Evolution and structure of a convection line over coastal region of South China in June 2008

NCEP 1°×1° reanalysis data, FY-2C TBB data, Dopplar radar data, automatic weather station data and conventional observational data were utilized to study a heavy rain process associated with convection line over Guangdong province on 16-17 June 2008 by using the observation data analyses and simulation. The results indicate that the convection line occurred over northern South China Sea, moved northwards, and it began to intensify while it approached the coastline of Guangdong province. The heavy rainfall occurred to the south of convection line. The intensification of convection line close to coastline was the result of convergence enhanced by the coastal front. The hourly surface wind analysis indicated that convergence line was formed between southwesterlies to the south of the coastal front and easterlies to the north of the coastal front. The numerical simulation reproduced the process showing that convection line was strengthened when it got to inshore and weakened when it moved northwards to the continent, and convergence line reached the highest intensity when it approached coastline, thus upward motion and convection along the convection line were enhanced making convection extend up to middle-upper troposphere.