An Integrated Convective Cloud Detection Method Using FY-2 VISSR Data

The characteristics of convective clouds on infrared brightness temperature (BTIR) and brightness temperature difference (BTD) image were analyzed using successive Infrared and Visible Spin-Scan Radiometer (VISSR) data of FY-2, and an integrated detection method of convective clouds using infrared multi-thresholds in combination with tracking techniques was implemented. In this method, BT and BTD thresholds are used to detect severe convection and uncertain clouds, then the tracking technique including overlap ratio, minimum BT change and cross-correlation coefficient is used to detect convection activities in uncertain clouds. The Application test results show that our integrated detection method can effectively detect convective clouds in different life periods, which show a better performance than any single step in it. The statistical results show that the alpha-type clouds are mostly large-scale systems, and the beta-and gamma-type clouds have the highest proportion of general type. However, the proportion of weak convective cloud is higher than that of severe ones in gamma-type cloud, and an opposite result is found in the beta-type.