The Center for Atmospheric Sciences | » Atmospheric Coupling via Gravity Wave Propagation from the Troposphere to the Mesopause Region Using NASA AIM and Other Satellites

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  • Atmospheric Coupling via Gravity Wave Propagation from the Troposphere to the Mesopause Region Using NASA AIM and Other Satellites

    Atmospheric Gravity or buoyancy waves (GWs) are fluid waves generated when two bodies of different densities come into contact with one another. Gravity becomes the restoring force, creating a wave pattern as the fluids move back and forth. GW amplitudes increase upwards with altitude due to the decrease in atmospheric density and conservation of energy. These waves are frequently observed near large mountain ranges, cold fronts, or convective events and vary in wavelength and period. The project mission is to estimate the impact of GWs on the middle atmosphere on a global scale. The (CIPS) instrument on the AIM satellite, AIRS on the Aqua satellite and VIIRS on the Suomi NPP and JPSS-1 satellites, provide a comprehensive new high resolution data set to study GW propagation through the lower and middle atmosphere. Medium and large GWs (with wavelengths of 100-1200 kilometers and periods of 10-80 min) are a critical driving force for upper atmospheric circulations. As GWs propagate upwards and increase in amplitude, they eventually become more unstable, dissipating and releasing momentum and energy. This momentum drives a zonal mean eastward flow in the mesosphere creating the equatorward and upward residual circulations that cause the cooling of the mesosphere and the cold summer high latitude mesopause [Vadas, 2007]. Despite receiving much more sunlight than the high latitude winter mesopause, the summer high latitude mesopause remains roughly 100 K colder [Holton, 1982]. GW activity is also responsible for most of the wave induced chemical and mass transport between the lower thermosphere and upper mesosphere [Vincent and Fritts, 1987]. Past studies using ground based airglow imagers and satellite measurements have explored GWs in both the stratosphere and mesosphere [Dewan et al., 1998; Yue et al., 2013; Miller et al., 2015] and more recently, have analyzed the connection between middle atmospheric waves and ionospheric disturbances [Nishioka et al., 2013; Azeem et al., 2015]. Gravity wave studies are also crucial for space weather which impacts the orbits of spacecraft and radio communications. Weak stratospheric background winds are necessary for these waves to reach the mesosphere, as stronger winds can block wave propagation through the stratosphere [Yue et al., 2009; Vadas et al., 2009]. As GWs propagate through different layers of the atmosphere, energy and momentum will be deposited establishing a connection between the lower, middle, and upper atmosphere. A description of the data to be presented in this study, the research plan, and a summary of the project follow.