地理因子对冰雹形成的影响  

Effects of Geographical Factors on the Formation of Hailstorm

作　　者：孙旭映[1] 渠永兴[1] 王坚 

机构地区：[1]中国气象局兰州干旱气象研究所甘肃省干旱气候变化与减灾重点实验室,甘肃兰州730020 [2]张掖市气象局,甘肃张掖734000

出　　处：《干旱区研究》2008年第3期452-456,共5页Arid Zone Research

基　　金：甘肃省人工增雨防雹作业体系工程建设科技开发第三批项目“测雨雷达现场指挥作业研究”课题资助

摘　　要：根据甘肃省永登地区1973-2003年的降雹资料,在调查自然地理条件的基础上,着重分析冰雹的时空分布与地形、植被、土壤的关系。结果表明:永登地区冰雹的空间分布特征主要表现为塬区和川区少,半山区和山区多。地形对对流云的形成具有特殊的加强作用;而森林对冰雹的形成和发展有阻碍作用;土壤对冰雹的作用,从水平温度梯度分析得出,高有机质含量的土壤与低有机质含量的土壤,在交界处因其储存能量大小不同,温度的水平梯度不同,更有利于对流不稳定发展。Hailstorm is a kind of mid-and small-scale local weather with high dispersion. Its formation is not only closely related to weather system, but also to nonadiabatic heating of landforms and underlaying surface. In this paper, the relationships between the spatiotemporal distribution of hailstorm and the landforms, vegetation and soil are mainly analyzed based on the data of hailstorm during the period of 1973 -2003 and the investigation of geophysical conditions in Yongdeng County. Yongdeng County is located in an alpine steppe in central Gansu Province and the northwest marginal zone of the Loess Plateau, its elevation varies in a range of 1 700～4 000 m a. s. 1. , the terrain slopes northeastward, the alpine zone is covered by limestone, some ponds are distributed in the alpine zone, the relative humidity is high, and fog occurs frequently. All these are advantageous form the formation and development of hailstorm, and the annual days of occurring hailstorm in the county are more than 20 days and even more than 30 days in some years. The results reveal that the occurring frequency of hailstorm in the mountainous regions is higher than that in the hilly and plain regions. Landforms can particularly facilitate the formation of convective cloud, forests can restrict the formation and development of hailstorm, and the boundaries of soils with high and low organic matter content are advantageous for the development of unstable convection current due to the different horizontal temperature gradient caused by different values of stored energy over the boundaries.

关 键 词：地理因子 冰雹 时空分布 永登 甘肃 

分 类 号：P461[天文地球—大气科学及气象学]