Atmosphere Ocean Science Colloquium

The Pattern Effect: Implications of sea-surface temperatures for climate sensitivity and climate dynamics

Speaker: Yue Dong, Columbia University

Location: Warren Weaver Hall 1302

Date: Wednesday, March 1, 2023, 3:30 p.m.

Synopsis:

Climate feedbacks depend on the spatial pattern of sea-surface temperatures (SSTs) and thus can change over time as SST patterns evolve – the so-called pattern effect. Accounting for the pattern effect reconciles a long-standing issue of incongruent estimates of equilibrium climate sensitivity between observed energy budget constraints and model projections. In this talk, I will focus on two questions: what causes the pattern effect and what sets the historical SST pattern? First, I will demonstrate the fundamental mechanism for the pattern effect revealed by an atmospheric Green’s Function study, highlighting the dominant control of the tropical western Pacific SSTs on global feedbacks. Second, I will show model biases in the historical SST pattern and the potential role of Antarctic ice-sheet meltwater in setting the tropical SST pattern through teleconnections. Results suggest that constraining climate sensitivity and future climate change requires a better understanding of energetic and dynamic interactions in the coupled climate system.