近70年来兰州城市气温的变化

Study on Air Temperature Change in Lanzhou City in Recent 70 Years

利用兰州市70年来的气温记录,采用城郊对比的方法定量的研究了城市化对兰州气温的影响。在分析了年平均气温和各特征气温的相关性的基础上,利用主成分分析的方法提取气温变化的主控制因子——低温控制因子、高温控制因子。利用两个控制因子的城郊对比,定量的揭示了城市化对城市气温变化的影响。任何区域气候变化不仅有城市化等人为因素的影响,而且带有大范围的气候背景的影响,所以在讨论城市发展对气温的影响之前,首先通过滑动T-检验研究了兰州市气温变化的大的趋势,得出兰州城市气温的11年变化周期,对于这一现象初步认为这于太阳的黑子活动的周期性有关。

Located in the transitional zone between the arid and semiarid areas, Lanzhou is the second largest city, second only to Xi'an in northwest China. The urbanization has resulted in some negative effects on the local climate due to the rapid industrial development in recent years, and the vegetation coverage is too low to regulate the local climate. The impacts of human activities on the local climate change are significant. Moreover, the urban buildings are congested due to the geographical location that Lanzhou City is delimited in a valley of the Yellow River. In this paper, the impacts of urbanization on the local climate change in Lanzhou City are quantitatively researched based on the air temperature records since recent 70 years by selecting the dominant factors affecting the low temperature and high temperature. The impacts of urbanization on the air temperature change in Lanzhou City are quantitatively revealed by comparing the dominant factors affecting the temperature between the urban area and the suburbs. It is considered that the regional climate change is not only affected by artificial factors including urbanization, but also by the large scale climatic background. The study reveals that there is an 11 year period of temperature fluctuation, and it is considered that this is related to the sunspot cycles.