Journal of Geographical Sciences ›› 2011, Vol. 21 ›› Issue (6): 994-1006.doi: 10.1007/s11442-011-0895-9

• Climate Change • Previous Articles     Next Articles

Impact of urban expansion on meteorological observation data and overestimation to regional air temperature in China

SHAO Quanqin1, SUN Chaoyang1,2,3, LIU Jiyuan1, HE Jianfeng1, KUANG Wenhui1, TAO Fulu1   

  1. 1. Division of Regional Environmental Change Research, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China;
    3. National Climate Center, Chinese Meteorological Administration, Beijing 100081, China
  • Received:2011-03-01 Revised:2011-04-15 Online:2011-12-15 Published:2011-10-03
  • Contact: Liu Jiyuan, Professor, E-mail: liujy@igsnrr.ac.cn E-mail:liujy@igsnrr.ac.cn
  • About author:Shao Quanqin, Professor, specialized in GIS and ecosystem informatics. E-mail: shaoqq@igsnrr.ac.cn
  • Supported by:

    National 973 Program of China, No.2010CB950900; Swedish Research Links, No.2006-24724-44416-13

Abstract:

Since the implementation of the reform and opening up policy in China in the late 1970s, some meteorological stations ‘entered’ cities passively due to urban expansion. Changes in the surface and built environment around the stations have influenced observations of air temperature. When the observational data from urban stations are applied in the interpolation of national or regional scale air temperature dataset, they could lead to overestimation of regional air temperature and inaccurate assessment of warming. In this study, the underlying surface surrounding 756 meteorological stations across China was identified based on remote sensing images over a number of time intervals to distinguish the rural stations that ’entered’ into cities. Then, after removing the observational data from these stations which have been influenced by urban expansion, a dataset of background air temperatures was generated by interpolating the observational data from the remaining rural stations. The mean urban heat island effect intensity since 1970 was estimated by comparing the original observational records from urban stations with the background air temperature interpolated. The result shows that urban heat island effect does occur due to urban expansion, with a higher intensity in winter than in other seasons. Then the overestimation of regional air temperature is evaluated by comparing the two kinds of grid datasets of air temperature which are respectively interpolated by all stations’ and rural stations’ observational data. Spatially, the overestimation is relatively higher in eastern China than in the central part of China; however, both areas exhibit a much higher effect than is observed in western China. We concluded that in the last 40 years the mean temperature in China increased by about 1.58℃, of which about 0.01℃ was attributed to urban expansion, with a contribution of up to 0.09℃ in the core areas from the overestimation of air temperature.

Key words: data interpolation, urban heat-island intensity, air temperature, urban expansion, meteorological stations, RS