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Climate & Radiation
Geodesy and Geophysics
Wallops Field Support
Branch Seminar Series: Zuhal Akyurek
Middle East Technical University, Civil Eng. Dept.
Sunday, September 7, 2008 - 21:30
Monitoring snow-covered areas and estimating the snow water equivalent play an important role in predicting discharges during spring months, especially in regions where snow is an important resource. Turkey is a mountainous country and many basins in the country are largely fed from snow precipitation whereby nearly two-thirds occur in winter and may remain in the form of snow for half of the year. Accordingly, modeling of snow-covered area in the mountainous regions of Eastern Turkey, as being one of the major headwaters of Euphrates–Tigris basin, has significant importance in order to forecast snowmelt discharge especially for optimum use of water in energy production, flood control, irrigation and reservoir operation optimization. The difficulty in accessibility to perform the measurements at the remote sites makes the use of satellite images and/or aerial photographs in monitoring and estimating the snow parameters more valuable. The accuracy of the snow cover mapping studies in the optical wavebands mostly depends on the developed algorithm's performance of truly detecting clouds. On very cloudy days it is not possible to make accurate snow cover mapping by using only optical satellite sensors. In this study the validation of Air Force Weather Agency (AFWA) - NASA Snow Algorithm (ANSA) blended snow cover products, having 25km and 5km, was performed for the eastern part of Turkey for five months in 2007-2008 winter period. This is the first time of validating the blended snow cover product in a mountainous area, where the elevation changes between 850 m to 3000m. Daily snow data collected at 36 meteorological stations were used in the validation analysis. In terms of snow cover mapping the contribution of blended snow cover product compared to MODIS and AMSR-E product alone was discussed. ANSA having 5km resolution products of February and March 2008 were used to derive snow depletion curves, which are the important parameters of snowmelt modeling. The results are compared with the curves obtained from MODIS daily snow products. Dr. Zuhal Akyurek received her B.S., M.S. and Ph.D. degrees in Civil Engineering from Middle East Technical University. She did research in Geography Department at Bristol University-UK for 15 months as a Chevenning Scholar from September 1997 to December 1998. She worked as a scientist in the Space Science and Technology Lab. of Turkish Scientific Technological Research Council of Turkey for one year. Currently she has been working as a faculty member of Civil Eng. Dept at METU since 2000. Her main areas of research are hydrology, water resources management, remote sensing and GIS.