Soil Temperature and Moisture Change and the Impacts on Vegetation over the Tibetan Plateau

Abstract:

Permafrost soil covers 25% of the area in the Northern Hemisphere, it is especially important on the Tibetan Plateau, with almost 75% the Tibetan Plateau land covered by the permafrost. Continuous, isolated and discontinuous permafrost soil and seasonally frozen soil coexist on the plateau. Changes in frozen soil are likely to have impact on ecosystems, hydrology and infrastructure. In this study, we use both modeling approach to study the historical changes in soil temperature and moisture over the past 50 years. The Variable Infiltration Capacity (VIC) model was modified and used to simulate the soil temperature and moisture on the plateau. Observed soil temperature and moisture down to 7 m were used to evaluate the VIC model. The evaluated model is then used to study the historical change of the frozen soil. The effects of the frozen soil change on the vegetation growth in the Northeastern Tibetan Plateau are examined by using empirical relationships between soil temperature/moisture and biomass.