Verification instability indices derived from MODIS images with the help of Radiosonde data (Case study: Tabriz station)

nformation about the stability of the atmosphere is a very important factor in now casting and short term forecasting. Atmospheric Stability is usually estimated based on Radiosonde instability indices data. But due to a very low number of meteorological stations having Radiosonde and the cost of lunching them using satellite images could be a proper alternative. In this study، the accuracy of survey data obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric profile products in order to predict atmospheric instability versus Radiosonde observed values has been investigated. Three extracted MODIS instability indices TT، L and K are compared with Tabriz station Radiosonde data at 00 (UTC). The Tabriz weather، airport station has been selected due to its high frequency of thunderstorms (over 35 thunderstorm days per year) and the existence of an upper air station in the spring and summer of 2007as a case study. It has been observed that the TT، L and K instability indices obtained from Radiosonde and MODIS show good correlation with respectively the correlation coefficient of 0. 46، 0. 55 and 0. 60 in spring and 0. 64، 0. 65 and 0. 67 in summer، and therefore the spatial interpolation of these indices in areas where there is no Radiosonde information is possible. Also by the investigation of the average absolute error، the K and TT indices showed less error in summer than spring while the L index showed less error in spring than in the summer. It was also observed that the instability indices values obtained from MODIS were underestimated compared with Radiosonde and it''s much more significant in the spring.