Geoscience Reference
In-Depth Information
The framework has also been accepted in the oceanographic community (
Moore
et al. 2011
). More recent studies (
Liu and Kalnay 2008
) have investigated obtaining
impact values with an ensemble of models (to replace the need for the adjoint
operators) and obtaining sensitivity to other parameters of the DA system for
performance tuning purposes (
Daescu and Todling 2010
).
6.2
COAMPS and NAVDAS
Results presented in this chapter were obtained from an adjoint observation impact
system developed for NRL's limited area model. The system includes the Coupled
Ocean Atmosphere Mesoscale Prediction System (COAMPS
R
)
1
atmospheric
model and its accompanying DA component, NAVDAS. Brief descriptions of these
components as well as their accompanying adjoint operators are provided below.
6.2.1
COAMPS
The COAMPS atmospheric model is a limited area, relocatable, grid point model.
The model is non-hyrdostatic and contains predictive equations for zonal wind
u
,
meridional wind
v
, vertical velocity
w
, the dimensionless Exner pressure function
,
the potential temperature
.Thebulk
cloud microphysics scheme calculates the source and sink terms in the prognostic
equations for cloud droplets
, water vapor
q
v
, and turbulent kinetic energy
e
q
g
.
The other parameterizations in the model for subgrid-scale processes are turbulent
mixing, surface fluxes, cumulus convection, and radiation. The vertical coordinate
of the model is a terrain following
q
c
, cloud ice
q
i
, rain water
q
r
,snow
q
s
, and graupel
z
defined as
z
t
.
z
z
s
/
z
t
z
s
;
z
D
(6.22)
where the constant
z
t
is the depth of the model domain and
z
s
is the terrain height.
Lateral boundary conditions are provided from NOGAPS. A detailed description of
COAMPS is given in
Hodur
(
1997
).
6.2.2
NAVDAS
NAVDAS is currently used by the U.S. Navy for its operational regional DA
system at the Fleet Numerical Meteorology and Oceanography Center (FNMOC).
is a registered trademark of NRL.
R
1
COAMPS
Search WWH ::
Custom Search