Spatial and temporal variability of the abrupt interannual temperature change and warming hiatus in China, 1951–2016

The abrupt temperature change (ATC) and warming hiatus (WH) phenomena impact global resources and the environment. However, information on the spatial and temporal variability in the ATC and WH over large regions, long time scales and densely distributed stations is lacking. In the study, based on average minimum, average and average maximum temperatures data from 1951 to 2016 from 622 meteorological stations in China, the spatial and temporal variability in the timing of the ATC and WH events and the characteristics before and after these events were revealed by using the Mann–Kendall test. In most areas of China, an ATC occurred in the three temperature parameters, and the onset of the changes occurred later at lower latitudes. The ATC in the average minimum temperature occurred earlier than that in the average temperature, and the ATC in the average maximum temperature occurred the latest. After the ATC, a WH occurred at most of the stations that experienced an increase in temperature, whereas a cooling hiatus (CH) did not occur at stations that experienced a decrease in temperature. The regions with decreasing temperatures were concentrated in the hilly and plain areas of southern China and in subtropical and tropical monsoon climate zones. The WH of the average temperature occurred earlier than that of the average maximum temperature, which occurred earlier than that of the average minimum temperature. Overall, the WH began later from east to west and was mainly concentrated in approximately 1998 and 2007. Both the ATC and the WH in the Qinghai–Tibet Plateau area showed hysteresis. The ATC to WH period was between three and 27 years, and the earlier the ATC was, the longer was the period. Before the ATC, all three temperature parameters increased slightly. The average minimum temperature rose faster than the average temperature, and the average maximum temperature rose the slowest. Furthermore, the variation became more dramatic from southeast to northwest. After the ATC, the temperatures in most areas increased rapidly, and the rate of temperature increase increased with decreasing latitude. The average maximum temperature decreased in the area east of 100° E and south of 30° N. In this area, the rates of temperature increase for the average minimum and average temperatures were on a par with the rate of decrease in the absolute average maximum temperature, with the rates being three to five times greater than those before the ATC, but without dramatic variations. After the ATC, a CH did not occur at the stations where the temperature had decreased, whereas a WH occurred after a certain period of time at most of the stations where the temperature had increased. Moreover, such occurrences differed with latitude. A comparison of the temperature after the WH with that both before and after the ATC but before the WH revealed that the temperature did not vary dramatically. Eight to 10 years after the WH, the temperatures at a small number of stations in northern China rose again; however, due to the short length of the time series, it is impossible to determine whether the WH had truly ended. The results of the study enrich the findings of climate change research and provide a reference for addressing resource and environmental issues.