Identification

Title

Future changes in the Brewer-Dobson circulation under different greenhouse gas concentrations in WACCM4

Abstract

The climatology and future changes of the Brewer–Dobson circulation (BDC) in three climate change scenarios are studied using the latest version of the Whole Atmosphere Community Climate Model (WACCM4), which is fully coupled to an ocean model. The results show an acceleration in both the shallow and deep branches of circulation in response to increasing greenhouse gases (GHGs) together with an upward displacement of the tropical upwelling in the deep branch near the stratopause. The downward control principle reveals that different waves are involved in forcing the acceleration of the upper and lower branches. Climatological-mean tropical upwelling in both the lower and upper stratosphere is dominated by explicitly resolved, planetary-scale waves. Trends in the tropical upwelling in the lower stratosphere are mainly attributed to explicitly resolved, planetary-scale waves. However, in the upper stratosphere, despite the fact that resolved waves control the forcing of the climatological upwelling, their contribution to the long-term trend diminishes with increasing GHGs, while the role of gravity waves associated with fronts increases and becomes dominant in the model scenario with the largest GHG increases. The intensification and upward displacement of the subtropical tropospheric jets due to climate change leads to filtering of the westerly part of the frontal gravity wave spectrum, leaving the easterly components to reach the upper stratosphere and force the changes in the circulation there.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7x63nxp

codeSpace

Dataset language

eng

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Classification of spatial data and services

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geoscientificInformation

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title

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reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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publication

effective date

2014-08-01T00:00:00Z

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Copyright 2014 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work.

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None

Responsible organisations

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contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

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