摘要
采用MM5中尺度数值模式对河南省2006年1月18—19日的暴雪天气过程进行了数值模拟,利用模式输出的时空分辨率较高的资料,对此次降雪的水汽条件、温度条件、不稳定条件、风场等进行了分析。结果表明:中低层水汽的辐合作用是暴雪天气发生的必不可少的条件;河南省上空逆温层的上界对应西南气流,下界对应东北气流,这种流场配置对降雪最有利;高低空急流的稳定维持使高低空急流产生两个独立的次级环流,在高空急流出口区,间接环流的北部形成辐合上升气流,十分有利于降水天气的发生发展;总螺旋度的变化对降雪的强度变化有一定的指示意义;对湿位涡这一物理量的分析发现,与暴雨过程中起主导地位的MPV1不同,MPV2在这次降雪过程中作用大于MPV1。
MM5 model is used to simulate the process of snowstorm in Henan Province from J anuary 18th to 19th in 2006. High space-time resolution data from model output are imposed to analyze vapor, temperature, instability, wind and other conditions of this process. Results show that the convergence of middle-low layer vapor is absolutely necessary condition. It is most favorable for snowstorm that upper boundary of inversion layer over Henan Province corresponds to southwest jet flow and lower boundary corresponds to northeast jet flow. The steady maintaining of high-low jet flow generated two separate secondary circumfluence and the north of indirect circumfluence formd convergence ascending air at the exit of upper-level jet flow. This situation quite favor the generation and development of precipitation. Total helicity changes have the significant indication to changes of snow intensity. Moist lotential vorticity was analyzed to find that MPV2 is more important than MPV1 in this event, whereas in the case of rainstorm, MPV1 plays a dominant role.
出处
《气象》
CSCD
北大核心
2008年第9期65-72,共8页
Meteorological Monthly
基金
国家重点基础研究项目2004CB418301
关键词
暴雪
数值模拟
诊断分析
降水天气
snowstorm numerical simulation diagnosis analysis
