Large-scale measurements and numerical simulations of in-cloud icing around a mountain ridge

Drage, Magne A.; Thiis, Thomas K.

doi:10.1016/j.jweia.2012.02.028

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…The largest amounts of LWC were around the top of the pass, around 0.25 g kg −1 . LWC in our study was considerable compared with the concentrations observed by Podolskiy et al [], although perhaps the weak wind at 04:00 UTC was the reason for lack of severe in‐cloud icing, as described by Drage and Thiis []. This methodology may be useful for mountain ranges exposed to strong and moist winds, where in‐cloud icing could be a serious problem.…”

Section: Mesoscalesupporting

confidence: 62%

Analysis of a seeder‐feeder and freezing drizzle event

et al. 2015

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Surface icing can cause dramatic consequences on human activities. What is more, numerical weather prediction models are not very accurate in determining freezing drizzle, which creates uncertainty when forecasting this type of weather phenomenon. Therefore, it is essential to improve the forecast accuracy of these models for such phenomena to mitigate risks caused by unforeseen freezing drizzle events. On 5 February 2012, an episode of freezing drizzle took place in the Guadarrama Mountains, at the center of the Iberian Peninsula. This episode was preceded by weak snowfall. After the freezing drizzle, moderate snowfall was recorded in the study area. This event was simulated using the Weather Research and Forecasting model. Through this analysis, we identified the meteorological factors at both synoptic scale and mesoscale that caused this episode. Wind perpendicular to an orographic barrier‐generated updrafts and retention of moisture upwind, which caused orographic clouds to appear on the north side of the Guadarrama Mountains. Atmospheric stability prevented cloud formation at midlevels at the time of the freezing drizzle, which maintained cloud top temperatures warmer than −15°C during the episode. The entrance of moisture and instability at midlevels caused cloud top temperatures substantially colder than −15°C, which coincided with snow in the mountain range. Cloud top temperature and thickness control the efficiency of the glaciation process, thereby determining the type of precipitation at the surface. Freezing drizzle risk and in‐cloud icing algorithms were developed with the aim of predicting similar events in the study area, which could mitigate impacts on human activities.

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Section: Mesoscalesupporting

confidence: 62%

Analysis of a seeder‐feeder and freezing drizzle event

et al. 2015

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A Field Study of Atmospheric Icing Analysis in a Complex Terrain of the High North

Rashid

Mughal

Mustafa

et al. 2014

The International Journal of Ocean and Climate Systems

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Analyses of atmospheric icing events hold the key for computing the significant parameters leading to icing load calculations. In the cold regions of the high north, atmospheric icing loads on structures become important when it comes to design and safety of infrastructures. Furthermore, icing load calculations over a certain period of time provide a vital input for designers to improve the safety of structures. Patterns of icing events can be evaluated in correlation with other meteorological parameters such as atmospheric temperature, relative humidity and wind speed to better estimate icing loads. A field study has been performed in the complex terrain of northern Norway, by the atmospheric icing research team of Narvik University College, where customized meteorological atmospheric ice monitoring stations were installed to study atmospheric icing events in relation with the associated weather parameters. The meteorological parameters of three different sites in the vicinity of Narvik (68°25′14′ N17°33′36′ E) were collected, sorted, averaged to standardized timeline and further validated with recordings of weathers parameters obtained from the national weather forecasts, where a good agreement was found. Analyses were mainly performed between accreted ice loads and associated meteorological parameters. The results presented can be used as base for the development of more detailed mathematical models for the better prediction of atmospheric icing events in complex terrains.

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Impact of Meteorological Factors on the Wire Icing Thickness and Growth Rate in Mountain Areas under Dry and Wet Growth Patterns

Zhou,

Zhang,

Pan

et al. 2024

Atmosphere

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Wire icing events pose a significant threat to the southern power grid’s transmission lines in China. Fifteen such events were identified from 2018 to 2020 on the Guilin-Haiyang Mountain transmission line. Hourly measurements of ice thickness and concurrent meteorological data were analyzed using the Makkonen model’s freezing rate formula to categorize the events into distinct growth patterns: dry and wet. The relationship between wire icing and meteorological factors across different micro-topography (windward slope, leeward slope, and pass) was further explored. Several key conclusions can be drawn. First, the altitude is positively correlated to the icing thickness, but relatively independent of the icing rate; however, such independence between the icing rate and altitude cannot be interpreted by the negative correlation of altitude with temperature and the positive relationship between wind speed and liquid water content. Second, a pronounced connection of the icing rate with meteorological factors is not shown until the wet and dry patterns are separated. Notably, the correlations differ between these two patterns, with icing rate being negatively correlated with temperature for the wet growth process, but positively correlated with wind speed and liquid water content for the dry growth process. Third, both wet and dry growth processes exist across the icing events. A shift from wet to dry growth was evident with increasing altitude. At the mountain’s base, wet growth predominates, with the icing rate determined by the temperature close to the freezing point, whereas the higher temperature and lower liquid water flux account for the shorter wire icing duration, lower icing rate, and thus the thinner icing thickness at the leeward slope compared to the windward slope at a similar altitude. This study sheds light on the variations in icing rates under different micro-topographies and the underlying physical mechanisms governing icing growth patterns and provides a much-needed understanding of these distinct growth processes on the development of a more sophisticated predictive model for conductor icing.

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Large-scale measurements and numerical simulations of in-cloud icing around a mountain ridge

Cited by 3 publications

References 7 publications

Analysis of a seeder‐feeder and freezing drizzle event

Analysis of a seeder‐feeder and freezing drizzle event

A Field Study of Atmospheric Icing Analysis in a Complex Terrain of the High North

Impact of Meteorological Factors on the Wire Icing Thickness and Growth Rate in Mountain Areas under Dry and Wet Growth Patterns

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