Introduction to the Third GEWEX Atmospheric Boundary Layer Study (GABLS3)

Holtslag, A.A.M.

doi:10.1007/s10546-014-9931-5

Cited by 11 publications

(9 citation statements)

References 27 publications

(30 reference statements)

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“…The aim of this investigation is to introduce a new approach for skill-testing CTMs regarding: (i) reproducing meteorological conditions, (ii) transporting and mixing primary emissions in the atmospheric boundary layer (ABL), and (iii) forming secondary gaseous and aerosol products. Since understanding of the physical processes associated with transport and mixing under fair-weather turbulent daytime conditions is more advanced than processes dominating near quiescent nocturnal conditions near the surface [12][13][14][15][16], model skill will also be dependent on atmospheric mixing state. Furthermore, the formation of secondary pollutants is also dependent on factors related to the atmospheric mixing state (e.g., mixing volume, temperature, sunlight intensity, humidity, etc.…”

Section: Introductionmentioning

confidence: 99%

Skill-Testing Chemical Transport Models across Contrasting Atmospheric Mixing States Using Radon-222

Chambers

Guérette

Monk³

et al. 2019

Atmosphere

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We propose a new technique to prepare statistically-robust benchmarking data for evaluating chemical transport model meteorology and air quality parameters within the urban boundary layer. The approach employs atmospheric class-typing, using nocturnal radon measurements to assign atmospheric mixing classes, and can be applied temporally (across the diurnal cycle), or spatially (to create angular distributions of pollutants as a top-down constraint on emissions inventories). In this study only a short (<1-month) campaign is used, but grouping of the relative mixing classes based on nocturnal mean radon concentrations can be adjusted according to dataset length (i.e., number of days per category), or desired range of within-class variability. Calculating hourly distributions of observed and simulated values across diurnal composites of each class-type helps to: (i) bridge the gap between scales of simulation and observation, (ii) represent the variability associated with spatial and temporal heterogeneity of sources and meteorology without being confused by it, and (iii) provide an objective way to group results over whole diurnal cycles that separates ‘natural complicating factors’ (synoptic non-stationarity, rainfall, mesoscale motions, extreme stability, etc.) from problems related to parameterizations, or between-model differences. We demonstrate the utility of this technique using output from a suite of seven contemporary regional forecast and chemical transport models. Meteorological model skill varied across the diurnal cycle for all models, with an additional dependence on the atmospheric mixing class that varied between models. From an air quality perspective, model skill regarding the duration and magnitude of morning and evening “rush hour” pollution events varied strongly as a function of mixing class. Model skill was typically the lowest when public exposure would have been the highest, which has important implications for assessing potential health risks in new and rapidly evolving urban regions, and also for prioritizing the areas of model improvement for future applications.

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Section: Introductionmentioning

confidence: 99%

Skill-Testing Chemical Transport Models across Contrasting Atmospheric Mixing States Using Radon-222

Chambers

Guérette

Monk³

et al. 2019

Atmosphere

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“…The challenges of the first two GABLS exercises inspired the setup of GABLS3, which deals with a real diurnal case with a strong nocturnal low-level jet (LLJ) at the Cabauw meteorological tower in the Netherlands (Baas et al, 2009;Holtslag, 2014;Basu et al, 2011;Bosveld et al, 2014a). Here, large-scale forcing is not constant throughout the diurnal cycle but depends on time and height.…”

Section: Introductionmentioning

confidence: 99%

A methodology for the design and testing of atmospheric boundary layer models for wind energy applications

