Project Details
Projekt
Gravity wave Ray tracing Parameterization and its Effects in Solar cycle modeling (GRAPES)
Applicant
Dr. Peter Preuße
Subject Area
Atmospheric Science
Term
from 2009 to 2013
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 128797829
Long term runs of general circulation modeling rely on column-based gravity wave parameterizations, i.e. gravity waves are assumed to propagate only vertically. However, using global ray tracing experiments we showed that there are substantial differences in the zonal mean accelerations of the background wind due to oblique propagation of gravity waves. In particular, the meridional acceleration is primarily caused by the spatial separation of waves part of them propagating northward and part southward (which would not happen in a column-based parameterization) and waves driving the mid-latitude mesosphere origin to a larger fraction from lower latitudes. These results are based on offline studies using a prescribed background atmosphere and a launch distribution tuned by satellite observations. We propose now to investigate these effects in a coupled GCM study. We will develop a ray tracing gravity wave parameterization based on the GROGRAT ray tracer. The launch distribution of the new scheme will be guided by satellite, ground-based and in-situ observations. Tuning in the GCM will nevertheless be necessary. The parameterization will be integrated in the ROSE model and simulations for different solar cycle conditions will be performed. Runs with purely vertical and oblique wave propagation will be compared in order to quantify the effects of oblique wave propagation on the atmospheric response to different solar activity.
DFG Programme
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