中国区域干旱的持续性特征研究

利用1961-2012年中国区域586个气象站的降水、气温、日照时数、相对湿度、风速等资料计算了逐月K干旱指数, 在此基础上, 对全国16个区的干旱持续性特征进行了研究. 结果表明: 华北、河套、西北地区东部、西南地区北部、黄淮及新疆南部地区干旱的持续性较强, 常发生3个月以上的长期干旱过程, 并且容易在旱情解除后的短期内(1个月)再次出现干旱; 而南方、东北和新疆北部地区干旱的持续性较弱, 以1个月的短期干旱为主, 且干旱过程之间的时间间隔相对较长, 大多为3个月以上; 华北、河套、西北地区东部、西南地区北部和南部、以及华南地区的干旱过程在冬、秋季开始的频次最高, 且大部分在春季结束, 而冬、春两季的干旱明显比夏、秋两季偏多. 100°E以西(新疆北部除外)的广大地区干旱过程的开始时间主要集中在秋季, 结束时间集中在春、冬两季; 同时, 冬季和秋季干旱多发, 其次是春季, 夏季出现的干旱频次最少.

Study of the sustainability of droughts in China

The sustainability of droughts in the 16 areas over China were studied using the monthly Index K calculated with precipitation, temperature, sunshine duration, relative humidity and wind speed data from 586 stations from 1961 to 2012. It is found that the sustainability of drought is larger in North China, Hetao Region, the east of Northwest China, the north of Southwest China, Huang-Huai Plain and the south of Xinjiang, where drought processes with duration more than 3 months are usually take place with high possibility of reoccurrence, while the sustainability of drought is smaller in South China, Northeast China and the north of Xinjiang, where the drought duration is one month mainly and the interval between two drought processes is as long as more than three months. Droughts in North China, Hetao Region, the east of Northwest China, the north and south of Southwest China and South China have high frequencies to start in winter and autumn and to end in spring mostly, with the drought durations in winter and spring evidently more than those in summer and autumn. In the vast swathes in the west of 100° E, except for north of Xinjiang, drought usually starts in autumn and ends in spring and winter, while frequent droughts in winter and autumn.