Direct, reliable observations of atmospheric conditions stretch as far back as the mid seventeenth century, with otherwise consistent records being punctuated by periodic updates in methods, practitioners, and observational equipment. To bridge these shifts in technique and technology, scientists develop reanalysis models designed to tie together diverse observations into a coherent picture of the system’s evolution. But, like all models or analytical techniques, reanalysis data sets can suffer from errors or biases. Identifying how the records produced by different reanalyses vary can be a difficult practice, but determining if a cluster of models consistently produces biased results can be even more difficult.
A number of reanalyses have recently been developed to track the rapidly changing Arctic atmosphere, and Serreze et al. compared them with one another and with the observational record. The authors focused on how the reanalyses represent the change in Arctic tropospheric water vapor from 1979 to 2010. They compared three of the most recent and complex reanalyses against meteorological measurements made using radiosondes at nine sites north of 70 degrees North. They find that the reanalyses consistently overestimate low-altitude temperatures and winter humidity. It is important to note that these positive biases caused the reanalyses to miss low-altitude wintertime temperature and humidity inversions identified by the radiosondes.
A finding shared by both reanalyses and radiosonde observations, however, is of an increasing availability of precipitable water in the low-altitude Arctic, which the authors suggest is associated with increasing air-sea surface temperatures, reduced sea ice extent, and other markers consistent with the polar amplification of global warming. Increasing Arctic humidity is a troubling result, as heightening atmospheric water vapor could further drive up regional temperatures.
Source: Journal of Geophysical Research-Atmospheres, doi:10.1029/2011JD017421, 2012 http://dx.doi.org/10.1029/2011JD017421
Title: Recent changes in tropospheric water vapor over the Arctic as assessed from radiosondes and atmospheric reanalyses
Authors: Mark C. Serreze, Andrew P. Barrett, and Julienne Stroeve: National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA;
- Positive trends in tropospheric water vapor are seen in parts of the Arctic
- Patterns are linked to warming air temperature and reduced sea ice extent
- Differences in trends occur between different reanalyses
Mark C. Serreze
National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
Andrew P. Barrett
National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
Julienne Stroeve
National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
Changes in tropospheric water vapor over the Arctic are examined for the period 1979 to 2010 using humidity and temperature data from nine high latitude radiosonde stations north of 70°N with nearly complete records, and from six atmospheric reanalyses, emphasizing the three most modern efforts, MERRA, CFSR and ERA-Interim. Based on comparisons with the radiosonde profiles, the reanalyses as a group have positive cold-season humidity and temperature biases below the 850 hPa level and consequently do not capture observed low-level humidity and temperature inversions. MERRA has the smallest biases. Trends in column-integrated (surface to 500 hPa) water vapor (precipitable water) computed using data from the radiosondes and from the three modern reanalyses at the radiosonde locations are mostly positive, but magnitudes and statistical significance vary widely between sites and seasons. Positive trends in precipitable water from MERRA, CFSR and ERA-Interim, largest in summer and early autumn, dominate the northern North Atlantic, including the Greenland, Norwegian and Barents seas, the Canadian Arctic Archipelago and (on the Pacific side) the Beaufort and Chukchi seas. This pattern is linked to positive anomalies in air and sea surface temperature and negative anomalies in end-of-summer sea ice extent. Trends from ERA-Interim are weaker than those from either MERRA or CFSR. As assessed for polar cap averages (the region north of 70°N), MERRA, CFSR and ERA-Interim all show increasing surface-500 hPa precipitable over the analysis period encompassing most months, consistent with increases in 850 hPa air temperature and 850 hPa specific humidity. Data from all of the reanalyses point to strong interannual and decadal variability. The MERRA record in particular shows evidence of artifacts likely introduced by changes in assimilation data streams. A focus on the most recent decade (2001–2010) reveals large differences between the three reanalyses in the vertical structure of specific humidity and temperature anomalies.
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So what? Submarines surfaced at the north pole decades ago.
Since when is “troubling” an appropriate scientific descriptor?
Oh, it’s our buddy Mark “death spiral” Serreze. I had mistaken this for a serious journal article by a credible, dispassionate researcher not a pathetic political attention whore.
I’ll have to pre-screen for his name from now on.
On the bright side, all that humidity could deposit more snow on the land masses such as Greenland in a mechanism not unlike lake effect snow.
On the depressing side, has anyone noticed this?
http://nsidc.org/data/seaice_index/images/daily_images/N_daily_concentration_hires.png
There’s way too much ice exiting the Fram strait and the concentration around the Queen Elizabeth Islands is at unheard of lows for June. The absence of solid white is downright creepy. The record low sea ice extent could be shattered this year.
But isn’t decreased humidity around Kilimanjaro associated with loss of ice?
“a cluster of models “………. no, it’s a cluster something, but a cluster of models? What’s that? Analogous to a gaggle?
