Preliminary evidence of Madden-Julian oscillation effects on ultra-fast tropospheric waves in the thermosphere

Mounting evidence has demonstrated that terrestrial weather significantly influences space weather. Much of this coupling is carried by waves that are excited by deep convection in the tropical troposphere and that propagate vertically into the thermosphere. Prominent among these wave are "ultra-fast tropical waves" (UFTW) with periods between about 0.5 days to 3.5 days. By analogy with the need to understand conditions on the Sun that translate to solar-driven space weather, it is also important to understand the meteorological conditions that give rise to waves that reach the thermosphere and the propagation conditions that make this possible. By taking advantage of state-of-the-art numerical simulations (i.e., SD/WACCM-X) and satellite observations (i.e., CHAMP, GOCE, and TIMED/SABER), we present preliminary evidence of the effect of the Madden-Julian Oscillation (MJO) on two of the largest thermospheric UFTW: the diurnal eastward propagating tide with zonal wavenumber 3 (DE3) and the quasi-3-day ultra-fast Kelvin wave (UFKW). This study suggests that strong coupling between the troposphere and the thermosphere is occurring on intra-seasonal timescales, raising important questions including implications for the whole atmosphere system.