Project Details
Projekt
Interaction of gravity waves and Madden-Julian Oscillation
Applicant
Dr. Silvio Kalisch
Subject Area
Atmospheric Science
Term
from 2015 to 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 291174817
The Madden-Julian Oscillation (MJO) (Madden & Julian 1971, 1972) is the prominent part of the intra-seasonal variability of the tropical atmosphere. It is apparent as an eastward propagating pattern of deep convection and precipitation. Due to dynamic coupling the MJO influences the local weather of the Indian Ocean and the western Pacific Islands. Further, vertical coupling with dynamic patterns like the Quasi-biennial Oscillation (QBO) in the stratosphere due to forcing and dissipation of gravity waves plays an important role in the understanding of tropical winds.Although the data basis on the MJO and tropical patterns of deep convection and precipitation improved over the course of the last decades, the modeling of those patterns, and the MJO in particular, still remain as a major problem of atmospheric models. This project addresses important questions related to this deficiency in modeling of tropical convection using methods developed during my PhD thesis project on convective gravity wave modeling. The project is subdivided into two parts to answer the following two major scientific questions:How does the MJO influence propagation and dissipation of convectively generated gravity waves? How do these gravity waves feed back on the MJO and the convection? The tools I will apply for this study are a coupled model of convective gravity wave excitation and propagation developed during my PhD thesis. This will be complemented by mesoscale numerical modeling employing the WRF (Weather Research and Forecasting) model. Particular emphasis will be given on the spectrum of gravity wave momentum flux and its modulation by the MJO. It will be investigated whether such modulations are observable by satellite measurements and may shine light on the respective gravity wave momentum flux emitted by shallow and deep convection. For the feedback mechanisms, the focus will be on gravity wave drag deposited in the secondary circulation of the MJO.
DFG Programme
Research Fellowships
International Connection
South Korea
