中国持续性高温事件的时空分析

The spatial-temporal analysis of persistent high-temperature events in China

本文利用我国1959—2008年522个站6—9月逐日最高气温资料,运用扩展经验正交函数分解(EEOF)研究了我国持续性高温事件的时空分布特征,并分析了我国南方地区典型持续高温事件的演变过程.结果表明,我国高温事件主要发生在东南部和新疆地区,而华北和东北地区相对较少,西藏、青海、四川西部地区基本没有高温事件出现.南方地区前三个特征场分别表现为整体区域一致性、长江以南和长江以北的反相分布以及华东与华南、华中、重庆等地的东西向反相变化.西北地区第一、二模态表现为南北向的反相变化,且第一模态表现为新疆北部变化显著,第二模态表现为南部变化显著,而第三模态主要为东西反相变化特征.北方地区前三个模态分别表现为整体区域变化的一致性、南部和北部的反相变化、东部和西部的反相变化特征.2000年以来南方高温持续时间相对较短,但华南和华东地区高温持续时间增长.我国南方地区持续性高温事件有4类典型演变过程:第1类持续高温事件主要影响我国的华中、华南以及重庆和四川东部地区,高温中心位于重庆和湖南西部地区,这类事件开始于湖南西南部,然后向东向北发展到最强后西退,消失在广西境内;第2类事件影响我国南方的大部分地区,高温中心位于湖北和安徽地区,这是一类高温强、范围广、持续时间长得事件,但在整个发展过程中对华南地区影响比较小,这一类事件开始于浙江北部,然后向西发展,最后在四川东部结束;第3类事件主要影响长江以南地区,高温中心位于浙江地区,事件起自浙江地区,然后向西发展,最后在江浙交界地区消亡;第4类始于浙江北部,主体向西南方向发展,影响两广地区后向西收缩,在广西地区消亡.

Based or daily maximum temperature data for 522 stations in China from June to September during 1959 2008, the spatial temporal characteristics of persistent high temperature events in China are analyzed by Extended Empirical Orthogonal Function（EEOF）and the evolutions of typical persistent high-temperature events in the south of China are revealed. The results show that the persistent high-temperature events mainly occur in the southeast of China and Xinjiang province, while rarely occur in Northeast China and North China and almost do not occur in Tibet,Qinghai and the west of Sichuan. The first three EOF patterns in the south of China are respectively characterized by a uniform anomaly over the whole area,a dipole pattern with two centers in southern China and the areas to north and an out of phase pattern between east and west parts of the area. In the northwest of China, the first two EOF patterns are characterized by a dipole pattern with two centers in the south and north of Xinjiang, while the significant change of the first pattern is in the north of Xinjiang and the second pattern is in the south,and the third pattern characterized by an out of phase pattern between east and west parts of the area. The first three E（）F patterns in the north of China are similar to the south. The duration of high-temperature events in the south of China are becoming shorter, while increasing in South and East China. In the south of China, there are four categories of the evolution of. typical persistent high temperature events： （ 1 ） It mainly influences Central China, South China, ChongQing and the east of Sichuan and its center is in ChongQing and the west of Hunan. It begins in the southwest of Hunan, and expands eastward and northward to the maximum strength,then withdraws westward and disappears in Guangxi; （2）It almost influences the whole area and its center is in Anhui and Hubei,but it has little impact on South China. It begins in the north of Zhejiang and expands westward to the maximum strength, then shrinks westward and ends in the east of Sichuan; （3）It mainly influences the south of Yangtze and its center is in Zhejiang. It begins in Zhejiang, then expands westward to the maximum strength and disappears in the junction of Jiangsu and Zhejing; （4）It begins in the north of Zhejiang and expands southwestward to Guangdong and Guangxi, ends in Guangxi.