2010/2011年秋冬季我国淮河以北地区干旱成因分析

Cause Analysis of the Drought in North of Huaihe River in the Fall and Winter from 2010 to 2011

2010/2011年秋冬季中国淮河以北大部地区降水量显著偏少,无降水时间长,致使华北、黄淮等地气象干旱迅速发展,受灾严重。利用中国气象局整编的1951年1月至2011年1月中国160站降水月平均资料和2010、2011年以及多年平均的NCEP/NCAR再分析数据集,包括逐日资料和月平均资料,分析了干旱灾害的大气环流异常及其对干旱的影响。结果表明:造成这次干旱灾害的主要原因是欧亚中高纬度存在稳定的准静止环流系统。东亚大槽维持在日本东北部,高原西侧上空为稳定的高压脊,中国大陆长时期处于东亚大槽槽后西北气流控制下;从亚洲西部过来的扰动系统不易东移到东亚上空,强度偏弱;此外,北非、印度次大陆、中南半岛和中国大部冬季风异常盛行,来自海洋上的水汽不易到达这些地区。

In the fall and winter from 2010 to 2011, a rare severe drought struck north of Huaihe River in China. It resulted to precipitation significantly less and precipitation length shorter. This paper used the Chinese 160 stations precipitation average monthly data from 1951 January to 2011 January by China Meteorological Administration analyzing the drought area precipitation and drought characteristics. The 2010-2011 data and mean NCEP/NCAR reanalysis data sets including the daily data and monthly data analyzed the anomalous atmospheric circulation and its influence on the drought. The results showed that this drought was due to a quasi stationary circulation system in the middle and high latitude over the Eurasia. There was a deep trough sustained over the northeast of Japan. In the west of Tibetan plateau there was a stationary ridge. There was emulous cold air outbreak over the East China. Due to the persist ence of the ridge over the plateau, the perturbations from West Asia could hardly reach East Asia. At the same time, the abnormal winter monsoon from North Africa, the subcontinent of India, South Peninsula and large parts of China prevented the water vapor from the ocean reaching the land.