Abstract:Using the hourly air temperature and wind data of 77 regional meteorological stations from 2011 to 2014, the influence of surface wind on urban heat island (UHI) in Shanghai and the cause of seasonal spatial distribution of UHI were studied. The influence of onshore wind on urban heat island intensity (IUHI) was preliminarily revealed from sea land thermal difference. Besides, the interannual variation of surface wind speed and IUHI in different seasons in Shanghai was studied based on the monthly air temperature and wind data of seven national meteorological stations from 1961 to 2014. The main conclusions are as follows: (1) The location of UHI center is closely related to wind direction and wind speed. The UHI center at night has the feature of moving to the leeward side of urban area when the average wind speed threshold is 2 m·s-1. With the increase of wind speed, the UHI area extends to the leeward side of city, but the IUHI decreases. (2) UHI characteristics are obvious in Shanghai at night, especially in autumn and winter, followed by spring and summer in order. UHI center appears in the northwest of urban areas at night in spring and summer, while UHI center is stabilized in urban areas at night in autumn and winter, showing typical UHI. In the daytime in each season, there is a large scale warming phenomenon in the downwind area. Seasonal surface prevailing wind determines the seasonal spatial distribution characteristics of UHI. (3) Onshore wind inhibits warming in the daytime, especially obvious in spring and summer. Affected by this phenomenon, the high temperature tends to appear in inland area. The IUHI is larger in the western urban area than in the eastern urban area in spring and summer. Onshore wind inhibits cooling at night, which is the most obvious and caused obvious warming in the eastern coastal areas in autumn and winter. The IUHI is larger in the eastern urban area than that in the western urban area in autumn and winter. Both the land sea thermal difference in different seasons and the prevailing wind speed determine the magnitude and impact scope of the onshore wind. (4) The average annual surface wind speed in each season has a significant negative correlation with the corresponding IUHI. The seasonal wind speed shows a decreasing trend (the most obvious in spring and winter) from 1961 to 2014 in Shanghai, which is good for IUHI increasing. Since the 21st century, the increasing trend of IUHI in all seasons has slowed down (the most obvious in summer and autumn), but wind speed is not the main factor causing the increasing trend of IUHI to slow down.