The Comparison of MODIS Land Surface Temperature with Meteorological Stations Measurements in Iran

Land surface temperature (LST) plays a key role in the transfer of heat to the atmosphere and to the subsurface layers of soil. This study aims at examining the determination coefficient of MODIS LST on air temperature and soil temperature at different depths of Iran. A new method was employed to create a time consistent LST from Terra and Aqua MODIS products, to eliminate the observation differences in local solar time. Preceding the production of time consistent MODIS LST for ۱۲:۳۰ PM, a comparison was carried out with temperature measurements of meteorological stations. The correlation of MODIS LST and Meteorological Station Measurement (hereafter MSM) demonstrate high values, especially for air temperature and ۵cm-deep subsurface soil temperature (R۲>۰.۹۵). The lowest value was obtained for ۱۰۰cm-deep soil temperature (R۲=۰.۸۳). The results of intra annual analysis revealed significant relationship between MODIS LST and MSM temperatures. In the comparison of MODIS LST with subsurface soil temperatures, the scatter plot changes from ۱:۱ to fusiform due to the delay in heat transfer from surface to the subsurface of soil layers. This result postulates that MODIS LST is consonant with MSM temperatures in arid and semiarid regions of Iran. Spatial variation of correlation is higher for ۱۰۰cm-deep soil temperature (۱۶%). On the contrary, for air temperature and ۵cm-deep soil temperature showing the highest correlation, the spatial variation is negligible throughout Iran (۶.۲%). However, Root Mean Square Error (RMSE) analysis revealed LST differences from ۲.۴۳ to ۲۴.۸۸ ˚C throughout Iran rather than MSM temperatures.

کلیدواژه ها:

Land surface temperature ، MODIS ، Time Consistent ، Heat transfer