The Impact of Oceanic Feedbacks on Stratosphere-Troposphere Coupling in an Idealised Model

• Main Authors: Trencham, Natasha E., Czaja, Arnaud, Haigh, Joanna D.
• Format: Other/Unknown Material
• Language: unknown
• Published: Authorea, Inc. 2023
• Subjects: Southern Ocean
• Online Access: http://dx.doi.org/10.22541/essoar.169447438.81945905/v1

Stratospheric temperature perturbations (STPs) caused by e.g. variations in stratospheric ozone, are an important driver of changes in tropospheric dynamics, particularly pertinent to the long-term climate evolution of the Southern Hemisphere. However, the impact of ocean feedbacks on this interaction has not been fully examined. To study it, positive STPs were applied in three otherwise identical, idealised model configurations –atmosphere-only (A), atmosphere + slab-ocean (AS), and fully-coupled atmosphere-ocean (AO) – and the resulting atmospheric changes compared. In the AO model, changes in the tropics/extratropics experienced a positive/negative feedback after ~100-200 years, whilst the AS model showed few significant changes, compared to the A model. Changes in tropical ocean heat content were responsible, attributable to changes in the Ekman transport. These results indicate that full atmosphere-ocean coupling should be accounted for when studying the long-term (100+ years) tropospheric response to STPs in the Southern Ocean region. Validation with higher-resolution and more realistic models is necessary.