You Aren't Making Arctic Snow 'Darker' - NASA Satellite Sensors have Degraded - Granite Grok

You Aren’t Making Arctic Snow ‘Darker’ – NASA Satellite Sensors have Degraded

Greenland - still not green

In October 2014 the world’s leading expert on Greenland, or to be more precise the absence of green on Greenland–which is to say the ice that makes Greenland white and not green–warned the world of a potential fossil-fuel induced dark-ice feedback loop that could doom the world. (Cue dramatic Prairie Dog!)

Unlike the black ice found on Britain’s streets, which is clear and takes on the colour of dark surfaces underneath it, Greenland’s ice and snow really is becoming darker. Dr Fox, who co-founded the Dark Snow Project to measure the impact of the blackening ice on its ability to reflect sunlight, has calculated that the ice sheet is 5.6 per cent darker this year than last.

Just one year later some cheeky bastards from Dartmouth College have ruined it all.

Science Daily | [A] new Dartmouth-led study shows that degrading satellite sensors, not soot or dust, are responsible for the apparent decline in reflectivity of inland ice across northern Greenland. The study’s results suggest the ice sheet hasn’t lost as much reflectivity as previously thought, and that black carbon and dust concentrations haven’t increased significantly and are thus not responsible for darkening on the upper ice sheet.

In trying to explain the apparent decline in reflectivity, lead author Chris Polashenski, an adjunct assistant professor at Dartmouth’s Thayer School of Engineering and a research geophysicist at the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory, and his colleagues analyzed dozens of snow-pit samples from the 2012-2014 snowfalls across northern Greenland and compared them with samples from earlier years. The results showed no significant change in the quantity of black carbon deposited for the past 60 years or the quantity and mineralogical makeup of dust compared to the last 12,000 years, meaning that deposition of these light absorbing impurities is not a primary cause of reflectivity reduction or surface melting in the dry snow zone. Algae growth, which darkens ice, also was ruled out as a factor.

Instead, the findings suggest the apparent decline in the dry snow zone’s reflectivity is being caused by uncorrected degradation of sensors in NASA’s aging MODIS satellites and that the declining trend will likely disappear when new measurements are reprocessed.

Seasonal ice melt is, well, seasonal, and annual, and last year had below normal melt and yet there was still an alarm sounded by an expert who has now been shown to be, what’s the word I’m looking for…?

2014 Seasonal Greenland ice melt Below average

Nothing to see here. As you were.

 

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