Acoustic waves in the upper mesosphere and lower thermosphere generated by deep tropical convection

A time‐dependent, nonlinear, fully compressible, axisymmetric, f‐plane, numerical model is used to simulate the propagation of acoustic waves in the mesosphere and thermosphere by intense deep convection in the troposphere. The simulations show that major convective storms in the tropics launch acoustic waves into the mesosphere‐thermosphere directly above the storm centers. The principal feature of the overhead acoustic wave field in the period interval of ∼3 to 5 min is a trapped oscillation below about 80 km altitude with a period of ∼5 min and a nearly vertically propagating wave with about a 3‐min period above this height. Acoustic oscillations in the troposphere‐mesosphere duct have a standing wave character directly over the storm; the oscillations that propagate off vertical mainly reflect off the top and bottom of the duct resulting in a horizontally propagating acoustic field within the duct. The acoustic oscillations that are mainly confined to the troposphere‐mesosphere duct persist for about an hour after the storm has ended. The vertically propagating thermospheric acoustic oscillations are waves propagating upward from the thunderstorm source through the stratosphere‐mesosphere. These predominantly 3‐min waves are strongly driven for ∼30 min after the storm event and weaken with time thereafter. The vertically propagating thermospheric acoustic waves may be the source of the F‐region 3‐min oscillations. Intense acoustic disturbances directly above thunderstorms may be responsible for localized heating of the thermosphere.