上海地区高温分布的诊断分析

如何利用个别气象站的单站气象资料值诊断整个上海地区详细的高温分布是目前高温气象服务发展提出的一个课题。该文根据1997~1998年7~8月高温加密观测资料, 应用EOF技术分解, 表明上海地区高温分布可由气候平均场和第一特征场合成而得, 第一特征场的方差贡献占总方差的90%以上。分析结果表明, 上海地区平均高温场分布特征有地形特点和城市热岛效应作用决定的, 是多年变化的较稳定变量。第一特征场系数是一个逐日变化量, 它与风向有很高的相关系数。该文利用2个气象站的资料建立了计算第一特征场系数的方程, 并建立了利用2个气象站的单站气象要素值制作上海地区逐日的高温分布的方法。该方法对1999~2000年的13个高温日的试算取得了较满意的结果, 比常用的回归方法计算精度有所提高, 而且物理意义清晰。

Diagnostic Analysis of High Temperature Distribution in Shanghai

Based on the intensive observation data of temperature in July and August of 199 7 to 1998, by means of the EOF technique, the high temperature distribution in S han gh ai is analyzed. The result indicates that the high temperature distribution in S hanghai can be composed of the climatic and the first characteristic fields. The variance contribution of the first characteristic filed is over 90% of the tota l variance. The results indicate that the mean distribution of the high temperat ure field in Shanghai is depended on the topography and urban heat island effect of Shanghai and is a relatively stable interannual variable. The coefficient of the first characteristic filed is a day-to-day variable with high correlat ion w ith wind direction. The equation of the first characteristic filed coefficient i s formulated based on the data from two weather stations and whereafter the meth od for determining the high temperature distribution in Shanghai is developed. T he trial calculation of 13 high temperature days in 1999 and 2000 is satisfactor y.