基于再分析资料的我国龙卷发生环境和通用龙卷指标

利用NCEP再分析资料,对2004~2009年《中国气象灾害年鉴》(许小峰,2005-2012)上记录的龙卷按区域进行整合分析,确定在中国适合龙卷发生的大气环境条件。结合国内外已有参数,用临近探空的分析方法初步建立了一个适用于中国的龙卷潜势预报通用指标。研究表明:我国龙卷主要发生在东部地区,其发生发展需要有利的高低空形势场配置,并且不稳定能量的累积、水汽的输送都至关重要;从环境场来看,首要条件是有合适的对流有效位能和大的深层(0~6 km)风切变,低的抬升凝结高度和大的低层(0~1 km)风切变也是重要因素;建立了基于NCEP资料的龙卷潜势预报通用指标,并利用2010~2011年的龙卷事件对该指标进行了预测检验。

Atmospheric Conditions of Tornado Genesis and Universal Tornadic Index Based on Reanalysis Data

The authors used the NCEP reanalysis system to make integrated analysis by region and have found environmental conditions associated with tornadoes taken from Year-book of Meteorological Disasters in China (Xu Xiaofeng, 2005-2012) for the period of 2004-2009. Then an index has been formulated from analyzing kinds of parameters derived from proximity soundings. Results show that favorite significant tornado environments were concentrated in the east of China. The coordinating between low and high situation was important as well as instability energy accumulation and vapor transport. It was also proven that tornadoes in China occur in conditions accompanied by moderate convective available potential energy (CAPE), high wind shear (0-6 km layer shear and 0-1 km layer shear) and low cloud base. The results of this study were used to create a universal tornadic index based on NCEP reanalysis data and designed to forecast activity in tornadic environment. The quality of this index was tested with tornado activities in China for the period from 2010 to 2011.