AOSC Departmental Seminar
September 17, 2015

The influence of cloud representation on climate change projections of summer rainfall

Cristiana Stan
George Mason University

Numerical models are the primary tools that climate scientists rely upon for predicting and understanding the evolution of the climate system under different scenarios and from a variety of disciplinary perspectives. The complexity of the climate system calls for climate models that incorporate a myriad of processes that act and interact on multiple scales in space and time. Among these processes, those that determine the formation and evolution of clouds play a fundamental role. Efforts to improve the representation of clouds in climate models have resulted in fundamental improvements of understanding and prediction. 

In this talk I will focus on our efforts to creatively exploit the unique properties of a multi-scale modeling framework that allows for the representation of cloud processes on their native scales within a global model. I will describe our work to model and understand the response of the climate system to future climate change scenarios. Special attention will be given to the role of cloud representation in the regional response of the hydrological cycle over the southeast U.S. to a future climate change scenario. Projections of the hydrological cycle over the southeastern U.S. are compared between a model with conventional representation of cloud processes and its super-parameterized version. The different representation of cloud processes in the two versions of the model yields different responses of precipitation to the climate change scenarios.