NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The Influence of Tropospheric Processes in Modeling the Middle Atmosphere with Gravity WavesOur Numerical Spectral Model (NSM) extends from the ground up into the thermosphere and has a vertical grid point resolution of about 0.5 km to resolve the interactions of gravity waves (GWs) described with Hines' Doppler Spread Parameterization (DSP). This model produces in the stratosphere and mesosphere the major features of QBO, SAO, tides, and planetary waves. The purpose of this paper is to discuss results from an initial study with our 3D model that shows how certain tropospheric processes can affect the dynamics of the middle atmosphere. Under the influence of tropospheric heating, and augmented by GW interactions, two distinct but related processes can be identified. (1) A meridional circulation develops in the stratosphere, with rising motions at low latitudes that are in magnitude comparable to the downward propagation of the QBO. As Dunkerton pointed out, a larger GW source is then required to reproduce the observed QBO, which tends to move us closer to the values recommended for the DSP. This has significant consequences for our model results that describe the upper mesosphere, considering the general importance of GWs for this region and in influencing planetary waves (e.g., 2-day wave) and tides in particular. (2) Tropospheric heating produces zonal jets near the tropopause that are related to latitudinal variations in pressure and reversing temperature variations (resembling the dynamical conditions near the mesopause), which in turn is conducive to generate baroclinic instability. Modeling results show that our ability to generate the QBO critically depends on the magnitude of the temperature reversal that is a measure of this instability. Planetary waves are generated in this process, which can apparently interfere with or augment the GW interactions. As originally demonstrated by Lindzen and Holton, the eastward propagating Kelvin waves and westward propagating Rossby gravity waves (generated by tropospheric convection) can in principle provide the acceleration to influence the QBO, and we were able to confirm this with our 3D model.
Document ID
20030108644
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Mayr, H. G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mengel, J. G.
(Science Systems and Applications, Inc. Greenbelt, MD, United States)
Drob, D. P.
(Naval Research Lab. Washington, DC, United States)
Porter, H. S.
(Furman Univ. Greenville, SC, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: American Geophysical Union Fall Meeting
Location: San Francisco, CA
Country: United States
Start Date: December 6, 2002
End Date: December 10, 2002
Sponsors: American Geophysical Union
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available