LAUSR

The ecosystem of the Tibetan Plateau is highly susceptible to climate change. Currently, there is little discussion on the temporal changes in the link between climatic factors and vegetation dynamics in this region under the changing climate. By employing Normalized Difference Vegetation Index data, the Climatic Research Unit temperature and precipitation data, and the in-situ meteorological observations, we report the temporal and spatial variations in the relationships between the vegetation dynamics and climatic factors on the Plateau over the past three decades. The results show that from the early 1980s to the mid-1990s, vegetation dynamics in the central and southeastern part of the Plateau appears to show a closer relationship with precipitation prior to the growing season than that of temperature. From the mid-1990s, the temperature rise seems to be the key climatic factor correlating vegetation growth in this region. The effects of increasing temperature on vegetation are spatially variable across the Plateau: it has negative impacts on vegetation activity in the southwestern and northeastern part of the Plateau, and positive impacts in the central and southeastern Plateau. In the context of global warming, the changing climate condition (increasing precipitation and significant rising temperature) might be the potential contributor to the shift in the climatic controls on vegetation dynamics in the central and southeastern Plateau.摘要青藏高原生态系统对气候变化十分敏感. 目前, 这一区域的植被活动与气候因子之间相关性随时间的变化研究仍然较少. 本文利用NDVI, CRU气温和降水格点数据以及气象站点资料, 分析了近30年来青藏高原植被活动与气候因子之间相关性的时空变化. 结果表明上世纪80年代初至90年代中期, 高原中部及东南部地区生长季NDVI与降水量之间存在显著正相关关系, 但随后相关系数持续下降; 而自90年代以来, 气温升高则为影响植被活动的关键因子. 气温升高对高原不同区域的植被活动产生不同的影响: 利于高原中部及东南部的植被生长, 但抑制了高原西南及东北部区域植被生长. 全球变暖背景下的青藏高原气候条件发生明显变化, 可能是这一区域植被活动主导气候因子转变的原因.