Measurements of DSD with a dense network of disdrometers associated with convective initiation and evolution

During the warm season over the Kanto Plain of Japan, strong isolated thunderstorms are often responsible for flooding and other rainfall-related hazards. Forecasting of quantitative precipitation associated with these mesoscale systems is known to be an important challenge. However, it has been difficult because of the poor knowledge of the convective initiation and evolution processes.

The Tokyo Metropolitan Area Convection Study (TOMACS) has been designed for better understanding of various mesoscale mechanisms over the Kanto Plain. As a part of the project, a dense network of disdrometers was designed and implemented at intervals of 3 kilometer in the study area. The network consists of six laser-based optical disdrometers (twelve disdrometers since July 2012) to measure drop size distribution (DSD) and rainfall intensity during the interval of 10seconds. Therefore, the network of disdrometers would provide a unique dataset for detail rainfall processes as well as comparisons with polarimetric radar rainfall estimates.

In this presentation, a case study of DSD with high temporal and spatial resolutions in convection during the TOMACS field experiment will be described. The DSD data were combined with data from 12 Automated Weather Stations (AWSs) and Ku-band FM-Chirp fast scanning radar to detail the initiation and evolution of convection.