黄河源区蒸散量变化与生态恶化的关系

利用20世纪80年代以来黄河源区水文和气象资料,分析了该区蒸散量、日照时数、气温、空气饱和差的变化趋势,并着重研究了诸因子对蒸散量的影响.结果表明,源区蒸散量呈逐年增大趋势;而作为主要影响因子的日照时数则以3.6h/a的速度增加;气温以0.04℃/a的速度递增;空气饱和差也以0.02hPa/a的速度递增.因此,可以认为,源区日照时数、气温及饱和差的增加,加剧了草地蒸散发,生态的恶化也加大了蒸散量,蒸散量的增大和降水量的减少则直接造成了源区流量的减少和生态的恶化.

Relationship between variation of evapotranspiration and ecological deterioration in source region of Yellow River

Using hydrological and meteorological data from the source region of the Yellow River from the 1980s onward, the variation trends of the evapotranspiration, sunshine duration, air temperature and air saturation deficit were analyzed. The influences of various factors on the evapotranspiration are highlighted. The results show that evapotranspiration in the source region of the Yellow River is increasing year by year. The sunshine duration, regarded as the main factor, is increasing at a rate of 3.6 h/a. The air temperature is increasing at a rate of 0.04℃/a. The air saturation deficit is increasing at a rate of 0.02 hPa/a. The increases of the sunshine duration, air temperature and air saturation deficit accelerate the evapotranspiration from the grassland, and the deterioration of the ecological environment also increases the evapotranspiration. The increase of the evapotranspiration and the decrease of the precipitation amount have a direct influence on the decrease of the flow discharge and the ecological deterioration in the source region of the Yellow River.