Measurements and Models of Snow and Ice Albedo on a Lake: Reports from the 1996 to 1997 Ryan Lake Winter Field Studies

Abstract

The albedos of snow and ice over a freshwater lake were measured in two separate field studies: (1) February 21 to March 16, 1996 and (2) December 17, 1996, to March 21, 1997. Both field studies were conducted on Ryan Lake, Minneapolis, Minnesota. Included herein (Section 1) is the report from the first winter field study. Two papers concerning the results of the second field study were submitted for publication and are included in Appendix A and B of this report. The titles of the manuscripts are (1) Snow and Ice Cover Albedos of a Winter Lake and (2) pyranometer Comparison in Measuring Snow and Ice Albedo. In addition to the albedo winter field study report, a number of short reports are, . included herein. The albedos measured during February and March of 1996 were for a limited waveband (0.4 to 1.1 um). Therefore, a set of adjustment equations were developed during the 1996-1997 field study which allowed the 1996 albedo data to be adjusted to the waveband of 0.4 to 2.8 J!m. The results of the adjustments are reported in Section 2. Section 3 gives the results of a literary search conducted to find the albedos of snow and ice at different wavelengths, specifically in the photosynthetically active radiation waveband of 0.4 to 0.7 J!m. During the 1996-1997 winter study, snow depths were measured over Ryan Lake. In Section 4 these data are reported and compared to snow depths measured over land. Lastly, in Section 5, the field observations from both winter field studies are reported along with selected photographs taken during each field study on Ryan Lake.