The dependence of the bulk Richardson number on stability in the surface layer

Zoumakis, N. M.; Kelessis, Apostolos

doi:10.1007/bf00120057

Cited by 37 publications

(13 citation statements)

References 20 publications

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“…4(b). As stability parameter, the Bulk-Richardson number (Zoumakis and Kelessis, 1991) was calculated from operational analysis data from the COSMO-DE numerical weather prediction (NWP) model (Doms and Schättler, 2002) as…”

Section: Measured Wake Effectsmentioning

confidence: 99%

The impact of stable atmospheric boundary layers on wind-turbine wakes within offshore wind farms

Dörenkämper

Witha

Steinfeld

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

123

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a b s t r a c tIn terms of predicting wind turbine wakes, the stably stratified atmospheric boundary layer (SABL) is taking an exceptional position as wake effects and thus loads on subsequent turbines are stronger. In this study we show the impact of the SABL on power production and wake effects (power deficits) in offshore wind farms by means of measurements as well as large-eddy simulations (LES). Measurements show enhanced wake effects in the SABL compared to the unstable situation. Another influence on the power generation of an offshore wind farm is the distance of the wind farm to the shore. This is accounted for in the LES by a modification of surface characteristics at the coastal discontinuity. In addition to the effect of the coast, the numerical case study also shows the existence of local jets between the turbines of the wind farm.

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Section: Measured Wake Effectsmentioning

confidence: 99%

The impact of stable atmospheric boundary layers on wind-turbine wakes within offshore wind farms

Dörenkämper

Witha

Steinfeld

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

123

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“…The flow conditions expressed in terms of atmospheric stability classification has been established with reference to the Bulk Richardson approach. The Bulk Richardson number has been used as a stability parameters in many atmospheric studies (e.g., Hsu ; Zoumakis and Kelessis ). The Bulk Richardson number ( Ri b ) is based on a paper by Grachev and Fairall from a single wind speed observation ( U h ), measured at 15–20 m height ( h ) above mean sea level combined with the air and water temperature difference ( Δt) from [equation ] and the absolute temperature ( T ) measured 13–16 m above mean sea level.…”

Section: Wind Farm Layoutmentioning

confidence: 99%

The impact of turbulence intensity and atmospheric stability on power deficits due to wind turbine wakes at Horns Rev wind farm

et al. 2011

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. (2012). The impact of turbulence intensity and atmospheric stability on power deficits due to wind turbine wakes at Horns Rev wind farm. Wind Energy, 15(1), 183-196. DOI: 10.1002/we.512 The impact of turbulence intensity and atmospheric stability on power deficits due to wind turbine wakes at Horns Rev wind farm Moreover, there is a strong stability directional dependence with southerly winds having fewer unstable conditions while northerly winds have fewer observations in the stable classes.Stable conditions also tend to be associated with lower levels of turbulence intensity and this relationship persists as wind speeds increase. Power deficit is a function of ambient turbulence intensity. The level of power deficit is strongly dependent on the wind turbine spacing and as turbulence intensity increases the power deficit decreases. The power deficit is determined for four different wind turbine spacing distances and for stability classified as very stable, unstable and other (near-neutral to very unstable). The more stable conditions are, the larger the power deficit.

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“…The histogram (bar-graph in Figure 3) presents the diurnal variation of the percentage of central heating fuel consumed hourly in Thessaloniki during the cold part of the year. During the morning hours the increase of the SO 2 emission sources, in conjunction with the shallow mixing height and the stable stratification of the atmosphere result in higher SO 2 columnar values (12,28,29). During midday and until the early afternoon, columnar SO 2 is declining due to the decreasing of local sources and increasing of intensity of mixing and wind speed into the mixing layer (9,30).…”

Section: Instrumentationmentioning

confidence: 99%

A study of the total amount of sulphur dioxide over major Thessaloniki area using solar ultraviolet spectrophotometric measurements

Kelessis

Zoumakis

1993

Environmental Technology

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Solar Ultraviolet spectrophotometric measurements are used to provide estimates of the total columnar sulphur dioxide concentrations over urban, semirural and industrial areas of Thessaloniki in Northern Greece. The systematic observations of the SO 2 column represent an estimate of the impact of anthropogenic sulphur dioxide on the solar radiation received at the surface of the earth. The measurements span over a period of more than ten years, giving the longest presently available record of the total columnar SO 2 in Europe. Total columnar and ground-level SO 2 measurements display an annual variation with maximum concentrations to occur in the winter period of the year. Finally, by combining the simultaneous columnar and surface SO 2 measurements, we obtain estimates of the height of the polluted layer and mean residence time for sulphur dioxide over Thessaloniki basin.

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The dependence of the bulk Richardson number on stability in the surface layer

Cited by 37 publications

References 20 publications

The impact of stable atmospheric boundary layers on wind-turbine wakes within offshore wind farms

The impact of stable atmospheric boundary layers on wind-turbine wakes within offshore wind farms

The impact of turbulence intensity and atmospheric stability on power deficits due to wind turbine wakes at Horns Rev wind farm

A study of the total amount of sulphur dioxide over major Thessaloniki area using solar ultraviolet spectrophotometric measurements

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