PROGRESS IN GEOGRAPHY ›› 2005, Vol. 24 ›› Issue (5): 13-22.

• Original Articles •

### Study on The Response of Vegetation Cover to Precipitation and Temperature in Central/East Tibetan Plateau

ZHANG Wenjiang1,2, GAO Zhiqiang1

1. 1. Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China|
2. Graduate School, Chinese Academy of Sciences, Beijing 100049, China
• Received:2005-06-01 Revised:2005-08-01 Online:2005-09-25 Published:2005-09-25

Abstract:

The Tibetan Plateau is among the few extensive regions remoted from human disturbance, and provides an ideal site to study the response of vegetation cover to water/thermal conditions (WTC), esp. the response of natural vegetation. Therefore, this paper focuses on the spatial variation and then relations of water/thermal climate elements and NDVI (Normalized Difference Vegetation Index, AVHRR NDVI product of 8km) from year 1982 to 2000, mainly in central and east Tibetan Plateau where the gauge is basically dense enough to qualify related analyses. In the study, to investigate the relationships between spatial variation of water/thermal conditions and multi-year mean NDVI, trend surfaces of N (short for NDVI), P (short for precipitation), N-P relation and N-T relation are simulated, transects of four directions are designed and vegetation types are compared by group. The relation differences of N-P and N-T are respectively investigated, both spatially and biologically. 　　According to our study, following conclusions are reached: a) Climate elements: Ten-day mean NDVI of certain region in Tibetan Plateau is influenced less by the water and thermal climate elements if the vegetation cover is evergreen dense or totally sparse. On the other hand, temperate WTC (thus vegetation cover of temperate density) tends to have stronger relationship with NDVI than extreme conditions. b) Spatial variation: As indicated by transect analysis and trend surface simulation, the relation values of peripheral Plateau are low (often because of extreme WTC and thus extreme vegetation cover) while the values of main plateau body are over 0.75 (because of temperate WTC and thus temperate vegetation cover). c) Zonality: Since altitude plays an important role in the distribution of thermal condition in Tibetan Plateau, annual NDVI bears a abvious vertical zonality while the horizontal zonalities are not so distinct. In addition, the relations of NDVI with precipitation and temperature have no clear zonal characteristics.