城市化对安徽省极端气温事件的影响

利用卫星遥感资料对安徽省46个台站进行分类，统计分析了城市站、郊区站和乡村站1961-2010年的极端气温指数的年和季节的变化趋势及其受城市化的影响和贡献。结果表明：1) 近50年来，除最高气温年极大值外，其他气温年极值都有明显上升趋势，以最低温度极小值最显著；暖日、暖夜天数呈增加趋势，而冷日、冷夜天数呈减少趋势，其中暖夜和冷夜变化趋势更明显；各极端指数的变化趋势总体均表现为城市站较乡村站更显著，郊区站介于两者之间。2) 城市站最高气温极大值、最低气温极大值和最低气温极小值因城市化造成的增温分别为0.144、0.184和0.161℃/10a，增温贡献率分别达100.0%、58.8%和21.6%，但城市化对最高气温极小值影响较弱；季节尺度的城市化影响基本都造成增温，春、秋季更明显，而增温贡献率以春、夏季更明显，冬季最小或不显著。3) 城市化效应使暖日和暖夜天数增加、冷夜天数减少的趋势更加显著，城市化影响贡献率都在40%以上；暖日、暖夜和冷夜天数的城市化影响贡献率都在冬季最小或不显著。

Effects of Urbanization on Extreme Temperature Events in Anhui Province

Using daily temperature data of 46 stations in Anhui province with satellite-based station classification during 1961-2010, annual and seasonal trends of both absolute and relative extreme temperature indices were analyzed. Furthermore, urbanization effects and contributions were also evaluated. The annual maximum of daily maximum temperature (maxTmax) presented insignificant trends, while the annual minimum of daily maximum temperature (minTmax), the annual maximum and minimum of daily minimum temperature (maxTmin and minTmin) showed remarkable increasing trends, especially minTmin. Both warm days and nights presented significantly increasing trends, while cold days and nights showed decreasing trends, however, trends for warm and cold nights were relatively larger. Trends of extreme temperature indices for urban stations were generally more significant than those for rural stations. Urbanization effects had led to a highly significantly increase of maxTmax, maxTmin and minTmin at rates of 0.144, 0.184, and 0.161℃ per decade, with contributions of 100%, 58.8%, and 21.6%, respectively. However, there was no significant urbanization effect for minTmax. Seasonal urbanization effect generally led to increasing trends for absolute extreme indices, which were larger in spring and autumn, while contributions in spring and summer. Urbanization effects induced more significant increasing trends on warm days and nights, and more significant decreasing trends on cold nights, with contributions all above 40%. Contributions for all relative extreme indices were the smallest or insignificant in winter.