A Boundary Layer Parameterization for a General Model.

Mahrt, L.; Pan, Hua-Lu; Paumier, James O.; Troen, Ib

doi:10.21236/ada144224

Cited by 7 publications

(7 citation statements)

References 24 publications

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“…Its dynamic core has an efficient time-stepping, with a short time-step for the forward-backward gravity wave scheme modified so as to address the E-grid's lattice separation problem (Mesinger, 1974;Janjic, 1979), a longer time step for its conservative advection schemes (Janjic, 1984), and a still longer time step for the physics terms. The physics package consists of a surface scheme (Mahrt et al, 1988), a radiation scheme (Fels and Schwarzkopf, 1975), a turbulence closure sub-model (Mellor and Yamada, 1974;Mellor and Yamada, 1982;Janjic, 1990), a viscous sub-layer (Janjic, 1996) and a convection parameterization (Betts, 1986;Betts and Miller, 1986;Janjic, 1990). The centre of the atmospheric model is at 16 • E, 42.5 • N and the horizontal resolution is 0.125 • .…”

Section: The Atmospheric Componentmentioning

confidence: 99%

Verification of a coupled atmosphere-ocean model using satellite observations over the Adriatic Sea

Djurdjević¹,

Rajkovic²

2008

Ann. Geophys.

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Abstract.Verification of the EBU-POM regional atmosphere-ocean coupled model (RAOCM) was carried out using satellite observations of SST and surface winds over the Adriatic Sea. The atmospheric component has a horizontal resolution of 0.125 degree (approximately 10 km) and 32 vertical levels, while the ocean component has a horizontal resolution of approximately 4 km with 21 sigma vertical levels.Verification of the forecasted SST was performed for 15 forecasts during 2006, each of them seven days long. These forecasts coincide with the operating cycle of the Adriatic Regional Model (AREG), which provided the initial fields and boundary conditions for the ocean component of EBU-POM. Two sources of data were used for the initial and boundary conditions of the atmosphere: primary data were obtained from the European Center for Medium-Range Weather Forecasting (ECMWF), while data from National Centers for Environmental Prediction (NCEP) were used to test the sensitivity to boundary conditions. Forecast skill was expressed in terms of BIAS and root mean square error (RMSE). During most the of verification period, the model had a negative BIAS of approximately −0.3 • , while RMSE varied between 1.1 • and 1.2 • . Interestingly, these errors did not increase over time, which means that the forecast skill did not decline during the integrations.The 10-m wind verification was conducted for one period of 17 days in February 2007, during a strong bora episode, for which satellite estimates of surface winds were available. During the same period, SST measurements were conducted twice a day, which enabled us to verify diurnal variations of SST simulated by the RAOCM model. Since ECMWF's deterministic forecasts do not cover such a long period, we decided to use the ECMWF analysis, i.e. we ran the model in hindcast mode. The winds simulated in this analysis were Correspondence to: V. Djurdjevic (vdj@ff.bg.ac.yu) weaker than the satellite estimates, with a mean BIAS of −0.8 m/s.

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Section: The Atmospheric Componentmentioning

confidence: 99%

Verification of a coupled atmosphere-ocean model using satellite observations over the Adriatic Sea

Djurdjević¹,

Rajkovic²

2008

Ann. Geophys.

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“…(c) The turbulent diffusion of heat and moisture formulation was essentially due to MAHRT et al (1991).…”

Section: A 1-d Fog Prediction Modelmentioning

confidence: 99%

A Review of some Recent Radiation Fog Prediction Studies and the Results of Integrating a Simple Numerical Model to Predict Radiation Fog over Brunei

Rao¹,

O'Sullivan²

2003

Pure and Applied Geophysics

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Several radiation fog studies with emphasis on numerical simulation and prediction are reviewed. One of the earliest attempts started with a given surface diurnal variation of temperature and water vapor, and concluded by forecasting the onset of saturation at various levels; thus fog, by examining the spread of temperature and moisture in the vertical. The one-dimensional (1-D) models are still popular. Some of the recent numerical simulations use more than 100 levels in the vertical and treat various kinds of vegetation, aerosols, and soils with moisture contents. Some also employ a mesoscale model in conjunction with a 1-D model to consider the advective effects. In the following a simple 1-D numerical model was used to predict the onset of fog at Brunei, based on a desktop computer and routine surface observations of dry bulb temperature (T), dewpoint temperature (T d ), and wind speed at 1800 Local Time (LT). Optimism exists in improved predictions of fog and stratus as 1-D models incorporate many physical processes, and mesoscale models continue to improve in predicting advection and cloud cover.Key words: 1-d fog model, radiation fog, fog prediction, fog over Brunei, numerical modeling of fog, review of fog.

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“…The turbulent flux of heat is developed following the formulation by MAHRT et al (1991). The tendency of the temperature field at 10 m is given by…”

Section: Turbulent Diffusion Of Heatmentioning

confidence: 99%

Radiation Fog Prediction Using a Simple Numerical Model

Meyer

Rao

1999

Pure and Applied Geophysics

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A simple one-dimensional numerical-analytical model was developed by MEYER and RAO (1995) to predict the onset of radiation fog. The model computes radiative cooling and turbulent diffusion of heat and vapor through the lower boundary layer and produces heat and vapor fluxes at the soil -atmosphere interface. The model is designed for Air Force forecasters who have access to a personal computer, an early evening surface observation of the dry bulb and dewpoint temperature, wind speed, the lapse rate in the upper boundary layer, and the previous 24-h precipitation amount. These initial data are used to predict the diurnal variation of the dry bulb and dewpoint temperatures at 10 m above the surface. In accordance with conventional synoptic observing practices, fog is defined as a restriction of the surface visibility generally to less than 1000 m. Fog is assumed to occur in the model predictions when the dewpoint depression falls to less than 1°C. Observations, from several Air Force bases for selected days when fog was observed to occur, were used to test the model. The present model with default parameters appears to predict the onset of fog slightly ahead of its occurrence. Better verification results are expected when site-relevant parameters are used in model predictions.

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A Boundary Layer Parameterization for a General Model.

Cited by 7 publications

References 24 publications

Verification of a coupled atmosphere-ocean model using satellite observations over the Adriatic Sea

Verification of a coupled atmosphere-ocean model using satellite observations over the Adriatic Sea

A Review of some Recent Radiation Fog Prediction Studies and the Results of Integrating a Simple Numerical Model to Predict Radiation Fog over Brunei

Radiation Fog Prediction Using a Simple Numerical Model

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