柴达木盆地气温降水的长序列变化及与水资源关系

Analysis of Long-Term Changes in Temperature and Precipitation and Their Relationships with Water Resources in the Qaidam Basin in China

根据柴达木盆地8个气象观测站点1960年-2009年共50年的逐月平均气温及降水量资料,综合运用线性趋势分析及Mann-Kendall趋势检验等气象统计分析方法对柴达木盆地气温及降水的变化趋势进行了分析。结果表明在过去的50年里,柴达木盆地经历了明显的升温过程,且增温幅度越来越大,特别是进入20世纪90年代,总的升温幅度在0.5℃/10a左右,远大于同期全球的升温幅度;柴达木盆地降水也略有上升,变化幅度6.2mm/10a左右。从空间分布上看,柴达木盆地气温增幅从东到西逐渐增高,而降水倾向率则逐渐减小。季节分布上,盆地内冬季的气温升温幅度最为明显,增温幅度达0.72℃/10a左右,降水倾向率则夏季最大,达3.4mm/10a。累积距平曲线及Mann-Kendall趋势突变检验综合分析表明,柴达木盆地气温在20世纪80年代有一个明显的增温过程,增温起点在1987年左右。气温、降水的变化也在一定程度上影响到水资源量的变化,相关分析表明,地表水资源量与降水呈显著相关关系,但与气温关系不明显。另外,上一年降水也对地表水资源量有一定的影响。

Global climate change induced by increasing emissions of greenhouse gasses is expected to have a considerable impact on the global hydrologic cycle. Along with global warming, temperature and rainfall varied across China, especially in northwestern China. The Qaidam basin, an important part of northwestern China, is very sensitive to climate change. In this paper, trends in temperature and rainfall in the Qaidam basin were derived by the linear trend analysis and Mann-Kendall trend test based on monthly meteorological data at 8 weather stations during the period 1960-2009. The Mann-Kendall abrupt test was also used to detect the abrupt changes of mean annual temperature and precipitation. The relationships between surface water resources and precipitations were comprehensively investigated. Results show that during the past fifty years, the temperature in the Qaidam basin increased significantly （p〈0.001） and the increment rate of temperature also increased. Since the 1990s, the increate rate has been about 0.5℃/10a, which was much larger than the rate of global increment. Mean annual precipitation also increased significantly at a rate of about 6.2mm/10a. Spatial analysis results show that except the Lenghu station, the increment rate of temperature increased from the east to the west across the basin. The Mangai station showed the highest rate of about 0.86℃/10a. However, the trend of precipitation decreased from the east to the west, with the largest rate occurring at the Delingha station. Results from temporal analysis indicated that temperature increment in winter was most obvious, showing a rate of about 0.72℃/10a, followed by autumn with a rate of 0.57℃/10a. Precipitation increment was about 3.4mm/10a in summer which was largest in all seasons. Results from both accumulative anomaly curve and Mann-Kendall abrupt test show that the temperature in the Qaidam Basin exhibited an abrupt change in the 1980s, with a start point likely taking place in 1987. This was generally accordant with the rate of global temperature change. It was found that the precipitation had no obvious abrupt change. Variation in temperature and precipitation will inevitably result in changes in water resources, particularly the variation of precipitation. Regression analysis shows that the surface water resources had statistically significant correlation with yearly precipitation. The precipitation ahead of a year had also some impacts on the surface water resources in this year. Precipitation in summer and spring had marked relationships with surface water resources, especially in summer. The surface water resources showed an increasing trend during these years principally due to increasing precipitation, even though the increasing trend was not significant.