Tropical and Monsoon Dynamics Revealed via Field Campaigns: The Visionary Leadership of Peter Webster

Over the past four decades, field campaigns in the tropics and monsoon regions of the world have led to a succession of significant advances in the physics and dynamics of their associated circulation systems. This symposium’s honoree, Peter Webster, has been instrumental in the development of fundamental theories of tropical and monsoon circulations and the success of key field campaigns designed to test those theories.

Peter Webster’s first foray into field efforts involved Winter and Summer MONEX (Monsoon Experiments in 1978 and 1979, respectively), dual campaigns under the Global Atmospheric Research Program (GARP) aimed at better understanding the role of the Asian monsoon in the global circulation. Recognizing from these experiments and the earlier 1974 GATE (GARP Atlantic Tropical Experiment) that deep convection was a critical but not well-understood component of monsoon and tropical dynamics, Peter organized the 1987 Equatorial Mesoscale Experiment (EMEX) over northern Australia to document air motions in tropical cloud systems using airborne Doppler radar. Then, realizing that prediction of the tropical climate system will require an improved understanding of the coupling between the ocean and atmosphere, Peter conceived and organized, jointly with oceanographer Roger Lukas, the 1992-93 Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). COARE observations led to fundamental advances in understanding air-sea coupling and exchanges, maintenance of the warm pool, structure and organization of convection, the diurnal cycle in the sea and atmosphere, structure and dynamics of the MJO, and convective momentum transport. Focusing more specifically on the role of convection and air-sea exchanges in the intraseasonal variability of the Asian summer monsoon, Peter next brought together research teams and resources to conduct the 1999 Joint Air-Sea Monsoon Interaction Experiment (JASMINE) over the eastern Indian Ocean.

Peter Webster’s visionary leadership in all of these campaigns has contributed to fundamental advances in understanding and improved prediction of the world’s tropical and monsoon circulations.