Influence of solar variability on gravity wave structure and dissipation in the thermosphere from tropospheric convection

[ 1] We investigate the role convection plays in the thermosphere using deep convection and ray trace models with a general dissipative anelastic GW dispersion relation. In the absence of dissipation, a GW's vertical wavelength lambda(z) increases by root(T) over bar/(T) over bar (0), or greater if its intrinsic frequency omega(Ir) is close to the smaller thermospheric buoyancy frequency N = root(T) over bar (0)/(T) over bar N-0. Here, (T) over bar and (T) over bar (0) are the asymptotic temperatures in the thermosphere and lower atmosphere, respectively, and N0 is the buoyancy frequency in the lower atmosphere. In the presence of dissipation, lambda(z) also increases in the thermosphere by a factor of similar to 2 - 3 when omega(Ir) > 0.2N(0) and lambda(z) > 25 km during active solar conditions. GW dissipation altitudes and maximum vertical wavelengths, which increase as (T) over bar increases, are displayed for small-scale and midscale GWs. GWs excited from deep convection encounter horizontal shears, which impose anisotropy on the spectrum. Along with dissipative filtering, momentum flux divergence and body forces result. The thermospheric body forces resulting from our convection model achieve maximum accelerations at z similar or equal to 180 - 200 km, extend down to z similar or equal to 130 km, last for the duration of deep convection, are similar to 600 km x 600 km x 40 - 80 km in the x, y, and z directions, and are very strong with accelerations similar or equal to 0.5 - 0.75 m s(-2) and similar or equal to 0.25 - 0.4 m s(-2) during extreme solar minimum ((T) over bar = 600 K) and active solar conditions ((T) over bar = 2000 K), respectively. During extreme solar minimum, there is negligible forcing above z similar or equal to 230 km, whereas the forcing extends up to z similar or equal to 360 km during active solar conditions. These horizontal, thermospheric body forces may be a new source of large-scale, long-period secondary GWs and induced TIDs ( traveling ionospheric disturbances) at high altitudes in the thermposphere.