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利用20个气象站1960-2006年的逐日气象资料,采用FAOPenman-Monteith模型,计算出祁连山及河西走廊各气象站的月潜在蒸发量,在此基础上计算各气象站的月湿润指数,然后进行季节、年地表湿润指数的统计,进而对研究区地表干湿状况的时空变化进行分析.结果表明:祁连山及河西走廊在20世纪80年代之前地表相对干旱,之后相对湿润,自60年代以来地表湿润指数有逐年增大的趋势;年地表湿润指数的年际变化率为0.0014a-1,相关系数为0.4281,通过了0.01的置信度检验,表明地表湿润状况有明显改善,其中春季和冬季增加趋势明显,夏季增加趋势和秋季减小趋势不太明显.地表干湿变化趋势在空间上有差异,东部表现为东西差异,自东向西逐渐变湿,乌鞘岭以东呈变干趋势,其他大部分地区显著变湿,中部大部分地区呈不明显的变干趋势,而托来南山以北地区显著变干,张掖绿洲显著变湿,西部除敦煌以西呈不显著的变湿趋势,其他大部分地区显著变湿.
Based on daily meteorological data of 20 meteorological stations from 1960 to 2006, the monthly potential evapotranspiration of each weather station in Qilian Mountains and Hexi Corridor was calculated by FAOPenman-Monteith model. Based on this, the monthly wetting index of each weather station was calculated and then calculated Seasonal and annual surface wetness index, the spatial and temporal variations of surface wet and dry conditions in the study area were analyzed.The results showed that the surface of the Qilian Mountains and the Hexi Corridor were relatively arid before the 1980s, and then relatively humid. Since the 1960s, The annual variation rate of annual wetland index was 0.0014a-1 with a correlation coefficient of 0.4281, which passed the test of the confidence level of 0.01, which showed that the surface wettability improved obviously, especially in spring and winter Obviously, the increasing tendency in summer and the decreasing trend in autumn are not obvious.The variation tendency of the surface wet and dry is spatially different, the east is the difference between the east and the west, the humidity gradually changes from east to west, Significantly wet in most areas, most of the central part of the trend was not obvious to dry, and Tuolaishan north of the region was significantly dry, Zhangye oasis significantly wet west In addition to the west of Dunhuang was no significant wetting trend in most other regions significantly wet.