嫩江流域径流时空演化规律分析

以流域时空分布理论框架为基础，分析嫩江流域径流时空演化规律，并着重从地形地貌影响因素方面进行归因分析。采用1955-2003年49 a的降水资料和1955-1973年19 a的径流资料，通过对代表性水文站自上游至下游（空间上）径流、地表径流和地下径流的年内与年际（时间上）演变规律进行分析。结果表明：1）嫩江流域降水年内变化及年际变化过程基本一致，可以忽略降水时空分布对径流时空演化规律的影响。2）从径流年内演化规律上可以判定上下游水源组合的差异性：上游以地表径流为主，在春季来源于融雪，汛期来源于大气降水，枯水季节来源于地下水补给；下游全年以地下径流为主。3）由于坡度和水文地质条件作用，上游更容易产流，下游受下垫面调蓄作用更强，不易产流;因此,从径流年际演化规律上可以判定径流产量自上游至下游逐渐减小。

Analysis on the Laws of Spatio-Temporal Changes of Runoff in Nenjiang River Basin

Based on the spatial and temporal distribution theory of basin, the evolution of the Nenjiang River basin runoff space-time laws was analyzed. And it focused on the attribution analysis of the factors of topography effect. Based on the precipitation data from 1955 to 2003(49 a) and runoff data from 1955 to 1973(19 a), the evolution of runoff, surface runoff and underground runoff were analyzed from upstream to downstream of the representa-tive hydrological stations. What the results shows is as follows: 1)In Nenjiang River basin，the inter-annual and space-time change of rainfall are consistent. So the impact of spatial and temporal distribution of precipitation can be ignored when runoff evolution is analyzed.2)The headwater differences from upstream to downstream can be determined through annual runoff evolution.The upstream is surface runoff. In the spring, the runoff is from snowmelt.  In the rainy season, it is from atmospheric precipitation. In the dry season, it comes from groundwater recharge. The downstream is mainly underground runoff.3)Because of slope and hydrogeological conditions, it is easier for upstream to produce flow. From upstream to downstream, the runoff volume is gradually reduced.