近30年中国地面风速分区及气候特征

Climate Regionalization and Characteristics of Surface Winds over China in Recent 30 Years

通过中国近地面风速区划可以深入了解风速分布规律,有助于研究风速的变化机制。利用1980-2009年中国608个测站的日平均风速资料,经过旋转经验正交函数分解法(REOF)得到10个分区,各分区范围和地形有一定的关系。风速频率曲线变化表明,中国北部地区(第3、4区)风速偏大,中部地区(第2、10区)风速普遍较小;对比分析了区域有效风速日数频率和风能分布。根据谐波方法得到各分区风速的年变化特征,大部分区域呈单峰单谷型或双峰双谷型,高值区主要出现在春季,并分析了形成上述特点的可能天气学成因。风速线性倾向估计结果表明,中国大部分地区风速呈减小趋势,第1、4、5区平均风速递减率在-0.028^-0.023 m·s-1·a-1之间,但是,中部地区(第2区、第6区西部、第10区)年平均风速出现递增。通过Mann-Kendan法和小波分析方法检测表明,第2、3、5区突变点出现在2000年附近,第1、4、6区突变点出现在20世纪90年代初。环流特征量指数和风速同期相关性分析,揭示了北极涡和副热带高压对风速的影响。

Climate regionalization of surface w inds imply associated to wind speed distribution in China. According to the daily mean wind speed data of 608 stations in China from 1980 to 2009,the distribution of predominant patters is analyzed by the Rotated Empirical Orthogonal Function( REOF) method. The results show that there are ten regions w hich is related to the topography of China. There is higher wind speed in the north and smaller in the middle of China. It is also analyzed betw een the frequency of effective wind speed and distribution of wind energy. Based on the harmonic analysis,the results show that there are tw o kind variation including a single peak-valley pattern and double peak-valley pattern. According to the different atmospheric circulation features,it is analyzed that the higher wind speed happed in spring. A significant declining trend of wind speed existed in a large part of China by using the methods of linear regression. The mean declining rate in first,fourth and fifth region is within range of- 0. 028 ^- 0. 023 m ·s- 1·a- 1. Therefore,it is inverse trend in the middle part of China( the second,sixth and tenth region). The results show ed that the abrupt change points appeared in 2000 for the second,third and fifth regions and in earlier year of 1990 for the first,fifth and sixth region by using M ann-Kendall test. The contemporaneous correlation betw een characteristic quantities of atmospheric circulation and wind speed in China is studied. The result show that northern polar vortex and subtropical anticyclone play a great role in the variation of wind speed.