Rapid warming of the Pacific during 2013-2020:identification and spatial-temporal characteristics
Using multiple observational subsurface temperature and salinity datasets based on Argo,we analyze the trend of 0-1 500 m ocean heat content in the Pacific between 2004 and 2020.It was found that the long-term trend of the Pacific ocean heat content showed a shift in 2013.The ocean heat content in 2013-2020 increased rapidly compared with that in 2004-2012.The linear trend of the former reaches about 0.50×1022 J/a,which is signific-antly higher than that of the latter.The Pacific has recently experienced rapid warming.During 2013-2020,the largest linear trend of the ocean heat content in the Pacific appeared in the western North Pacific,followed by the Tropical Pacific and eastern North Pacific.While the ocean heat content in the entire South Pacific showed a slightly decreasing trend.In the western North Pacific,the rapid increase of ocean heat content was concentrated in the Kuroshio Extension areas,and this warming trend is likely to be caused by the northward shift of the Kuroshio Extension main axis.It is worth mentioning that there was a local decreasing trend of ocean heat content in the sea south of Japan,and this cooling trend is associated with the strengthening of the Kuroshio large meander.In the Tropical Pacific where the warming trend is the second largest,the rapid increase of ocean heat content is likely to be induced by the thermocline deepening.In addition,we point out that the rapid warming in the Pacific is reflec-ted by the rapid rise of sea level.The linear trend of sea level per 1 cm/a corresponds to the linear trend of ocean heat content of 0.11×109 J/(m2·a).This study elucidates the rapid warming of the Pacific since the end of the glob-al warming hiatus,deepening our understanding of recent thermal conditions in the Pacific.
ocean heat contentrapid warming of the Pacificnorthward shift of Kuroshio Extension main axisKuroshio large meanderthermocline deepening