Topography influence on rainfall and precipitation distribution of Hunan Province

Hunan Province has a complex terrain, the distribution of water resources is quite uneven, the feature of wet areas and arid areas is distinctly. Using the mesoscale numerical model WRF, a series of simulations and sensitivity experiments have been performed to simulate a heavy rain at beginning of November in 2008. It can be found from simulation results that ascending motion intensified by convergence at low levels during rainfall. Sensitivity experiments results show that mountains and hills located in the middle and north of Hunan province not only has influence on precipitation location and rainfall, but also induce convection between different levels, which acted as a trigger. The topography force can be a resistance for the flow and it also can make the atmosphere more stable. This work provides a theoretical basis for water resources scheduling and disaster prevention and mitigation.