Application of an automated cloud-tracking algorithm on satellite imagery for tracking and monitoring small mesoscale convective cloud systems

摘要

In this study, an automatic algorithm for tracking convective cloud cells, on the basis of infrared and water vapour Meteosat images, is applied in the case of intense precipitation events of 26 and 27 January 1996 in Greece, and the results are presented. The case presented in this study has the particularity of consisting of several localized maximum precipitation events that resulted from small mesoscale convective systems. The ability of the algorithm to detect and track in Meteosat images, in real mode, propagating cloud systems of this size, through the monitoring of several cloud parameters that express cloud development and movement, is examined. It was found that the algorithm was capable of identifying small mesoscale cloud cells and tracking them consistently to the point of dissipation. Moreover, the introduction in the algorithm of new cloud parameters, which are directly related to the cloud-top structure, has proved very valuable in providing additional information on the convective potential of the detected cloud cells. Finally, an empirical nowcasting of convective cloud movement and evolution could be carried out in many cases to support the forecaster's decisions by using information on cloud speed, direction and development in conjunction with synoptic analysis.