Snowcover Distribution Study and Snowmelt Runoff Prediction System of the Songhuajiang River Basin

1.基于分布式径流模型的1998年松花江洪水径流分析以中国为例，建立了松花江全流域经纬向网格间距均为30min的分布式径流模型。该模型成功地再现了1998年的历史洪水过程。2.1对松花江流域进行了积雪调查，结合已发表的报告，得到了积雪的分布情况。2.2利用分布式水文模型进行了融雪径流分析。通过对采集数据的统计分析，揭示了降水量对海拔高度的依赖关系，建立了拉林河融雪径流分布式模型，模型的纵横向网格间距均为90min。该模型既适用于洪流，也适用于小流域径流。对洪水流量的计算结果表明，与观测值相比，计算值偏小。对于融雪计算，构造了一个新的模型来考虑融雪季初期产生融雪径流的日温度变化。

1.River runoff analysis of 1998 Songhuajiang river flood based on the distributed runoff model.The distributed river runoff model with grid spacing of 30 minutes in both latitude and longitude directions is constructed for the whole basin of the Songhuajiang River, China. The model is run for the historic 1998 flood reproducing successfully the flood hydrograph of that event.2.1 The snow survey is conducted for the Songhuajiang River basin and, combined with the published reports, the distribution of snowcover is obtained.2.2 Snowmelt runoff analysis with the distributed hydrologic model.The measured data of precipitation and river discharge is collected for the Lalinhe River and Gang He River, both tributaries of the Songhuajiang River. The statistical analysis of the collected data shows the dependency of the precipitation on the altitude.The distributed snowmelt runoff model with the grid spacing of 90 min both latitudinal and longitudinal direction is constructed for the Lalinhe River. The model is run for both flood flow and smwmelt runoff. The result for flood flow shows that the calculated river flow tends to be small compared to the observed values. For the snowmelt calculation a new model is constructed to account for the diurnal temperature change to produce the snowmelt runoff for the early stage of the melting season.