| Abstract: | The climatology and long term trends of sunshine duration (SSD), total cloud amount (TCC) and surface temperature are studied based on surface observations at 84 stations across China from 1961 to 2009. These stations were classified into metropolis, large city, small city and rural station based on their populations and specific station locations. Difference in SSD and its implication for surface temperature among four station categories are analyzed. Different SSD decreasing rates among four station categories were found. The maximum decreasing rate occurred at metropolis stations (-89.2 h per decade) and the minimum rate occurred at rural station (-54.1 h per decade). TCC also showed a negative trend. The correlation coefficients between decadal variability of SSD and TCC were significantly positive, which implied that the dimming during this period was apparently not explained by TCC. Among all station categories, the maximum temperatures (Tmax) showed a similar positive trend, however, the minimum temperatures (Tmin) increased much faster at urban stations than at rural stations. This suggested that the faster decline of SSD at urban stations could partly dampen the effect of urban heat island on Tmax. |
