Snow-cover reconstruction methodology for mountainous regions based on historic in situ observations and recent remote sensing data

摘要

Spatially distributed snow-cover extent can be derived from remote sensingdata with good accuracy. However, such data are available for recent decadesonly, after satellite missions with proper snow detection capabilities werelaunched. Yet, longer time series of snow-cover area are usuallyrequired, e.g., for hydrological model calibration or water availabilityassessment in the past. We present a methodology to reconstruct historicalsnow coverage using recently available remote sensing data and long-termpoint observations of snow depth from existing meteorological stations. Themethodology is mainly based on correlations between station records andspatial snow-cover patterns. Additionally, topography and temporalpersistence of snow patterns are taken into account. The methodology wasapplied to the Zerafshan River basin in Central Asia – a very data-sparseregion. Reconstructed snow cover was cross validated against independentremote sensing data and shows an accuracy of about 85%. The methodologycan be used in mountainous regions to overcome the data gap for earlierdecades when the availability of remote sensing snow-cover data was stronglylimited.