湖北鹤峰一次特大暴雨过程的数值模拟及偏差成因分析  

Numerical Simulation and an Analysis on the Origion of Deviation of an Excessive Storm in Hefeng, Hubei Province

作　　者：张斌[1] 张立凤[1] 彭军[1] 杨袁慧[2] 

机构地区：[1]解放军理工大学气象学院,南京211101 [2]南京信息工程大学遥感学院,南京210044

出　　处：《暴雨灾害》2011年第4期343-348,共6页Torrential Rain and Disasters

基　　金：国家自然科学基金项目"暴雨预报中初始误差的演变和可预报性研究"(40975031)

摘　　要：利用WRF模式对2009年6月29日湖北地区的一次特大暴雨过程进行数值模拟。对24 h累积降水和逐时降水的模拟结果表明:无论是强度还是落区,模式对湖北鹤峰地区的累积降水模拟非常接近实际,但其逐时降水的模拟与实况差异较大。为了揭示影响逐时降水模拟效果的因子,对鹤峰地区3个时刻的不同模拟效果进行对比分析,结果表明:强降水的模拟效果与水汽、垂直速度及大气层结的模拟紧密相关;模式对于这些物理量在各个时刻的不同模拟效果导致逐时降水模拟的偏差,对于05时、13时、21时的降水峰值预报分别为漏报、准确模拟和虚假模拟;强降水期间,鹤峰中低层大气维持中性层结,位势不稳定区在其南侧,最终形成强的湿位温水平梯度,有利于辐合上升运动的增强;逐时降水模拟效果不仅反映了降水模拟的精度,还会影响后期大气层结稳定度的模拟,进而影响后期降水模拟效果。Numerical simulation is carried out with WRF model for the heavy rain in Hubei province on 29th Jul,2009.It shows that the simulated accumulated precipitation in Hefeng of Hubei Province is very close to the observations as to both the intensity and the rainfall area.But the hourly rainfall simulation is quite different from the observations.Further analysis is carried out on different simulation effects of three time points to find factors related to hourly precipitation simulation.It shows that heavy rainfall simulation is closely related to the simulation of water vapor,vertical velocity and atmosphere stratification.The different simulation effect at various moments by the model for physical quantities leads to the deviation of hourly precipitation simulation.The simulation for precipitation peak at 05,13 and 21 is omitted,accurate and false respectively.During the heavy precipitation period,atmosphere at the middle and lower level maintains a neutral stratification and potential instability region is on its south side.This situation ultimately leads to a strong horizontal gradient of wet potential temperature,which is beneficial to the enhancement of convergence and ascending motion.Hourly precipitation simulation not only reflects rainfall simulation precision but also affects the latter atmosphere stratification stability simulation,and then affects the latter precipitation simulation results.

关 键 词：特大暴雨 数值模拟 水汽辐合 湿位温 垂直速度 

分 类 号：P456.7[天文地球—大气科学及气象学]