Taking China's temperature: Daily range, warming trends, and regional variations, 1955-2000

In analyzing daily climate data from 305 weather stations in China for the period from 1955 to 2000, the authors found that surface air temperatures are increasing with an accelerating trend after 1990. They also found that the daily maximum (T-max) and minimum (T-min) air temperature increased at a rate of 1.27degrees and 3.23degreesC (100 yr)(-1) between 1955 and 2000. Both temperature trends were faster than those reported for the Northern Hemisphere, where T-max and T-min increased by 0.87degrees and 1.84degreesC (100 yr)(-1) between 1950 and 1993. The daily temperature range (DTR) decreased rapidly by 22.5degreesC (100 yr)(-1) from 1960 to 1990; during that time, minimum temperature increased while maximum temperature decreased slightly. Since 1990, the decline in DTR has halted because T-max and T-min increased at a similar pace during the 1990s. Increased minimum and maximum temperatures were most pronounced in northeast China and were lowest in the southwest. Cloud cover and precipitation correlated poorly with the decreasing temperature range. It is argued that a decline in solar irradiance better explains the decreasing range of daily temperatures through its influence on maximum temperature. With declining solar irradiance even on clear days, and with decreases in cloud cover, it is posited that atmospheric aerosols may be contributing to the changing solar irradiance and trends of daily temperatures observed in China.