Fog Prediction for Road Traffic Safety in a Coastal Desert Region

Bartok, Juraj; Bott, Andreas; Gera, Martin

doi:10.1007/s10546-012-9750-5

Cited by 43 publications

(20 citation statements)

References 30 publications

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“…For instance, correct forecasting of near-surface temperatures and wind speed may improve road de-icing, as well as timely warnings to the transportation sector for low visibility caused by nocturnal fog or haze (van der Velde et al, 2010;Cuxart and Jiménez, 2011;Bartok et al, 2012). Agriculture relies on accurate nearsurface frost forecasts to take measures to protect plants and yields (Prabha et al, 2011).…”

Section: Societal Impactmentioning

confidence: 99%

Current challenges in understanding and forecasting stable boundary layers over land and ice

Steeneveld

2014

Front. Environ. Sci.

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Understanding and prediction of the stable atmospheric boundary layer is challenging. Many physical processes come into play in the stable boundary layer (SBL), i.e., turbulence, radiation, land surface coupling and heterogeneity, orographic turbulent and gravity wave drag (GWD). The development of robust stable boundary-layer parameterizations for weather and climate models is difficult because of the multiplicity of processes and their complex interactions. As a result, these models suffer from biases in key variables, such as the 2-m temperature, boundary-layer depth and wind speed. This short paper briefly summarizes the state-of-the-art of SBL research, and highlights physical processes that received only limited attention so far, in particular orographically-induced GWD, longwave radiation divergence, and the land-atmosphere coupling over a snow-covered surface. Finally, a conceptual framework with relevant processes and particularly their interactions is proposed.

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Section: Societal Impactmentioning

confidence: 99%

Current challenges in understanding and forecasting stable boundary layers over land and ice

Steeneveld

2014

Front. Environ. Sci.

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“…For example, low stratus clouds cover an extensive area over ocean and land (Warren et al, 1986(Warren et al, , 1988, can persist for several days (e.g., Bendix, 2002) and cool the surface in the annual mean (e.g., Randall et al, 1984). Second, low visibilities associated with fog can impact road, ship and aviation traffic, causing accidents, delays or cancellations (e.g., Fabbian et al, 2007;Bartok et al, 2012). The resulting economic losses are comparable to those caused by winter storms (Gultepe et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds

et al. 2020

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Abstract. Conventional techniques to measure boundary layer clouds such as research aircraft are unable to sample in orographically diverse or densely populated areas. In this paper, we present a newly developed measurement platform on a tethered balloon system (HoloBalloon) to measure in situ vertical profiles of microphysical and meteorological cloud properties up to 1 km above ground. The main component of the HoloBalloon platform is a holographic imager, which uses digital in-line holography to image an ensemble of cloud particles in the size range from small cloud droplets to precipitation-sized particles in a three-dimensional volume. Based on a set of two-dimensional images, information about the phase-resolved particle size distribution, shape and spatial distribution can be obtained. The velocity-independent sample volume makes holographic imagers particularly well suited for measurements on a balloon. The unique combination of holography and balloon-borne measurements allows for observations with high spatial resolution, covering cloud structures from the kilometer down to the millimeter scale. The potential of the measurement technique in studying boundary layer clouds is demonstrated on the basis of a case study. We present observations of a supercooled low stratus cloud during a Bise situation over the Swiss Plateau in February 2018. In situ microphysical profiles up to 700 m altitude above the ground were performed at temperatures down to −8 ∘C and wind speeds up to 15 m s−1. We were able to capture unique microphysical signatures in stratus clouds, in the form of inhomogeneities in the cloud droplet number concentration and in cloud droplet size, from the kilometer down to the meter scale.

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“…It reduces the horizontal visibility to less than 1 km (DOC/NOAA, 1995). The societal problems associated with these poor visibility conditions are well known, specifically those related to air (Fabbian et al, 2007), maritime (Fu et al, 2010) and terrestrial (Bartok et al, 2012) transport. Regarding air transport, fog can cause cancellations, delays or deviation to other airports (Stolaki et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Forecasting radiation fog at climatologically contrasting sites: evaluation of statistical methods and WRF

Román‐Cascón

Steeneveld

Yagüe

et al. 2016

Quart J Royal Meteoro Soc

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A six‐year climatology of radiation fog has been compiled at two sites: the Research Centre for the Lower Atmosphere (CIBA, Spain) and the Cabauw Experimental Site for Atmospheric Research (CESAR, The Netherlands). These sites are contrasted in terms of geographical situation, climate zone, altitude, humidity and soil water availability. Therefore, several climatological differences in fog abundance, onset, dissipation and duration have been quantified between the two sites. The more humid site (CESAR) is characterised by relatively short radiation fog events distributed throughout the year. However, radiation fog at the drier site (CIBA) is more persistent and appears during late autumn/winter months. In general, its formation requires more time after sunset (∼2 h more), since further cooling is required to reach saturation. The forecast of these fog events has been evaluated through two different approaches. First, we extend the statistical method presented by Menut et al. (2014) (M14). This method uses statistics to define threshold values on key variables for fog formation (pre‐fog) and verifies its predictability using observations and numerical model output. We present some of the most appropriate threshold values for the forecasting of pre‐fog periods at both sites, which differ from those presented in M14 and depend on the optimisation of the hit rate or the false‐alarm rate. Additionally, we also extend M14 by suggesting other variables as potential predictors for fog formation (friction velocity and visibility tendency). Finally, we focus on fog simulation by the Weather Research and Forecasting (WRF) model in terms of liquid water content. The WRF model was able to simulate radiation fog when configured with sophisticated physical options and high resolution. However it failed in simulating the onset, dissipation and the vertical extent of fog (which was overestimated). The model results were extremely sensitive to the spin‐up time.

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Fog Prediction for Road Traffic Safety in a Coastal Desert Region

Cited by 43 publications

References 30 publications

Current challenges in understanding and forecasting stable boundary layers over land and ice

Current challenges in understanding and forecasting stable boundary layers over land and ice

Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds

Forecasting radiation fog at climatologically contrasting sites: evaluation of statistical methods and WRF

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