Lifting satellite winds from 10 m to hub-height

Transcription

1 Lifting satellite winds from 10 m to hub-height Hasager, C.B., Badger, M., Peña, A., Hahmann, A., Volker, P. 23 May 2016 VindkraftNet meeting, DONG Energy, Skærbæk

2 Motivation We have: Satellite wind maps valid at 10 m height at 1 km by 1 km spatial resolution. It is the equivalent neutral wind, i.e. not real wind. WRF can provide results on stability. We would like to have: Estimate of wind resource at 100 m, i.e. with stabilitydependent winds combining satellite winds and WRF stability.

3 Envisat ASAR and Sentinel-1a/b Envisat years data archive Envisat concept art via ESA Artist's view of the deployed Sentinel-1 spacecraft (image credit: ESA, TAS-I) Sentinel-1A - 03 April Sentinel-1B - 25 April Operational lifespan: 7 years (with consumables for 12).

4 SAR wind data archive at DTU 15,000+ ENVISAT ASAR scenes ( ) 26,000+ Sentinel-1A SAR scenes (2014->) 4

5 SAR Operational Products System (SAROPS) SAR wind retrieval in near-real-time (< 6h from data acquisition) at DTU for the European Seas since Download and pre-processing SAR GFS Ice SAROPS Wind maps S-WAsP Wind resource maps (10 m) WRF + MOST Wind resource maps (100 m) Wind retrieval (APL/NOAA) Wind resource assessment (DTU) Wind resource extrapolation (DTU)

6 Sentinel-1a wind map Wind field from Sentinel-1A, 25 April 2015 at 05:40 UTC

7 Wind resource mapping

8 NORSEWInD 10-m wind atlas from Envisat ASAR 5/23/2016 8

9 9 5/23/2016

10 SAR and mast wind comparisons RMSE R Horns Rev M2 Egmond aan Zee Fino-1 Horns Rev M7 Greater Gabbard Wind speeds from SAR and 5 masts in the North Sea, At Horns Rev M2 and Egmond aan Zee we have information to derive the atmospheric stability. Hasager, C.B. et al. (2015): Offshore wind climatology based on synergetic use of Envisat ASAR, ASCAT and QuikSCAT. Remote Sensing of Environment, 156, /j.rse /23/2016

11 The New European Wind Atlas (NEWA) Larger area Envisat ASAR and Sentinel-1 A/B Extrapolation to different heights up to 100 m Extensive measurement campaigns and modeling Coverage of the satellite based atlas in NEWA (image courtesy Google Earth)

12 Wind speed comparisons Envisat ASAR vs. GFS model Sentinel-1A SAR vs. GFS model

13 Preliminary 10-m atlas for Europe Envisat ASAR and Sentinel-1A combined

14 Wind speed extrapolation to 100 m Horns Rev M2 mast The North Sea Peña, A. & Hahmann, A.N. (2012): Atmospheric stability and turbulence fluxes at Horns Rev an intercomparison of sonic, bulk and WRF model data, Wind Energy, 15, , DOI: /we /23/2016

15 Frequency distribution of 1/L Obukhov length, L - from WRF outputs of UST, T2 and HFX: L WRF = UST3 T2 g κ HFX L > 0: stable L 0: unstable Distribution of 1/L from WRF outputs at Fino-2 ( ) 15

16 Long-term stability correction Probability density function of 1/L: Long-term standard deviation: σ ± = g T2 HFX HFX ± UST 3 2 C ± exp (C ± 1/L / σ ± ) 2/3 P = n ± σ ± Γ 1 + 3/2 Long-term stability correction: ψ m = n + 3σ + C + b z + n f Kelly, M. and Gryning, S.-E. (2010): Long-term mean wind profiles based on similarity theory, Boundary-Layer Meteorology, 136,

17 Stability correction at 100 m The South Baltic Sea

18 Long-term average wind profile κ u(z) u = ln z z 0 ψ m Fino-2 in the South Baltic Sea

19 Wind speed extrapolated to 100 m Without stability correction With stability correction Badger, M. et al.: Extrapolating satellite winds to turbine operating heights, Journal of Applied Meteorology and Climatology, 44, , doi: /JAMC-D

20 Conclusions The bias on SAR wind speeds with respect to GFS model wind speeds is lower for Sentinel-1A than for Envisat ASAR. Extrapolation of SAR winds to the turbine height can be achieved through application of a modelled long-term stability correction to the wind profile.

21 Acknowledgements Satellite data: The European Space Agency (ESA) SAR wind retrieval systems: JHU/APL and NOAA Collecte Localisation Satellites (CLS) Mast observations: All mast data accessed through the NORSEWInD project. Horns Rev: DONG energy and Vattenfall, Fino-1 and Fino-2: Deutsches Windenergie Institut, Egmond an Zee: NoordZeewind, Greater Gabbard: SSE Renewables. Funding: EU-NORSEWInD, South Baltic OFFER, New European Wind Atlas Collaboration: Frank Monaldo & Christopher Jackson, NOAA; Alexis Mouche, IFREMER

22 Journal of Applied Meteorology and Climatology, 44, , doi: /JAMC-D