岷江上游不同景观结构小流域水量平衡的比较

A comparison of water balance in small basins with different landscape pattern in the upper reaches of Minjiang River.

研究了1988～2002年岷江上游两个小流域(镇江关流域和黑水河流域)不同景观结构(土地覆盖、海拔、坡度、斑块密度、最大斑块指数等)对水量平衡的影响.基于两个流域土地覆盖类型、1988～2002年多年平均降水量和蒸散量的空间分布、两个流域土地覆盖类型同期多年平均径流深度的数据,得到不同土地覆盖类型的海拔、坡度、坡向与降雨、蒸散、径流的关系.结果表明,两个流域有林地海拔、坡度、坡向的不同导致其降水、蒸散降水比、径流降水比各异;两个流域草地水量平衡对景观格局的响应模式与有林地基本一致;由于黑水河流域的耕地分布在干旱河谷中,其蒸散量远远大于降水量,耕地本身的景观结构(坡向、坡度,斑块密度)并不对其水量平衡产生影响,这一点与镇江关完全不同.

This paper studied the effects of landscape pattern （land cover types, altitude, slope, aspect, patch density and maximum patch index） on the elements of water balance （precipitation, evapotranspiration, and runoff） in two small basins （Zhenjiangguan River and Heishui River） in the upper reaches of Minjiang River during 1988 ～2002. Based on the spatial distribution of mean annual precipitation and evapotranspiration as well as the mean annual runoff on different land cover （woodland, grassland and cropland） during 1988 ～ 2002, the relationships of landscape pattern with water balance was approached, and the results showed that in these two basins, the precipitation, evapotranspiration / precipitation ratio, and runoff / precipitation ratio had a greater difference with the altitude, slope, and aspect of woodland, and grassland had a similar hydrological effect as woodland. On the farmland of Heishui River basin, which was distributed in dry valley, evapotranspiration was much higher than precipitation. This abnormal water balance was caused by the arid valley climate in the upper reaches of Minjiang River but not the landscape pattern of farmland, being totally different with that in Zhenjiangguan River basin.