地理学报 ›› 2019, Vol. 74 ›› Issue (9): 1789-1802.doi: 10.11821/dlxb201909007

• 气候变化 • 上一篇    下一篇

上海城市热岛与热浪协同作用及其影响因子

敖翔宇1,2,4,谈建国3,4,支星5,过霁冰6,陆一闻1,刘冬韡1()   

  1. 1. 上海市生态气象和卫星遥感中心,上海 200030
    2. 南京大学大气科学学院,南京 210023
    3. 上海市气候中心,上海 200030
    4. 上海市气象与健康重点实验室,上海 200030
    5. 上海市气象局科技发展处,上海 200030
    6. 上海市奉贤区气象局,上海 201499
  • 收稿日期:2018-04-10 修回日期:2019-07-18 出版日期:2019-09-25 发布日期:2019-09-25
  • 通讯作者: 刘冬韡 E-mail:54745469@qq.com
  • 作者简介:敖翔宇(1988-), 女, 江西萍乡人, 博士生, 工程师, 研究方向为城市气象。E-mail: aoxy@simets.cn
  • 基金资助:
    上海市科委项目(17DZ1205300);上海市科委项目(19YF1443900);国家自然科学基金项目(41775019);上海市气象局面上项目(MS201803)

Synergistic interaction between urban heat island and heat waves and its impact factors in Shanghai

AO Xiangyu1,2,4,TAN Jianguo3,4,ZHI Xing5,GUO Jibing6,LU Yiwen1,LIU Dongwei1()   

  1. 1. Shanghai Ecological Forecasting and Remote Sensing Center, Shanghai 200030, China
    2. School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
    3. Shanghai Climate Centre, Shanghai 200030, China
    4. Shanghai Key Laboratory of Meteorology and Health, Shanghai 200030, China
    5. Department of Science and Technology Development, Shanghai Meteorological Service, Shanghai 200030, China
    6. Fengxian Meteorological Service, Shanghai Meteorological Service, Shanghai 201416, China
  • Received:2018-04-10 Revised:2019-07-18 Online:2019-09-25 Published:2019-09-25
  • Contact: LIU Dongwei E-mail:54745469@qq.com
  • Supported by:
    Project of Science and Technology Commission of Shanghai Municipality(17DZ1205300);Project of Science and Technology Commission of Shanghai Municipality(19YF1443900);National Natural Science Foundation of China(41775019);Project of Scientific and Technological Development of the Shanghai Meteorological Service(MS201803)

摘要:

在全球变暖的背景下,热浪变得更加频繁。城市地区由于城市热岛效应在热浪事件中承受更大的风险。然而城市热岛与热浪之间的相互作用还少有研究。利用2016-2017年两个夏季(6-8月)上海城、郊气象站逐时气温、风速、相对湿度资料、城区徐家汇和郊区奉贤涡动相关通量观测资料对比分析了热浪和非热浪期间城市热岛强度的差异,并利用一个平流扩散解析模型揭示了城市热岛与热浪相互作用的物理机制。结果表明,热浪期间的城市热岛强度相比非热浪期间明显增强,且白天增强大于夜间,显示出城市热岛与热浪之间的协同效应。热浪期间城、郊相对湿度比值相对非热浪期间明显减小,表明热浪期间城区地表相对郊区变得更干,从而抑制了蒸发作用,加剧了城市热岛强度;平均风速也明显减小,平流降温效应减弱,对城市热岛强度起正反馈效应。热浪期间城区净辐射通量的增加大于郊区,使城区获得更大地表辐射输入;由于城区更少的植被覆盖和更多的不透水下垫面,热浪期间城区潜热通量略有降低,而郊区明显增加;城区感热通量增幅则大于郊区,这种感热和潜热通量分配的改变也加剧了城市热岛强度。本研究对城市如何应对加剧的热风险具有重要的科学指示意义。

关键词: 城市热岛, 热浪, 解析模型, 辐射通量, 感热通量, 潜热通量

Abstract:

Under the background of global warming, heat waves are expected to be more frequent and long lasting. Cities endure greater risk under heat wave events because of the pre-existing urban heat island. However, research on the interaction between heat wave and urban heat island is still lacking. Based on hourly data of air temperature, wind speed, relatively humidity, and eddy covariance energy flux data from Shanghai urban (XJH) and rural site (FX) during two summers (June-August) in 2016-2017, the difference of urban heat island (UHI) between heat wave (HW) and non-heat wave (NHW) conditions is analysed. In addition, an advection-diffusion analytical model has been used to unravel the mechanism of the interaction between UHI and HW. Results show that the UHI intensity is obviously enhanced during HWs, and the enhancement is stronger during daytime than that of nighttime, which indicates the synergistic effect between UHI and HW. The relative humidity ratio of urban and suburban areas during HWs significantly decreases compared with NHW conditions, indicating the urban surface becomes even drier than suburban areas during HWs that suppresses evaporation and intensifies UHI intensity. The mean wind speed also has an obvious decrease, leading to weaker advection cooling effect, which has a positive effect on UHI intensity. The increase of net radiation at the urban site is larger than that of the suburban site during HWs so that urban area receives more radiation input. Due to low vegetation cover and more impervious surfaces, the latent heat flux at the urban site has a slight decrease while it has an obvious increase at the suburban site. The increase of the urban sensible heat flux is larger than that of the suburban site. This change of the partition between sensible and latent heat flux also exacerbates the UHI intensity. This study has important implications for cities to cope with intensified thermal risks.

Key words: urban heat island, heat wave, analytical model, radiation flux, sensible heat flux, latent heat flux