Prediction of Quasi-Periodic Oscillations in Radiation Fogs. Part I: Comparison of Simple Similarity Approaches

Welch, Ronald M.; Ravichandran, M.; Cox, Stephen K.

doi:10.1175/1520-0469(1986)043<0633:poqpoi>2.0.co;2

Cited by 48 publications

(19 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Some models with more resolution (ReVelle, 1993;Welch et al, 1986) were also able to reproduce intermittent turbulence. On the other hand, the models by Sharan and Gopalakrishnan (1997) and Derbyshire (1999) did not show any intermittency.…”

Section: A) Surface Fluxesmentioning

confidence: 99%

Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Steeneveld

Wiel

Holtslag

2006

Journal of the Atmospheric Sciences

114

124

View full text Add to dashboard Cite

The modeling and prediction of the stable boundary layer over land is a persistent problematic feature in weather, climate and air quality topics. Here, the performance of a state-of-the-art single column boundary-layer model is evaluated with observations from the CASES-99 field experiment. Very high model resolution in the atmosphere and the soil is utilized to represent three different stable boundary-layer archetypes, namely: a fully turbulent night, an intermittently turbulent night and a radiative night with hardly any turbulence (all at clear skies). Each archetype represents a different class of atmospheric stability. In the current model, the atmosphere is fully coupled to a vegetation layer and the underlying soil. In addition, stability functions (local scaling) are utilized based on local observations. Overall it is found that the vertical structure, the surface fluxes (apart from the intermittent character) and the surface temperature in the stable boundary layer can be satisfactorily modeled for a broad stability range (at a local scale) with our current understanding of the physics of the stable boundary layer. This can also be achieved by the use of a rather detailed coupling between the atmosphere and the underlying soil and vegetation, together with high resolution in both the atmosphere and the soil. This is especially true for the very stable nights, where longwave radiative cooling is dominant. Both model outcome and observations show that in the latter case the soil heat flux is a dominant term of the surface energy budget.3

show abstract

Section: A) Surface Fluxesmentioning

confidence: 99%

Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Steeneveld

Wiel

Holtslag

2006

Journal of the Atmospheric Sciences

114

124

View full text Add to dashboard Cite

show abstract

“…Radiosondes, tethered balloons and remote sensing techniques were used in the experiments which involved surface and vertical measurements of various meteorological parameters including turbulence and surface fluxes (for PARISFOG), downward longwave and shortwave fluxes (for both experiments), aerosol and fog microphysics measurements. Moreover, lots of efforts have focused on the study of fog through 1-D, 2-D and 3-D numerical models (Fisher and Caplan, 1963;Zdunkowski and Nielsen, 1969;Brown and Roach, 1976;Oliver et al, 1978;Brown, 1980;Welch et al, 1986;Forkel, 1987;Tardif and Rasmussen, 2007). Most of these studies were related to radiation and sea fog.…”

Section: Introductionmentioning

confidence: 99%

Fog characteristics at the airport of Thessaloniki, Greece

Stolaki¹,

Kazadzis

Foris

et al. 2009

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract.A statistical approach in order to study fog event characteristics occuring at the airport of Thessaloniki, Northern Greece is presented in this work. To achieve this, the seasonal and diurnal characteristics of fog are investigated using 35 years of observations of meteorological parameters such as: visibility, air temperature, dew point temperature, air relative humidity, wind vector, precipitation, and cloud base height and coverage. Hourly surface observations of fifteen (15) years (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) are used to identify fog events induced by various physical mechanisms. Fog events are classified into fog types through the application of objective criteria that are derived upon fog formation processes and under the influence of various physiographic features. The temporal variability of different fog type occurrences are examined and the events are characterized according to their duration and intensity.

show abstract

“…For example, Turton and Brown (1987) suggest that the development of mature fog is dominated by radiative cooling from the fog top. Clearly, however, there is still considerable uncertainty as to the processes responsible for fog formation (Welch, Ravichandran et al 1986). …”

Section: Fogmentioning

confidence: 99%

“…The constant flux layer may only be a few meters deep in fogs, with patchy regions of turbulence above this layer. Due to the scarcity of turbulence measurements in fogs, there is great uncertainty as to the proper parameterization of various coefficients required in the higher-order closure formulations (Welch, Ravichandran et al 1986). In addition, boundary layer models usually place the first grid point in air several meters above the surface.…”

Section: Fogmentioning

confidence: 99%

“…The scaling becomes height independent under these conditions and the Monin-Obukhov (MO) length becomes the only length scale. As a result, we often refer to such conditions as z-less stratification (Welch, Ravichandran et al 1986;Wyngaard, Busch et al 1973). The weak and intermittent turbulence often observed in stable conditions, particularly in low wind conditions, leads to non-stationarity and inhomogeneity, which strongly impacts our ability to model the turbulent mixing of heat and water vapor.…”

Section: Air-sea Interaction Towermentioning

confidence: 99%

See 1 more Smart Citation

Investigations of scalar transfer coefficients in fog during the Coupled Boundary Layers and Air Sea Transfer Experiment : a case study

Crofoot¹

2004

View full text Add to dashboard Cite

The uncertainty in the determination of the momentum and scalar fluxes remains one of the main obstacles to accurate numerical forecasts in low to moderate wind conditions. For example, latent heat fluxes computed from data using direct covariance and bulk aerodynamic methods show that there is good agreement in unstable conditions when the latent heat flux values are generally positive. However, the agreement is relatively poor in stable conditions, particularly when the moisture flux is directed downward. If the direct covariance measurements are indeed accurate, then they clearly indicate that the bulk aerodynamic formula overestimate the downward moisture flux in stable conditions. As a result, comparisons of the Dalton number for unstable and stable conditions indicate a marked difference in value between the two stability regimes.Investigations done for this thesis used data taken primarily at the Air-Sea Interaction Tower (ASIT) during the Coupled Boundary Layers and Air-Sea Transfer (CBLAST) Experiment 2003 from the 20-27 August 2003. Other data from the shore based Martha's Vineyard Coastal Observatory (MVCO) and moored buoys in the vicinity of the ASIT were also incorporated. During this eight day period, the boundary layer was often characterized by light winds, a stably stratified surface layer and a swell dominated wave field. Additionally, the advection of warm moist air over cooler water resulted in fog formation and a downward flux of moisture on at least three occasions. Therefore, a primary objective of this thesis is to present a case study to investigate the cause of this shortcoming in the bulk formula under these conditions by examining the physical processes that are unique to these boundary layers. Particular attention will be paid to the behavior of the Dalton number in a stable marine atmospheric boundary layer under foggy conditions using insights derived from the study of fog formation and current flux parameterization methods.

show abstract

Prediction of Quasi-Periodic Oscillations in Radiation Fogs. Part I: Comparison of Simple Similarity Approaches

Cited by 48 publications

References 0 publications

Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Fog characteristics at the airport of Thessaloniki, Greece

Investigations of scalar transfer coefficients in fog during the Coupled Boundary Layers and Air Sea Transfer Experiment : a case study

Contact Info

Product

Resources

About