DATE/TIME: Friday, March 26, 2021, 2:30 pm PLACE:
University of Maryland
To couple or not to couple? New insights into the cloud-topped boundary layer
Low-lying clouds significantly regulate the Earth’s radiative budgets. How low clouds respond to a warming planet remains highly uncertain, limiting the accuracy of climate projections. The low clouds typically sit on top of the planetary boundary layer, the lowest part of the atmosphere that is directly influenced by the surface. This forms the cloud-topped boundary layer (CTBL). I ask a fundamental question about the CTBL: how tightly are the clouds coupled with the surface? This question is important because the cloud-surface decoupling can profoundly influence the ability of clouds to reflect sunlight, thus impinging on the atmospheric temperature and its future change. To that end, I synthesize a pencil-and-paper theory, field experiment data, and a high-resolution computer model to elucidate the fundamental physics of the coupling and decoupling of the CTBL. I show how this improved understanding may open a new door for unlocking a series of unresolved problems concerning climate change.