An intercomparison of mesoscale models at simple sites for wind energy applications

Abstract

Abstract. Understanding uncertainties in wind resource assessment associated with the use of the output from numerical weather prediction (NWP) models is important for wind energy applications. A better understanding of the sources of error reduces risk and lowers costs. Here, an intercomparison of the output from 25 NWP models is presented for three sites in northern Europe characterized by simple terrain. The models are evaluated using a number of statistical properties relevant to wind energy and verified with observations. On average the models have small wind speed biases offshore and aloft ( < 4 %) and larger biases closer to the surface over land (> 7 %). A similar pattern is detected for the inter-model spread. Strongly stable and strongly unstable atmospheric stability conditions are associated with larger wind speed errors. Strong indications are found that using a grid spacing larger than 3 km decreases the accuracy of the models, but we found no evidence that using a grid spacing smaller than 3 km is necessary for these simple sites. Applying the models to a simple wind energy offshore wind farm highlights the importance of capturing the correct distributions of wind speed and direction.

Measurements and Modelling of Offshore Wind Profiles in a Semi-Enclosed Sea

“…Simulations during non-neutral stratification have been shown to deviate more from observations compared to neutral [26,27]. Especially stable conditions and LLJs are hard to capture, and therefore the focus of this paper will be on these conditions.…”

The NEWA Ferry Lidar Experiment: Measuring Mesoscale Winds in the Southern Baltic Sea

“…Both for the horizontal wind speed and direction, the two time series showed a very similar course. Deviations seem to be in the order of, and not larger than, the scatter, i.e., the deviations between individual data points, in typical WRF-to-met-mast comparisons offshore [9]. Larger deviations are observed for the periods where the ship lies in the harbor (cf.…”

“…the scatter, i.e., the deviations between individual data points, in typical WRF-to-met-mast comparisons offshore [9].…”

“…Comparisons with data of meteorological (met) masts show that mesoscale models are capable of resolving the most important features of the marine atmospheric boundary layer and compare well with the in-situ measurements of a mast [7,8]. In this sense, it is common practice to validate and verify the data simulated with a mesoscale model (as, e.g., the known Numerical Weather Prediction (NWP) models) against data from offshore met masts [9]. In most cases, this is a fair comparison, just because of the absence of relevant microscale terrain effects impacting the mast measurements for the height ranges of interest.…”

Sodar Observation of the ABL Structure and Waves over the Black Sea Offshore Site

“…This has primarily been driven by an increased interest in wind energy, although regional weather events and the dispersion of air pollutants in coastal zones remain important issues as well. An overwhelming majority of the publications have been devoted to the numerical modeling of sea breezes (see, e.g., [1][2][3][4][5][6][7]). At the same time, the number of experimental studies of sea breezes in various countries and regions has also increased significantly.…”