The evolutionary characteristics of temperature change in China during 1961-2020

The changes of annual average, minimum and maximum temperature (T-avg, T-min and T-max) in China over 1961-2020 were examined based on the Chinese gridded observation dataset (CN05.1), and the relative contributions of T-min and T-max to the tendency of T-avg were addressed. The results show that the nationwide mean warming rate reached 0.29 degrees C<middle dot>decade(-1) for T-avg, 0.39 degrees C<middle dot>decade(-1) for T-min and 0.24 degrees C<middle dot>decade(-1) for T-max, respectively, from 1961 to 2020, which depended on temporal windows. The relative contributions of T-min and T-max to the trends of T-avg over China during 1961-2020 are 56% and 44%, respectively. On the spatial scale, the majority of China exhibits a greater relative contribution of T-min than T-max, except for some areas along the Hu Huanyong Line. As in the case of the warming rate, the temporal patterns of the magnitude of the relative contribution of T-min and T-max are also identified. For the first 30 years (1961-1990), T-min is the primary contributor to changes in the trend of T-avg over a broad area excluding the Qinling Mountain-Huai River to the Nanling Mountain. The national average magnitudes of the relative contribution of T-max is slightly larger than T-min in the latter 30 years (1991-2020). The areas with larger contributions of T-max are mainly scattered along Hu Huanyong Line, the southern part of the Qinghai-Tibet Plateau and the patchy parts of Northwest China. Changes in downward longwave radiation, solar radiation, cloud cover, land use, soil moisture, atmospheric circulation and urbanization likely accounted for much of the trend difference of T-min and T-max, thereby leading to various relative contributions across different regions during different periods. The warming mechanisms in China have been subjected to novel changes. The study could provide information for decision making on scientific response to warming.