Spatial variability of the trends in climatic variables across China during 1961-2010

Distribution of meteorological stations is not uniform in many regions of the world, especially in developing countries like China. To eliminate the effect of uneven stations, this study produced a data set of areal average precipitation, air temperature, solar radiation, and wind speed from 736 meteorological station observations during 1961-2010 using an inverse-distance weighted technique. Based on the data set, this study detected the trends in climatic variables. Precipitation has a slight but no significant (p=0.78) trend for the whole of China and has a significant increase trend in northwest China. Surface air temperature has a significant (p<0.001) accelerating warming trend of 0.032 degrees C/a for the whole of China, and spatially larger in northern China than that in southern China, Solar radiation has a significant (p<0.001) dimming trend of -0.14 W/(m(2) . a) for the whole of China, and the largest dimming trend appears in eastern China, the possible cause for which is a high-aerosol concentration. Surface wind speed has a significant (p<0.001) stilling trend of -0.012 m/(s.a) for the whole of China, the causes for which were speculated the changes in atmospheric circulation and surface roughness, as well as increases in aerosol concentration and the decrease in the south-north temperature gradient in China. In addition, three large-scale instrument replacements increase uncertainties of the trend analysis.