Evaluating Mesoscale Simulations of the Coastal Flow Using Lidar Measurements

Floors, Rogier; Hahmann, Andrea N.; Peña, Alfredo

doi:10.1002/2017jd027504

Cited by 10 publications

(7 citation statements)

References 48 publications

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“…An important aspect of the LSM, PBL, and SL sensitivity studies was the use of an alternative lookup table for the surface roughness length as a function of land use class. A custom NEWA lookup table was created since many values used in the WRF-distributed tables do not match the aerodynamic characteristics of European vegetation, especially over forests (Hahmann et al, 2015;Floors et al, 2018a). The new lookup table was created by polling wind energy resource assessment experts from the NEWA consortium.…”

Section: Effect Of Surface and Planetary Boundary Layer And Land Surfmentioning

confidence: 99%

“…Nowadays, wind atlases rely on the output from mesoscale model simulations, either sampling recurrent atmospheric states (e.g. Frank and Landberg, 1997;Pinard et al, 2005;Badger et al, 2014;Chávez-Arroyo et al, 2015) or by longterm simulations with Numerical Weather Prediction models (e.g. Tammelin et al, 2013;Nawri et al, 2014;Hahmann et al, 2015;Draxl et al, 2015;Wijnant et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Very few studies afforded an exhaustive sensitivity analysis of the model performance on the nearsurface long-term wind climatology, and many lack the verification at wind turbine heights. Two examples that looked at the sensitivity of the modelled wind climate are Hahmann et al (2015), which investigated a limited number of model parameters over the sea in Northern Europe, and Floors et al (2018b), which concentrated on the impact of the model's spatial resolution on the atmospheric flow in the coastal region. This study expands on these earlier attempts with a much larger set of sensitivity simulations and the comparison to a limited set of observations.…”

Section: Introductionmentioning

confidence: 99%

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The making of the New European Wind Atlas – Part 1: Model sensitivity

et al. 2020

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Abstract. This is the first of two papers that document the creation of the New European Wind Atlas (NEWA). It describes the sensitivity analysis and evaluation procedures that formed the basis for choosing the final setup of the mesoscale model simulations of the wind atlas. The suitable combination of model setup and parameterizations, bound by practical constraints, was found for simulating the climatology of the wind field at turbine-relevant heights with the Weather Research and Forecasting (WRF) model. Initial WRF model sensitivity experiments compared the wind climate generated by using two commonly used planetary boundary layer schemes and were carried out over several regions in Europe. They confirmed that the most significant differences in annual mean wind speed at 100 m a.g.l. (above ground level) mostly coincide with areas of high surface roughness length and not with the location of the domains or maximum wind speed. Then an ensemble of more than 50 simulations with different setups for a single year was carried out for one domain covering northern Europe for which tall mast observations were available. We varied many different parameters across the simulations, e.g. model version, forcing data, various physical parameterizations, and the size of the model domain. These simulations showed that although virtually every parameter change affects the results in some way, significant changes in the wind climate in the boundary layer are mostly due to using different physical parameterizations, especially the planetary boundary layer scheme, the representation of the land surface, and the prescribed surface roughness length. Also, the setup of the simulations, such as the integration length and the domain size, can considerably influence the results. We assessed the degree of similarity between winds simulated by the WRF ensemble members and the observations using a suite of metrics, including the Earth Mover's Distance (EMD), a statistic that measures the distance between two probability distributions. The EMD was used to diagnose the performance of each ensemble member using the full wind speed and direction distribution, which is essential for wind resource assessment. We identified the most realistic ensemble members to determine the most suitable configuration to be used in the final production run, which is fully described and evaluated in the second part of this study (Dörenkämper et al., 2020).

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Section: Effect Of Surface and Planetary Boundary Layer And Land Surfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The making of the New European Wind Atlas – Part 1: Model sensitivity

et al. 2020

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“…ERA5 resolves scales around 150 km. The use of structure functions and spectra from other numerical weather models has shown the effective model resolution to be about 6 times lower than the size of the grid cell (Frehlich and Sharman, 2008).…”

Section: Comparison Of Offshore Mean Wind Speed Maps At 100 M Heightmentioning

confidence: 99%

Europe's offshore winds assessed with synthetic aperture radar, ASCAT and WRF

et al. 2020

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Abstract. Europe's offshore wind resource mapping is part of the New European Wind Atlas (NEWA) international consortium effort. This study presents the results of analysis of synthetic aperture radar (SAR) ocean wind maps based on Envisat and Sentinel-1 with a brief description of the wind retrieval process and Advanced Scatterometer (ASCAT) ocean wind maps. The wind statistics at 10 and 100 m above mean sea level (a.m.s.l.) height using an extrapolation procedure involving simulated long-term stability over oceans are presented for both SAR and ASCAT. Furthermore, the Weather Research and Forecasting (WRF) offshore wind atlas of NEWA is presented. This has 3 km grid spacing with data every 30 min for 30 years from 1989 to 2018, while ASCAT has 12.5 km and SAR has 2 km grid spacing. Offshore mean wind speed maps at 100 m a.m.s.l. height from ASCAT, SAR, WRF and ERA5 at a European scale are compared. A case study on offshore winds near Crete compares SAR and WRF for flow from the north, west and all directions. The paper highlights the ability of the WRF model to simulate the overall European wind climatology and the near-coastal winds constrained by the resolution of the coastal topography in the WRF model simulations.

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“…Mesoscale meteorological models are useful for offshore wind resource assessments [4]. However, some previous studies [5][6][7] have shown that offshore winds simulated by WRF near the coast, where offshore wind farms are likely to be located in Japan in the near future, are less accurate than those simulated over the open ocean. Therefore, the authors have recently focused on the horizontal wind speed gradient near the coast to improve the WRF offshore wind simulation in this location.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Fetch Effect Using Onshore and Offshore Vertical LiDAR Devices

et al. 2018

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An offshore wind measurement campaign using vertical light detection and ranging (LiDAR) devices was conducted at the Hazaki Oceanographic Research Station (HORS) as part of an investigation into determining the optimal distance from the coast for a nearshore wind farm from a meteorological perspective. The research platform was a 427 m long pier located on a rectilinear coastline on the Pacific coast of the central Honshu Island in Japan. The relationship between the ratios of the increase of wind speed near the surface and fetch length within 5 km of the coast was analyzed via LiDAR observations taken at heights from 40 to 200 m. The results showed that the speed of the coastal wind blowing from land to sea gradually increased as the fetch length increased, by approximately 15–20% at 50 m above sea level around a fetch length of 2 km. Moreover, empirical equations were derived by applying the power law to the relationship between the increase of wind speed and fetch lengths at 1–5 km, as obtained from the LiDAR measurements. It was also found that the wind speed increase at a 2 km fetch length was equivalent to the effect of a 50–90 m vertical height increase on the coast in this region.

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Evaluating Mesoscale Simulations of the Coastal Flow Using Lidar Measurements

Cited by 10 publications

References 48 publications

The making of the New European Wind Atlas – Part 1: Model sensitivity

The making of the New European Wind Atlas – Part 1: Model sensitivity

Europe's offshore winds assessed with synthetic aperture radar, ASCAT and WRF

Investigation of the Fetch Effect Using Onshore and Offshore Vertical LiDAR Devices

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