Tuesday, August 2, 2011

Antarctica sea ice shows accelerating increase over past 30 years

A paper published last month in the journal Climate Dynamics finds that "The Antarctic sea ice extent (SIE) shows an increased trend during 1979–2009, with a trend rate of 1.36 ± 0.43% per decade. Ensemble empirical mode decomposition analysis shows that the rate of the increased trend has been accelerating in the past decade."
Sea ice trends in the Antarctic and their relationship to surface air temperature during 1979–2009 

Qi Shu, Fangli Qiao, Zhenya Song and Chunzai Wang

Abstract: Surface air temperature (SAT) from four reanalysis/analysis datasets are analyzed and compared with the observed SAT from 11 stations in the Antarctic. It is found that the SAT variation from Goddard Institute for Space Studies (GISS) is the best to represent the observed SAT. Then we use the sea ice concentration (SIC) data from satellite measurements, the SAT data from the GISS dataset and station observations to examine the trends and variations of sea ice and SAT in the Antarctic during 1979–2009. The Antarctic sea ice extent (SIE) shows an increased trend during 1979–2009, with a trend rate of 1.36 ± 0.43% per decade. Ensemble empirical mode decomposition analysis shows that the rate of the increased trend has been accelerating in the past decade. Antarctic SIE trend depends on the season, with the maximum increase occurring in autumn. If the relationship between SIC and GISS SAT trends is examined regionally, Antarctic SIC trends agree well with the local SAT trends in the most Antarctic regions. That is, Antarctic SIC and SAT show an inverse relationship: a cooling (warming) SAT trend is associated with an upward (downward) SIC trend. It is also concluded that the relationship between sea ice and SAT trends in the Antarctic should be examined regionally rather than integrally.

3 comments:

  1. The net amount of ice continues to drop. Insolation is greatest during the Antarctic summer and least during the Arctic summer (perihelion and aphelion positions of the planet cause a 20W/m2 difference July-Jan). So what ever is cooling the Antarctic OR increasing precipitation in the Antarctic is very powerful. CO2 is not credited by the IPCC with this sort of power.

    When you average out the insolation throughout the year and over the planet, the large differences that actually exist in time and region disappear. Much the same must happen with SSTs: is there a narrow sea-current that is carrying heat into the Arctic right now that is lost in all the averaging?

    The only reason GISTemp shows such a high global temperature is that Hansen's team includes a modelled Arctic that other data processors don't. That gives a >1.2C GLOBAL temperature increase (relative to HadCruT. That is a lot of energy focused in one place.

    If we were to selectively remove regions and parts of regions until the world was not warming, I wonder where and how much we would have to remove? And whether the "global" warming would become narrow, regional warming.

    My bet is on oceanic currents. Look at what the 1998 El Nino could do: in one year the temps go up 0.6C from an event in the Pacific, and the next year go down by 0.75C. Heat was not produced in 1998, it was redistributed and showed up as a cooler replacement in 1999.

    How much of our heating is just minor heat redistribution?

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  2. I would argue all of it outside of solar changes, since the Sun is the only source of heat (other than minor volcanic input)

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  3. http://www.the-cryosphere.net/6/871/2012/tc-6-871-2012.html

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