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Bellemisc
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DOH! "I came up with 0.00067 for the earthwide effective albedo change, and a solar forcing of 0.23 watts/m2." REVERSED albedo and absorbed energy in the final calc. I now get solar forcing of 0.56 watts/m2 and an albedo change of 0.0016
Neat! The calculation I was trying to do. I came up with an "annual Barrow solar gain weighted effective albedo change" for the arctic sea ice, and then distributed that over the full earth. I came up with 0.00067 for the earthwide effective albedo change, and a solar forcing of 0.23 watts/m2. I thought that was too big to offer up, so I've been re-analyzing. Not sure why Wadhams is about 5x higher, but bottom line: either number is a huge jolt to the climate system.
Earlier I posted (first time ever) about my quest to estimate the solar gain impact of these snow and ice anomolies, on an annual basis. The number is bigger than I imagined, and rather than post that number, I am going to check for help from some former UW Solar Lab alumni from my long ago Master's work, here: http://sel.me.wisc.edu/ My investigation leads me to this conclusion: Between the 2012 annual actic sea ice anomolies and the northern hemisphere snow cover anomoly, I think we are looking at two dead canaries. I think we are in the midst of a step change in the climate system.
Oh, and 2012 is running about 1% lower than 2011, probably because of the early year high ice extent.
Although the annual minimum SIA and SIE are significant as canaries in the coal mine for climate change, as an energy engineer I am now on a quest see the differences, year to year, in annual solar energy absorbed. To that end, as a rough cut starting point I took annual solar gain data for Barrow AK for a horizontal surface (what you would measure on the roof of a building, clouds, sun, all weather), and created a daily gain profile for a year. I took NSIDC data for northern hemisphere: what they estimate for ice I gave an albedo of 0.6; open ocean is 16.2 million km2 minus what they estimate for ice and I assigned an albedo of 0.05. Then I sum solar gain each day for ice and ocean, and total for the year. The important part is that 42% of annual solar gains in Barrow occur by the end of May. It is more significant to have 1 million km2 of open water rather than ice throughout May than in September, because the solar gains are about 4 times greater. September ocean may look awesome, but having Barents sea, Baffin Bay and Hudson bay melting out early are a big component of extra annual energy gain to the Northern Hemisphere from the sun (I think in my simple model). Results: using 1990 through 1999 as a baseline set at 100%, I see that 2011 is the biggest gain year, with solar absorbed 7.5% above baseline, with 2007 second at 7.2% above baseline. That, over 16.2 million km2 is a lot of solar energy gain. The non-linear trend from 2000 is launched upward to 6% for the decade, looking like an s curve. 1995 was an outlier in the baseline at 103%, while 1992 was a cool 98%. Next I'd like to get solar gain data specific to each major sea.
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Aug 20, 2012