【摘要】 2006年6月至2008年9月,在祁连山中段北坡黑河流域上游进行了降水空间变化的统观测.结果表明:在黑河上游流域中山区,夏季降水量从东向西呈减少趋势,递减率约为80 mm.(100 km)-1;最大降水高度带位于海拔4 500~4 700 m左右,年降水量为485 mm,该高度带与本区最大相对湿度高度层(海拔4 600 m左右)以及夏季气温零温层高度(海拔4 680 m左右)相一致.研究区域2008年夏季的凝结高度大致位于海拔4 900 m左右,个别降水日的凝结高度可降至海拔4 460 m左右.在最大降水高度带以下的高山和中低山区,年降水量随海拔升高的递增率为17.2 mm.(100 m)-1,夏季降水量的递增率为11.5 mm.(100m)-1.更多还原

【Abstract】 During the period of June 2006 through September 2008,an investigation in spatial variations in precipitation in the upper catchment of the Heihe River in the north slopes of the central Qilian Mountains was conducted.Based on the data observed,it was found that: 1) summer precipitation displayed a decreasing trend from east to west in the intermediate altitude with a rate of approximately 80 mm·(100 km-1);2) the zone of maximum precipitation lay between 4 500 to 4 700 m a.s.l.(where annual precipitation is 485 mm),which coincided with the zone of maximum relative humidity(above 4 400 m a.s.l.,with a central height of 4 600 m a.s.l.) and the height of 0 ℃ in summer(about 4 680 m a.s.l.).By analysis of the difference between air temperature and dew point at different heights in the days that precipitation occurred,it is deduced that the average condensation height was 4 900 m a.s.l.in the summertime of 2008,and it might decrease to 4 460 m a.s.l.sporadically.In the studied mountainous area under the zone of maximum precipitation,mean annual precipitation increased with the height with a rate of 17.2 mm·(100 m-1),and summer precipitation increased with a rate of 11.5 mm·(100m)-1.更多还原