1982—2015年柴达木盆地不同流域植被气候响应差异

Different correlations between NDVI and climate factors in different watershed over Qaidam Basin from 1982—2015

基于1982—2015年生长季(5～10月)GIMMS-MODIS融合数据、气象数据,利用一元线性回归和相关分析等方法研究柴达木盆地及各流域植被NDVI的时空演变及其与气候要素的关系。结果表明:(1)柴达木盆地植被整体上趋于改善,NDVI与气温和降水呈显著正相关。(2)盆地内各流域NDVI呈现不同程度的增长趋势,区域气候差异明显,盆地东部NDVI平均值与气温和降水的关系表现为以1989年和2002年为转折点的3段式特征,而盆地西部呈现出以1994—1995年为节点的2段式特征。(3)盆地东西部植被对气候要素响应的差异性显著,这可能与高原季风、西风环流及下垫面等因素有关。

Global climate change has led to significant vegetation changes in recent decades. Vegetation NDVI is an important indicator for evaluating terrestrial eco-system change. Its response to climate change has become one of the main contents in current global change research. The Qaidam Basin, located in the northeast of the Qinghai Tibet Plateau, is most sensitive to climate change. Based on GIMMS NDVI from 1982 to 2006, MO- DIS NDVIfrom 2001 to 2015 and climate data from 54 meteorological stations from 1982 to 2015, we analyzed the temporal and spatial evolution of the NDV1 in different watersheds and their correlations with the precipita- tion ＆ temperature using linear regression and correlation analysis. The results were shown as follows： （1） From1982 to 2015, the NDVIof vegetation growing season in the study area was improved progressively, with a linear tendency of 0.1%· a-1. The relationship between vegetation change and precipitation ＆ temperature showed a significant positive correlation, the correlation coefficients were 0.536 and 0.400 respectively. The res- toration area was mainly distributed in the areas of high altitudes in the Qimantag Mt, Burhan Budai Mt, Ela Mt and Zongwulong Mt surrounding areas of the Donggi Conga Lake and the core areas of those oases. （2）The climatic change and vegetation change had stages, which was remarkable in different regions. The vegetation restoration was characterized by two fast-growing periods, with an ＂Shaped＂ increasing curve in Dulan Lake Basin, Dabuxun Lake basin and Tuosu Lake basin. For Dulan Lake Basin, Dabuxun Lake Basin and Tuosu Lake basin in the eastern Qaidam Basin, the relationship between NDVI in vegetation growing season and precipitation ＆ temperature presented a three-section response law with 1989 and 2002 being the turning points. While for Gasikule Lake basin, Dachaidan Lake basin, Xiaochaidan Lake Basin, Sugan Lake Basin and Taijinaier Lake Basin in the western Qaidam Basin, it presented a two-section response law with the extreme events of dry year in 1994 and 1995 being the turning point. （3） In the global warming situation, the western Qaidam Basin was mainly controlled by the westerly circulation, while it was influenced by the Asian summer monsoon in the east. The stronger plateau monsoon, the weaker westerly circulation, and the underlying surface, are the contributing factors for the different responses of the vegetation to the climate in the Qaidam Basin.