The Role of Resolved and Unresolved Wave Forcing in MERRA analysis

PULIDO M.; SCHEFFLER G

Berna

Workshop; Gravity Wave Workshop at International Space Science Insitute; 2014

International Space Science Insitute

An intercomparison of the unresolved gravity wave drag given by MERRA analysis and the resolved Elliasen-Palm flux divergence is given for a 20 year period. Evidence of interactions between the resolved and unresolved waves is found. The missing gravity wave drag is estimated using the ASDE system and compared with the  unresolved gravity wave drag given by MERRA gravity wave parameterization. The shape of the forcing appears to be incorrect in GWDparameterization of GEOS5. In principle, this must be related to themomentum deposition of the waves. Even if we launch the rightmomentum flux, the parameterization may give a wrong drag profile. The forcing of the parameterization in the stratosphere has the wrongsign, it should be accelerating the jet. Perhaps the spectral resolution ofthe parameterization is not enough (not clear the parameterizationdetails). There are important resolved and unresolved forcing trends at 0.1hPa,these are present in both MERRA and ASDE. The resolved zonal forcingis decreasing.