RESPONSE OF SHALLOW GROUND TEMPERATURE TO PRECIPITATION AT DIFFERENT GROUND COVERS IN PERMAFROST REGION

There are complex hydrothermal processes in the atmosphere, the ground surface and the frozen soil. Precipitation is the main source of water supply on Qinghai-Tibetan Plateau, forms a discontinuous change layer of hydrothermal in the shallow ground. We analyze the temperature changes under the difference ground surface at different precipitation times. We use the in-situ monitoring data of precipitation and the temperature in the shallow ground from 0 to 80cm in depth under the engineering pavement(asphalt and gravel pavement) and the natural ground(alpine steppe and alpine meadow).The results show the follows. Annual precipitation is increased every year in Beiluhe area. The increase rate is 22.9mma-1. Precipitation mainly concentrates in 5~9months. Response to temperature during daytime is intense than that at night for precipitation. Temperature change under engineering pavement is greater than that under natural ground at night. Under the same precipitation condition, temperature variations in 10 :00~15:30 duration is greater than those in 16 :00~18:00. As the precipitation increases, the decrease of temperature increases. The depth of temperature response to the precipitation is 0~30cm deep range of gravel pavement, alpine steppe, and alpine meadow. The influence depth of asphalt pavement is 0~20cm deep range. Affected by the impermeable layer of pavement, and magnitude of the temperature at 5cm depth is greater than that at the surface. This study provides data to divide the different heat transfer mode stratification under different ground surfaces.