Status: this discussion paper is a preprint. It has been under review for the journal Natural Hazards and Earth System Sciences (NHESS). The manuscript was not accepted for further review after discussion.
A numerical study of the early stages of a tropical cyclogenesis in relation to the MJO
J. Guerbette,M. Plu,C. Barthe,and J.-F. Mahfouf
Abstract. The role of an active phase of the Madden–Julian Oscillation (MJO) on the evolution of a mesoscale convective systems (MCS) leading to a tropical depression is investigated in the South-West Indian Ocean during the Dynamics of the Madden–Julian Oscillation (DYNAMO) field experiment, with a numerical limited-area atmospheric model. A mesoscale vortex is followed in the low-troposphere from the initiation of the active MJO phase. It is shown that the interaction of the vortex with the Equatorial jet associated with the MJO plays an important role on the vortex development. As the vortex encounters the southern part of the low-level jet, it undergoes intensification that is explained by the barotropic conversion of kinetic energy from the low-level jet to the vortex.
Received: 01 Jul 2015 – Discussion started: 19 Aug 2015
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Active phases of the Madden-Julian Oscillation (MJO) are known to favour the formation of tropical cyclones in the South-West Indian Ocean. A meso-scale numerical simulation of a tropical cyclogenesis during such an event is investigated. A large-scale Equatorial jet that is associated with the active phase of the MJO is shown to play a major role on the early stage of the cyclogenesis, through a transfer of kinetic energy from the jet to the cyclone.
Active phases of the Madden-Julian Oscillation (MJO) are known to favour the formation of...
- Printer-friendly version
- Supplement