Ocean warming acceleration in Atlantic tied to the changes in ocean heat transport

Change in ocean warming rate is essential for evaluating the current climate change and predict future climate conditions. It has been confirmed that in the context of accelerated warming of the Earth climate system, the global oceans have been warming, especiallysince the 21st century, with a certain rate of acceleration. Because the local ocean heat content (OHC) changes are mainly balanced by the net sea surface heat flux (FS) and the oceanicheatdivergence/convergence (OHD), the acceleration of ocean warming is closely related to the trend of the latter two. In this study, we first calculate the oceanic meridional heat transport (MHT) as a residual of energy budget including OHC, FS, and heat related to sea ice volume changes (Qice), and then adjust the discrepancy caused by systematic errors in different data and mismatch between them on a monthly basis. Our estimated MHT is compared to the results from RAPIDobservations, which shows good agreement between the two, with a correlation coefficient of 0.73 in the time series during January 2009 - December 2020. Based on the multiple datasets, we further evaluate the accelerated/deceleratedchanges in AtlanticOHC associated with theocean and air-sea energy flowchanges. The results show that during 1985-2016, in the north Atlantic Ocean, the ocean warming is slowing down, which are mainly dominated by the decreased OHD, while the southern Atlantic Ocean is accelerating warming mainly caused by the strengthened OHD. Therefore, MHT changes accompanied by the energy flowwithin the oceanplay a more important role to the regional ocean warming acceleration than the changesin regional sea air heat exchange. The methodology we use here providesa method to estimate the heat transports, and can be used to analysis the ocean warming rates and Earths energy changes, and to detect the future climate variability.