2003年浙江省夏秋季干旱特征及成因

Features and Cause of Drought in Summer and Autumn of 2003 in Zhejiang

为了探索2003年夏秋季(6～10月)浙江省严重干旱形成的气候原因,用切比雪夫多项式展开500hPa高度场格点资料作环流分析,结果表明2003年夏秋季环流形势不利于形成大范围降水,江南受稳定的副高控制,异常高温是发生严重干旱的重要原因。进一步分析环流形成的原因表明,2003年春季4￣5月赤道东太平洋海温的季节性波动有重要作用。

For probed the climate reasons about the serious drought during summer and autumn in 2003 in Zhejiang Province, it analyses the circulation by spreading grid data over 500hPa with Chebyshev polynomial, the result indicate the circulation unfavorable to form precipitation on big range, being steadily controlled by the subtropical highs in south of the lower reaches of the Changjiang River, unusual high temperature, and these are the important reasons of formation of serious drought. Further, the analysis indicates that the seasonal fluctuation in spring play an important role in circulation formation.