黄土高原气候变化及其对植被覆盖的影响

The Climate Change in the Loess Plateau and Its Impacts on Vegetation Coverage

气候变化是当前学术界和管理者共同关心的热点问题,在干旱-半干旱区尤其受到关注。黄土高原是我国典型的干旱-半干旱地区,也是近年来生态恢复的热点区。明确黄土高原气候变化趋势以及气候对植被覆盖的影响,对于未来该区域的生态保护和环境管理具有重要参考价值。本研究采用集合经验模态分解(EEMD)方法对1951-2016年黄土高原气候变化趋势进行分析,并在此基础上分析退耕还林工程实施以来气候变化对植被覆盖的影响。结果显示,黄土高原气候呈明显暖干化趋势,区域温度升高幅度达到2.33℃,升高速率为0.35℃/decade,在空间上表现出东南向西北增温逐渐凸显的格局;区域降水量降低幅度为75.4 mm,降低速率为13.7 mm/decade,在空间上表现出自西北向东南逐渐增强的格局。气候因素对植被覆盖具有显著影响,其中降水对植被覆盖的影响自南向北逐渐趋于增强,温度与植被覆盖则倾向于自南向北由正相关转为负相关。

Climate change is currently a hot issue concerned by both academics and managers,which is particularly noticeable in arid and semi-arid regions.As a typical arid and semi-arid area in China,the Loess Plateau is a hot spot of ecological restoration in recent years.It is thus necessary to clarify the trend of climate change and its impacts on vegetation coverage in the Loess Plateau,in order to provide important references for the ecological conservation and environmental management in the future.In this study,we utilize the EEMD method to identify the climate change trend of the Loess Plateau in 1951-2016,and further analyze the impacts of climate change on vegetation coverage since the“Grain to Green”program.The results indicated that the climate of the Loess Plateau showed an obvious warming and drying trend.The regional temperature increased by 2.33℃with the increase rate of 0.35℃/decade,exhibiting a pattern of gradually strengthening from southeast to northwest.The regional precipitation decreased by 75.4 mm with the decrease rate of 13.7 mm/decade,exhibiting a pattern of strengthening from northwest to southeast.The climatic factors significantly impacted the vegetation coverage.The impacts of precipitation tended to enhance from south to north,while the relationship between temperature and vegetation coverage tended to change from positive to negative from south to north.