Date of Award




Document Type

Master's Thesis

Degree Name

Master of Science (MS)


Department of Atmospheric and Environmental Sciences

Content Description

1 online resource (ii, 54 pages) : illustrations (some color)

Dissertation/Thesis Chair

Brian EJ Rose


climate feedback, ocean heat uptake, Ocean-atmosphere interaction, Ocean temperature, Heat, Clouds, Climatic changes, Radiative forcing

Subject Categories

Atmospheric Sciences | Climate


Ocean heat uptake and radiative forcing are important for understanding transient climate change. Differences in efficacy of ocean heat uptake (suppression of surface warming per unit energy flux into the deep oceans relative to CO2 forcing) account for a substantial fraction of the spread in transient warming between models. Rose et al. (2014) studied the dependence of efficacy on the spatial pattern of ocean heat uptake in an ensemble of aquaplanet simulations with prescribed ocean heat uptake, and found large differences in model responses to high versus low latitude uptake. This study accurately quantifies these model responses through the use of radiative ker- nels, the approximate partial radiative perturbation (APRP) method and a detailed surface energy budget analysis. We find large and robust differences in both clear-sky longwave feedbacks and shortwave cloud feedbacks, with high latitude uptake exciting substantially more positive feedback (higher efficacy) than low latitude uptake. These robust clear-sky longwave feedbacks are particularly associated with lapse rate feed- backs, suggesting a strong dependence of vertical temperature structure on the ocean heat uptake pattern. Robustness across several independent GCMs in subtropical low cloud feedback (positive under high latitude uptake, strongly negative under tropical uptake) is particularly significant. Therefore, in diagnosing large-scale circulation, boundary layer moisture and lower-tropospheric inversion strength, we find a strong relationship between tropospheric temperature stratification and low cloud changes in response to different ocean heat uptake patterns. Our results provide important implications for understanding how inter-model differences in heat uptake patterns may be driving differences in global cloud feedback under global warming.