Asymmetric trends of extreme temperature over the Loess Plateau during 1998–2018

Abstract

AbstractA slowdown in the warming rate of the global mean surface temperature has been observed since late 1990s. However, it is still controversial whether the spatiotemporal variability of extreme temperature events will increase after global warming slowdown, and whether the regional diversity of change trends will increase. Here, we investigated the variations in extreme temperature indices over the Loess Plateau in China since 1961 and focused on the recent global warming slowdown (1998–2018). We found that, during 1961–2018, all the extreme temperature indices showed a significant warming trend and its intensity varied according to extreme temperature indices over different regions. A warming slowdown of annual mean temperature during 1998–2018 was primarily due to the slight increases of annual mean maximum temperatures (TXm) while the annual mean minimum temperature (TNm) still indicated prominently warming trends. During the recent warming slowdown period, the warm indices showed continued intensification of the warming trends, while the cold indices showed a slight cooling trend. Moreover, all extreme temperature indices showed the largest warming trend in summer and a slight cooling trend in winter. Overall, the extreme temperature events have become more diverse in spatial and temporal, indicating that regional climate are more unstable than previously reported for this region. Further analyses revealed that the extreme temperature events during the recent warming slowdown were primarily the result of the natural variability of the climate system, especially the large‐scale ocean–atmosphere interactions of the Pacific and Atlantic oceans.