超大城市热岛效应的季节变化特征及其年际差异.docVIP

 超大城市热岛效应的季节变化特征及其年 际差异# 张艳，鲍文杰，余琦，马蔚纯** 5 10 15 （复旦大学环境科学与工程系） 摘要：本文以超大城市上海为例，分析了近 50 年四季城郊温差的总体变化趋势，同时利用 4 个年份（1987、1990、1997 和 2004 年）11 个气象站点逐日 4 个时刻（2:00，8:00，14:00， 20:00）的气温数据，重点研究了上海地区热岛效应的季节变化特征及年际差异。结果表明， 城郊温差逐年显著增长，上海地区年平均热岛天数频率为 86.0%，年平均热岛强度为 1.17， 秋季热岛频率和强度高于其他季节。进一步分析表明，四季差异主要在于较强热岛和强热岛 出现频率的差异；在秋季，最稳定的 F 类天气出现频率高于其他三个季节，这可能也是秋季 热岛比其他季节更加显著的原因之一。四个季节中，秋季热岛累积强度最大，夏季最小。在 1997 年之前，这种热岛效应的四季差异比较显著。但随着年代的推移，1997 年到 2004 年间， 四季累积热岛强度逐渐趋于均化，并且夏季低强度热岛有向中强热岛和强热岛转化的趋势。 不同时刻热岛研究表明，夜间热岛（2:00，20:00 时刻）累积强度在四季都较大，在春、夏 季 14:00 时刻热岛累积强度较大，而在秋、冬季 8:00 时刻热岛累积强度较大。 关键词：气象学,热岛效应，热岛累积强度，季节差异，上海 中图分类号：P4 20 Study on seasonal variations of the urban heat island and its inter-annual differences in a typical megacity Zhang Yan, Bao Wenjie, Yu Qi, Ma weichun (Department of Environmental Science and Engineering,Fudan University) 25 30 35 40 Abstract: The differences between the urban and rural temperatures in the past 50 years were analyzed based on the seasonal averaged data from 1960 to 2006 at two meteorological stations in Shanghai megacity. Moreover, the characteristics of the urban heat island (UHI) in Shanghai for the last two decades were studied based on the air temperatures measured four times a day at eleven stations in 1987, 1990, 1997 and 2004. The corresponding seasonal variations of UHI in Shanghai were discussed. Results showed that the temperature differences between urban and suburb were increasing in fluctuations, UHI occurred in 86.0% days of a year with an average magnitude of 1.17℃, and the frequency and magnitude of UHI in autumn were higher than those in other seasons. It can be inferred that the seasonal variations could mainly be attributed to the frequency difference between mid-intensity UHI and high-intensity UHI. Besides, the F-level stability condition occurred more frequently in autumn, which could account for the enhancement of autumn UHIs. Among four seasons, the accumulated intensity of UHI was the strongest in autumn, while weakest i