Effects of coastline and terrain on warm-sector heavy rainfall in the Pearl River Delta, South China
We conducted three experiments using the WRF-Chem model to examine the physical ef-fects of the coastline and numerous low mountains along the coast in the Pearl River Delta (PRD) area on the intensity and distribution of warm-sector heavy rainfall. We analyzed dynamic effects and water vapor transport, and found that by replacing the mountains in the PRD with flat land, orographic lifting disappears, resulting in a considerable reduction of coastal convergence and water vapor accumulation at 925 hPa along the coastline;the 12 hours accumulated precipitation area is mainly confined to the north of 22. 7° N which is 80 km north than without moving out the mountains, and precipitation intensity decreases. By shifting the coastline northward and thus, removing the special topography of the low mountains and the contrast of frictional forces along the original coastline, the convection caused by the convergence is greatly reduced. As a result, almost no precipitation falls in the PRD region. Instead, convection, water vapor accumulation and precipitation centers appear near the new coastline because of orographic lifting and discontinuities in surface friction. The coastline and coastal mountains of the PRD play important roles in the occurrence, intensity and distribution of precipitation.
warm-sector heavy rainfallcoastlineterrainWRF-Chem modelthe Pearl River Delta area
国家科技期刊平台
NSTL
万方数据
维普
