Uydu görüntüleri ile dinamik derece-gün faktörü tahmini ve hidrolojik modellemede kullanımı

Ergüç, Birkan
Akyürek, Sevda Zuhal
Mountain watersheds are one of the main sources of fresh water. Modeling snow accumulation and melting in these high-altitude basins is crucial. Although snow accumulation and melting depend on the factors such as distance from the sea, altitude, slope, temperature and precipitation, it is very difficult to consider all these variables during modelling. In literature, snowmelt modeling is generally carried out in two basic approaches: energy balance and temperature indices. Temperature indices are preferred because of their ease of calculation, good performance and less data requirement. These indices employ a threshold temperature and degree-day factor for the calculations. The degree-day factor (DDF) is usually calculated by calibration for the entire basin. Some models, such as the Mesoscale Hydrologic Model (mHM), calibrate modified DDFs according to the type of land use. mHM uses 3 different degree-day factors for forests, nonforest and impermeable surfaces. In mHM and similar models, some improvements have been made spatially but many models do not take the temporal variability into account. In this study, daily degree-day factors were calculated by using 500m resolution MODIS daily Snow-Covered Area data between 2014 and 2018 water years and these data were tested in Karanlıkdere basin by using mHM model. mHM was run using the calculated daily degree-day factors and re-calibrated with calculated DDFs. The performance of runoff simulations of mHM is slightly improved, while snow-water-equivalent simulations are improved better.
Citation Formats
B. Ergüç and S. Z. Akyürek, “Uydu görüntüleri ile dinamik derece-gün faktörü tahmini ve hidrolojik modellemede kullanımı,” Muğla, Turkey, 2019, vol. 1, Accessed: 00, 2021. [Online]. Available: