[A-CG32] Extratropical oceans and atmosphere

[ACG32-11] Oceanic Reemergence Memory Links Atlantic and Pacific Multidecadal Variability

★Invited Papers

*BAOLAN WU¹, LISAN YU², XIAOPEI LIN³, JIANPING GAN¹, BO QIU⁴, LIXIAO XU³ (1.HKUST, 2.WHOI, 3.OUC, 4.U Hawaii)

Keywords:mode water, multidecadal variability, Pacific , Reemergence, Oceanic memory

Understanding how the ocean provides the memory needed for maintaining decadal to multidecadal variability is key to climate prediction. An important question is what process in the ocean could provide the observed significant time-lag between the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Here we show that the Pacific Ocean could store climate anomalies within the subtropical recirculation gyre for a decadal duration, providing a “seeding” link between the AMO and PDO. The AMO-induced multidecadal temperature anomalies in the Subtropical Northwestern Pacific Ocean are subducted into the thermocline and sequestered in the North Pacific subtropical mode water. These temperature anomalies carried by the mode water would propagate southwestward along the recirculation gyre pathway to eventually re-join the Kuroshio one decade later. Once reemerged in the isopycnal outcropping area of the Kuroshio-Oyashio Extension region, the anomalies that carry the memory of the previous decade may engage with local air-sea feedback to trigger the PDO. Thus, the AMO provides important memory for prediction of decadal climate and ecosystem variability in the Pacific Ocean.