不同天气条件下沈阳城市热岛特征

Urban heat island characteristics in Shenyang under different weather conditions

利用1992—2008年沈阳站和新城子站逐日4个时次的平均气温、平均风速、降水量、云量和能见度资料,对不同天气条件下沈阳的城市热岛效应进行研究。结果表明:除雾和浓雾天气条件下,沈阳城市热岛强度在08时最弱外,其他天气条件下均表现为20时最强,14时最弱;不同天气条件下,夜间城市热岛强度均高于白天;晴朗无风条件下昼夜城市热岛强度差最大,为0.73℃。四季相比,除雾条件下秋季城市热岛强度最强外,其他天气条件下均为冬季最强;除大雨条件下春季城市热岛强度最弱外,其他条件下均为夏季最弱。沈阳城市热岛强度随降水量的增加而减弱,随能见度的降低而减弱,随着风速的增加而减弱。白天和夜间两个时次的差值表现为,1～3级风夜间变化幅度大于白天,0级和4～5级风速有相反规律,其他天气条件下无明显规律。

Based on the mean air temperature,mean wind speed,precipitation,cloud cover and visibility data at Shengyang and Xinchengzi stations at 02：00,08：00,14：00 and 20：00 BST from 1992 to 2008,the effect of urban heat island（UHI）was analyzed under different weather conditions.Results show that UHI intensity in Shenyang region is the lowest at 08：00 BST under light and heavy fog conditions,while it is the highest at 20：00 BST and the lowest at 14：00 BST under other weather conditions.UHI intensity is higher in night than in daytime under different weather conditions.Difference of UHI intensity between nighttime and daytime is the largest under the clear and calm wind condition,with the value of 0.73 ℃.Under the light fog condition,UHI intensity is the strongest in autumn,but under other weather conditions,it is the strongest in winter.Under the heavy rain condition,UHI intensity is the lowest in spring,and under the other precipitation conditions,it is the lowest in summer.UHI intensity decreases with the precipitation increase,wind speed increases,and visibility decrease.The UHI intensity difference（UHI20：00-UHI02：00）is larger in night than that（UHI08：00-UHI14：00）in daytime under the condition from the first to third wind levels,and the rule is contrary under the other wind levels.There are not obvious rules under other weather conditions.