Analysis on Heavy Rainfall in Coastal Areas of Guangdong Province Caused by the Landfall Typhoon "Neoguri"

Based on NCEP/NCAR reanalysis data with the resolution of 1°×1° four times a day,conventional observation data,added surface observation data with higher spatial and temporal resolution,the atmospheric large scale circulation,water vapor condition and convective instability condition et al.related to the heavy rain(the daily precipitation amount over 100 mm) process induced by the typhoon Neoguri were analyzed in order to explore the cause of the heavy rain process.And the results show: the heavy rain process occurred under the atmospheric large-scale circulation background of South Asia High strengthening and moving from the southeast to the northwest,and West Pacific Subtropical High weakening and retreating from the west to the east.High-level(500 hpa) trough which moved to the southern coast areas of Guangdong from the east side of the Qinghai-Tibet Plateau was incorporated with the typhoon Neoguri in southern coastal areas of Guangdong,which are the important synoptic systems that caused the heavy rain.There were convective instability phenomena,wind and moisture convergence over the heavy rain area.The West Pacific Ocean and the South China Sea are the common water vapor source areas of the heavy rain process.The interactions of the typhoon Neoguri circulation itself and the southwest circulation of West Pacific subtropical High lead to that convergence of the wind and water vapor occurred in the right side areas of the typhoon Neoguri route,and which finally casused the heavy rain occurred in the right side areas of the typhoon Neoguri route.