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(with the fewest samples). The uncertainty of Weibull k is around 0.04 and for energy density
from 20 to 50 Wm −2 .
15.13 Lifting satellite winds to hub-height
The SAR-based wind results are valid at 10 m above sea level (modern turbines operate at
100 m). The vertical wind profile offshore is a function of atmospheric stability, roughness and
boundary layer height (Peña et al. 2012). A method to extrapolate the satellite wind resource
statistics to wind turbine hub-height is developed. It is based on combining atmospheric
stabilityinformationfrom mesoscalemodelsintothestabilitydependentwindprofileequation.
Preliminary results are presented (Hasager at al., 2012). The potential use of the lifting
of satellite winds to hub-height is applicable for all types of 10 m satellite wind resource
statistics including SAR and scatterometer. An improvement to the method is currently being
investigated. The key difference is the use of stability information per scene versus average
stability. It is expected to be more robust and reliable to use average stability for lifting winds
to hub-height.
15.14 Future advances in ocean wind mapping from SAR
For end-users the level 2 wind product from Sentinel-1 is foreseen to be important new
data. There will still be the need for evaluation and improvement on SAR wind retrieval.
Investigations of Doppler shift anomaly in combination with GMF is one way as well as new
adjustment to polarization ratio and validated GMFs for X- and L-band. Re-processing of
the full Envisat archive to wind fields would be relevant for European scale wind resource
mapping such as the New European Wind Atlas.
15.15 Acknowledgements
We are very thankful for collaboration with Frank Monaldo and Alexis Mouche. Envisat
data provided by the European Space Agency and RADARSAT-1 data from MacDonald,
Dettwiler and Associates Ltd are acknowledged. Projects we acknowledge are Offshore wind
mapping in India with Centre for Wind Energy Technology (C-WET), FP7 NORSEWInD
TREN-FP7-219048, FP7 EERA DTOC FP7-ENERGY-2011-1/ n ◦ 282797, ICEWIND Nordic
Top-levelResearchInitiative,FP7 EuropeanRegionalDevelopmentFundandtheSouthBaltic
Programme: South Baltic Offshore Wind Energy Regions project, Off-Shore Wind Energy
Resource Assessment and Feasibility Study of Off-Shore Wind Farm Development in China
(EU-China Energy and Environment Programme), Offshore wind energy analyses over the
United Arab Emirates is funded by Abu Dhabi Future Energy Company (Masdar). We enjoy
the long-term visit of Yuko Takeyama.
Notation
A function of wind speed and local incident angle in a GMF
A Weibull scale parameter
ALOS Advanced Land Observing Satellite (Japan)
ANSWRS APL/NOAA SAR wind retrieval system
ASAR advanced C-band SAR
ASCAT Advanced Scatterometer
ASI Italian Space Agency
B function of wind speed and local incident angle in a GMF
C function of wind speed and local incident angle in a GMF
CAST China Association for Science and Technology
CSA Canadian Space Agency
DTU Wind Energy-E-Report-0029(EN) 291