What’s does this tell us? That models are wrong? No doubt, thanks for cluing us in on that NOAA. Brilliant deductive work! Or that warmer conditions may be associated with higher humidity over bodies of water? Julienne or Mark, what’s the take away from this?
jorgekafkazar says:
June 29, 2012 at 9:18 pm
But isn’t decreased humidity around Kilimanjaro associated with loss of ice?
==========================================================
It sure was! But, now the ice is back….. so maybe the humidity increased and they didn’t tell us? Or maybe they were FOS? Hard telling…….
“A finding shared by both reanalyses and radiosonde observations, however, is of an increasing availability of precipitable water in the low-altitude Arctic, which the authors suggest is associated with increasing air-sea surface temperatures, reduced sea ice extent, and other markers consistent with the polar amplification of global warming. Increasing Arctic humidity is a troubling result, as heightening atmospheric water vapor could further drive up regional temperatures.”
==
Serreze et al. are evidently discovering what Marcel Leroux has explained for quite a while now namely that the 1970s change to a rapid mode of circulation is sending more powerful polar anticyclone -colder air, high pressure- deeper into the tropics and as a result is renewing advection of warmer, moist air toward the Arctic explaining both the increase in moisture in the Arctic and the melting of Greenland east coast. I invite readers to enjoy “Dynamic Analysis of Weather and Climate”, Springer 2010 2nd English Edition.
So when Serreze et al. claim “polar amplification of global warming” and that it is “troubling”, it sadly demonstrates their utter lack of understanding of the dynamics of atmospheric circulation and how their ideological blinders prevent them to see the light. Furthermore, this dynamic is not reflected in the favored AGWists use of temperature averages over the Arctic as some areas are cooling while others are warming as a consequence of the dynamic.
Global warming has from the beginning been about the throwing off of morality and a means to an end. It explains everything: it’s all about liberal fascism.
http://evilincandescentbulb.wordpress.com/2012/03/19/liberal-fascism/
Two sweaty polar bears, ice cold Coca-Colas in hand:
“Whoa, hot enough for you, Whiskers?”
“It’s not the heat, Fuzzy, it’s the humidity!”
What about the talk about enthalpy, total heat content, how it makes the idea of a “global average temperature” worthless as 100°F dry air can have the same heat content as 70°F moist air so averaging the bare temperatures together tells you nothing about the actual heat energy, which should be the important metric?
If the Arctic humidity is rising while the Arctic temperatures are rising several times faster than the rest of the globe in line with the modeled predictions of polar amplification, doesn’t that mean there’s a whole lot more heat energy in the Arctic now than in the past, perhaps exceeding what the modeled CAGW predictions said there’d be?
My understanding being that NASA’s own studies show that on a global basis water vapour has declined… this would be (supposing that is that their results are accurate) a regional effect only. How a regional effect in opposition to the global trend can be construed as “polar amplification” of a global trend is beyond me.
Not to mention that the notion that colder is better is just…. words fail me. How about dumber than a bag of ice cubes for sale in the arctic. To polar bears. Who are sitting on ice flows.
Increasing precipitable water vapor is almost irrelevant to the greenhouse effect. Precipitable water vapor is the total column amount of water vapor in the atmosphere. But an absolute change of humidity in the upper atmosphere at 300 mb to 400 mb pressure level has 30 times the effect on the outgoing longwave radiation as the same change near the surface, as determined by line-by-line radiative code computer simulations. It matters where in the vertical column the water vapor changes, not the total column amount.
http://members.shaw.ca/sch25/FOS/H2O_OLR.jpg
The IPCC states 4AR Chapter 8 page 632;
Polar amplification of global warming is not caused by increasing water vapour. The specific humidity trend at 300 mbars from 1979 to 2011 of the NOAA radiosonde dataset shows a 11.6% decline.
The greenhouse effect, which is the difference between the surface temperature and the effective top of atmosphere temperature, has not increased in the Arctic. The outgoing radiation in the far north has increased along with the surface temperatures. Greenhouse gas emissions have not inhibited the outgoing radiation to space. The top of atmosphere temperature is determined from the outgoing radiation as measured by satellites. The greenhouse effect best fit linear trend using the HadCRUT3 database has actually decreased slightly from 1979 to 2011 as shown in this graph:
http://www.friendsofscience.org/assets/documents/Arctic_GHE.jpg
This means that the increase in Arctic temperatures could not have been caused by anthropogenic greenhouse gas emissions.
Full details are here;
http://www.friendsofscience.org/assets/documents/The_Melting_North.htm
The odd patterns of weather that bring the air from the Arctic down to North America and Europe would thus hold more moisture. This does not auger well for the AGW crowd as some severe white global warming may be a problem in the coming winters. They do tend to have trouble seeing the forest with all the trees in the way.
Mark C. Serreze, as in “Arctic Death Spiral” Serreze? Pinch of salt.
