Evidence of the solar cycle in the tropical troposphere

An analysis of low-frequency variability in the National Centers for Environmental Prediction record reveals a decadal oscillation inside the tropical troposphere, one that operates coherently and in phase with the 11-year variation of solar irradiance. The oscillation represents a robust signature of solar variability, achieving higher levels of significance than have previously been required. Characterized by symmetric latitudinal structure, the oscillation involves anomalous temperature that maximizes over the equator and anomalous zonal wind that maximizes in the tropics of each hemisphere. Its deep vertical structure, in concert with the horizontal distribution of anomalous temperature, suggests the involvement of organized convection, as well as a direct radiative influence at upper levels, inside the tropical tropopause layer.