Numerical Forecasting of Radiation Fog. Part II: A Comparison of Model Simulation with Several Observed Fog Events

Guédalia, D.; Bergot, Thierry

doi:10.1175/1520-0493(1994)122<1231:nforfp>2.0.co;2

Cited by 77 publications

(52 citation statements)

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“…Several field experiments have been carried out since the 1970s and have contributed to the important progress made in understanding fog processes. Noteworthy studies include campaigns at Cardington in the UK (Roach et al, 1976;; Fog-82 in Albany, New York (Meyer et al, 1986); Lille 91 in France (Guedalia and Bergot, 1994); a campaign in the Po valley in Italy (Fuzzi et al, 1998) and ParisFog in France (Haeffelin et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of radiation fog: impact of dynamics on the fog life cycle

et al. 2017

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Abstract. Large eddy simulations (LESs) of a radiation fog event occurring during the ParisFog experiment are studied with a view to analyse the impact of the dynamics of the boundary layer on the fog life cycle. The LES, performed with the Meso-NH model at 5 m resolution horizontally and 1 m vertically, and with a 2-moment microphysical scheme, includes the drag effect of a tree barrier and the deposition of droplets on vegetation. The model shows good agreement with measurements of near-surface dynamic and thermodynamic parameters and liquid water path. The blocking effect of the trees induces elevated fog formation, as actually observed, and horizontal heterogeneities during the formation. It also limits cooling and cloud water production. Deposition is found to exert the most significant impact on fog prediction as it not only erodes the fog near the surface but also modifies the fog life cycle and induces vertical heterogeneities. A comparison with the 2 m horizontal resolution simulation reveals small differences, meaning that grid convergence is achieved. Conversely, increasing numerical diffusion through a wind advection operator of lower order leads to an increase in the liquid water path and has a very similar effect to removing the tree barrier. This study allows us to establish the major dynamical ingredients needed to accurately represent the fog life cycle at very high-resolution.

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Section: Introductionmentioning

confidence: 99%

Large eddy simulation of radiation fog: impact of dynamics on the fog life cycle

et al. 2017

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“…Soil-atmosphere exchanges are also important for fog formation and dissipation. Fog forecasting/nowcasting is usually done using detailed one-dimensional (ID) boundary layer (BL) models that utilize initial boundary conditions obtained from 3D limited-area models (Guedalia and Bergot 1994;Bergot et al 2005;Kunkel 1984) or from cloud and fog models (Gultepe and Milbrandt 2007;Bott 1991;Bott et al 1990). Current parameterizations for fog visibility (Vis) in numerical models are not accurate (Gultepe et al 2006a;Muller et al 2007) because of the incomplete treatment of the physics and unresolved microphysical issues (Teixeira 1999), such as neglected droplet number concentration (NJ.…”

mentioning

confidence: 99%

The Fog Remote Sensing and Modeling Field Project

Gültepe¹,

Pearson²,

Milbrandt³

et al. 2009

Bull. Amer. Meteor. Soc.

234

138

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“…The COBEL-ISBA system results from the coupling of the high-resolution atmospheric boundary-layer 1D model COBEL (Bergot, 1993;Bergot and Guédalia, 1994;Guédalia and Bergot, 1994) with the 7-layer land-surface scheme ISBA (Noilhan and Planton, 1989;Boone, 2000). The atmospheric model possesses a high vertical resolution: 30 levels between 0.5 and 1360 m, with 20 levels below 200 m, to be able to adequately forecast radiative fog events.…”

Section: The Modelmentioning

confidence: 99%

“…1D models are suitable for the nowcasting of radiation fog events for airports located in flat terrain Guédalia and Bergot, 1994). They are currently used in real time to forecast fog at the local scale at several airports (e.g.…”

Section: Introductionmentioning

confidence: 99%

Adaptation of a particle filtering method for data assimilation in a 1D numerical model used for fog forecasting

Rémy

Pannekoucke

Bergot

et al. 2011

Quart J Royal Meteoro Soc

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COBEL-ISBA, a boundary-layer 1D numerical model, has been developed for the very-short-term forecasting of fog and low clouds. This forecast system assimilates local observations to produce initial profiles of temperature, specific humidity and liquid water content. As fog forecasting is a threshold problem, the model is strongly nonlinear.A new assimilation method based on a genetic selection particle filter was tested to produce the initial conditions. The particle filter was adapted for a deterministic forecast and to take into account the time dimension by minimizing the error on a time window. A simplified particle filter was also used to determine the initial conditions in the soil. The filter was tested with two sets of simulated observations. In all cases, the initial conditions produced by this algorithm were of considerably better quality than the ones obtained with a Best Linear Unbiased Estimator (BLUE). The forecast of the control variables and of fog events was also improved. When comparing scores with the ones obtained with an ensemble Kalman filter (EnKF), the particle filter showed better performances for most of the cases. The ensemble size impacted the frequency of filter collapse and the quality of the initial temperature and specific humidity profiles in the lower part of the domain.

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Numerical Forecasting of Radiation Fog. Part II: A Comparison of Model Simulation with Several Observed Fog Events

Cited by 77 publications

References 0 publications

Large eddy simulation of radiation fog: impact of dynamics on the fog life cycle

Large eddy simulation of radiation fog: impact of dynamics on the fog life cycle

The Fog Remote Sensing and Modeling Field Project

Adaptation of a particle filtering method for data assimilation in a 1D numerical model used for fog forecasting

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