台风活动及其与中国西部降水特征分析

应用1949—2016年台风资料和中国地面逐日降水资料,针对中国内陆西部地区,通过对较长样本资料的统计分析,研究台风活动及其在台风登陆背景下,中国西部年、夏半年和盛夏平均降水特征。研究得到:①67年间登陆中国大陆的台风年平均9.09个,6—10月是台风活跃期,登陆台风最早在4月,最晚在12月,8月登陆台风频率最高。②台风活动对宁夏全省、陕西大部、四川盆地、甘肃中东部和青海大部降水影响明显,台风活动多寡与该地区降水多寡总体成正相关。新疆和西藏降水受台风影响极小,贵州、重庆降水与台风活动呈相反情况,台风活动对云南降水影响不明显。③台风活动与中国西部部分地区降水呈正相关特征,其年均降水最明显,其次是6—10月平均降水。此项研究首次聚焦在远距离台风与中国西部降水特征上,将有助于系统全面地认识台风活动特征、登陆台风与中国西部降水的关系以及中国西部降水机理。

Characteristics of Typhoon Activities and Rainfall in Western China

Based on the typhoon (TC) data in 1949-2016 and daily precipitation data of the surface climate data in China, (annual: June to October; monthly: July to September) mean precipitation characteristics in the western China under the background of TC activity and their landing are studied by using the statistical analysis and long sample data. The results are as follows: (1) In 67 years, the annual average number of the TCs landing on the mainland of China is 9.09. The active phase of typhoons is June to October. The TC landing appeared first in April and the latest in December, and the highest frequency of the landing typhoon is in August. (2) Typhoon activity has a significant impact on the precipitation in Ningxia, Shaanxi, the Sichuan Basin, the central and eastern Gansu and Qinghai. The numbers of typhoon activities are positively correlated with the precipitation in the corresponding areas. The precipitation in Xinjiang and the Tibet is very little affected by typhoons, and in Guizhou and Chongqing, the correlation is reverse. TC activities have little effect on precipitation in Yunnan. (3) TC activities are positively correlated with precipitation in some parts of the western China, which is the most significant for the annual average precipitation, followed by the precipitation from June to October. The characteristics of long distance TC and precipitation in the western China are focused in this study, which will help systematically and comprehensively understand the characteristics of TC activities, the relationship between landing TC and precipitation in the western China and the mechanisms of precipitation in the western China.