1961—2021年广西沿海地区极端冷暖事件时空变化

Temporal and Spatial Variations of Extreme Cold and Warm Events in Coastal Areas of Guangxi from 1961 to 2021

为给红树林保护修复和气象保障服务提供科学依据,基于1961—2021年大气环流指数以及北海、防城港和钦州10个国家站逐日最高、最低气温,采用RClimDex模型计算极端气温指数,采用线性趋势分析、MK突变检验和偏相关分析,研究广西沿海地区极端冷暖事件时空变化规律。结果表明,1961—2021年,霜冻日数、持续冷期指数、冷夜日数、冷昼日数和气温日较差显著下降,热带夜数、夏季日数、持续暖期指数、暖夜日数、暖昼日数、日最高气温的最大值、日最低气温的最大值和日最低气温的最小值显著上升,说明广西红树林生态区冷、暖指数都趋于变暖,与全球变暖趋势正响应,且夜间气温的上升幅度大于白天,昼夜温差变小。冷指数突变年为1988—2015年,暖指数突变年为1996—2012年,冷、暖指数突变时间段相差不大。冷夜日数、冷昼日数、暖夜日数、暖昼日数和持续暖期指数空间分布规律一致,都是除防城港市东南部偏低外,其他地方普遍高;其中暖夜日数、暖昼日数和持续暖期指数在北海市北部地区增加趋势较明显,说明冷、暖指数在研究区的空间差异不大,在北海市北部地区变暖现象较明显。西太平洋副热带高压和欧亚纬向环流增强有利于极端气温上升。

In order to provide scientific basis for mangrove protection and restoration and meteorological support services,based on atmospheric circulation indices,daily maximum and minimum temperatures of 10 national stations in Beihai,Fangchenggang and Qinzhou from 1961 to 2021,extreme temperature indices were calculated by using RClimDex model,and temporal and spatial variations of extreme cold and warm events in coastal areas of Guangxi were studied through linear trend analysis,MK mutation test and partial correlation analysis.Results showed that from 1961 to 2021,trends of frost days,cold spell duration indicator,cool nights,cool days,and diurnal temperature range significantly decreased,while trends of tropical nights,summer days,warm spell duration indicator,warm nights,warm days,yearly maximum value of daily maximum temperature,yearly maximum value of daily minimum temperature,and yearly minimum value of daily minimum temperature significantly increased,which indicated that cold and warm indices tended to become warm in mangrove biomes of Guangxi,which were positive response to global warming trend.Range of temperature at night was greater than that in daytime,and temperature difference between day and night became smaller.Mutation years of cold indices were from 1988 to 2015,and mutation years of warm indices were from 1996 to 2012.There was little difference between mutation time periods of cold indices and mutation time periods of warm indices.Spatial distribution characteristics of cool nights,cool days,warm nights,warm days,and warm spell duration indicator were highly consistent,which were generally high in other places except southeast of Fangchenggang.Rising trends of warm nights,warm days,and warm spell duration indicator in north of Beihai were obvious,which indicated that spatial differences among cold indices and warm indices in study area were not large,and warming phenomenon was obvious in north of Beihai.Enhancements of western Pacific subtropical high and Eurasian zonal circulation were conducive to rise of extreme temperature.