摘要
基于青海地区1981—2011年的地面天气现象月报表记录,整理出雷暴、冰雹天气的逐小时数据集和持续时间数据集,并利用该数据集对青海地区雷暴、冰雹的时空分布及变化特征进行分析。结果表明:青海地区雷暴、冰雹的发生频率受地形影响显著,呈现出“南多北少”的分布特征,雷暴过程的平均持续时间一般不超过40 min,冰雹过程的持续时间一般不超过10 min;雷暴、冰雹具有显著的年变化与日变化特征,一年之中主要集中出现在5—9月,一日之中主要出现在午后,但雷暴、冰雹峰值的出现时间表现为一致的由北向南逐渐推迟,平均而言北部比南部提前3 h左右;不同持续时间的雷暴、冰雹出现概率不同,随着持续时间的增长,雷暴过程数呈现出指数递减的变化特征,而冰雹过程的发生次数呈现出先增加后减少的特征;近31年来青海地区的雷暴、冰雹均呈明显的下降趋势,雷暴频数的下降速率为15.0次·(10 a)^-1,冰雹频数的下降速率为2.3次·(10 a)^-1,雷暴、冰雹多发地区/多发时段的下降趋势明显大于少发地区/少发时段;虽然雷暴天气过程在减少,但天气过程的平均持续时间却在缓慢增加,持续时间增加的站点主要位于人口较密集的青海中部和东北部,意味着每次雷暴过程带来的潜在危害在增大,冰雹天气过程与雷暴不同,冰雹天气过程数及其持续时间均呈现出减少的趋势。
Based on a comprehensive collection of thunderstorm and hail observation data from the National Meteorological Information Center(NMIC)of China,the hourly and duration datasets which include the onset and end time of thunderstorm and hail were established.Then the characteristics of spatio-temporal distribution,duration and their long-term trends over Qinghai Province from 1981 to 2011 were documented in this study.The results showed as follows.The frequencies of thunderstorm and hail are significantly influenced by the topography,so both of them occur more frequently in the south part than in the north part over Qinghai Province.Generally speaking,the duration of a thunderstorm process does not last for longer than 40 minutes,and the duration of the hailstorm process does not exceed 10 minutes.The frequencies of thunderstorm and hail both present significant monthly and diurnal variations.In a year,they are mainly concentrated in May to September;in the daytime,they are mainly concentrated in the afternoon,but the occurring time shows an obvious decaying from north to south,and the peak time in the north is about 3 h earlier than in the south part of Qinghai Province.With the duration increasing,the number of thunderstorm processes shows an e-folding decay derived from the exponential distribution,while the number of hailstorm processes increases first and then decreases according to the e-folding decay.The frequencies of thunderstorm and hail both have presented significant decreasing tendencies since 1981,and the climatic tendencies of thunderstorm and hail are-15.0·(10 a)^-1 and-2.3·(10 a)^-1,respectively.Although the number of thunderstorm process is decreasing,the average duration of each process shows a slightly increasing trend.And the increasing-duration stations are mainly located in the northeastern and central parts of Qinghai,which is the most densely populated area,implying that the potential damage caused by thunderstorm is increasing.Different from that of thunderstorm,the number of hail process and its duration both show decreasing trends,which may be related to the increased height of the melting layer.
作者
马晓玲
李德帅
胡淑娟
MA Xiaoling;LI Deshuai;HU Shujuan(College of Atmospheric Sciences,Lanzhou University,Lanzhou 730000;Qinghai Weather Station of Air Traffic Management Bureau of Civil Aviation,Xining 810000;Unit 93995 of the Chinese People’s Liberation Army,Xi’an 710300)
出处
《气象》
CSCD
北大核心
2020年第3期301-312,共12页
Meteorological Monthly
基金
国家重点研发计划(2017YFC1502300、2017YFC1502305)
国家自然科学基金项目(41775069、41475068)
空军军事理论课题(19KJ3C1-0076R)共同资助。
关键词
雷暴
冰雹
持续时间
时空特征
青海地区
thunderstorm
hail
duration
spatio-temporal characteristics
Qinghai Province