Wednesday, 26 July 2017: 2:30 PM
Coral Reef Harbor (Crowne Plaza San Diego)
The spectral parameterizations of non-orographic gravity wave drag (GWD) induced by
convection and front are implemented in a global atmospheric forecast model with low top near
0.3 hPa. The convective GWD parameterization replaces the existing one that considers only
stationary GW induced by convection, and the effects of frontal GWD are included additionally.
When the new convective and frontal GWD parameterizations are used, the Rayleigh friction,
which has been applied above 2 hPa to mimic the effects of missing GWD in the model with
the stationary convective GWD only, is removed. Including the new GWD parameterizations
improves the seasonal climatology of zonal-mean zonal wind in both the stratosphere and
troposphere. The improvements are induced not only by the GWD change but also by the
changes in other forcing terms such as resolved wave forcing that interact with the GWD. The
experiments for short- and medium-range forecasts are also conducted and improved skill
scores on wind speed are achieved with the new GWD, especially in the winter upper
stratosphere and tropical upper troposphere.
convection and front are implemented in a global atmospheric forecast model with low top near
0.3 hPa. The convective GWD parameterization replaces the existing one that considers only
stationary GW induced by convection, and the effects of frontal GWD are included additionally.
When the new convective and frontal GWD parameterizations are used, the Rayleigh friction,
which has been applied above 2 hPa to mimic the effects of missing GWD in the model with
the stationary convective GWD only, is removed. Including the new GWD parameterizations
improves the seasonal climatology of zonal-mean zonal wind in both the stratosphere and
troposphere. The improvements are induced not only by the GWD change but also by the
changes in other forcing terms such as resolved wave forcing that interact with the GWD. The
experiments for short- and medium-range forecasts are also conducted and improved skill
scores on wind speed are achieved with the new GWD, especially in the winter upper
stratosphere and tropical upper troposphere.
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