Ridge formation in the lower stratosphere and its influence on ozone transport: A general circulation model study during late January 1992

Abstract This work examines the life cycle of sudden stratospheric warmings (SSWs) from composites of a large number of events. The events are sampled from idealized general circulation model (GCM) integrations and form a database of several hundred major, displacement, splitting, and weak vortex events. It is shown that except for a few details, the generic zonal-mean evolution does not depend on the definition used to detect SSWs. In all cases, the composites show the stratosphere in a positive annular mode phase prior to the events and a barotropic response in the stratosphere at onset. There is a clear positive peak in upward Eliassen–Palm (EP) flux prior to the onset date in the stratosphere and a much weaker peak in the troposphere, making the evolution more consistent with the picture of the stratosphere acting as a variable filter of tropospheric EP flux, rather than SSWs being forced by a strong “burst” in the troposphere. When comparing composites of SSWs from the database with apparent influence at the surface (downward “propagating”) to those without such influence, the only significant differences are a somewhat more barotropic response at the onset date and longer persistence in the lower stratosphere after the onset for propagating SSWs. There is no significant difference in EP flux between propagating and nonpropagating events, and none of the definitions considered here shows a particular skill in selecting propagating events.

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A general circulation model study of the dynamics of the upper ocean circulation of the South China Sea

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jc001084 ◽

2002 ◽

Vol 107 (C7) ◽

Cited By ~ 49

Author(s):

Haijun Yang

Keyword(s):

South China Sea ◽

General Circulation Model ◽

Ocean Circulation ◽

South China ◽

General Circulation ◽

Circulation Model ◽

The South China Sea ◽

Upper Ocean ◽

China Sea ◽

Model Study

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Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radon-222 and lead-210 to input meteorological data

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-5325-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 5325-5372 ◽

Cited By ~ 4

Author(s):

D. B. Considine ◽

D. J. Bergmann ◽

H. Liu

Keyword(s):

General Circulation Model ◽

General Circulation ◽

Lower Stratosphere ◽

Transport Model ◽

Meteorological Data ◽

Circulation Model ◽

Convective Transport ◽

Global Modeling ◽

Upper Troposphere ◽

Lead 210

Abstract. We have used the Global Modeling Initiative chemistry and transport model to simulate the radionuclides radon-222 and lead-210 using three different sets of input meteorological information: 1. Output from the Goddard Space Flight Center Global Modeling and Assimilation Office GEOS-STRAT assimilation; 2. Output from the Goddard Institute for Space Studies GISS II′ general circulation model; and 3. Output from the National Center for Atmospheric Research MACCM3 general circulation model. We intercompare these simulations with observations to determine the variability resulting from the different meteorological data used to drive the model, and to assess the agreement of the simulations with observations at the surface and in the upper troposphere/lower stratosphere region. The observational datasets we use are primarily climatologies developed from multiple years of observations. In the upper troposphere/lower stratosphere region, climatological distributions of lead-210 were constructed from ~25 years of aircraft and balloon observations compiled into the US Environmental Measurements Laboratory RANDAB database. Taken as a whole, no simulation stands out as superior to the others. However, the simulation driven by the NCAR MACCM3 meteorological data compares better with lead-210 observations in the upper troposphere/lower stratosphere region. Comparisons of simulations made with and without convection show that the role played by convective transport and scavenging in the three simulations differs substantially. These differences may have implications for evaluation of the importance of very short-lived halogen-containing species on stratospheric halogen budgets.

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