A new paper (With Dylan White) on easterly waves was submitted to WCD. Comments and reviews are welcome and can be included in the open discussions linked below:
| Plain language Summary |
| African easterly waves are weather disturbances of the North African monsoon. Their formation has been traditionally linked to energy exchanges with the African easterly jet, a narrow ribbon of fast winds in the lower-to-middle troposphere. A few recent studies have suggested that this jet can be stabilized by damping and it is too short to sustain the amplification of easterly waves. We use a simple general circulation model to capture some basic properties of these waves. We show that easterly wavepackets remain nearly stationary, thereby increasing their residence time within the jet. Since the wavepackets are not swept out of the jet, this provides the opportunity for them to amplify via feedback from additional sources of energy associated with rain-producing cloud systems and Saharan mineral dust. Our results show the importance of wavepacket behaviour in understanding how African easterly waves are maintained in the real atmosphere. |