流域水文模型对土壤数据响应的多尺度分析

Response of Simulated Stream Flow to Soil Data Spatial Detail across Different Routing Areas

流域水文模拟对输入数据空间详细程度的要求受流域面积大小的影响,而流域面积影响作用的定量描述有助于模拟时的数据选取。本文以美国Brewery Creek流域(约19.5 km2)为例,在逐级连续的汇流面积上,分析了SWAT模型基于1∶2.4万的SSURGO和10m分辨率的SoLIM土壤数据模拟的径流量的差别随汇流面积的变化。结果显示:汇流面积较小时,基于不同土壤图的模拟径流一致性较差;随着汇流面积的增大,模拟径流的差别逐渐减小并趋于稳定,在汇流面积大于约10 km2时,差别变得相对不明显,不同土壤数据的模拟径流相当。根据实验结果,流域径流模拟对数据的要求受模拟面积的潜在影响,当流域面积大于一定值时,较粗分辨率的输入数据同样可能取得较好的模拟效果。研究度量了面积对模型响应的潜在影响作用,为中小流域水文模拟时土壤数据的选取提供了初步参考。

Appropriate spatial detail of input data for watershed modeling is partly dependent on the scale of the watershed modeled.It will facilitate data selection for modeling if the effect of watershed scale can be quantitatively described.This paper aims at investigating the variations of simulated differences between different soil data across a series of water routing areas.The study was conducted using soil and water assessment tool,with the 1：24,000 SSURGO soil data and digital soil mapping data from Soil Land Inference Model（SoLIM） at 10m resolution as different input data,to investigate the stream flow differences arising from different soil data at Brewery Creek,Dane county,Wisconsin of the USA.Results show the low consistency of simulated stream flow between the two soil data at small water routing areas,but the consistency generally rises with the increase of routing area.Simulated stream flow based on SSURGO and SoLIM becomes similar especially for area larger than 10 km2.Based on the effects of continuous routing scales on simulated stream flow differences between different soil data,a preliminary conclusion can be made that coarser input data can also be used for a larger watershed for stream flow simulation.