PAOC Colloquium: Zhiming Kuang (Harvard)

Tilte: Applications of linear response functions in moist and jet dynamics

Abstract: For a number of problems in climate dynamics, it is useful to describe the system with a set of macroscopic state variables and consider the statistics of the other variables, which may involve highly nonlinear processes, to be smooth functions of this set of macroscopic variables. The utility of a linear approximation to these functions, namely the linear response functions, is illustrated with two examples in atmospheric dynamics. The first example is the stability of a moist convecting atmosphere, where the linear response functions are used to shed light on the dynamics of convectively coupled tropical waves and convective self-aggregation. The second example is the dynamics of the annular mode, where the linear response functions are used to quantify the strength of the eddy-mean-flow feedback.

About the Speaker: The main goal of my current research is to better understand and simulate how tropical convection interacts with the large-scale flow. This interaction is key to the tropical circulation, particularly the rainfall distribution and its variability. These issues are important to society. Variations in the Asian monsoon rain, for example, can bring droughts or floods and affect the lives of billions of people. Despite its well appreciated importance, our understanding of how tropical convection interacts with the large-scale flow remains poor, so does our ability to simulate this interaction. In our research, we use novel high resolution numerical model experiments, together with observational data analysis, to guide development of theoretical models. Besides the meteorological implications of tropical convection, we are also interested in its role in global chemistry.

Speaker's Website: http://www.people.fas.harvard.edu/~kuang/

About this Series: The PAOC Colloquium is a weekly interdisciplinary seminar series that brings together the whole PAOC community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, but also talks about e.g. societal impacts of climatic processes. The seminars generally take place on Monday from 12-1pm. Lunch is provided to encourage students and post-docs to meet with the speaker. Besides the seminar and lunch, individual meetings with professors, post-docs, and students are arranged.