Fog-82: A Cooperative Field Study of Radiation Fog

Meyer, M.; Lala, G. Garland; Jiusto, James E.

doi:10.1175/1520-0477(1986)067<0825:facfso>2.0.co;2

Cited by 45 publications

(23 citation statements)

References 16 publications

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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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“…It usually forms near the surface under clear skies in stagnant air in association with anticyclonic conditions (Gultepe et al, 2007). However, the mechanisms of radiation fog formation, development and dissipation are very complex and have been extensively studied with a series of numerical simulations and comprehensive observational programs including in situ measurements (Meyer et al, 1986;Fitzjarrald and Lala, 1989;Fuzzi et al, 1992Fuzzi et al, , 1998Gultepe et al, 2007;Zhou and Ferrier, 2008;Liu et al, 2011;Dupont et al, 2012). Recently, field experiments have been conducted to investigate dynamic, thermodynamic, microphysical, and radiative processes in Beijing and Nanjing, China (Liu et al, 2011), in Canada (Gultepe et al, 2009), and in Paris, France (Haeffelin et al, 2010;Dupont et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Development and application of a method for the objective differentiation of fog life cycle phases

Maier

Bendix

Thies

2013

Tellus B: Chemical and Physical Meteorology

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A B S T R A C T An objective classification of radiation fog in distinct evolutionary stages during its life cycle based on reliable criteria is essential for various applications, for example for numerical fog modelling and fog forecasting. However, there have been Á up to now Á merely qualitative approaches for the distinction of different evolutionary stages in radiation fog. Measurements of the microphysical fog properties with an optical particle counter obtained from droplet measurement technologies together with recordings of the horizontal visibility (VIS) are statistically analyzed to determine individual evolutionary stages of radiation fog with consistent microphysical properties. The developed three-stage approach is based on a statistical change point analysis of the double sum curves of the VIS, the liquid water content, the droplet concentration and the mean radius of the drop size distributions. It could be shown that each of the three recorded radiation fog occurrences could be split into three consecutive phases from formation to dissipation, regardless whether the VIS or the microphysical properties were considered. Having featured consistent microphysical patterns, it could be assumed that the three separated phases of the single fog occurrence could be aggregated for radiation fog. Although this classification is statistically reliable, the dataset still has to be extended for a generalization concerning the separated evolutionary stages.

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“…Especially for fog and low stratus clouds, several authors have identified different evolutionary stages with strong influences on the drop size spectrum and thus the relationship between Z and LWC (e.g. Pilié et al 1975b, MEYER et al 1986, WELCH and RAVICHANDRAN 1986, WENDISCH et al 1998.…”

Section: Introductionmentioning

confidence: 99%

Simulating Z–LWC Relations in Natural Fogs with Radiative Transfer Calculations for Future Application to a Cloud Radar Profiler

Maier

Bendix

Thies

2011

Pure Appl. Geophys.

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The vertical distribution of liquid water content (LWC) in natural fog and low stratus is a crucial variable in many applications, e.g. the development of satellite based retrievals of ground fog. Unfortunately, there is very little data concerning fog LWC-profiles, mainly due to the lack of suitable operational instrumentation. A novel ground-based 94 GHz FMCW cloud radar could fill this gap if radar reflectivity Z could be converted to LWC by using appropriate Z-LWC relations. However, this relation strongly depends on drop size distribution (DSD) and is hardly known for natural fog types. In this sensitivity study, the influence of the DSD on the Z-LWC relation in different types and life cycle stages of natural fogs is analyzed using a radiative transfer code (RTC) and published fog drop size distributions. It could be shown that there is a direct but nonlinear relationship between LWC and radar reflectivity. The proportionality factor of the Z-LWC equation in particular reveals specific ranges for the different life cycle stages. If a proper classification of fog life cycle in the field is possible, the results could be used to properly convert Z to LWC.

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Fog-82: A Cooperative Field Study of Radiation Fog

Cited by 45 publications

References 16 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

Development and application of a method for the objective differentiation of fog life cycle phases

Simulating Z–LWC Relations in Natural Fogs with Radiative Transfer Calculations for Future Application to a Cloud Radar Profiler

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