摘要
采用WRF(weather research and forecasting)模式输出资料、NCEP/NCAR1°×1°再分析资料以及地面站降水资料,对2009年7月31日至8月1日四川省一次暴雨过程进行了分析。结果表明:水汽辐合区与降水区基本一致;散度场、水汽通量和水汽通量散度对降水具有较好的指示作用。在降水之前的6h中,降水中心上空的大气层结基本稳定,这种层结条件并不利于对流运动发生和发展;但是通过对散度场、非线性平衡方程和理查森数的分析,发现在暴雨开始前存在着中尺度重力波,它激发了对流运动的发展,而对流运动对暴雨的发展起到了主要作用。这说明,在整个暴雨过程中,只有同时考虑中尺度重力波与对流运动的相互作用,才能较完整地解释雨带的强度和特征得以发展和维持的原因。
Based on the WRF(weather research and forecasting) model output data with high spatial and temporal resolutions,the NCEP/NCAR 1°×1° reanalysis data,and the ground station precipitation data,this paper analyses a heavy rainstorm event in Sichuan Province from 31 July to 1 August 2009.Results show that the rainstorm bands approximately locate along the water vapor convergence regions,and the divergence field,water vapor flux and its divergence have excellent indicative function in the rainfall event.However,the atmospheric stratification is weakly stable for six hours before precipitation occurrence,which is not conductive to the occurrence and development of convection.But the analysis of the divergence field,the nonlinear balance equation and Richardson number shows that the mesoscale gravity waves exist before the rain begins,which induce the development of convective motion,while the convection plays a major role in stimulating the development of the rainstorm.Therefore,during the process,we must consider the interaction between the mesoscale gravity waves and convective motion,in order to explain the reason why the rain bands develop and maintain reasonably.
出处
《大气科学学报》
CSCD
北大核心
2011年第6期737-747,共11页
Transactions of Atmospheric Sciences
基金
高原气象开放实验室基金(LPM2009003)
公益性行业(气象)科研专项(GYHY201006039)
江苏高校优势学科建设工程资助项目
关键词
暴雨
西南低涡
重力波
对流运动
rainstorm
Southwest Vortex
gravity wave
convective motion