Measurement masts along the Norwegian coast

A network of measurement masts collects information about the wind climate along the Norwegian coast. The network is operated by the Norwegian meteorological institute. Long-term statistical data is available from most of the masts. This project uses wind data from the measurement masts listed in the below table. The wind data is presented as wind roses, giving the probability of occurrence of a given wind speed and direction during a given time interval. Click on the "link-icon" in the table for detailed wind data.

In general all wind data is presented at 10 meters height, as the anemometer height in most cases is situated at this height. However, the wind resources are presented at 50 meters height, which is a typical hub height for wind turbines. Therefore all wind data has been transferred from 10 to 50 meters before calibration of the simulation. The vertical translation is carried out by using a logarithmic velocity profile and taking into account the sector wise roughness variation.

Applicability of the wind climatology

The wind data is used in the calibration of the simulated wind fields, in such a way that the simulations reproduce exactly the measurements at the measurement mast locations. However, the background wind speed may not be uniform through a model. Thus, non - representative input data may influence the results, giving a skewed picture through the model area. If no wind station is located within an actual terrain model, a station is translated in to the area by extrapolation. A combined physical and subjective extrapolation method is used, using estimated roughness - data, translation of the wind data to higher levels along curves determined from the station roughness, and down to surface level by curves estimated from the translated location. Weighted data from two stations may be used. In many situations the air stream stratification is non - neutral, especially during low to moderate wind speeds in the cold season. This may force the wind more around than over obstacles, and the wind speed may be too high at hill-tops. Unfortunately, we have not knowledge whenever this is an error which significantly influences the results.

In the wind resource section the applied wind data for each model is presented, together with comments about the applicability of the wind climate within the modelled area.

Micro modelling

Some of the measurement stations are severely affected by micro scale speed-ups, detailed micro modelling has been undertaken for these models. The micro models has been used in order to filtrate the micro scale effects for the site by doing a speed-up correction; Micro modelling. The location where the speed-up corrected wind data is applied is slightly translated to a new position at open sea, in accordance with the removal of micro scale effects.