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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Key points? Not even close to the abstract. So is this also post normal science? Now even the ABSTRACT can say something different than the key-points press release? This whole thing looks like an attempt to get a study that demonstrated no significant findings into publication and spin it so that it would be reported that it did find such significant results. And it wasn’t the mass media that did it, it looks like the people at the National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado in Boulder did that spin themselves. This is rather bold-faced, no apologies lying in my opinion.
Higher humidity in the arctic – higher snowfall and build up of glaciers in Greenland.
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.
That’s my theory of the next glaciation. When the Arctic Ocean is open all year we will have ocean-effect snow all round the perimeter of the Arctic every day of the year. Think of the accumulation in winter! Everywhere around the Arctic would be like Buffalo in a bad year (well, maybe not that bad).
H.R. says: “Need a new term for a group of models. How about, ‘a mendacity of models.'”
(1) The models are lyin.’ (2) The models are based as much on hubris as science.
So I’d go with “a pride of models.”
.
The Arctic ocean cannot be open all year. The tilt of our Earth and the current set of land masses keeping the oceanic circulation patterns in their course will keep the freeze-melt cycle going. You would have to change something in the physics maths, something really big, in order to get a year round ice free Arctic.
Watervapour is a powerful greenhouse gas.
Could the increase in watervapour be the cause of rapid warming of the Arctic?
Or am I mixing up cause and effect?
Warning! Warning! Warning! Obfuscation in progress!
What they’re really saying, is that they intend to model them observations until politically correct meanings are realized
Let’s see, from their graph it looks like they’ve managed to squeeze an extra mm of precipitable water at the peak modeled difference using their ‘new’ models. Just wait till they finish their newer longer wider wetter models next year!
/sarc
jorgekafkazar says:
The models are based as much on hubris as science. So I’d go with “a pride of models.”
The way the models perform I don’t see much to be proud of yet.
Frederick Michael says:
“The absence of solid white is downright creepy. The record low sea ice extent could be shattered this year.”
As an antidote to the wild-eyed climate alarmism of Mark C. Serreze, Andrew P. Barrett, and Julienne Stroeve, a few points to remember:
1. The “record low” covers only a few decades. Prior to that the record is sparse
2. The North Pole has been ice free 60 years ago, and in the early 1800’s. During most of the Holocene it was warmer than now
3. The planet is still emerging from the LIA, so it is no surprise that sea ice is in decline
4. There is zero evidence that CO2 has anything to do with this natural fluctuation, no matter what Serreze, Barrett, and Stroeve are trying to imply. And as usual, Serreze, Barrett, and Stroeve never mention the Antarctic
5. The Antarctic has 90% of the planet’s ice. Antarctic ice is increasing:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
My simple understanding is that humid air takes much more energy to heat than dry air. Compare the tropics to deserts. An increase in humidity in the arctic would seem, to me, an inhibiting factor to a rise in temperature. Although water vapour is our most abundant greenhouse gas, to have a warming effect, wouldn’t it have to be much higher in the atmosphere?
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.
Increased water vapour is also consistent with black carbon deposition and increased solar insolation melting ice and allowing increased ocean evaporation.
I’d add that albedo changes from snow/sea ice to open ocean will be much larger than any water vapour GHG effect. When sea ice melts the percentage of solar insolation reflected changes from more than 60% to less than 10%.
Clearly, melting sea ice causes a strong warming feedback from the albedo change. The limiting factor has to be increased snowfall and snow accumulation on land adjacent to the Arctic causing land surface cooling (from albedo changes again).
And indeed we have seen large increases in winter snow cover in the last decade, but curiously large decreases in summer snow cover. Its snowing a lot more in the NH, but snow is melting a lot faster. The faster snow melt will from the same cause as the sea ice melt – BC deposition and increased insolation.
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=4
At some point cooling from snow albedo changes will exceed the BC/insolation effect. Lets hope this isn’t the trigger for the next glacial phase.
Nice to see that many responding here are zeroing in on the Ewing/Donn theory of Ice Ages.
Well worth your time to dig into. The colderside webpages may also help!
“””””…..Data from all of the reanalyses point to strong interannual and decadal variability. …..”””””
This is a scientific way of saying; “can’t tell anything since numbers are all over the map.” Do all scientists write gobbledegook as good as this stuff ?
More water vapor (aka precipitable water; meaning it can snow more to increase albedo) in the amosphere leads to more solar radiation absorbed in the atmosphere, specially in those much longer atmospheric air mass oblique paths in the arctic, and this increased absorption leads to less solar radiant energy being deposited in the arctic oceans and land areas, so it leads to a cooling surface.
James Sexton says:
June 29, 2012 at 9:24 pm
“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?
James, one of the main purposes of the paper was to evaluate the accuracy of the reanalysis, especially the three most recent efforts to see how well they match each other (i.e. how robust their signals are) and how well they match the limited number of in situ observations. Since scientists rely on reanalysis data to give a larger picture in space and time than the rawinsonde data can provide, it’s important to access their accuracy and conclusions based on those data.
The second purpose was to evaluate the trends. Results shouldn’t surprise anyone, as the Arctic warms and there’s more transfer of sensible and latent heat to the atmosphere from more open water, you would expect an increase in precipitable water vapor and humidity in the Arctic atmosphere.
Since climatologists are always making adjustments to the data, how about a “meddling of models?”