近60年宝鸡市主城区极端天气变化特征分析

Characteristics of extreme weather change in the main urban areas of Baoji City nearly 60 years

全球气候变暖背景下研究极端天气发生规律对了解地区气候变化特征与提高区域防灾减灾能力具有重要的现实意义。以宝鸡市主城区1953-2013年逐日气温和降水资料为基础,运用线性倾向估计法、距平分析、异常度分析和Morlet小波分析等统计学方法研究其变化特征,并探讨了区域气候变化与极端天气事件的相关关系。结果表明:近60年宝鸡市主城区极端气温指标中极端最高气温、夏季日数和热夜日数均呈现出上升的趋势,极端最低气温、冰冻日数、霜冻日数表征为下降的趋势;近60年宝鸡市主城区年降水量与年极端最高降水量总体上呈减少的趋势;热夜日数存在11~14 a和26~28 a 2个时间尺度的周期变化,与太阳活动周期关系密切;霜冻日数存在阶段性变化周期。区域气候变暖、气候变率与极端天气事件的发生频率具有较高的相关性,但并不存在必然的联系。总体来看,近60年宝鸡市主城区气候向暖干化趋势发展,但也不能忽视极端强降水事件、低温霜冻等灾害的发生,相关部门应提高警惕以最大程度降低灾损。

Under the background of gloabal warming,it is of great significance to study the regularity of extreme weather in order to understand the characteristics of regional climate change and improve the ability of disaster prevention and mitigation. Based on the daily temperature and precipitation data from1953 to 2013 in Baoji main urban area,the variation characteristics were analyzed by means of linear tendency estimation,distance-leveling analysis,anomaly analysis and Morlet wavelet analysis,and the correlation between regional climate change and extreme weather events was discussed. The results showed that： The trend of extreme maximum temperature,the number of Summer days and the number of hot nights of the extreme temperature index was increasing in the main urban areas of Baoji City in the past60 years. Extreme minimum temperature,frozen days and days of frost were characterized by declining trend. The annual precipitation and annual extreme precipitation in the main urban areas were decreasing generally of Baoji City in the past 60 years. Days of hot nights had a periodic change of two time scales of11-14 a and 26-28 a,which was closely related to solar activity cycle. Days of frost had a periodic changing cycle. There was a high correlation between regional climate warming and climate change rate and occurrence frequency of extreme weather events,but there was no inevitable connection. On the whole,the climate has been warming and drying in the main urban areas of Baoji City in the past 60 years,but the occurrence of extreme heavy precipitation events,low-temperature frost and other disasters should not be ignored. Therefore,relevant departments should be vigilant to minimize disaster damage.