基于EOF分解的辽宁省城市化气候效应检测

论文利用1961—2017年逐日气象数据以及社会经济数据,构建新的城市化指标,分析了城市化对辽宁气候变化的影响。研究表明:辽宁省气温呈显著增加趋势,国家站增温速率明显快于乡村站;城市化对平均最低气温影响最显著,平均气温次之,平均最高气温相对较弱;就四季而言,秋季城市化影响贡献率最大,冬季和夏季次之,春季相对较小。空间分布上,城市化影响高值区位于辽宁中部和西部地区,与辽宁省城市化发展水平基本吻合,城市化对气温的影响不是单一的,对于多数地区尤其是沈阳、大连等经济发展水平较高的地区,起到增温作用,但也对少数台站的升温起到了抑制作用。气温指标中,城市化对年和四季平均气温的影响最显著,对应模态均是第一模态,方差贡献率均在89%以上,空间相关性均通过显著性检验,其次是平均最低气温和日较差;季节变化特征上,冬季和春季的增温相对于秋季和夏季明显。降水指标基本对应第二模态,方差贡献率在9%~18%之间,城市化对气温的影响强于降水;结合时间系数,城市化效应表现为春季和冬季降水、大雨和暴雨日数略有增加,年、夏季、秋季降水、小雨、中雨日数减少。城市化对降水的影响表现出两面性,一方面使年降水和小量级降水减少,另一方面又使极端降水事件增多。

Detection of urbanization effect on the climate change in Liaoning Province based on empirical orthogonal function methods

Based on the daily climate data and socioeconomic data from 1961 to 2017, a new urbanization index was established and the influence of urbanization on climate change of Liaoning Province was analyzed. The results show that the temperature in Liaoning Province exhibits a significant warming trend, and the rate of warming at the national stations is obviously faster than at the rural stations. The influence of urbanization from large to small are in the following order: The average minimum temperature > the average temperature > the average maximum temperature. The contributions of urbanization in the four seasons are as follows: Autumn > winter > summer > spring. In terms of spatial distribution, the high-value areas affected by urbanization are located in the central and western regions of Liaoning Province, which are basically in line with the urbanization development level of the province. Urbanization does not have a spatially consistent influence on temperature—it plays a warming role in most areas, especially in areas with high economic development level such as Shenyang and Dalian, but it also has a restraining effect on the warming of a few stations. Among the temperature indices, urbanization has the most significant influence on the annual and four-season average temperature, with corresponding first mode, and contribution rate over 89%. The spatial correlation of the annual and four-season average temperature has passed the significance test. In addition, urbanization has influence on the mean minimum air temperature and the daily range. In terms of seasonal variation characteristics, the temperature increase in winter and spring is more obvious than that in autumn and summer. The precipitation index basically corresponds to the second mode, and the contribution rate is between 9% and 18%. The influence of urbanization on temperature is stronger than that on precipitation. Combined with the time coefficient, the urbanization effect shows that the precipitation in the spring and winter and the number of days of heavy rain and rainstorm increased slightly, but the number of days of light rain and moderate rain and the precipitation in the summer and autumn decreased. Urbanization has a two-sided influence on precipitation. On the one hand, urbanization reduces annual precipitation and precipitation of small magnitude; on the other hand, it increases extreme precipitation events.