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The Dynamics of the Global Monsoon: Connecting Theory and Observations

Geen, Ruth and Bordoni, Simona and Battisti, David S. and Hui, Katrina L. (2020) The Dynamics of the Global Monsoon: Connecting Theory and Observations. . (Unpublished)

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Earth's monsoons are complex systems, governed by both large-scale constraints on the atmospheric general circulation and regional interactions with continents and orography, and coupled to the ocean. Monsoons have historically been considered as distinct regional systems, and the prevailing view has been, and remains, an intuitive picture of monsoons as a form of large-scale sea breeze, driven by land-sea contrast. However, climate dynamics is seldom intuitive. More recently, a perspective has emerged within the observational and Earth system modeling communities of a global monsoon that is the result of a seasonally migrating tropical convergence zone, intimately connected to the global tropical atmospheric overturning and localized by regional characteristics. Parallel with this, over the past decade, much theoretical progress has been made in understanding the fundamental dynamics of the seasonal Hadley cells and Intertropical Convergence Zones via the use of hierarchical modeling approaches, including highly idealized simulations such as aquaplanets. Here we review the theoretical progress made, and explore the extent to which these theoretical advances can help synthesize theory with observations and understand differing characteristics of regional monsoons. We show that this theoretical work provides strong support for the migrating convergence zone picture, allows constraints on the circulation to be identified via the momentum and energy budgets, and lays out a framework to assess variability and possible future changes to the monsoon. Limitations of current theories are discussed, including the need for a better understanding of the influence of zonal asymmetries and transients on the large-scale tropical circulation.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Geen, Ruth0000-0001-7480-2768
Bordoni, Simona0000-0003-4771-3350
Battisti, David S.0000-0003-4871-1293
Hui, Katrina L.0000-0003-0325-8800
Additional Information:© 2020 American Geophysical Union. Submitted: Mon, 30 Mar 2020. Published Online: Fri, 28 Feb 2020. RG was supported by the UK-China Research and Innovation Partnership Fund, through the Met Office Climate Science for Service Partnership (CSSP) China, as part of the Newton Fund. SB and KLH acknowledge support from the Caltech Terrestrial Hazard Observation and Reporting (THOR) center and the Caltech GPS Discovery Fund. DSB was funded by the Tamaki Foundation. The research materials supporting this publication can be accessed by contacting Ruth Geen (
Funding AgencyGrant Number
UK-China Research and Innovation Partnership FundUNSPECIFIED
Caltech Terrestrial Hazard Observation and Reporting (THOR) CenterUNSPECIFIED
Caltech Division of Geological and Planetary SciencesUNSPECIFIED
Tamaki FoundationUNSPECIFIED
Subject Keywords:Climatology (Global Change), Atmospheric Sciences, Atmospheric Sciences / Numerical Modelling, Atmospheric Sciences / Atmospheric Dynamics, Atmospheric Sciences / Precipitation Physics, Climatology (Global Change) / Regional Climatology, Atmospheric Sciences / Atmospheric Thermodynamics, Meteorology, Meteorology / Tropical Meteorology
Record Number:CaltechAUTHORS:20200625-120638230
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104057
Deposited By: Tony Diaz
Deposited On:25 Jun 2020 20:57
Last Modified:16 Nov 2021 18:28

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