辽宁省气温变化趋势中的城市化影响研究

利用1961 - 2017年逐日平均、 最低、 最高气温资料、 DMSP/OLS卫星夜晚灯光数据， 定量分析了城市化对辽宁省平均气温和极端气温指数趋势变化的影响。研究表明： 辽宁省气温呈显著增加趋势， 城市站增温速率明显快于乡村站； 平均最低气温增温率最快， 平均气温次之， 平均最高气温相对较慢； 四季增温速率依次为： 冬季>春季>秋季>夏季； 最低气温的城市化影响贡献率最大， 平均气温次之， 最高气温相对较小； 城市站最低气温的明显升高和最高气温增幅较小， 必将导致日较差明显减小和日较差城市化影响贡献率的增大。城市化加剧了辽宁省极端低温事件的显著减少和极端高温事件的明显增加， 城市化对极端气温事件影响显著。与冷事件有关的极端气温指数的城市化影响均为负值， 与暖事件有关的均为正值； 相对指数的城市化影响贡献率较大， 持续时间指数次之， 除气温日较差以外的绝对指数相对较小。基于最低气温的极端气温指数比基于最高气温的极端气温指数受城市化影响更显著， 其原因可能是城市热岛强度的非对称性以及城市站和乡村站气溶胶浓度之间的差异， 导致最高气温的增加没有最低气温的增加显著。

Effect of urbanization on the air temperature variation of Liaoning Province

Based on the daily average temperature， the average maximum temperature and the average minimum temperature data from 1961 to 2017 and DMSP/OLS satellite nighttime light data， the influence of urbanization on the trend of average temperature and extreme temperature indices of Liaoning Province was quantitatively analyzed. The results show that the temperature in Liaoning Province exhibits a significant warming trend， and the rate of warming trend at urban stations is obviously faster than at rural stations. The growth rate of the average minimum temperature is the fastest， followed by the average temperature， and the average maximum temperature is relatively slow. The warming rates of four seasons are as follows： winter > spring > autumn > summer； the contributions of urbanization from large to small are in order： the average minimum temperature > the average temperature > the average maximum temperature. The significant increase of the minimum temperature and the slight growth of the maximum temperature at the city stations should lead to the decrease of the daily range of temperature， and enhance the contribution of urbanization. Urbanization aggravates the significant decrease of the extreme low temperature events and the significant increase of extreme high temperature events in Liaoning Province. Urbanization has a significant impact on extreme temperature events. The urban effect of the extreme temperature index related to the cold events is negative， while that related to the warm events is positive. In terms of the contribution rate of urbanization effect， the relative index is larger， followed by the duration index， and the absolute index except the daily temperature range is relatively small. The extreme temperature index based on the lowest temperature is more affected by urbanization than that based on the highest temperature. The spatial asymmetry of urban heat island intensity and the difference of aerosol concentration between urban station and rural station results in the increase of maximum temperature not as significant as that of minimum temperature， which may explain the urban effect on the extreme temperature index.