Trace gas emissions through a winter snowpack in the subalpine ecosystem at Niwot Ridge, Colorado

Abstract

A preliminary study of whole air measurements within a snowpack in the subalpine forest of Colorado found that lower snow layers and underlying soil were a strong source of chemically active trace gases (VOC). The emissions of trace gases were correlated with emissions of radiatively active greenhouse gases (CO2 and N2O) through the snowpack. Carbon dioxide was enhanced in the lower snowpack to over 1000 ppmv, similar to previous studies, which have shown that a thermal insulation of snow covering the soil leads to enhanced emissions of CO2 equivalent to a large fraction of annual respiration. Comparable enhancements of several VOCs reached 1275, 1670, and 1000 pptv for methyl chloride, propane, and α-pinene, respectively. The measurements are limited to a one-day pilot study, however, considering that previous studies have reported significant CO2 emissions through snowpacks any emissions of VOC may also be important on a local or potentially global scale. Copyright 2005 by the American Geophysical Union.