo (in early August) was 0.38. But the “averaged” lowest arctic sea ice albedo in across the whole months of July and August was 0.46. So, you are still only able to compare the heat energy absorbed by the “dark ocean” at 0.25 – 0.38 (depending on time of day each morning and evening) against an Arctic sea ice albedo of 0.46!
Regardless; Yes, Virginia, the open ocean does absorb slightly more energy than does an ice-covered arctic patch.
Now, which loses more energy over 24 hours?
Ice-covered water, or open ocean?
Well, assume the water is 2 degrees C, the air temperature is -15 degrees C.
The top of sea ice will be -15 deg C.
So, radiation losses will be much greater from a 275^4 K surface than a 258^4 K surface.
(Both sea water and sea ice have about the same emissivity.)
“Biggest Loser?” Open ocean, by far.
Convection and conduction?
If sea ice covers the ocean, the air temperature = -15 Deg C, the top of sea ice becomes -15 deg C, the bottom of the sea stays right at 2 deg C in contact with the water underneath the sea ice. Heat energy from the water must cross the solid ice barrier by conduction, and then must be lost to the air across the very small delta T of the ice-air boundary layer. If open ocean is hit by winds, convection losses are MUCH higher, and waves stir the ocean further to keep the entire surface layer at that balmy 2 deg C.
“Biggest Loser?” Open ocean, by far.
Evaporation?
If sea ice covers the water, only the little bit of latent heat lost is that of sublimation.
If open ocean is exposed to air, evaporation losses can be as much 50-80 watts/m^2.
(Depends on wind speed and delta T to the air and relative humidity levels and air pressure.)
“Biggest Loser?” Open ocean, by far.
So, to the “great surprise” of this supposed Arctic PhD, under today’s conditions of sea ice extents in the arctic between late August and October, OPEN ARCTIC OCEAN LOSES MORE ENERGY TO SPACE AND TO THE ARCTIC AIR THAN THE OPEN OCEAN ABSORBS FROM THE SUN. The greater the Arctic sea ice loss, the greater the energy lost from the planet.
The day of minimum for Arctic Ice is almost at the mean and no higher than the period around 1990.
http://sunshinehours.files.wordpress.com/2014/03/comparing-arctic-day-of-min-max.png
2013 is right at the mean actually.
http://sunshinehours.wordpress.com/2014/03/27/comparing-sea-ice-extent-day-of-minimummaximum-from-1979-2013/
The day of max is a little weird though.
Arctic sea ice loss is a direct negative feedback due to global cooling. HT Ulric Lyons.
Any warmist wanting to back away should run with that premise as a source of funding 😉
Roger Pielke and [Anthony] Watts:
The charts I have are up to date (2013) for the NH. I have been updating this since I first read Roger’s post on the topic in 2009.
My conclusions are exactly those Roger had in 2009. (and others who are doing similar tracking)
“The time of occurrence of the maximum and minimum sea ice coverage in the Arctic showed slight trends towards occurring earlier in the year, although not significant.
I find both the ice minimum and maximum are arriving earlier in the year, with the maximum slightly outpacing the minimum, giving a slightly longer melt season.
I find a total increase in the melt season of 0.5 days per hundred years, which of course is insignificant.
http://oi62.tinypic.com/20uae79.jpg
I use the Cryosphere data.
http://arctic.atmos.uiuc.edu/cryosphere/timeseries.anom.1979-2008
Anthony Watts: I mispelled your name in the previous post. Sorry-o….
“The researchers calculated the increase in solar radiation absorbed by the ice and ocean for the period ranging from 2007 to 2011, which in some areas of the Arctic Ocean exceed 300 to 400 megajoules per square meter”
So, averaging it out to 350 MJ/M2, we have an increase roughly equivalent to 14,000 Hiroshimas going off per square mile. Yikes. We’re doomed.
Arctic death spiral, here we come.
I wonder if they realize that the tilt of the earth’s axis changes.
Google Axial tilt. “…The Earth currently has an axial tilt of about 23.4°. This value remains approximately the same relative to a stationary orbital plane throughout the cycles of precession. However, because the ecliptic (i.e. the Earth’s orbit) moves due to planetary perturbations, the obliquity of the ecliptic is not a fixed quantity. At present, it is decreasing at a rate of about 47″ per century…”
One chart on wiki shows the axial tilt was 24.2 degrees about 8000 years ago, and is dropping to a tilt of 22.6 degrees in the next 10000 years.
Of course neither the increase in Antarctic sea ice nor this years large amount of snow in North America will enhance albedo effects on the globe as these are only transitory states and the models don’t see them. OK?
“Claim: NSIDC, NASA Say Arctic Melt Season Lengthening, Ocean Rapidly Warming”
and the reality,
http://www.arctic-info.com/ExpertOpinion/Page/-the-need-for-icebreakers-will-increase-after-the-year-2016-
“…..For this reason, especially in the summer, there has been an increase in the need for icebreakers on the Northern Sea Route.”
Hi Les Johnson
Excellent! I am glad you have updated. Anthony – I suggest you make this one of the analysis links on the sea ice page of WUWT.
Roger Sr.
Several days per decade?! Soa lets say 3.65 days per 3650 days or 0.1% of a year or about 0.2% of the ‘melt’ season. Gee whiz, that sure sounds like armaggeddon folks … or another April Fools joke for imbeciles!
sarc off.
“Arctic sea ice has been in sharp decline during the last four decades. The sea ice cover is shrinking and thinning, making scientists think an ice-free Arctic Ocean during the summer might be reached this century. The seven lowest September sea ice extents in the satellite record have all occurred in the past seven years.”
OK, we have reliable data since 1979. That’s 34 years not “four decades” and it has been recovering since the 2012 min. So it’s more like three decades.
Now that’s three decades in a system known to have 60 year cycles in last 150 years. So three decades more or less in one direction may not be that surprising. Neither is it very surprising if short term lows are all grouped together.
“making scientists think …. might be…this century. ”
Oh really? Which scientists? Anyone prepared to put their name to it, or just some scientists somewhere who will not be named?
If they only think it “might be”, they must also think it “might not be”. This is a NON claim by a unnamed “scientist” who thinks “may be”.
Big friggin deal. And they call that “science”? Pathetic.
I love that picture of Julienne Stroeve kneeling on the ice in the Arctic, actively taking notes on the vast expanse of nothing but ever expanding ice, before her. No extra albedo there, I’m afraid.
SUN SUN SUN SUN AMO AMO AMO AMO
http://www.reportingclimatescience.com/news-stories/article/natural-variations-in-atlantic-ocean-affect-climate-says-research.html
I forget…Can someone recap again why we are supposed to be terrified of an ice-free arctic summer again? Would an ice- free arctic summer bring about climate apocalypse? And if so, in which direction (hot or cold)?