CSAS Data: Graphs & Plot
We measure incoming and reflected shortwave radiation with pyranometers (filtered and unfiltered) at two sites: SBSP (alpine) and SASP (sub-alpine). We also measure longwave incoming radiation with a pyrgeometer at both sites. We have snow surface temperature data to correlate with radiation data.
Plots of average “broadband” snow albedo from 1200-1300 hours each day of WY 2012 snowpack at the Swamp Angel and Senator Beck Study Plots in Senator Beck Basin Study Area. Gaps in the data represent days during which snow covered the up-looking sensor measuring incoming, short-wave radiation (the “broad band” pyranometers). Data at either end of the plot represent albedo of bare soil or vegetation on the ground. Red bars show WY 2012 dust-on-snow events, by date. The point of “snow all gone” (SAG) is indicated, and albedo values for the preceding day or two were reduced by dark soil seen through the shallow, wet snow by the down-looking pyranometer. Albedo is calculated as the ratio of reflected radiation to incident (incoming) radiation upon a surface; valid snow albedo values in these plots range from ~0.3 (30% reflectance) to ~0.9 (90% reflectance). Both sites experienced declines in snow albedo beginning with event D4 (March 6th), frequently reversed by clean snow.
Radiation instrumentation at each site includes two up-looking, full-range pyranometers (Kipp & Zonen CM21, 305-2800 nm (50% points)), a third filtered pyranometer (Kipp & Zonen™ CM21 with RG695 filter dome, 780-2800 nm (50% points)), and a pyrgeometer (Kipp & Zonen™ CG4). One of the full-range up-looking pyranometers is deployed with a fixed shadow band for measurements of diffuse radiation at solar noon. The shadow post is modeled upon the Swiss's Alpine Surface Radiation Budget project specifications. On a separate arm, we have two down-looking pyranometers measuring reflected radiation from the snow surface, one full-range (Kipp & Zonen CM21, 305-2800 nm (50% points)) and one filtered (Kipp & Zonen™ CM21 with RG695 filter dome, 780-2800 nm (50% points)).