摘要
基于2008—2021年夏季19个国家级气象观测站逐小时最高气温观测资料,分析了北京高温时长的空间分布和年代际、季节内及日内等多时间尺度变化特征。研究结果表明,受地形和城市热岛效应等因素综合影响,北京夏季高温日数和高温时长呈现出中心城区及以南多、西部和北部少的特征;其中海淀、丰台和昌平是北京高温最集中的地区。在季节内尺度上,北京高温时长多的时段主要集中在6月中旬后期至7月中旬前期,也即华北雨季开始之前的时段;其中7月上旬是北京高温最集中的旬。日内尺度上,北京高温过程出现在09—21时,14—17时尤为集中。文章还基于线性回归拟合了最高气温和高温时长的对应关系,拟合结果和实际观测相关系数高达0.82。对北京地区而言,在35℃高温阈值基础上,最高气温每升高1℃,相应的高温时长约增加1.7 h。北京高温时长同样表现出明显的年代际变化特征。后一时段(2015—2021年)与前一时段(2008—2014年)的差值分析表明,夏季累计高温时长的差值分布和高温时长的气候态空间分布显著不同,年代际差值大值区并非位于高温日和高温时长中心。在后一时段北京高温时长在11—19时范围内均呈一致性增多,意味着后一时段日内高温时长增多,也即高温开始时间提早结束滞后。
Based on the hourly maximum temperature observations from 19 national meteorological stations during the summers of 2008-2021,this paper analyzes the spatial distribution of high temperature(HT)hours and the features of interdecadal,intraseasonal and diurnal variabilities in Beijing.The results show that the numbers of both HT days and HT hours are much greater in the dountown area and the south of the city,but less in the north and west parts as the result of the combined influences of topography and urban heat island effect.Among them,the Haidian,Fengtai and Changping districts are the most concentrated areas of HT days and hours.On the intraseasonal scale,the HT hours in Beijing are mainly concentrated in the period from late mid-June to early mid-July,which is the period before the beginning of the rainy season in North China.The first dekad of July is the most concentrated period of HT activities.On the diurnal variation,the HT activities can be seen mainly from 09:00 BT to 21:00 BT,particularly concentrated from 14:00 BT to 17:00 BT.In addition,linear regression is also employed in this paper to fit the relationship between maximum temperature and HT hours.The correlation coefficient between the fitting result and the observation reaches as high as 0.82.In Beijing,for each 1℃increase in maximum temperature over the 35℃threshold,the HT hours increase by about 1.7 hours.The HT hours in Beijing also exhibits an obvious interdecadal variability.The distribution of the differences of accumulated summer HT hours between 2015-2021 and 2008-2014 is quite different from the spatial distribution of HT hours in climatic state.The area with large interdecadal differences is not located at the central part of HT days or HT hours.Relative to the period of 2008-2014,the HT hours in 2015-2021 are commonly added from 11:00 BT to 19:00 BT,which means the HT periods in Beijing tend to start earlier and end later in the latter period.
作者
张英娟
高辉
丁婷
王冀
ZHANG Yingjuan;GAO Hui;DING Ting;WANG Ji(Beijing Municipal Climate Centre,Beijing 100089;National Climate Centre,Beijing 100081)
出处
《气象》
CSCD
北大核心
2023年第9期1131-1141,共11页
Meteorological Monthly
基金
国家自然科学基金项目(42175078)
中国气象局创新发展专项(CXFZ2022J030)共同资助。
关键词
最高气温
高温日数
高温时长
日内变化
maximum temperature
high temperature day
high temperature hour
diurnal variation
