上海城市热岛的变化特征

利用上海77个区域站2011—2014年逐时气温资料，运用城乡对比法分析了城市热岛(UHI)的时空变化特征。其次利用长三角20个国家站1961—2013年逐年平均气温资料，运用空间滤波法研究了上海城市化进程对城市热岛强度(I_UHI)的影响。结果表明:1961—2013年I_UHI整体上呈缓慢上升的趋势，I_UHI递增率达0.15~ 0.17 ℃/(10 a)，年平均最大I_UHI达1.10~1.33 ℃，出现在2006年。上海城市化进程的加快有利于I_UHI的增大。21世纪以来I_UHI呈现减缓特征与全球气候变暖减缓的趋势一致。近年来，上海城区集中在外环以内，三个城市内部区域(内环区、中环至内环区、外环至中环区)I_UHI存在一致的日变化特征，但受到城区内部下垫面差异性影响，I_UHI呈现从内环区往外环依次递减的特征，并在夜间强热岛阶段最为明显。冬季I_UHI和I_UHI日变化均最大，秋季与之相当，春季次之，夏季最小。从I_UHI空间分布特征看，春夏季较为一致(即东部气温较低，西部气温较高，强热岛中心集中在西北部)、秋冬季较为一致(即东部气温较高，西部气温较低，强热岛中心稳定在城区附近)，这可能与季风有关。 

VARIATIONS OF THE URBAN HEAT ISLAND EFFECT IN SHANGHAI

This paper used the hourly air temperature of 77 regional meteorological stations in Shanghai from 2011 to 2014 to study the temporal and spatial characteristics of the urban heat island (UHI) effect by the method of urban and rural comparison. Then, with the annual mean air temperature data of 20 national meteorological stations in the Yangtze River Delta region from 1961 to 2013, the influence of urbanization on the I_UHI in Shanghai was studied by the spatial filtering method. The main conclusions are as follows: The I_UHI showed a slowly increasing trend from 1961 to 2013 with a rate of 0.15~0.17℃ per 10 years and the maximum of annual I_UHI reached 1.10~1.33℃, which appeared in 2006. The acceleration of urbanization in Shanghai was conducive to the increase of I_UHI.Since the beginning of the 21st century, the increasing trend of I_UHI had slowed down, which was consistent with global warming breaks. In recent years, the urban areas of Shanghai were concentrated within the outer ring. The I_UHI of three different urban inner regions (the region within the inner ring, the region between the central and the inner ring, and the region between the outer and the central ring) showed the same diurnal variation characteristics. For the effect of different underlying surface, the I_UHI decreased gradually from the inner ring to the outer ring, which was obvious at night. Both the I_UHI and its diurnal variation were the strongest in winter, followed by autumn and spring, and the weakest in summer. The spatial distribution characteristics of I_UHI in spring and summer were similar(the temperature in the east of Shanghai was lower than in the west and a strong UHI center was concentrated in the northwest of Shanghai). The spatial distribution characteristics of I_UHI in autumn and winter were similar(the temperature in the west of Shanghai was lower than in the east and the strong UHI center was located near the urban area). It could be related to the monsoon.