Topics Spectral reflectance of snow and its variability Reasons: optics of ice –Snow is a collection of ice grains –Along with dust, algae, and (eventually) liquid water Why do we care? –Implications for energy balance of snowpack Implications for remote sensing –What can we measure? –How do we integrate imaging spectrometry with multispectral measurements? –How can we use the information in hydrology?
Applications: snowmelt modeling, Marble Fork of the Kaweah River Snow Covered Area net radiation > 0 degree days > 0 where: m q = Energy to water depth conversion, 0.026 cm W -1 m 2 day -1 a r = Convection parameter, based on wind speed, temperature, humidity, and roughness
Magnitude of snowmelt: Modeled – Observed snow water equivalent assumed albedo assumed w/ update AVIRIS albedo SWE difference, cm Tokopah basin, Sierra Nevada
27 Acknowledgments Steve Warren & Warren Wiscombe –Model for the spectral albedo of snow (1980) NASA –Funding on remote sensing of snow since 1977 UC Santa Barbara –Great place to think about snow and ice Former and current students on this topic –Bert Davis, Rob Green, Danny Marks, Anne Nolin, Tom Painter, Karl Rittger, Walter Rosenthal, Jiancheng Shi