Evaluation of MODIS Atmospheric Temperature and Humidity Profiles by Using Radiosonde Data in Tehran

Two most important parameters for climate numerical forecast modeling are temperature and humidity vertical profiles of the atmosphere. In Iran, these are only produced by Radiosonde instruments at some special stations. Hence the radiosondes are expensive instruments; they are only used at special stations and during specific periods. Nowadays space technology could provide different kinds of atmospheric parameters like temperature and humidity profiles at different pressure levels and in a vast region with lower price. In this research, MYD07_L2 product of MODIS sensor onboard Aqua satellite with 5km spatial resolution has been used to extract the temperature and humidity vertical profiles of the atmosphere. In order to process and evaluate MYD07_L2 product, the atmospheric profiles of Tehran-Mehrabad station were extracted from the MYD07_L2 product, using the IDL environment. The MYD07_L2 products were related to different days and nights of 2007. At the next step, the radiosonde observations and MYD07_L2 data over the Tehran-Mehrabad station were compared, and finally Bias and RMSE of these two data types were computed. The results showed that the temperature profiles obtained from MODIS sensor were acceptable in accordance to radiosonde data with the total bias of 1.95 Kelvin and RMSE of 2.41 Kelvin. The humidity profiles of MODIS data and Radiosonde observations revealed more differences with the total bias of 5.77 Kelvin and RMSE of 6.58 Kelvin.