单次极端高温过程中城市热岛效应的识别  

Identification of Urban Effect on a Single Extreme High Temperature Event

作　　者：张雷[1,2,3] 任国玉[2] 任玉玉[2] 

机构地区：[1]南京信息工程大学大气科学学院,南京210044 [2]中国气象局气候研究开放实验室,国家气候中心,北京100081 [3]中国气象局国家气象信息中心,北京100081

出　　处：《气候与环境研究》2015年第2期167-176,共10页Climatic and Environmental Research

基　　金：国家公益性行业(气象)科研专项GYHY201206012;中国气象局气候变化专项CCSF201340

摘　　要：利用高密度自动观测站逐时气温资料和NCEP再分析资料，按照客观的标准选择参考站，分析2010年7月2～6日北京一次极端高温过程中城市热岛强度（IUHI）对城区地面气温时空分布的影响。此次高温过程连续5日的日最高气温均超过35.0°C，为北京站1951年以来连续5日平均最高气温的最高值。大陆暖高压控制我国大部分地区，北京处于高压脊前，西北气流下沉增温，加之气流越山引起的焚风效应，是导致此次极端高温过程发生的环流背景。但受城市热岛效应影响，最高、最低和平均气温的空间分布均出现了以城区为中心的高值区，从城区中心向郊区平均IUHI逐渐减小，最低气温IUHI较大，四环线以内5日平均IUHI达到2.93°C，四、五环线之间1.87°C，五、六环线之间1.43°C；最高气温IUHI较小，但四环线以内，四、五环线之间和五、六环线之间5日平均IUHI仍分别达到1.45°C、0.96°C和0.72°C。在7月3～6日夜间，四环内IUHI极值均在3.00°C以上，特别是7月6日凌晨达到5.50°C；白天IUHI相对较小，其中2日早晨甚至还出现了负值。城区各地带IUHI日变化规律几乎同步，具有两个相对稳定阶段和两个快速变化阶段。稳定的强IUHI阶段从21：00（北京时间，下同）持续到次日05：00，稳定的弱IUHI阶段从08：00至18：00；05：00至08：00是IUHI快速℃衰减阶段，而18：00至21：00是IUHI快速上升阶段。因此，城市热岛效应对北京城区夏季单次极端高温过程的强度及其空间分布具有显著影响，在很大程度上加重了城区特别是中心城区的高温影响。On basis of selecting reference stations by using a relatively objective standard, this paper analyzes the influence of urban heat island （UHI） intensity （IUHI） on spatial and temporal temperature characteristics in a high temperature process of Beijing from 2 July to 6 July 2010, by applying hourly data of high density automatic weather stations and NCEP reanalysis data. The maximum temperature （Tmax） during the process is more than 35.0 °C for each day, and the five-day mean Tmax breaks the records at Beijing Weather Station since 1951. Continental warm high pressure controls most parts of China in the high-temperature process, and Beijing is in front of the high-pressure ridge. Major causes for the high-temperature process in Beijing are strong subsidence and the fohn effect of the northwesterly flowing over the Taihang Mountains. Affected by UHI effect, the distribution of the Trnax, minimum temperature （Tmin）, and mean temperature （Tmean） exhibits a high-temperature area in the center of the city, with the mean luui gradually decreasing from the within fourth-ring area to the fifth-sixth-ring areas. The Ivni of Trnin is obviously larger, reaching 2.93 ℃, 1.87 ℃, and 1.43 ℃, respectively, for the central urban area, fourth-fifth-ring area, and fifth-sixth-ring area. The IUHI of Tmax is smaller, although the temperatures are as high as 1.45 ℃, 0.96 ℃, and 0.72 ℃, respectively, for the three urban zones mentioned above. The night IUHI high values within the fourth ring during 3-6 July are more than 3.00 ℃, and the maximum IuHl reaches 5.50 ℃ in the early morning on 6 July. The daytime IUH1 is relatively small, and the IuHl shows a negative value in the morning of 2 July likely because the heating rate at reference stations is greater than that in the urban areas. The IuH diurnal variation of the three urban zones is nearly synchronic, and is characterized by a steadily strong IuHl stage from 2100 LST to 0500 LST and a steadily weak IUH stage from 0800 LST to 1800 LST, with t

关 键 词：极端高温 城市热岛强度 城市化影响 自动气象站 北京城区 

分 类 号：P463.1[天文地球—大气科学及气象学]