1981-2010年柴达木盆地气候要素变化特征及湖泊和植被响应

Climate factors change and its impact on lake area and vegetation growth in the Qaidam Basin during 1981-2010

以1981-2010年柴达木盆地及其周边气象站点逐月气温和降水量资料为基础,通过气候趋势分析、气候突变分析等方法,研究了柴达木盆地气候要素的变化特征,并结合Landsat TM/ETM+影像、NOAA/AVHRR-NDVI和EOS/MODIS-NDVI数据,研究了近30年来柴达木盆地湖泊面积和植被生长的动态变化及其对气候要素的响应。结果表明:①1981-2010年,柴达木盆地气温整体升高,秋冬增幅最为明显,年平均气温在1997年发生暖突变,1998年以后升温趋势显著。②1981-2010年,柴达木盆地年可利用降水量经历了"减少—增加—减少—增加"的变化,但整体呈增加趋势,1980-1985年、1990-2001年,年可利用降水量呈减少趋势;1985-1990年、2001-2010年,年可利用降水量呈增加趋势。③柴达木盆地湖泊面积受夏季可利用降水量影响显著,1985-2010年,托素和冬给措纳湖泊面积呈"扩张—萎缩—扩张"变化;1985-1990年,湖面轻微扩张;1990-2001年,湖面明显萎缩;2001年以后,湖面显著扩张。④柴达木盆地植被生长受生长季可利用降水量影响显著,1982-2010年柴达木盆地植被生长呈"退化—改善—退化—改善"变化,但整体呈改善趋势;1982-1985年植被轻微退化,1985-1990年植被轻微改善,1990-2001年植被显著退化,2001年以后植被显著改善。

Changes of climate factors in the Qaidam Basin during 1981-2010 were analyzed based on the monthly temperature and precipitation data from meteorological stations.Rate of linear tendency and Mann-Kendall test were used to illustrate the change trends and detect abrupt changes of meteorological elements respectively.In addition,lake area changes and vegetation activity changes in the Qaidam Basin in response to climate changes were discussed using Landsat TM/ETM＋ images,NOAA/AVHRR-NDVI and EOS/MODIS-NDVI products.The results showed that（1） The Qaidam Basin experienced an overall rise in temperature,especially in autumn and winter during 1981-2010.Temperature changed abruptly from low to high in 1987 and the increase has become more rapid since 1998.（2） The annual available precipitation showed a ＂decrease-increase-decrease-increase＂ change in recent 30 years,but the inter-annual trend of annual available precipitation was similar to annual mean temperature at a rate of 5.65 mm/10a.Available precipitations were low in 1981-1985,1990-2001,but high in 1985-1990,2001-2010.An abrupt change to warm-wet happened in the mid-late 1980s.However,an overall trend of warm-dry was detected from the mid-1990s to the end of the 20th century.A significant warm-wet trend of climate has arrived once again since the early 21th century.（3） Variations of lake area and vegetation growth were significantly affected by the change of wet and dry climate.The ＂expansion-atrophy-expansion＂ pattern in lake areas correlated with summer available precipitations which happened in 1985-1990,1990-2001,2001-2010 respectively.（4） The ＂degradation-amelioration-degradation-amelioration＂ pattern in vegetation growth was closely related with growing season available precipitation which happened in 1981-1985,1985-1990,1990-2001,2001-2010.