Greenland Ice Sheet albedo drops ‘off the bottom of the chart’ – but look closer as to why | Watts Up With That?

Got this in the mail just as I posted my open thread announcemnt. I’m too busy this weekend to say much else except to post this tweet from Bill McKibben and some past blog excerpts and invite discussion.

Bill McKibben@billmckibben

 The reflectivity of the Greenland ice sheet has…literally dropped off the bottom of the chart. This means MELT.

That graph says one thing to me – black carbon soot, especially since lower levels of Greenland, near the oceans and glacial terminae don’t exhibit the same effect:

CO2 doesn’t change ice albedo, but smoke from the industrialization of Asia does, and I think it is a factor.  See why below. 

It is possibly the same reason for the sea ice decline and the melt pools we’ve been seeing on the surface. Note that this year the melt accelerated quickly once the sun was regularly over the horizon in May…so that an energy dissipation in the ice when soot absorbs solar radiation.

Recall this experiment with soot on snow done by meteorologist Michael Smith of WeatherData where soot made a huge difference.

I also covered the issue in:

Greenland Ground Zero for Global Soot Warming

They say a  picture is worth a thousand words, this moulin in Greenland  a real eye opener:

Image from National Geographic online slide show – Photo: James Balog – click for more

He writes:

In the winter a huge among of snow are accumulated on the Ice (2-3 meters, sometimes more) and we are not talking about 1 or 2 square-miles, it’s about 100.000′s of square miles (up to 1 million) on the Westside of the Ice cap and a similar picture on the Eastside… when the melting season starts in april-sep… the meltwater has to go somewhere, and for sure it goes downhill in huge meltwater rivers.

The black stuff on the bottom of the lakes is carbon dust and pollution in general… but not from one year, but several decades (the topographical conditions don’t change from year to year). On a flight over the Ice Cap a sky clear day, you can see hundreds of huge lakes with the black spot on the bottom.

– Anthony

The website of Jason E. Box, Ph.D. has more graphs and says:

Latest Greenland ice sheet reflectivity

These albedo visualizations are discussed here and here.

About the Data

Surface albedo retrievals from the NASA Terra platform MODIS sensor MOD10A1 product beginning 5 March 2000 are available from the National Snow and Ice Data Center (NSIDC) (Hall et al., 2011). The daily MOD10A1 product is chosen instead of the MODIS MOD43 or MCD43 8-day products to increase temporal resolution. Release version 005 data are compiled over Greenland spanning March 2000 to October 2011. Surface albedo is calculated using the first seven visible and near-infrared MODIS bands (Klein and Stroeve, 2002; Klein and Barnett, 2003). The MOD10A1 product contains snow extent, snow albedo, fractional snow cover, and quality assessment data at 500m resolution, gridded in a sinusoidal map projection. The data are interpolated to a 5 km Equal Area Scalable Earth (EASE) grid using the NSIDC regrid utility April and after September, there are few valid data, especially in Northern Greenland because of the extremely low solar incidence angles. The accuracy of retrieving albedo from satellite or ground-based instruments declines as the solar zenith angle (SZA) increases, especially beyond 75 degrees, resulting in many instances of albedo values that exceed the expected maximum clear sky snow albedo of 0.84 measured byKonzelmann and Ohmura (1995). Here, we limit problematic data by focusing on the June–August period when SZA is minimal.

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