LAUSR

ABSTRACT Under the ongoing global warming, the sea surface temperature (SST) over the entire Indian Ocean (IO) has been warming saliently at a rate of 0.014°C yr−1 since the 1950s, which is larger than that in other regions of the globe. The salient IO warming reflects the synergistic effect of global warming and the internal variability of the climate system, and the warming could lead to climate anomalies in peripheral regions. The simulation performance of the sustained IO warming was evaluated by comparing 37 CMIP5 and 37 CMIP6 models with observed data. The results show that the warming in the IO can be captured by nearly all the CMIP models, but most tend to underestimate the magnitude of IO warming trends. There is no qualitative improvement in the simulation of the salient IO warming from CMIP5 to CMIP6. In addition, six metrics were used to investigate the performance of all models. Concerning the spatial pattern of warming trends, the CMIP5 models reveal a better simulation performance than those in CMIP6 models. Only nine best models (seven CMIP5 models and two CMIP6 models) can simulate a high warming trend in the IO region of 0.014 ± 0.001°C yr−1 during 1950–2005, but these nine models still have some disadvantages among other metrics. The overall evaluation here provides necessary information for future investigation about the mechanism of the sustained IO warming based on the climate models with better performances. Graphical Abstract