用瞬时扰动法考察龙卷环境系统的模式预报
Examining Performances of Numerical Models in Predicting Tornado Environmental Systems
中文摘要：
龙卷作为局地强对流性天气事件的发生与天气和次天气尺度的扰动系统有关。应用“扣除瞬变气候场”的瞬时扰动法对两个全球模式（ECMWF和GFS）预报的中国和美国龙卷“扰动系统”进行了考察。回顾了近期研究的2016年6月23日发生在中国东部阜宁的龙卷事件扰动系统和2011年4月27—28日发生在美国南部的多龙卷过程扰动系统。ECMWF对前者的龙卷环境扰动系统能够提前54h，GFS能够提前18h预报出低层大气的低压扰动和高层大气的高压扰动以及冷暖扰动气团的变化与对比。ECMWF分别提前3、5、7和9d对上述美国南部的多龙卷预报出了与观测相吻合的高度扰动和温度扰动，包括它们的空间结构和随时间的变化。
中文关键词：
瞬时扰动，全球模式，龙卷环境系统
KeyWords：
temporal climatology, global model, tornado environmental systems
Abstract：
The tornado formation is largely influenced by the synoptic-scale and sub-synoptic scale anomalous systems. In this paper, the “anomalous weather chart”, which removes the temporal climatology from the conventional weather chart, is applied to analyze the tornado-related anomalous systems and evaluate the global forecasting models’ (ECMWF model and NCEP GFS) performances in predicting such anomalous systems. In this paper, two cases were studied: 1) the recent tornado event occurring in Funing County, China on 23 June 2016 and 2) the strong tornado outbreak in Southern US during 27-28 April 2011. Results showed that both cases are associated with the lower-level anomalous low pressure, upper-level anomalous high pressure systems and the contrast of anomalous warm/cool air masses in the troposphere. The ECMWF model and the NCEP GFS can predict the tornado-related anomalous system for the case 1 in advance of 54 hours and 18 hours, respectively. Furthermore, the ECMWF model is able to predict the spatial structures of strong geopotential height and temperature anomalies, and their evolution for the case 2 in advance of 3, 5, 7, 9 days.