【摘要】 2008/2009年秋冬季我国12省区出现30～50年一遇的罕见干旱,这次我国大范围严重干旱是较长时期降水稀少所造成的。欧亚中高纬度存在稳定的准静止环流系统是造成这次干旱灾害的主要成因。东亚大槽维持在日本东北部,高原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;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。欧亚大陆稳定长达3个月的异常环流的形成机制,有待深入研究。更多还原

【Abstract】 In the fall and winter of 2008 to 2009, a rare severe drought struck twelve provinces in East China. This severe drought is due to the lack of rainfall for a sustained period. There was a quasi-stationary circulation system in the middle latitude over the Eurasia. There was a deep trough sustained over the northeast of Japan. In the Tibetan Plateau there was a stationary ridge. There was emulous cold air outbreak over the East China. Due to the persistence of the ridge over the plateau, the perturbations from West Asia could hardly reach East Asia. At the same time, the abnormal winter monsoon prevented the water vapor from the ocean reaching the land. The formation mechanism of such anomalous atmospheric circulation which lasted three months stably over Eurasia Continent is yet to be further studied.更多还原