1961-2010年青海高原蒸发皿蒸发量变化及其对水资源的影响

利用1961-2010年青海省气象观测资料,分析了青海高原近50年蒸发皿蒸发量的时空分布特征和变化趋势,并采用偏相关及主成分分析法,探讨了青海高原蒸发皿蒸发量变化的气候成因及其对水资源的影响。结果表明：近50 a来青海高原蒸发皿蒸发量呈显著下降趋势,它是热力、水分、动力因子综合作用的结果,在三类因子中,动力及水分因子对蒸发皿蒸发量的影响较大,而热力因子相对较小;区域分析表明,影响东部农业区和柴达木盆地蒸发量的主导因子是平均风速和相对湿度,三江源区为相对湿度,而唐古拉山区为气温日较差。通过分析黄河上游可能蒸散量与地表水资源的关系发现,蒸散量对地表水资源的负效应十分显著,其中夏季蒸散量对于平均流量的影响最为显著,而秋季平均流量对蒸散量的响应最为敏感。

Changes of pan evaporation and its impact on water resource in Qinghai plateau from 1961 to 2010

Based on the meteorological data from 1961 to 2010 in Qinghai province, the spatial and temporal distri- butions and the trend of the pan evaporation were analyzed. The major climate factors affecting the pan evaporation were also studied by methods of a partial correlation and a principal component analysis. The results show that the pan evaporation is in a decreasing trend in the recent 50 years in Qinghai plateau, which is caused by thermody- namic, water and dynamic factors together. Among three factors, the dynamic and water factors have greater impact on the pan evaporation than thermodynamic factor. Regional analysis suggests that the major factors influencing pan evaporation are wind speed and relative humidity in the eastern agricultural areas and Qaidam Basin and rela- tive humidity in three rivers source areas respectively, while the main impacting factor is diurnal temperature range in Tangula mountain areas. It is negative correlation between evapotranspiration and surface water resource by ana- lyzing both relationships. Summer evapotranspiration has a significant effect on the mean flow, while the response of mean autumn flow to evapotranspiration is the most sensitive.