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利用分布式生态水文模型SWIM,基于泾河上游(泾川测站以上)植被、土壤、气象和水文数据对研究区进行了水文过程的模拟,从而估算了流域的实际蒸散量及其各组分。结果表明:SWIM模型能够较好的模拟泾河上游流域的水文过程,模拟的流域多年(1997-2003年)平均实际蒸散量为443mm,其中土壤蒸发量为259mm,植被蒸腾量为157mm,冠层截持量为27mm。石质山区的森林覆盖区和非森林地的年蒸散总量在整个流域分别具有最大值和最小值,为484mm和418mm;黄土区实际蒸散量介于二者之间,平均为447mm。森林覆盖地区土壤蒸发明显小于其它区域,而蒸腾和冠层截留明显大于其它区域。年内蒸散量主要集中在5-8月份,占全年总蒸散量的60%,且冠层蒸散比例较大达63%。整个流域湿润年份较干旱年份蒸散量增加了78mm,其中土壤蒸发增加最多,其次是冠层蒸腾,冠层截留蒸发最小。
Using the distributed ecohydrological model SWIM, the hydrological process was simulated based on the vegetation, soil, meteorological and hydrological data in the upstream of Jinghe River (above Jingchuan Station) to estimate the actual evapotranspiration and its components . The results show that the SWIM model can simulate the hydrological process in the upper reaches of the Jinghe River. The average actual evapotranspiration for the years (1997-2003) in the simulated watershed is 443mm, in which the soil evaporation is 259mm, the vegetation transpiration is 157mm, Interception of 27mm. The total annual evapotranspiration in forest cover and non-forest in stony mountainous area has the maximum and minimum values of 484mm and 418mm, respectively. The actual evapotranspiration in the loess area is between 447mm. Soil evaporation in forest covered areas was significantly less than that in other areas, while transpiration and canopy interception were significantly larger than those in other areas. Evapotranspiration during the year mainly concentrated in May-August, accounting for 60% of the total annual evapotranspiration, and a large proportion of canopy evapotranspiration reached 63%. The evapotranspiration increased by 78mm in the wet years of the whole basin compared with the drought years, of which the soil evaporation increased most, followed by the canopy transpiration and the canopy interception evaporation.