Naval Research Laboratory (NRL)

Domains

Horizontal

• 81 km (115 by 103) / 27 km (91 by 91) / 9 km (169 by 169)
• NRL1: 9 km grid
• 81 km (115 by 103) / 27 km (91 by 91) / 9 km (169 by 169) / 3 km (235 by 235)
• NRL2: 3 km grid
• NRL5: 9 km grid

Vertical

40 levels with model top at 32 km

Atmosphere

Model: Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS)

Overview

The Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) is the Navy high-resolution regional operational prediction system. COAMPS is developed by NRL and consists of data quality control, data assimilation, initialization, a non-hydrostatic atmospheric model and a hydrostatic ocean model (Hodur 1997). The Arakawa C grid is used for both the atmospheric and ocean models. The atmospheric model utilizes the sigma-z vertical coordinate and the ocean model uses the hybrid Sigma/z. A version of COAMPS has recently been developed which is dedicated to the prediction of tropical cyclones (COAMPS-TC). For the HFIP tests, the model is run on a Mercator projection with one fixed coarse mesh domain and either two or three moving, two-way interactive nested domains.

Initialization

The Navy Operational Global Atmospheric Prediction System (NOGAPS) fields are used to provide the first guess field for the cold start and the COAMPS output from previous 12-hour simulations is used as the first guess for the warm start. A relocation method is used to place the vortex at the officially issued position in the first guess field for each simulation. Synthetic observations are then used to enhance the initial vortex structure. The NRL Atmospheric Variational Data Assimilation System (NAVDAS) is used to assimilate the observational data.

Lateral Boundary Conditions

COAMPS-TC uses the NOGAPS forecast output on 1-deg grid at a 6-hr interval.

Physics

Cumulus	Kain Fritsch Scheme and Shallow Cumulus parameterization
Microphysics	Rutledge and Hobbs (1983)
PBL	Mellor-Yamada, Dissipative heating (Jin et al 2007).
Surface Layer	Louis et al (1979), Wang et al (2002), Sea Spray (Fairall et al. 1993 with recent updates), Level-off drag coefficient for high winds (Donelan et al. 2004)
Land Surface	Noah Land Surface Model (not used here)
Radiation	Harshvardardet et al (1987)

Ocean

The NRL Coupled Ocean Data Assimilation (NCODA) is for ocean data assimilation (including altimeter, SSMI, MCSST, profile and ship data).

Archival

SLP, temperature, dewpoint, geopotential height, absolute vorticity, wind u and v at 850 hPa, 700 hPa and 500 hPa are archived every 30 minutes intervals.

References

Donelan, M. A., B. K. Haus, N. Reul, W. J. Plant, M. Stiassnie, and H. C. Graber, 2004: On the limiting aerodynamic roughness of the ocean in very strong winds. Geophys. Res. Lett., 31, L18306, doi:10.1029/2004GL019460.

Fairall, C., F. Bradley, D. P. Rogers, J. B. Edson, and G. S. Young, 1996: Bulk parameterization of air–sea fluxes for Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment. J. Geophys. Res., 101, 3747–3764.

Harshvardhan, R. Davies, D. Randall, and T. Corsetti, 1987: A fast radiation parameterization for atmospheric circultation models. J. Geophys. Res., 92, 1009-1015.

Hodur, R.M., 1997: The Naval Research Laboratory's Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS). Mon. Wea. Rev., 135, 1414-1430.

Jin, Y., W. T. Thompson, S. Wang, and C.-S. Liou, 2007: A numerical study of the effect of dissipative heating on tropical cyclone intensity.  Wea. Forecasting. 22, 950-966.

Louis, J.-F., 1979: A parametric model of vertical eddy fluxes in the atmosphere.  Bound. Layer. Meteor., 17, 187-202.

Rutledge , S. A., and P. V. Hobbs, 1983: The mesoscale and microscale structure of organization of clouds and precipitation in midlatitude cyclones. VIII: A model for the "seeder-feeder" process in warm-frontal rainbands. J. Atmos. Sci., 40, 1185-1206.

Wang, S., Q. Wang, and J. Doyle, 2002: Some improvement of Louis surface flux parameterization. Preprints, 15th Symp. On Boundary Layers and Turbulence, Wageningen, Netherlands, Amer. Meteor. Soc., 547–550.