Recent Modifications of the Emanuel Convective Scheme in the Navy Operational Global Atmospheric Prediction System

Peng, Melinda S.; Ridout, James A.; Hogan, Timothy F.

doi:10.1175/1520-0493(2004)132<1254:rmotec>2.0.co;2

Cited by 73 publications

(85 citation statements)

References 36 publications

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“…The model is central in time with a semi-implicit treatment of gravity wave propagation, implicit zonal advection of moisture and vorticity, and Robert (Asselin) time filtering (Simmons et al, 1978;Simmons and Jarraud, 1983). The operational model includes physical parameterizations of vertical diffusive transport in the planetary boundary layer (Louis, 1979;Louis et al, 1982) coupled to a land surface model , orographic gravitywave and flow-blocking drag (Webster et al, 2003), shallow cumulus mixing (Tiedtke, 1984), deep cumulus convection (Emanuel and Zivkovic-Rothman, 1999;Peng et al, 2004), convective, stratiform and boundary layer clouds and precipitation (Slingo, 1987;Teixeira and Hogan, 2002), and shortwave and longwave radiation (Harshvardhan et al, 1987). NOGAPS runs operationally at T239L30 with only a few thick highly-diffused stratospheric levels above ∼25 hPa.…”

Section: Nogaps-alpha Global Forecast Modelmentioning

confidence: 99%

Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

Hoppel

Baker²,

Coy

et al. 2008

Atmos. Chem. Phys.

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Abstract. The forecast model and three-dimensional variational data assimilation components of the Navy Operational Global Atmospheric Prediction System (NOGAPS) have each been extended into the upper stratosphere and mesosphere to form an Advanced Level Physics High Altitude (ALPHA) version of NOGAPS extending to ∼100 km. This NOGAPS-ALPHA NWP prototype is used to assimilate stratospheric and mesospheric temperature data from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instruments. A 60-day analysis period in January and February 2006, was chosen that includes a well documented stratospheric sudden warming. SABER and MLS temperatures indicate that the SSW caused the polar winter stratopause at ∼40 km to disappear, then reform at ∼80 km altitude and slowly descend during February. The NOGAPS-ALPHA analysis reproduces this observed stratospheric and mesospheric temperature structure, as well as realistic evolution of zonal winds, residual velocities, and Eliassen-Palm fluxes that aid interpretation of the vertically deep circulation and eddy flux anomalies that developed in response to this wavebreaking event. The observation minus forecast (O-F) standard deviations for MLS and SABER are ∼2 K in the midstratosphere and increase monotonically to about 6 K in the upper mesosphere. Increasing O-F standard deviations in the mesosphere are expected due to increasing instrument error and increasing geophysical variance at small spatial scales in the forecast model. In the mid/high latitude winter regions, 10-day forecast skill is improved throughout the upper stratosphere and mesosphere when the model is initialized using the high-altitude analysis based on assimilation of both SABER and MLS data.

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Section: Nogaps-alpha Global Forecast Modelmentioning

confidence: 99%

Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

Hoppel

Baker²,

Coy

et al. 2008

Atmos. Chem. Phys.

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“…These include shallow cumulus mixing (Tiedtke, 1984), deep cumulus convection (Peng et al, 2004), and convective, stratiform, and boundary layer cloud formation and precipitation (Slingo, 1987;Teixeira and Hogan, 2002). For a more complete description of NOGAPS-ALPHA model physics, see McCormack et al (2006) and E2008.…”

Section: Chem2d-h2o In Nogaps-alphamentioning

confidence: 99%

Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

2008

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Abstract. This paper describes CHEM2D-H2O, a new parameterization of H 2 O photochemical production and loss based on the CHEM2D photochemical-transport model of the middle atmosphere. This parameterization accounts for the altitude, latitude, and seasonal variations in the photochemical sources and sinks of water vapor over the pressure region from 100-0.001 hPa (∼16-90 km altitude). A series of free-running NOGAPS-ALPHA forecast model simulations offers a preliminary assessment of CHEM2D-H2O performance over the June 2007 period. Results indicate that the CHEM2D-H2O parameterization improves global 10-day forecasts of upper mesospheric water vapor compared to forecasts using an existing one-dimensional (altitude only) parameterization. Most of the improvement is seen at high winter latitudes where the one-dimensional parameterization specifies photolytic H 2 O loss year round despite the lack of sunlight in winter. The new CHEM2D-H2O parameterization should provide a better representation of the downwelling of dry mesospheric air into the stratospheric polar vortex in operational analyses that do not assimilate middle atmospheric H 2 O measurements.

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“…The current operational model's physics packages include a bulk Richardson number-dependent vertical mixing scheme (Louis et al, 1982), a time-implicit Louis surface flux parameterization (Louis, 1979), orographic gravity wave and flow-blocking drag (Webster et al, 2003), shallow cumulus mixing of moisture, temperature, and winds (Tiedtke, 1984), the Emanuel cumulus parameterization (Emanuel and Zivkovic-Rothman, 1999;Peng et al, 2004), convective, stratiform and boundary-layer cloud parameterizations (Slingo, 1987;Teixeira and Hogan, 2002), and a shortwave and longwave radiation scheme (Harshvardhan et al, 1987).…”

Section: Overview Of Nogaps Gcm and Operational Schemesmentioning

confidence: 99%

NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign

et al. 2004

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Abstract. This paper presents three-dimensional prognostic O 3 simulations with parameterized gas-phase photochemistry from the new NOGAPS-ALPHA middle atmosphere forecast model. We compare 5-day NOGAPS-ALPHA hindcasts of stratospheric O 3 with satellite and DC-8 aircraft measurements for two cases during the SOLVE II campaign: (1) the cold, isolated vortex during 11-16 January 2003; and (2) the rapidly developing stratospheric warming of 17-22 January 2003. In the first case we test three different photochemistry parameterizations. NOGAPS-ALPHA O 3 simulations using the NRL-CHEM2D parameterization give the best agreement with SAGE III and POAM III profile measurements. 5-day NOGAPS-ALPHA hindcasts of polar O 3 initialized with the NASA GEOS4 analyses produce better agreement with observations than do the operational ECMWF O 3 forecasts of case 1. For case 2, both NOGAPS-ALPHA and ECMWF 114-h forecasts of the split vortex structure in lower stratospheric O 3 on 21 January 2003 show comparable skill. Updated ECMWF O 3 forecasts of this event at hour 42 display marked improvement from the 114-h forecast; corresponding updated 42-hour NOGAPS-ALPHA prognostic O 3 fields initialized with the GEOS4 analyses do not improve significantly. When NOGAPS-ALPHA prognostic O 3 is initialized with the higher resolution ECMWF O 3 analyses, the NOGAPS-ALPHA 42-hour lower stratospheric O 3 fields closely match the operational 42-hour ECMWF O 3 forecast of the 21 January event. We find that stratospheric O 3 forecasts at high latitudes in winter can depend on both model initial conditions and the treatment of photochemistry over periods of 1-5 days. OverCorrespondence to: J. P. McCormack (mccormack@nrl.navy.mil) all, these results show that the new O 3 initialization, photochemistry parameterization, and spectral transport in the NOGAPS-ALPHA NWP model can provide reliable shortrange stratospheric O 3 forecasts during Arctic winter.

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Recent Modifications of the Emanuel Convective Scheme in the Navy Operational Global Atmospheric Prediction System

Cited by 73 publications

References 36 publications

Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign

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