Operational processing of NOAA-AVHRR data for mapping lake surface temperatures in an alpine environment: feasibility and validation

Lake surface water temperature (LSWT) are operationally derived from the National Oceanic and Atmospheric Administration operated Advanced Very High Resolution Radiometer (NOAA - AVHRR) data using a nonlinear sea surface temperature (NLSST) algorithm. The adapted method has been widely examined with the bias of the algorithm around 0.5degreesC or better. Preliminary analysis shows good agreement between satellite derived LSWT and in - situ measurements at two different lakes. A comparison of LSWT at noon (mean local time) for three lakes is presented. Surface water temperature variations are dominating the annual cycle, however, the varying geospatial attributes of each lake result in specific surface temperature characteristics. Lakes located close to each other can display considerable differences in average surface temperatures by as much as 3degreesC. Knowledge of this fact gives new insights and possibilities for modeling local scale meteorological phenomena like heat flux, energy budget and evapotranspiration. Using operational satellite-derived lake surface temperature can also improve numerical weather prediction models on local scales.