[A-OS08] Seasonal-to-decadal climate variability and predictability

[AOS08-01] Decadal variability and predictability in the Southern Ocean - implications for interpreting recent observed trends

★Invited Papers

*Thomas L Delworth¹, Liping Zhang¹, Will Cooke¹, Xiaosong Yang¹ (1.GFDL/NOAA)

Keywords:climate, decadal, variability, predictability

While decadal variability and predictability in the North Atlantic and North Pacific have received considerable attention, there has been less work on decadal variability in the Southern ocean. As shown previously, a coherent mode of decadal to centennial variability exists in multiple climate models. The mechanism involves a multidecadal accumulation of heat in the subsurface of the Southern Ocean, which is then rapidly discharged through intense oceanic convection when the accumulation of subsurface heat reduces the stratification of the water column. The release of this accumulated subsurface heat can have considerable regional scale climatic impacts, along with substantial impacts on ocean heat uptake. We further show that this variability has a high degree of predictability, as estimated by perfect predictability experiments. Finally, we present results that show this type of variability may play an important role for interpreting recently observed trends of sea ice and temperature in the Southern Ocean. Specifically, observed trends over the last several decades resemble a particular phase of this variability, in concert with other factors.