Sunday, April 27, 2014

The more snow and ice lost to the climate crisis the dirtier the snow and less albedo is realized.


acquired November 29, 2005

...The map (click here) above shows the outlines of glaciers around Everest, overlaid on a topographic map of the region based on digital elevation model (DEM) data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite. Progressively lighter shades of brown depict higher elevations of bare land; glaciers are shown with progressively lighter shades of blue (higher is lighter). 

A Mt. Everest ice core spanning 1860–2000 AD (click here) and analyzed at high resolution for black carbon (BC) using a Single Particle Soot Photometer (SP2) demonstrates strong seasonality, with peak concentrations during the winter‐spring, and low concentrations during the summer monsoon season. BC concentrations from 1975–2000 relative to1860–1975 have increased approximately threefold, indicating that BC from anthropogenic sources is being transportedto high elevation regions of the Himalaya....


April 7, 2014

...In June 2013 (click here) my field assistant Sam Ecenia from the University of Colorado, Boulder and I trekked up to the base of Cho Oyu, the sixth highest peak in the world and the source of the Ngozumpa glacier. Imagery from then and in August revealed a lot of dirty snow and ice as the melt season progressed. The contamination is partly natural dust and partly man-made soot from incomplete combustion of fossil fuels, biofuels and biomass.

Then in October 2013 a cyclone from the Bay of Bengal moved toward the Himalaya and dumped over a meter of snow in just two days. I set up a temporary weather station to track air temperatures and snow albedo (reflectivity) changes, and physically sampled snow with another field assistants, Emma Marcucci, a recent Ph.D. from Boulder, and Martin Coleman, a retired Lockheed Martin engineer. Just days after the storm, the snow was already quite dirty. Although it appeared white to the naked eye, we found plenty of contaminants after melting down the samples and running them through a filter. The samples are currently in the lab so it remains to be determined how much is due to natural dust and how much is man-made pollution or debris from road construction in Kathmandu or from extensive trail erosion along the route to base camp
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Over the course of three weeks, as the snow melted despite decreasing temperature, instruments called pyranometers recorded a reflectivity decrease of nearly 20 percent. You know how you feel much warmer in the sun if you wear a dark shirt rather than a light-colored shirt? That’s because the dark material absorbs more solar radiation. Dark particles on the white snow do the same thing, melting the snow faster....