摘要
应用 MM5中尺度模式 ,在 60、2 0和 1 0 km模式分辨率下 ,分别选用 4种不同对流参数化方案 (KUO方案、GRELL方案、KAIN- FRITSCH方案和 BETTS- MILL ER方案 ,以下简称KU、GR、KF和 BM方案 )对 1 996年 8月 3～ 4日石家庄暴雨过程进行数值模拟试验 .模拟结果的对比分析及其与观测的比较表明 :主要雨带位置对参数化方案并不是十分敏感 ,但随分辨率提高 ,雨带分布特征的模拟更接近实况 ;当分辨率提高到 1 0 km时 ,虚假的降水中心也明显增加 ;模拟的暴雨中心强度随分辨率的提高而增强并随参数化方案的不同有所变化 ,但均比实况偏弱 .分析还发现 ,MM5模式的 GR、KF及 BM方案的次网格降水对总降水的贡献率随分辨率的提高而减小 ,而 KU方案的情况则呈现出不合理的缓慢增加态势 .虽然 4种方案下模拟的水平环流特征有较好的一致性 ,但模拟的云物理特征和垂直运动特征还是存在一定差别的 ,这种差别对定点、定量降水和天空状况、地面气温、湿度等要素的准确预报都会产生影响 .因此 ,在预报和模拟中应考虑预报和研究对象的特点来选择对流参数化方案 .
Numerical simulation experiments on cumulus parameterization schemes, KUO, GRELL, KAIN FRITSCH and BETTS MILLER (KU, GR, KF and BM), of the MM5 are carried out using real time data of the Shijiazhuang torrential rain event happened in Aug. 3-4 of 1996, under three kinds of model horizontal resolutions (60, 20 and 10 km). Comparisons among the experiments and against the observations indicate that the higher the model resolution is, the closer the simulations of main rain belt distributions to the truth are, while the location of main rain belt is not very sensitive to the cumulus parameterization schemes (CPSs). And spurious rainfall centers occurred when the model resolution increased to 10 km. In addition, the intensities of torrential rainfall increase with the decrease of the model grid size and change with the CPSs quite clear, but the torrential rainfall amount is underpredicted in all experiments.It was found that the contribution of the sub grid scale precipitation to the total by KU scheme is higher than that by its three counterparts, and has an unreasonable trend of increasing with the model resolution, which is opposite from GR, KF and BM schemes. Although the characteristics of the horizontal circulation from four CPSs' simulation results are nearly the same, the certain differences of distributions of the cloud water, rain water and vertical motions among four CPSs' simulation results are obvious, which could affect the accuracy of the quantitative precipitation, the cloud amount, the surface air temperature and humidity forecasts. Therefore, choosing suitable CPSs for one's study is necessary.
出处
《应用气象学报》
CSCD
北大核心
2001年第1期41-53,共13页
Journal of Applied Meteorological Science
基金
国家气象中心"九五"课题! ( ZX95-0 1 )资助
