为了检验陆面模式SSiB耦合TOPMODEL模型对流域水量平衡模拟结果的影响， 用原始SSiB与TOPMODEL按饱和区和非饱和区两种方案耦合的耦合模型（下称SSiBT）进行长江下游青弋江流域水文的数值试验， 通过耦合模型与原始SSiB模式模拟结果的比较， 并利用流域实测逐日流量和水量平衡资料， 揭示了流域水文模拟结果对SSiB耦合TOPMODEL的响应和原因。结果表明： （1）与原始SSiB的模拟结果相比， SSiBT增加了土壤湿度的模拟结果和各层土壤湿度之间的差异， 流域蒸散发增加而总径流减小。（2）原始SSiB不能准确地将径流在地表径流和基流之间分配， 对于较小的土壤饱和导水率， 原始SSiB产生过多的地表径流和洪峰流量； 对于较大的土壤饱和导水率又产生过多的基流和明显偏小的洪峰流量。（3）即使土壤饱和导水率大到不会产生超渗产流， 由于饱和区的存在， SSiBT在洪水期间也能产生足够大的地表径流， 从而形成洪峰流量。由于考虑了地形引起的土壤湿度空间非均匀形成的饱和区产流， SSiBT改善了雨季逐日流量的模拟结果。
In order to examine and analyze the effects of integration of land surface model SSiB with TOPMODEL on hydrological simulations, the coupled model (hereinafter SSiBT) which partitions the catchment into saturated and unsaturated zones is used to conduct hydrological simulations at basin scale using data from the Qingyijiang basin. By assessing SSiBT outputs against original SSiB outputs and using observational data sets of daily runoff and water balance of the basin the responses of hydrological simulations to incorporation of TOPMODEL into original SSiB are analyzed and the reasons for such responses are investigated. The study shows that comparing with the results from original SSiB simulations, the coupled model SSiBT predicts more strong vertical changes in soil wetness, higher soil wetness and evaporation and lower total runoff. The study also indicates that original SSiB produces unrealistic partition of runoff between surface runoff and baseflow. When the soil saturated hydraulic conductivity at surface is taken a small value it produces more unrealistic surface runoff and flood discharge while it produces more unrealistic baseflow and much lower flood discharge when the soil saturated hydraulic conductivity at surface is taken a large value. The study also shows that even if the value of soil saturated hydraulic conductivity at surface is so large that there is no overland flow, SSiBT still produces high enough flood runoff during the flood period. Because SSiBT can represent saturated area in the basin resulting from horizontally variations of soil moisture due to topography, it improves simulations of flood runoff during raining season.
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