【摘要】 利用1967—2008年日降水资料,对黑河流域荒漠区降水格局及其脉动特征进行系统研究。结果表明:年均降水量为113.3mm,年际变化27.93%,降水呈平稳下降趋势。小降水事件(≤5mm)为主,年际变化较小。大降水事件(≥10mm)频率较低,但年际变化及其对年降水量的贡献较大。降水日期以≤5mmd-1为主,≥10mmd-1变异较大。<10d间隔期所占比率最大,频率基本稳定(CV=18.29%),而>10d间隔期变异较大(CV=27.21%)。年降水量与降水事件、降水期、<10d间隔期以及总降水间隔期存在显著正相关性。≤5mm降水总量变异系数为24.57%,接近年降水量(27.93%),>10mm变异系数为76.68%,表明大降水事件在不同年份的差异是降水总量和降水格局差异的主要原因。更多还原

【Abstract】 Rainfall data were collected to systematic study rainfall patterns and pulse characteristics from 1967 to 2008 in desert regions of the Heihe River basin.The results showed that the annual rainfall averaged 113.3 mm and the interannual variability accounted for 27.93% of the annual rainfall that were described as a downward trend.The majority of rainfall events were characteristic by ≤5 mm,and the interannual variability were relative small.Large rainfall events(≥10 mm)were infrequent but the interannual variability was wide comparatively.Rainfall date of ≤ 5 mm d-1 were the most common,whereas the date of ≥10 mm d-1 varied widely.Inter-rainfall period of < 10 d accounted for the most proportion and the variability were relative small(CV=18.29%),whereas the variability of >10 d were relative large(CV=27.21%).Annual rainfall were significantly positively correlated with rainfall events,rainfall period,<10 d inter-rainfall period and total inter-rainfall period.The variation coefficient of ≤5 mm were 24.57% and approached to that of annual rainfall(27.93%),whereas >10 mm were 76.68%,which indicated that the interannual variability of large rainfall events were mainly resulted in the difference of annual rainfall and rainfall pattern.更多还原