Ken Gregory says:
June 29, 2012 at 11:01 pm
Interesting. I’ll read the links shortly.
“What’s that? Analogous to a gaggle?”
You’re thinking geese; you want crows. A murder of models.
I can exactly tell you what winters had more humidity in the Arctic. Tell me if I’m wrong.
http://ocean.dmi.dk/arctic/meant80n.uk.php
If there is a lot of red above normal like 2012 more humidity if not low humidity. This has nothing to do with CO2 but with warm moisty air from lower latitudes going in. We will see also extreme cold in some part of the lower latitudes because of cold air going out of the Arctic. If you have less cold air because of this in the Arctic there will be less thick sea ice. 1 + 1 makes 2
This is all because of the jet stream. Ofcourse if you tell me that CO2 changes the jet stream than CO2 is the problem. But what I see is Global Cooling.
http://wxmaps.org/pix/temp7.html
blue Australia
http://wxmaps.org/pix/temp8.html
blue South America
http://wxmaps.org/pix/temp8.html
blue South Africa
http://www.osdpd.noaa.gov/data/sst/anomaly/2012/anomnight.6.25.2012.gif
lot of cold sea
http://policlimate.com/weather/current/gfs_dyntrop_sh.html
All this cold air cooling the Southern Hemisphere will have as a consequence that the Antarctic sea ice will grow less thick on the edges, this year
A cackle of Casandras?
Get with the program….
Climate change is bad.
Changing conditions are bad.
In an ever-changing world, things are getting ever-worse.
Not different, never better, only “troubling” or some other modifier that implies a threat.
Only more money will fix the problem.
Just like it always has….
“A finding shared by both reanalyses and radiosonde observations, however, is of an increasing availability of [Polar Bear Populations] in the low-altitude Arctic, which the authors suggest is associated with increasing air-sea surface temperatures, reduced sea ice extent, and other markers consistent with the Polar [Bear] amplification of global warming. Increasing Arctic [Polar Bear populations] is a troubling result, as [more Polar Bears] could further drive up regional temperatures.
“Differences in trends occur between different reanalyses”
””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””’
Our computer analyses never get the same result twice..
Error bars? Sorry, I forgot, this is climate science. They’re optional.
Need a new term for a group of models. How about, “a mendacity of models.”
.
.
And closer to the topic
Frederick Michael says:
June 29, 2012 at 9:12 pm
On the bright side, all that humidity could deposit more snow on the land masses such as Greenland in a mechanism not unlike lake effect snow.
Frederick beat me to it, except I’m rooting for global warming while expecting the opposite.
Whenever I see something used reanalysis data I get out a big grain of salt to take the results with. It is very uncertain what biases may exist in them or how reliable they may be. Nevertheless it doesn’t seem unreasonable to think that there may be some increase in humidity in parts of the atmosphere if temperatures go up. By itself, that would amplify warming as a “positive feedback”-but it is hardly the end of the story. Depending on how clouds and their properties change any positive feedback from water vapor can easily be canceled. And if one is going to analyze the feedback processes at work, focusing on a narrow domain like the Arctic rather than the whole Earth can mislead you. Better to look everywhere at once. People that have carefully done this have tended to find little evidence that the total feedback is positive, indeed, the evidence points more toward negative total feedback.
Humidity is a weather thing. I’ld be looking at Arctic pressure systems and oscillation over this same time period. My bet is that humidity is a function of the types of weather patterns that have predominated during this time period, not some wriggle matching between CO2 and humidity. Weather systems beat the heck out of teeny, tiny increases in human-sourced CO2. Weather systems are so powerful they not only cause a blocking high, they can eventually sweep one away. Try to get CO2 to do that. Oh, my bad. Gore could. He has lots and lots of CO2.
I have two further thoughts on this.
From the article
“A finding shared by both reanalyses and radiosonde observations, however, is of an increasing availability of precipitable water in the low-altitude Arctic, which the authors suggest is associated with increasing air-sea surface temperatures, reduced sea ice extent, and other markers consistent with the polar amplification of global warming. Increasing Arctic humidity is a troubling result, as heightening atmospheric water vapor could further drive up regional temperatures.”
First, it is a breath of fresh air to find that the “reanalysis” runs did not match the raw un-reanalysed (read unhomogenized and unadjusted) observations very well and they admitted it (kind of).
Second, I smell a fudge, or at least a dodge. What is the difference between “availability of precipitable water” and “humidity”? They seem to be saying that the “increasing availability of precipitable water in the low-altitude Arctic” could result in increasing “troubling” Arctic humidity. I would like to check the raw data for the actual humidity measures. In this day and age of changed meanings, could they be doing the same trick that the marine gal did (suggesting increasing acidity from the change in hydrogen ion concentration)? What metric did they use to measure “increasing availability of precipitable water”? And did they then extrapolate that to say “increasing Arctic humidity”?