陆面参数的扰动对一次西北暴雨模拟影响的研究

Numerical study of the effects of disturbances of land surface parameters on the simulation of a heavy rainfall over Northwest China

利用中尺度模式WRFV2.2及NCEP FNL资料,模拟了2007年6月16—17日的兰州暴雨,检验此次暴雨模拟对NOAH陆面模式参数初始扰动的敏感性。结果表明,此次模拟暴雨对陆面参数的扰动(如土壤孔隙度以及地表反照率的扰动)比较敏感;陆面参数扰动对此次暴雨模拟影响的最小时间尺度小于10h;陆面参数的扰动直接引起地表通量的变化,更为重要的是通过改变水汽输送的环流形势,从而对暴雨模拟产生较大的影响。

The simulation of the heavy rainfall occurring in Lanzhou during 16 - 17 June, 2007 was conducted to test the sensitivity of the rainfall to the disturbances of NOAH land surface parameters by u- sing WRFV2.2 and NCEP/FNL data. The results showed that the simulated heavy rainfall is sensitive to the disturbances of the parameters （ e. g. , soil porosity and albedo） and that the smallest timescale of the simulated heavy rainfall affected by the disturbances is lower than 10 h. These disturbances directly result in the change in the surfaces fluxes, and more importantly, through the change in the low-level circulations that transport water vapor, they exert substantial influences on the simulated heavy rainfall.