Regime shifts in the thermal dynamics of offshore China due to accelerated global warming

Thermal dynamics play a pivotal role in offshore ecosystems, influencing a multitude of ecological and biogeochemical processes. Assessing how water temperature (WT) responds to climate change is vital for the sustainable development of marine ecosystems. Despite the scarcity of long-term sea surface temperature (SST) data, this study reconstructs SSTs from 1973 to 2020 in China's coastal zones using the data-driven Air2water model. A probabilistic approach was applied to investigate the joint dependency structures between air temperature (AT) and WT at offshore oceanic stations in China, focusing on variations during periods of decelerated and accelerated warming. The results indicate that the Air2water model performs well in reconstructing SSTs of the coastal zone of China. Furthermore, the joint probability of AT-WT events, characterized by bimodal distributions, tends to increase during accelerated warming. This suggests intensified extreme SST events in the coastal zone of China due to global warming, with the significant warming primarily related with regional oscillations, atmospheric dynamics, and the complex temperature trends in the regional marine environment. These findings highlight the escalating impact of global warming on marine ecosystems in China's coastal regions, underscoring the urgency of developing adaptive strategies to mitigate these effects.