Influence of Anomalous Ocean Heat Transport on the Extratropical
Atmospheric Circulation in a High-Resolution Slab-Ocean Coupled Model
Abstract
Key questions remain about the atmospheric response to variability in
the oceanic western boundary currents (WBCs). Here we exploit a unique
high-resolution slab-ocean coupled climate model to investigate how
ocean heat transport (OHT) anomalies in the major WBCs of both
hemispheres affect the atmospheric circulation. In both hemispheres,
prescribed OHT anomalies lead to robust changes in convective
precipitation anomalies equatorward of the maximum surface warming. The
response is deepest and most pronounced over the Northern Hemisphere
(NH) WBCs, where it is associated with significant changes in upper
tropospheric vertical motion, condensational heating and geopotential
heights. The response is relatively shallow over the Southern Hemisphere
(SH) WBCs. The findings reveal the robustness of the atmospheric
response to OHT anomalies and highlight key hemispheric differences: in
the NH, realistic OHT anomalies are balanced by deep atmospheric
vertical motion; in the SH, they are balanced primarily by shallow
horizontal temperature advection.