城市化对地面气温变化趋势影响研究综述

An Overview of Researches of Urbanization Effect on Land Surface Air Temperature Trends

在综述城市化对地面气温资料序列影响研究进展的基础上,总结评估了不同空间尺度上地面气温序列中城市化影响的性质和强度。在城市台站和局地尺度上,多数研究均发现城市化对地面气温序列影响明显;区域尺度的研究主要集中在中国、美国和欧洲等少数地区,研究结果存在较大的差异,但采用严格遴选乡村站资料的分析都得到了城市化影响很明显的结论。在中国大陆地区,国家级气象台站年平均地面气温的上升趋势中,至少有27.3%可归因于城市化影响;对于全球或半球陆地平均气温序列而言,研究工作还很不充分,但一般认为城市化影响较小,可能不超过总增温的10%。现有研究还表明,城市化对地面气温序列的影响随时间和区域有不同的表现;城市化对包括中国在内的东亚地区近半个世纪长序列地面气温趋势的影响是非常显著的,但对欧洲地区的明显影响可能主要发生在20世纪早期甚至19世纪后期。目前的研究仍然存在一些问题和困难,其中包括研究覆盖的区域和时间段有限、乡村站遴选标准不统一、城市化影响偏差订正方法有待完善等。

Urbanization may have affected the surface air temperature records at many stations in continents,especially in industrial regions like Europe,North America and East Asia. However,this issue is still under debate at present,especially at regional and global scales. Based on an overview of researches on urbanization effects on surface air temperature series mostly in the continents of northern Hemisphere,the nature and intensity of urbanization effects at different spatial scales are summarized and assessed. At city and local scales,most studies have found obvious urbanization effects,with big cities showing the most significant urban warming. At regional scale,the studies focused on China's Mainland and the United States also have showed significant urban warming in varied extents,in spite of the fact that a few studies have claimed an insignificant urban bias. It is obvious that the researches with robust methods to select reference stations have generally found significant urbanization effect on surface air temperature trends. For global or hemispheric average temperature series,researches are far from enough at present,but they have mostly indicated that the urbanization effect may be minor or insignificant,and it may have not exceeded 10% of the total warming observed. Studies have also found that the urbanization effect changes over time and regions. In East Asia,including China,Korea and Japan,urbanization has had very significant impact on surface temperature trend during the past half a century,but in Europe the significant urbanization effect might have occurred in the early 20th century and even the late 19th century. At present,there are still many problems and difficulties on the study of urbanization effect on temperature series,including the limited areas and time periods studied,radically different selection criteria of reference stations and imperfect methodology for urban bias adjustment. To solve these problems in the near future will help promote the progress of research.