Geothermal Flux Change Research In The Watershed Of Permafrost Region

Ecological and hydrological processes due to the physical and chemical properties of frozen soil show different characteristics with the non-permafrost regions. Frozen soil content of ice varies with temperature, and is derived four kinds of state:being frozing, being melting, frozen, and melt. As the natural climate fluctuations, due to the temperature factor, the soil water system which is not stabilize furnitures for freezing and thawing, dry wet, swell-shrink, dispersion and condensed primary cracking and reunite and a series of alternate evolution of physics, chemistry and mechanics. That adds the difficulty of the frozen soil simulation.The study area is divided into a lot of hydrological calculation basic units (e.g., grid, irregular triangle net, hydrological response unit, sub basin, etc.) in the distributed hydrological model to consider the spatial distribution of various hydrological response influence factors, and it bases on thehe space distribution information of data source liking GIS, RS, radar and global climate models, numerical weather prediction, etc. Distributed hydrological model have certain physical basis, and each unit has different input, output, and parameters.This article selects the grassy areas of Qinghai-Tibet plateau permafrost Fenghuoshan watershed, and small watershed was divided into118972grid, each grid is a single vegetation type, and the division and extraction of hydrologic unit using30*30m DEM by ArcGIS and ENVI,. Based on this, Using2008meteorological data, soil moisture and soil temperature, the distributed hydrological model of Fenghuoshan small watershed was constructed, and the transmission of radiation, evaporation, geothermal flux was simulatied and calculatied. Finally, through parameters optimization, the simulation results were compared with measured results.The changes of geothermal flux and the surface temperature, as the boundary conditions, tightly affects the distribution of soil moisture, soil temperature, and also seriously affects the surface vegetation growth, development, and so on. When geothermal flux is positive, the surface temperature rises, surface soil melts, soil moisture increases, vegetation growth needed water is replenished. At the same time, with the surface of heat continuing, subsoil melts, and the soil water moves, underground runoff moves. On the contrary, ground temperature drops, geothermal flux decreases, and the soil begins to freeze.