【摘要】 针对西北地区2004年夏季(6和7月)严重干旱,对干旱特征和成因进行了分析.干旱持续之长,范围之广,强度之重,危害之大少有.干旱形成原因主要是500 hPa高度场上乌拉尔山阻塞高压和新疆脊强.亚洲40°N以北和青藏高原东部西风气流强盛,南支槽位置偏南,西太平洋副热带高压偏弱、位置偏东,西北地区上空水汽偏少.这些结果对防灾减灾措施制定有重要作用,也是短期气候预测的重要气候背景.更多还原

【Abstract】 A study was carried out on arid features and causes of the Northwest China in the summer of 2004.The drought lasted very long and brought about serious results.Its main causes were that the Ural mountains blocked the high pressure and the Xinjiang ridge,and the Westerly circumfluence was strong at 40°N northward of Asia and east of Qinghai-Xizang Plateau.The position of the trough over the southern Indian Peninsula was southward of the mean and the subtropical High of Southwestern Pacific was rather weak,and its position was southward of the mean and the water vapor were less over the Northwest China.All these resulted in the continuous drought in the Northwest.This study is significant for us to take measres in preventing and reducing calamities and valuable to short-term climatic forecasts.更多还原