MULTIFRACTAL PROPERTIES OF WATER VAPOR FLUX AND PRECIPITATION PARTICLES IN LINE-SHAPED RAIN BAND

Abstract

 Multifractal has been widely applied as the tool of quantitative pattern analysis. In this study, multifractal properties of water vapor flux and precipitation particles distribution associated with line-shaped rain bands were analyzed to identify the three-dimensional patterns of self-organization of convection systems. We analyzed water vapor flux obtained by the numerical simulation of the heavy rainfall event over Kameoka City on 15 July 2012. Before heavy rainfall occurred, water vapor flux approached to monofractal corresponding to increasing the convective instability at lower atmosphere. While during heavy rainfall, strong multifractality was shown due to the development of convection systems. Multifractal analysis was also conducted to characterize the multifractality of the mixing ratio distributions of ice-phase precipitation particles obtained by volume scans of X-band MP radars. The time period when the line-shaped rain band area began to expand and the regional averaged rainrate increased coincided with the one when the multifractality of the graupel and snowflake mixing ratio changed significantly.