A Research on Distributed Time Variant Gain Modeling
分布式时变增益流域水循环模拟

Based on requirement of distributed hydrological modelling and considering the real conditions of the arid and semi-arid regions in China, this paper develops a Distributed Time Variant Gain Model (DTVGM) by coupling the mechanism and special digit information of water cycle with hydrologic system approach. It simulates the movement of the water in the soil-vegetation-atmosphere system, describes the relation between the cellular grids in the horizontal direction, and performs mathematical calculations of the surface water and the groundwater on the watershed cellular grids divided by DEM. DTVGM includes two components: one is runoff generation process on grid elements; the other is flow routing process based on ranked grids. At present, the runoff generation process is divided into two layers in the vertical direction: the upper layer is the surface flow; the lower layer is the subsurface flow. On the other hand, the kinematic wave models are applied to simulate the flow routing process. The article also addresses a case study on Heihe mountainous basin by applying DTVGM. The basin, with an area of 9,569.25 km2, is divided into 38,277 grid elements; and the grids are partitioned into 456 ranks for flow routing.