Weak Cooling of Cold Extremes Versus Continued Warming of Hot Extremes in China During the Recent Global Surface Warming Hiatus

Using daily maximum temperature (T-max), minimum temperature (T-min), and mean temperature data of 437 weather stations in China, we compared variations of the mean with extreme ends of probability distribution of temperatures in China from 1960 to 2015. Our analysis confirmed that annual mean T-max and T-min experienced warming hiatus in China after 1998. The warming hiatus is also reflected by the weak cooling of cold extremes across China, but hot extremes continue the significant warming trend nationally and in climate regions of East China, Southwest China, and the Tibetan Plateau. During 1999-2015, the hot day frequency (T-x90, based on base period 1961-1990) and averaged T-max above the 90th percentile of each year (T-xp90) increased significantly by 3.70d/decade and 0.20 degrees C/decade nationally. But there were significant cooling trends of cold extremes in East China and Southeast China from 1999 to 2015. During the warming hiatus period, the obvious decline in warm season precipitation contributed to the ongoing warming of hot extremes in East China and Southwest China. Both the decrease of warming season solar irradiance and increase of warm season precipitation facilitated the weak cooling trends of hot extremes in Northeast China and North China Plain. Although mean temperature experienced warming hiatus after 1998, the continued warming of hot extremes and reverse from warming to weak cooling of cold extremes imply an increase of temperature variability in China simultaneously.