CERRA

Spatial domain for the CERRA mesoscale data in windPRO (we cover approx. 300km from the coastline). Image showing average wind speeds at 100m from January 2012 - taken from the https://www.windprospecting.com platform.

Temparatures from the CERRA model. 100m height on Januray 1st 2000 @ 00:00.

Introduction

The Copernicus Regional Reanalysis for Europe, CERRA, is a high-resolution regional reanalysis (RRA) for a pan-European domain. It is being provided by the European Copernicus programme, and delivered though a contract with the Swedish Meteorological and Hydrological Institute (SMHI) and with Meteo-France and the Norwegian Meteorological Institute as subcontractors. The model holds data at 5.5km resolution. CERRA is downscaling to its 5.5km resolution with initial conditions and boundary conditions provided from ERA5 reanalysis data. The CERRA dataset is making extensive use of remote sensing data as well as local observations, sea-ice records and sea-surface temperature fields.

CERRA is based on the HARMONIE-ALADIN data assimilation system and is applying a 3D variational analysis (3D-VAR). Assimilation is run with 8 cycles per day at 00, 03, 06, 09, 12, 15, 18 and 21 UTC. While quite many of the mesoscale datasets used in wind energy industry are developed using the excellent WRF model, here the numerical weather prediction model used is HARMONIE–ALADIN. As such, the CERRA dataset provides a welcome and alternative modelling chain to what is commonly used for wind-energy modelling - providing valuable input for uncertainty modelling and second-opinion analyses. The HARMONIE-ALADIN model is developed by the ACCORD consortium - and used by many meteorological institutes in Europe.

Dataset Overview

• Content: Limited feature and spatial-domain subset of the CERRA mesoscale dataset
  (we provide about 973.000 nodes in a distance of approx. 300km from the coastlines).
• Spatial resolution: 5.5km
• Temporal resolution: Timestep 1 hour
• Coverage: See the map to the right
• Period: In windPRO: 20+ years of data from 1999-01-01 to 2021-06-30
  (source data dates back to 1984 from the Copernicus system)
  
• Update schedule: Unknown.
  The original contract (2017/C3S_322_Lot1_SMHI/SC2) between ECMWF/Copernicus and SMHI initially lasted 4 years and is now terminated. We expect updated data in late 2023, and will update this dataset when more recent data becomes available. For on update on CERRA-data status, please visit the official documentation here.
  

Usage Notes

1. I am interested in other parameters and model ensembles - where can I get those? The data is freely available from the Copernicus Climate Data Store (C3S) - here. Ensemble data are available on a coarser 11km grid.
2. How do I find more on model details? See the external references below.
3. Two days of data (in ealy april 2021) are missing? This is due to a data-sample missing from the ECMWF Copernicus Climate Change Data Store (C3S) - @2022-11-01. We have contacted C3S about these data, but currently they have not been able to restore the data. We have two days missing, as we need an extra day to extract data based on accumulated data-fields.
4. I am already using EMD-WRF Europe+ wind speed data. How does CERRA perform in comparison? An evaluation memo is available - comparing modelling-data from CERRA, EMD-WRF EUR+ and ERA5 with 194 high-quality and tall masts - access the validation-one-pager here.

Dataset Parameters

A total of 80 parameters are available from the CERRA mesoscale data-subset in windPRO.

Table: Overview of CERRA Dataset Parameters (5.5 km grid).

Parameter	Unit	Description	Type
time		UTC time stamp (YYYY-MM-DD HH:MM)
wSpeed.x	m/s	Wind speeds at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
wDir.x	deg	Wind directions at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
sqrtTKE.x	m/s	Wind speed given as standard deviation in m/s. Derived from the turbulent kinetic energy (TKE) at different heights above ground (x). Use with caution, and avoid use for site assessment and loads as variability is underestimated. Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
press.x	Pa	Pressure at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
temp.x	celcius	Temperature at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
rh.x	%	Relative humidity at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
cloudWater.x	mg/kg	Cloud water content at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
cloudIce.x	mg/kg	Cloud icing content at different heights above ground (x). Heights (x): 15,50,75,100,150,200,300,500m	Instantaneous
wSpeed.10	m/s	Wind speeds at 10m.	Instantaneous
wDir.10	deg	Wind direction at 10m.	Instantaneous
wGust.10	deg	Wind gust at 10m.	Instantaneous
temp.2	celcius	Temperatures at 2m	Instantaneous
rh.2	%	Relative humidity at 2m	Instantaneous
psfc	Pa	Pressure at site	Instantaneous
msl	Pa	Pressure at mean sea level	Instantaneous
z0	m	Rougnhess length	Instantaneous
totalCloudCover	%	Total cloud cover in atmosphere	1h Average
totPrecip	kg/m2	Total Precipitation at surface	1h Accumulated
sensHeatFlux	W/m2	Sensible Heat Flux at surface	Instantaneous
momFluxU	N/m2	Instantaneous northward turbulent surface stress	Instantaneous
momFluxV	N/m2	Instantaneous eastward turbulent surface stress	Instantaneous
zust	m/s	U-star (friction velocity)	Instantaneous
ssr	W/m2	Surface net solar radiation	1h Accumulated
ssrc	W/m2	Surface net solar radiation, clear sky	1h Accumulated
ssrd	W/m2	Surface solar radiation downwards	1h Accumulated

License and Attribution

If data from this dataset is used within any private or public disseminations, then EMD and its data providers must be acknowledged.

Source: 
CERRA: The Copernicus Regional Reanalysis for Europe. Distribution through EMD and windPRO - EMD International A/S, 2022.
This dataset uses CERRA which is being developed through the Copernicus Climate Change Service (C3S). 
Data processing for CERRA is carried out by SMHI and distribution by ECMWF.

More details on free and open Copernicus licensing conditions here in this pdf (version 1.2 from November 2019).

Required windPRO License and Modules

This dataset can be accessed from the most recent version of windPRO given that you hold an active service agreement and a license to the following modules:

• BASIS
• METEO

External Links and References

CERRA Data

• CERRA Home Page - here
• CERRA Product User Guide (at ECMWF Wiki) - here

CERRA Developers

• ACCORD Consortium home-page (developers of HARMONIE-ALADIN model) - here
• Swedish Meteorological and Hydrological Instutute (SMHI) - here
• Meteo France - here
• Norwegeian Meteorological Institute - here

Acknowledgement and Credits

Credits and Acknowledgement: The European Commission, the ECMWF, the Copercius Climate Change Service, SMHI, MeteoFrance and MET-NO are acknowledged for the development and release of the free and open CERRA data. Thanks a lot: this dataset will surely aid the development of renewable energy and help us adressing some of the uncertainties in our modelling of wind-energy.