NEWA Meso-Micro Challenge Phase 2: Rödeser Berg
Test your wind assessment methodologies at the NEWA forested hill experimental site: Rödeser Berg
The Forested Hill Experiment Kassel was conducted within the EU project NEWA — New European Wind Atlas (ERA-NET Plus, topic FP7-ENERGY.2013.10.1.2).
Status: The benchmark is open for participation. Minor modifications might occur based on the experience and also questions of the benchmark participants. Feel free to post questions in the comment section or e-mail the benchmark manager. If you consider to participate in this benchmark, let the benchmark manager know to keep you updated on possible changes: martin.doerenkaemper@iwes.fraunhofer.de
Update (31.03.2019): We are still open for receiving results from interested participants. We will finally close the submission by May 1st, 2019.
This field campaign provides a unique dataset of wind measurements for validating models for flow over forested hilly terrain. The experiment was conducted on the Rödeser Berg, a hill (380m height) near Kassel, Germany (see Fig. 1). In October 2016, a three month intensive campaign relying heavily on remote sensing devices, i.e. lidar and sodar wind measurement systems, marked the beginning of the experiment. At the same time a one year long-term campaign using two tall masts started.
The Rödeser Berg site is located in the federal state Hessia (Germany), around 20km northwest of the city of Kassel. The terrain height is between 200 m and 400m (hill top) (see. Fig 2 — left). The hill site is characterized by broadleaf forests with some spots of coniferous wood.
Tree heights are around 20–35 m (see. Fig. 2-right). The roughness length in the area is in the range of 0.03 to 0.75 m (see Fig. 3).
In Spring of 2015 a wind farm, consisting of four Enercon E 101 (3 MW, rotor diameter: 101 m, hub height 35 m) became operational at the site. These turbines are located northwest of the 200m met mast on the hill-top.
The benchmarks will provide a one year time series of one met mast (reference) and ask for prediction of the wind conditions at a different point in terrain where the second met mast (target) operated. The target met mast data will not be provided in order to emulate a realistic modelling situation typical in site assessment.
The two met masts are located at the following positions:
Input Data
All input data is provided via b2drop and can be accessed via the following link: https://b2drop.eudat.eu/s/6AsjPnRL8x7KBHk
Namely, the input data set consists of terrain data (including terrain height and forest information) as well as met mast time series. Mesoscale forcing data can be provided by the NEWA consortium upon request.
a) Terrain Data
Terrain data (terrain height, inclination, forest height, forest density) is provided in netCDF format for an 8 x 8 km patch in a resolution of 10 m. In addition, aerodynamic roughness data based on CORINE is provided. The simulation domain does not necessarily need to be fixed to this patch. Feel free to use your best practice approach and reduce/increase the domain size with other data sources (e.g. lower resolution satellite data) if needed.
b) Met Mast Time Series
A one year time series (31.10.2016–30.10.2017) from one of the two met mast (MM140) is provided. This time series consists of wind speed at two heights (80m and 135m), wind direction (80m) and the dimensionless Obukhov length (20m/L) in a single netCDF file. The data of the second evaluation point is hold back. For a correct and fair evaluation it was made sure that data from both masts and all relevant sensors are available at every time step. This explains the comparatively large number of missing values of the time series provided.
c) [Optional:] Mesoscale Forcing
Mesoscale forcing data for the simulation period from WRF simulations can be provided by CENER upon request. Please contact Javier Sanz Rodrigo in case you need or want to use this data for setting up your modelling approach.
Output Data
The ultimate goal is to provide annual quantities, derived by bin-averaging model simulations from relevant wind direction sectors and stability classes. To homogenize the output data please consider these indications:
- One netCDF file per site and per simulation run including both of the two validation positions grouped by “profiles”.
- Each profile is defined in terms of 3D tables, where the third index denotes the stability class (1 = ‘u’, 2 = ’n’, 3 = ‘s’), the first index refers to a point in the profile (identified by an ID number) and the second index provides the value for the following bin-averaged quantities. Hence, for each stability class, the following 2D tables will be generated:
ID, x, y, z, f1, S1, WD1, tke1, … , f12, S12, WD12, tke12where x,y,z are coordinates of a sensor location in the microscale map, with z being the height above ground level, f being the frequency of the corresponding bin, and the subscripts denote the wind direction sector number.
The binning of the results should be done in 30 degree windows and three stability classes. We suggest the following binning:
WD = 15, 45, 75, …, 345˚ (30 degree steps, centered on middle)
Unstable: z/L < -0.05
Neutral: -0.05<z/L<0.05
Stable: z/L>0.05
The evaluation will focus on the bins 195, 225, 255˚ to neglect the impact of wakes on the wind conditions. However, you are invited to provide data for all bins.
A python3 script is provided (see Link given in section Input data) to support you writing your data to the correct NetCDF format. Please respect the naming convention for variables to allow automatic post-processing.
Together with the output data you should provide a summary of your model set-up and methodology to extract the bin-averaged output quantities.
All data (i.e. the netCDF Output data and the model setup description) should be uploaded in a single zip file to the following directory:
https://b2drop.eudat.eu/s/e26nQxeKCKE8R2L
Remarks
You may want to read about these previous benchmarks at the Rödeser Berg site:
or have a look to the full documentation of the Rödeser Berg experiment:
