区域气候模式中径流计算方案的数值试验

Numerical Simulation of the Run-off Scheme in the RegCM2

采用由曼宁方程推导而来的动力波方程来改进陆面模式BATS中的径流计算方案，并将改进径流方案后的BA偈模式应用到区域气候模式RegCM2中。利用1998年6—8月T106资料做边界场，对改进后的区域气候模式在中国东部地区进行检验。模拟结果表明，改进后的方案在夏季6—8月内模拟的径流值达到80—500mm左右，较原方案模拟的径流量（30—80mm）更加接近径流实况（50—500mm），体现了径流的大尺度平流效应。取单站（武汉）的模拟结果与原模式进行比较，发现模拟场的平均气温与实况场的误差较原模式减小了0．66℃，几次明显的降水过程也有很好的模拟。文中还分析了气温、降水、土壤含水量、蒸发等量的模拟情况。

The dynamic-wave equation derived from the Manning equation was proposed to estimate runoff in BATS, which introduces surface slope and roughness to take into account the interaction between grid physical variables. The modified BATS was then coupled into the RegCM2. By using the T106 data in June to August 1998 as the boundary field, simulations of runoff were performed for eastern China. Simulations show that the runoff of the modified model reaches 80-500 mm in the June to August, more closer to the observed values（50-500 mm） than the value of the original（30-80 mm） model. Therefore the modified BATS better manifests the large scale advection effect of runoff. From comparison of simulations by the modified model and original model at Wuhan station, it is found that the error of simulated average temperature by the modified model and the observed data reduces 0. 66 ℃. The simulated precipitation by the modified model also agrees better with the observed than the original model. The paper also analysed the temperature, precipitation, soil water, evaporation, etc.