摘要: |
本文利用遵义市2016-2020年夏季逐时降水资料和ERA5再分析资料,分析遵义市夏季短时强降水的时空分布特征,并统计午后和后半夜前发生短时强降水的物理量特征,得到以下结论:(1)遵义市夏季短时强降水日变化呈现双锋结构,夜间的峰值主要发生在6月,白天峰值贡献主要来自7-8月。6月和7月的短时强降水是夜间多于白天,而8月则是白天多于夜间,且多为午后强对流。遵义市夏季短时强降水夜间出现异常值概率的大于白天。(2)有6个县的夜雨均值明显高于昼雨,且在昼雨的1倍以上,仅有凤冈和湄潭的夜雨均值低于昼雨均值,7个县日变化双峰结构较为明显,仁怀有明显的4峰结构,可能与我市西高东低的地形分布有关。(3)遵义市夏季短时强降水在西部、北部地区发生短时强降水的概率较高,西部主要集中在河谷地带,北部主要集中在娄山山脉,短时强降水平均站次6-8月逐渐减少,10站次以上站点逐渐北推且减少,可能与副高西伸北抬有关。(4)高海拔站点午后短时强降水对CAPE、K、LI要求更低,低海拔站点需要更好的抬升和中低层暖湿条件,850hPa与500hPa温差则是高海拔站点高于低海拔站点。(5)与14时相比,后半夜发生短时强降水对CAPE、LI、T850-500等要求变低,且抬升指数有4个站均值高于0℃,指示意义没有午后好,后半夜短时强降水K指数的要求变高,大气可降水量要求也是变高的,但主要是高海拔站点变高。 |
关键词: 短时强降水 时空分布 物理量 |
DOI: |
投稿时间:2023-01-11修订日期:2023-06-06 |
基金项目: |
|
Temporal and spatial characteristics of short-time heavy precipitation in summer in Zunyi City |
liuhongshuang |
(Zunyi Meteorological Bureau) |
Abstract: |
Based on the 2016-2020 summer hourly precipitation data and ERA5 reanalysis data of Zunyi City, this paper analyzes the temporal and spatial distribution characteristics of short-term heavy precipitation in summer in Zunyi City, and calculates the physical quantity characteristics of short-term heavy precipitation occurring in the afternoon and before the second half of the night, and draws the following conclusions: (1) The diurnal variation of short-term heavy precipitation in summer in Zunyi presented a bifrontal structure, with the peak value at night mainly occurring in June, and the contribution of peak value during the day mainly coming from July to August. In June and July, the short-time heavy precipitation is more in the night than in the day, while in August, the short-time heavy precipitation is more in the day than in the night, and it is mostly in the afternoon strong convection. The anomaly probability of short-time heavy precipitation in summer in Zunyi City is greater at night than in day. (2) The mean value of night rain was significantly higher than that of day rain in 6 counties, and it was more than one times that of day rain. Only Fenggang and Meitan had the mean value of night rain lower than that of day rain. The diurnal variation structure of 7 counties was obvious, and Renhuai had the obvious four-peak structure, which might be related to the topographic distribution of high west and low east of the city. (3) The probability of short-term heavy precipitation in summer in Zunyi City is relatively high in the western and northern regions. The western region is mainly concentrated in the valley region and the northern region is mainly concentrated in Loushan Mountain Range. The average number of short-term heavy precipitation stations gradually decreased from June to August, and the stations with more than 10 stations gradually pushed and decreased northward, which may be related to the westward extension and northward lifting of the subtropical high. (4) Short afternoon heavy precipitation at high altitude stations has lower requirements on CAPE, K and LI, while low altitude stations need better uplift and warm and humid conditions at middle and low levels. Temperature difference between 850hPa and 500hPa at high altitude stations is higher than that at low altitude stations. (5) Compared with 14:00, the requirement of CAPE, LI and T850-500 for short-time heavy precipitation occurred in the late night was lower, and the mean value of four stations of the rise index was higher than 0℃, which was not as good as that in the afternoon. The requirement of K index of short-time heavy precipitation in the late night was higher, and the requirement of atmospheric precipable water was also higher, but mainly the high-altitude stations were higher. |
Key words: Short-time heavy precipitation Spatial and temporal distribution Physical quantity |