摘要: |
收集整理2007~2016年岳阳冰雹、雷雨大风、短时强降水三类强对流天气过程及其实况、再分析资料,基于探空图计算能量指标及不稳定指标,分析其与强对流发生的关系,寻找预报指标阈值,并进行预报试验。研究结果表明:(1)TT≥49℃、A≥20℃、K≥40℃时比较容易出现短时强降水天气,但在降雹与雷雨大风过程中,A>10℃或K≥35℃的机率比短时强降水中的低,雷雨大风中的CAPE值明显比冰雹和短时强降水中的大。(2)2月下旬~4月上旬, LI>20℃、Wm>1.2m/s、△Z<3000m(2~3个条件满足)可作为冰雹的预报指标;雷雨大风指标阈值为△θse700-850≤-7℃、SI≤-1.2℃、垂直风切变(1000hPa~500hPa)≥10m/s;(3)每年的日能量平衡高度变化可分为两个阶段,当第一阶段中能量平衡高度高于250hPa,且处于变化曲线中的极值时,往往对应出现强对流天气;第二阶段中能量平衡高度大部分高于250hPa,要参考其他预报指标进行强对流天气预报。 |
关键词: 探空图;强对流天气;预报指标 |
DOI: |
投稿时间:2019-03-18修订日期:2019-05-17 |
基金项目: |
|
Analysis of Severe Convective Weather Forecasting Index of Yueyang Based on Sounding Graphs |
Xu lili,Yang Ling,Jiang Shuai |
(Yueyang Meteorological Bureau of Hunan Province;Yiyang Meteorological Bureau of Hunan Province) |
Abstract: |
We sorted out severe convective weather processes and data between 2007 and 2016, and plotted sounding graphs of 113.12°E, 29.15°N based on FNL reanalysis data. According to the plotted sounding graphs of Yueyang and real sounding graphs of Changsha and Wuhan, we calculated the K index, A index, energy balance level, DCAPE and △θse700-850, etc., and conducted forecasting experiments. The results showed: 1. The annual energy balance level daily change can be divided into two phases, when energy balance level is higher than 250hPa in the first phase and peak in the curve, severe convective weather happens; when most energy balance level is higher than 250hPa in the second phase, other forecasting indexes should be referred to. 2. Values of A index, K index, TT index and proper CAPE are effective to short-term severe precipitation forecasting; values of LI, Wm and △Z can be used as hail predicting index; △θse700-850, SI, vertical wind shear and CAPE have certain effect to predict thunderstorm. 3. The ratio of invalid forecasting is more than 50% after experiments, as a result, the application of forecasting index should combine synoptic situation and doppler radar graphs to predict the short-term severe weather. |
Key words: Sounding Graphs; Severe Convective Weather; Forecasting Index |