Study On The Typhoon Torrential Rainfalls And The Effects Of The Remission Of The Precipitation Resources To The Drought In North Jiangsu

Typhoon is the strongest weather system of China’s torrential rain.Jiangsu is located in the climatic transition zone between the north and south of the Yangtze River.Affected by the monsoon climate,there are obvious differences in seasonal and interannual variations of precipitation and alternatively droughts and floods occuring frequently especially in Northern Jiangsu.We selected a typical torrential rain affected of typhoon in Jiangsu.Taking comprehensive advantage of statistical analysis, diagnostic analysis and comparative analysis,we concentrates on the spatial distribution of precipitation by analyzing the occurrence and development mechanism of the typhoon Storm. On this basis,we further explored the value of the rain resources in the practical application through comparative and quantitative analysis of the Jiangsu’s historical climate characteristic and the distribution and the re-utilization of precipitation resources during the typhoon rainstorm.The key and innovative components of the paper are as follows:1.We statisticed the perennial historic characteristics of the spatial and temporal distribution mainly including drought, rainfall and runoff in Jiangsu.It is prepared for the further research about the distribution and utilization of the rain sources.The terrestrial water cycle process after producing precipitation showed as follows.After the precipitation reached the surface, part of the rainwater trapped plants,in the same time the remainder of the rain moisturized and filled holes of the soil.Part of the leakage in the soil turned into the soilwater and the groundwater which we called soil runoffs and subsurface runoffs. When the depth of infiltration reached the peak,in other words that the intensity of the rainfall was larger than the infiltration,the runoff began to increase quickly.Throughout the process part of the rainfall was dissipated to the atmosphere through foliar or soil surface evaporation. A common feature showed that northern Jiangsu was a growing typical arid area as well as a concentration area of rainstorm and high-runoff.2.A diagnose and analysis of a torrential rain process caused by ’HAIKUI’ typhoon in Jiangsu province on August 8-10,2012 was performed. Therefor we can learn the characteristics of the rainfall’s spatial and temporal distribution and the large-scale background field of the dynamic and thermodynamic.The rainstorm was composed of two different development stages,the results showed that two kinds of systems and energy mechanisms led to different rain areas and intensity.The first-stage rainstorm was caused by typhoon in the southern Jiangsu along the Yangtze River.With the landing of the ’haikui’ typhoon,the plentiful warm air which came from the southeast low-level jet in the northeast of the typhoon extended to the southern Jiangsu. It accumulated a large number of unstable energy in the case of the instability stratification with the lower-warm and the upper-dry condition.The second-stage rainstorm was caused by typhoon trough in the northern Jiangsu.As well as the typhoon moved to southeastern Anhui, the reinforced southwest monsoon mixing with the low-level jet in the southern of the typhoon supplied abundant water vapor for the torrnential rain.The superposition of the cold air from the upper trough and the warm-wet air eastern of the typhoon trough and the intersection of the cool and warm air could triggered the instable energy to be released and activated the heaviest rainstorm.The severe rain process lasted long and led to heavy rainfall. The precipitation area and time of the second stage was smaller and shorter than the first,but the rainfall amount was bigger in the center of the rainstorm.The coupling of the LLJ and the high-level jet stream as well as the deep helicity column provided dynamic lifting mechanism.3.We further explored the effects of the remission of the precipitation resources to the drought in Northern Jiangsu through comparative and quantitative analysis of the Jiangsu’s historical climate characteristic and the distribution and the re-utilization of precipitation resources during the typhoon rainstorm.Firstly we classified the rainstorm by different magnitude,by comparison the area of high-rainfall and high-runoff had the consistent variation tendency.In the process the runoff taked a greater proportion and distribution area than the infiltrationAfter that we divided Jiangsu arid-area into northern Jiangsu,central Jiangsu and south Jiangsu by the irrigation line.All aspects of the report showed that most of Jiangsu was hot and dry weather before the typhoon rainstorm,especially the northern Jiangsu. We compared the amount of precipitation in the process with the corresponding historical average.The results showed that the large-numerical area was focus on the northern Jiangsu both in rainfall and runoff.When the difference was in greater amount,the degree of the corresponding precipitation,runoff and the soil moisture were deeper.We considered to establish a rational collection device for the precipitation and make scientific planning especially at the high-difference area in order to reach the greatest extent about the distribution and utilization of rainfall resources.