ASSESSING THE IMPACT OF TOPOGRAPHIC FACTORS ON THE ECOSYSTEM CLIMATE SENSITIVITY OF THE CHINESE LOESS PLATEAU

There is strong heterogeneity and gradient in various environmental variables in different terrains, resulting in a microclimate zone that deviates from the regional climate, and its impact on ecosystem function is very complex. Based on long-term moderate-resolution imaging spectroradiometer (MODIS) datasets, terrain and vegetation data of Chinese Loess Plateau, we estimate the ecosystem climate sensitivity under different terrain conditions. Our results show that, the ecosystem precipitation sensitivity is significantly higher than the temperature sensitivity in the Loess Plateau. The regional net primary productivity (NPP) shows a significant positive correlation with the precipitation more than 47.41% areas in the Loess Plateau, while with the temperature accounts for 2.06%. The precipitation sensitivity is the highest in flat territory with an average altitude around 2200 meters. Water deficit restricts the growth of plants in the temperate meadow at the middle altitude more seriously than in alpine meadow and deciduous broadleaf at high and low altitudes. With the increase of altitude and terrain position index, the precipitation sensitivity has an obvious linear trend of increasing first and then decreasing. This result can provide an important reference for us to delimit key environmental protection areas in the Loess Plateau and predict climate sensitivity.