摘要
本文分析了瑞典地区1961～2000年极端日降水量的空间尺度、区域变化和与之相关的天气类型。根据30km滞后距离计算的统计相关图估计年平均降水量、日降水量的99%分位值和平均年最大日雨量变化的空间尺度分别为100km、60～100km和40～70km。采用最大相似因子分析方法确定了82个站点极端降水量的区域相关。并发现有11个因子可以提供给最佳因子解决方案。极端事件发生时的天气类型是根据以逐日海平面气压为基础的客观系统划分的,并经过主观(包括锋面)修正。总体来看,极端降水事件的发生,63%在气旋类天气,32%在锋面类天气,3%在定向类天气,2%在反气旋类天气。然而,极端事件各种天气类型的发生频次不同地区之间有所不同。
Extreme daily precipitation in Sweden for the years 1961-2000 is analyzed with respect to spatial scale,regional variations and associated weather types. Correlograms based on a lag distance of 30 km estimated the spatial scale of variation of the annual mean precipitation,the 99^(th) percentile of daily precipitation and the average of annual maximum daily precipitation to 100 km,60-100 km and 40-70 km,respectively.Regions of correlation with respect to precipitation at 82 stations during days of extreme events are identified through Maximum-Likelihood Factor Analysis.Eleven factors are found to provide the optimum factor solution. Weather types for the days of extreme events are determined by an objective classification scheme,based on daily sea level pressure,which is modified by subjective inclusion of fronts.In total,63% of the extreme events occurred during cyclonic weather types,32% during frontal,3% during directional and 2% during anticyclonic types.The frequency of the weather types during extreme events varied between the regions however.
