Impact of Land Use/Land Cover and Its Change on Climate Warming in Beijing Area

The effects of three types of land cover on the temperature trends in Beijing area were analyzed on the basis of meteorological data recorded by 13 climatological surface stations from 1979 to 2005. In addition, reanalysis data obtained by NCEP/DOE AMIP-Ⅱ and 1:100000 national land cover data reported from 1990 to 2005 were used in this study. The authors identified statistics on the area proportion of land cover type in 3-km radius buffer zones around the meteorological stations to clarify the observational environment. The data was then used to compare annual and seasonal temperature variations in addition to observational and observation minus reanalysis (OMR) temperature trends in a variety of historical periods and observational environments. Result shows that among the three main land cover types including forest, grassland, and cropland, the annual mean observational temperature trend over urban areas is the largest (0.822 ℃ /10 a); that over mixed areas of forest, grassland, and cropland is smaller (0.296 ℃ /10 a); and that over forest areas is the least (0.197 ℃ /10 a). Moreover, the annual mean OMR temperature trend over urban areas is also the largest (0.527 ℃ /10 a); that over mixed areas of forest, grassland, and cropland is smaller (-0.012 ℃ /10 a); that over forest areas is the least (-0.118 ℃ /10 a). Therefore, climate warming is inhibited in forests and enhanced in urban areas. Furthermore, growth of intensity in land use or cover from other types to urban can result in a slightly higher temperature variation.