Effects of Dynamical and Diabatic Processes on Stationary and Transient Kelvin Waves

Abstract Atmospheric Kelvin waves (KWs) are influenced by both tropical convective heating and dry dynamical processes, but the relative contributions of these mechanisms remain uncertain. This study examines the effects of various processes on stationary and transient KWs in ERA5 data using a global, multivariate framework that identifies KWs based on their spatial structure. The nonlinear dynamical momentum and temperature tendencies, that is, those arising from advection, are quantified together with tendencies due to physical parametrizations derived from short‐term ERA5 forecasts. A large part of the KW signal is stationary; this wave pattern is associated with non‐radiative diabatic heating and warm vertical advection over the Maritime Continent. These processes act as KW energy sinks because the temperature tendencies are phase‐shifted relative to the stationary KW pattern. For both stationary and transient KWs, the largest energy source is the meridional advection of zonal momentum, which induces easterly momentum tendencies in the upper troposphere, thereby strengthening the KW easterlies in the eastern hemisphere. The main KW energy sink originates from momentum dissipation. The day‐to‐day variability of KW energy tendencies is dominated by non‐radiative diabatic heating. The developed global numerical framework paves the way for future investigations of wave interactions in the tropics and extratropics.