2017

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Abstract. The GEWEX Atmospheric Boundary Layer Studies (GABLS) 1, 2 and 3 are used to develop a methodology for the design and testing of Reynolds-averaged Navier-Stokes (RANS) atmospheric boundary layer (ABL) models for wind energy applications. The first two GABLS cases are based on idealized boundary conditions and are suitable for verification purposes by comparing with results from higher-fidelity models based on large-eddy simulation. Results from three single-column RANS models, of 1st, 1.5th and 2nd turbulence closure order, show high consistency in predicting the mean flow. The third GABLS case is suitable for the study of these ABL models under realistic forcing such that validation versus observations from the Cabauw meteorological tower are possible. The case consists on a diurnal cycle that leads to a nocturnal low-level jet and addresses fundamental questions related to the definition of the large-scale forcing, the interaction of the ABL with the surface and the evaluation of model results with observations. The simulations are evaluated in terms of surface-layer fluxes and wind energy quantities of interest: rotor equivalent wind speed, hub-height wind direction, wind speed shear and wind direction veer. The characterization of mesoscale forcing is based on spatially and temporally averaged momentum budget terms from Weather Research and Forecasting (WRF) simulations. These mesoscale tendencies are used to drive single-column models, which were verified previously in the first two GABLS cases, to first demonstrate that they can produce similar wind profile characteristics to the WRF simulations even though the physics are more simplified. The added value of incorporating different forcing mechanisms into microscale models is quantified by systematically removing forcing terms in the momentum and heat equations. This mesoscale-to-microscale modeling approach is affected, to a large extent, by the input uncertainties of the mesoscale tendencies. Deviations from the profile observations are reduced by introducing observational nudging based on measurements that are typically available from wind energy campaigns. This allows the discussion of the added value of using remote sensing instruments versus tower measurements in the assessment of wind profiles for tall wind turbines reaching heights of 200 m.Published by Copernicus Publications on behalf of the European Academy of Wind Energy e.V. 36 J. Sanz Rodrigo et al.: A methodology for the design and testing of atmospheric boundary layer models

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“…Still, there is a quite significant variability depending on the PBL scheme and grid set‐up. These studies showed how the complexity of interpreting large‐scale forcing and the interaction with the surface made it difficult to compare models with observations …”

Section: Microscale Modelingmentioning

confidence: 99%

Mesoscale to microscale wind farm flow modeling and evaluation

Rodrigo

Arroyo

Moriarty

et al. 2016

WIREs Energy & Environment

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The increasing size of wind turbines, with rotors already spanning more than 150 m diameter and hub heights above 100 m, requires proper modeling of the atmospheric boundary layer (ABL) from the surface to the free atmosphere. Furthermore, large wind farm arrays create their own boundary layer structure with unique physics. This poses significant challenges to traditional wind engineering models that rely on surface-layer theories and engineering wind farm models to simulate the flow in and around wind farms. However, adopting an ABL approach offers the opportunity to better integrate wind farm design tools and meteorological models. The challenge is how to build the bridge between atmospheric and wind engineering model communities and how to establish a comprehensive evaluation process that identifies relevant physical phenomena for wind energy applications with modeling and experimental requirements. A framework for model verification, validation, and uncertainty quantification is established to guide this process by a systematic evaluation of the modeling system at increasing levels of complexity. In terms of atmospheric physics, 'building the bridge' means developing models for the so-called 'terra incognita,' a term used to designate the turbulent scales that transition from mesoscale to microscale. This range of scales within atmospheric research deals with the transition from parameterized to resolved turbulence and the improvement of surface boundary-layer parameterizations. The coupling of meteorological and wind engineering flow models and the definition of a formal model evaluation methodology, is a strong area of research for the next generation of wind conditions assessment and wind farm and wind turbine design tools. Some fundamental challenges are identified in order to guide future research in this area. mesoscale model at~4 km horizontal resolution (a), nested down with WRF to 1.67 and 0.55 km resolution, and introducing microscale speedups with WAsP at 100 m resolution (b). (Reprinted with permission from Ref 35.

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Introduction to the Third GEWEX Atmospheric Boundary Layer Study (GABLS3)

Cited by 11 publications

References 27 publications

Skill-Testing Chemical Transport Models across Contrasting Atmospheric Mixing States Using Radon-222

Skill-Testing Chemical Transport Models across Contrasting Atmospheric Mixing States Using Radon-222

A methodology for the design and testing of atmospheric boundary layer models for wind energy applications

Mesoscale to microscale wind farm flow modeling and evaluation

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