Four Theories of the Madden‐Julian Oscillation
Abstract
Studies of the Madden‐Julian Oscillation (MJO) have progressed considerably during the past decades in observations, numerical modeling, and theoretical understanding. Many theoretical attempts have been made to identify the most essential processes responsible for the existence of the MJO. Criteria are proposed to separate a hypothesis from a theory (based on the first principles with quantitative and testable assumptions, able to predict quantitatively the fundamental scales and eastward propagation of the MJO). Four MJO theories are selected to be summarized and compared in this article: the skeleton theory, moisture‐mode theory, gravity‐wave theory, and trio‐interaction theory of the MJO. These four MJO theories are distinct from each other in their key assumptions, parameterized processes, and, particularly, selection mechanisms for the zonal spatial scale, time scale, and eastward propagation of the MJO. The comparison of the four theories and more recent development in MJO dynamical approaches lead to a realization that theoretical thinking of the MJO is diverse and understanding of MJO dynamics needs to be further advanced.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 21, 2020
- Source ID
- 10.1029/2019rg000685
Entities
People
- Benjamin Wang
- Boualem Khouider
- Chidong Zhang
- Da Yang
- Á. F. Adames
Organizations
- Lawrence Berkeley National Laboratory
- National Oceanic and Atmospheric Administration
- National Science Foundation
- Office of Naval Research
- Pacific Marine Environmental Laboratory
- United States Department of Energy
- University of California
- University of Hawaiʻi System
- University of Michigan
- University of Victoria