Thermospheric Responses to Secondary Gravity Waves from Local Body Forces

* Calculate the gravity waves scales important in the thermosphere after dissipative filtering. Include realistic temperatures and winds.

* Use OH airglow observations of concentric rings of gravity waves from convective plumes to test and validate the convective and ray trace models using realistic winds.

* Extract the thermospheric neutral winds from PFISR (Poker Flat ISR) data of gravity waves. Allow for time variation via extraction along constant phase lines.

* Reconstruct the gravity wave field in the mesosphere and thermosphere from convective plumes

* Calculate the effect of gravity waves on ESF (equatorial spread F).

* Calculate the spectrum of excited secondary gravity waves from thermospheric body forces. These body forces are created by the dissipation of smaller-scale gravity waves from deep convection.

Activities to date towards achieving these goals:

* Collaborated with Jia Yue at Colorado State Univ. for the OH airglow imager project. Ran the convective plume and ray trace models, including a new upgrade which includes gravity wave phases. Found that the model results agree very well with the airglow data.

* Collaborated with scientists at INPE in brazil to determine how gravity waves may have caused ESF during the SpreadFEx campaign.

* Collaborated with Dr. Nicolls on the extraction of the neutral winds from PFISR electron density data of gravity waves. Found that we can determine the neutral winds, within 40 m/s (error) for z=180 to 250 km every 11 minutes (or 1/2 a wave period). We found evidence of thermospheric body forcing. We also found that the wave source was likely secondary gravity waves excited by breaking mountain waves.

* Collaborated with Dr. Liu of NCAR, who inputted a thermospheric body force into the TIME-GCM. Found that this body force excites large-scale, fast secondary gravity waves. The amplitudes of these waves agree well with CHAMP and DE2 satellite data. Also found that this body forces creates "mean" neutral thermospheric winds as large as 400 m/s (from a single convective plume) with horizontal and vertical shear.

Publications under this grant:

* Sharon L. Vadas and Han-Li Liu, 2009: ``The Generation of Large-Scale Gravity Waves and Neutral Winds in the Thermosphere From the Dissipation of Convectively-Generated Gravity Waves'', JGR, in press Pdf version of this paper

* Sharon L. Vadas and Mike Nicolls, 2009: "Temporal Evolution of Neutral, Thermospheric Winds and Plasma Response using PFISR Measurements of Gravity Waves" JASTP, 71, 740-770. Pdf version of this paper

* Sharon L. Vadas, Jia Yue, Joe She, Pete Stamus, and Alan Liu, 2009: "A model study of the effects of winds on concentric rings of gravity waves from a convective plume near Fort Collins on 11 May 2004", Jour. Geoph. Res, 114, D06103, doi:10.1029/2008JD010753. Pdf version of this paper

* Yue, J., S.L. Vadas, C.-Y. She, T. Nakamura, S. Reising, D. Krueger, H.-Li Liu, P. Stamus, D. Thorsen, W. Lyons, T. Li, 2009: "A study of OH imager observed concentric gravity waves near Fort Collins on 11 May 2004", Jour. Geoph. Res, 114, D06104, doi:10.1029/2008JD011244. Pdf version of this paper

* Fritts, D.C., S.L. Vadas, D.M. Riggin, M.A. Abdu, I.S. Batista, H. Takahashi, A. Medeiros, F. Kamalabadi, H.-L. Liu, B. J. Fejer,and M.J. Taylor, 2008: "Gravity wave and tidal influences on equatorial spread F based on observations during the spread F experiment (SpreadFEx)", Annals Geoph., 26, 3235-3252.

* Sharon L. Vadas and Dave C. Fritts, 2009: "Reconstruction of the gravity wave field excited by convective plumes via ray tracing in real space", Annals. Geophys., 27, 147-177. Pdf version of this paper

* Dave C. Fritts and Sharon L. Vadas, 2008: "Gravity wave penetration into the thermosphere: Sensitivity to solar cycle variations and mean winds", Annals. Geophys, 26, 3841-3861. pdf version of this paper

* Sharon L. Vadas and Mike Nicolls, 2008: "Using PFISR Measurements and Gravity Wave Dissipative Theory to Determine the Neutral, Background Thermospheric Winds" Geoph. Res. Letters, 35, {L02105, doi:10.1029/2007GL031522} Pdf version of this paper

* Earle, G.D., A. Mwene-Musumba, and S.L. Vadas, 2008: "Satellite-Based measurements of gravity wave-induced Mid-latitude plasma density perturbations" J. Geoph. Res, 113, A03303, doi:10.1029/2007JA012766. Pdf version of this paper

* Sharon L. Vadas, 2007: "Horizontal and vertical propagation, and dissipation of gravity waves in the thermosphere from lower atmospheric and thermospheric sources", J. Geoph. Res., {112}'{A06305, doi:10.1029/2006JA011845}. Pdf version of this paper

This research was supported in part by the National Science Foundation under grant ATM-0537311.