不同气象条件下济宁城市热岛效应的变化特征

Urban heat island effect under different meteorological conditions in Jining of Shandong province

利用1981—2013年济宁、兖州、嘉祥、汶上站逐日4个时次的平均气温、平均风速、降水量、云量和能见度资料,对不同天气条件下济宁市的城市热岛效应进行研究.结果表明:济宁城市热岛效应具有明显的月季变化特征和日变化特征,具体为冬半年明显高于夏半年,白天的热岛强度明显低于夜间,中午前后最弱;济宁市四季热岛强度的变化规律是冬季最强,夏季最弱,春秋居中,除秋季外均呈现缓慢上升趋势.在不同气象条件下,济宁城市热岛强度也存在很大差异,其中在晴朗无风气象条件下表现最为突出,平均值达到0.79℃,其昼夜变化幅度也最大;在降雨时城市热岛强度最小,平均仅有0.09℃,其昼夜变化幅度也最小;大于等于4.0 m/s大风天气和雾均多发生在秋冬季,且雾对城市热岛的形成和昼夜变化影响明显大于风对城市热岛的影响;在晴朗无风和大雾条件下,02时热岛强度最强,当有降水出现时,20时热岛强度最强,出现大风天气时,08时热岛强度最强,所有研究天气条件下,14时热岛强度均表现为最弱.

The variation of urban heat island （ UHI） effect in Jining of Shandong province was analyzed using me？teorological measurements such as mean air temperature,mean wind speed,precipitation,cloud cover and visibility data from Jining,Yanzhou,Jiaxiang and Wenshang station at 02：00,08：00,14：00,and 20：00 BST from 1981 to 2013.Results show that the UHI effect in Jining has obvious monthly and diurnal variation characteristics.The UHI effect was stronger in the winter half year than in the summer half year;significantly weaker in daytime than in nighttime,and the weakest at noon.As for seasonal variation,the UHI effect in Jining is strongest in winter and wea？kest in summer,and in a slowly growing trend in seasons of spring,summer and winter.The UHI effect varies greatly under different weather conditions,which is most obvious at sunny windless weather with average value of 0？79℃, and least obvious at rainy weather with average value of 0？09 ℃. Fog and wind with speed equal to or greater than 4？0 m/s mostly occur in autumn or winter,but fog effects greater than wind on the formation and diurnal variation of UHI.As for the diurnal variation,the UHI effect is strongest at different time of a day under different weather condi？tions,which occurs at 02：00,20：00,and 08：00 at sunny windless foggy weather,precipitation weather,and strong windy weather conditions,respectively;while the UHI effect is weakest at 14：00 under all weather conditions.