Self-organization Process In Local Heavy Rain

This paper analyzes a hazard heavy rain occurred on July 27 2006 in eastern part of Shandong Peninsula by using automatic stations, Doppler radar, satellite images, conventional weather maps and NCEP/NCAR 1°×1°grid point data, and explores effects of the environmental field on the synoptic scale on clouds self-organization such as tropical low pressure trough, high-altitude westerly trough and the subtropical high and so on. Numerical study of influences of multiple randomly distributed small-scale vortexes on the vortex self-organization has been carried on with a quasi-geostrophic barotropic vorticity equation model. Also self-organizations of negative removal entropy index have been studied in this paper. On the basis of many cases, a number of predicted criteria of occurrence and development of self-organization have refined, which are used to study prediction of heavy rain events, and achieve good results.Major developments are as follows:(1) Stage characteristics of self-organization of clouds in local heavy rain are found, which is one local rainstorm don't complete by only one but several self-organization. As in a hazard heavy rain process, on July 27 2006 in eastern part of Shandong Peninsula,4 clouds self-organizing process could be identified clearly.(2) It is found that the interaction of different scale systems have a major impact on self-organization. Systems at different scales include synoptic-scale systems larger than mesoscale clouds and small-scale systems smaller than mesoscale clouds. Synoptic-scale systems, the former, provide environment field conditions of self-organization including high-altitude westerly trough, tropical low pressure trough and the subtropical high. The latter include small-scale randomly distributed systems, and they provide micro-environment field conditions of self-organization. Although small-scale systems were artificially given in previous similar studies, which is random generated in this research in order to reduce the artificiality. The introduction of randomly distributed small-scale vortex could lead to differences in final state of self-organization.(3) Making the self-organization theory and dissipative structures theory together into work ideas shows the convergence of negative removal entropy index of self-organization reflects the rainstorm falling area clearly, and provides useful information to falling center forecast of convective rain.(4) On the basis of analyzing summer satellite image data from 2000 to 2007, it is found that the evolution of mesoscale clouds which can cause rainstorm experiences processes from non-organized to organized, from irregular shape to regular, and obtained a number of criteria of self-organization clouds, which have been initially applied in operational applications.