HR: 16:50h
AN: C42C-04    [PDF]
TI: Snow Water Equivalent in the Mesocell Study Areas, Cold Land Processes Field Experiment (CLPX)
AU: * Cline, D
EM: cline@nohrsc.nws.gov
AF: National Operational Hydrologic Remote Sensing Center, 1735 Lake Drive West, Chanhassen, MN 55317 United States
AU: Carroll, T
EM: tom@nohrsc.nws.gov
AF: National Operational Hydrologic Remote Sensing Center, 1735 Lake Drive West, Chanhassen, MN 55317 United States
AB: One goal of the NASA Cold Land Processes Field Experiment (CLPX) was to estimate the mean snow water equivalent (SWE), and its associated uncertainty, for each of the three 25-km by 25-km Mesocell Study Areas (MSA). The principal purpose of these estimates is to serve as "ground truth" to validate single-footprint SWE retrievals from the EOS Advanced Microwave Sounding Radiometer (AMSR-E) and to compare with various models. Many factors make accurate estimation of SWE over areas of this size (625-km2) challenging. The large spatial variability of SWE within areas of this size demands a very large number of ground observation to adequately represent the mean and variation. Limited accessibility and logistical constraints prohibited this approach. Instead, airborne gamma radiation measurements were used to measure SWE throughout each MSA. This technique, used operationally by the National Weather Service, is based on the attenuation of natural terrestrial gamma radiation by the atomic mass cross-section of water (ice or liquid) contained in the snowpack and the upper 20-cm of soil. The background gamma radiation is measured in the fall, then the radiation is measured again when snow is present. The attenuation characteristics are well-known, making this a reliable approach to measuring the total SWE + soil moisture present. To separate these two components, soil moisture is estimated. Initial real-time SWE estimates for the three MSA were based only on rough estimates of soil moisture characteristics. In subsequent analysis, we have used soil moisture data collected during each of the flights to refine the SWE estimates for each MSA. These new estimates are discussed, together with the uncertainty associated with estimated SWE for each MSA.
DE: 1863 Snow and ice (1827)
DE: 1866 Soil moisture
SC: Cryosphere [C]
MN: 2003 Fall Meeting