Detection of anthropogenic influence on the intensity of extreme temperatures in China

The anthropogenic (ANT) influence on the intensity of temperature extremes in China is detected over the period 1958-2012 using the newest homogenized daily observation data set and multi-model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We applied an optimal fingerprinting method to compare spatial-temporal changes in the intensity of temperature extremes, including annual maxima of daily maximum and daily minimum temperatures (warmest day and night, TXx and TNx) and annual minima of daily maximum and daily minimum temperatures (coldest day and night, TXn and TNn). For China as a whole, the results show that the ANT influence can be robustly detected in all four extreme indices. The ANT signal is also clearly separable from the response to natural-only (NAT) forcing in the two-signal analyses. The NAT signal was detectable for the warmest night TNx but not for other indices. At smaller regional scales for Eastern and Western China, the ANT signals were also clearly detected in the changes of temperature extremes. With the use of more observational data and multi-model simulations, this study updates a previous work and confirms that the human influence can be robustly detected in the changes of extreme temperature intensity in China.