US East Coast Synthetic Aperture Radar Wind Atlas for Offshore Wind Energy

Tobias Ahsbahs, Galen Maclaurin, Caroline Draxl, Christopher Jackson, Frank Monaldo, Merete Badger

Research output: Contribution to journalArticlepeer-review

22 Scopus Citations

Abstract

We present the first synthetic aperture radar (SAR) offshore wind atlas of the US East Coast from Georgia to the Canadian border. Images from RADARSAT-1, Envisat, and Sentinel-1A/B are processed to wind maps using the geophysical model function (GMF) CMOD5.N. Extensive comparisons with 6008 collocated buoy observations of the wind speed reveal that biases of the individual systems range from -0.8 to 0.6ms -1. Unbiased wind retrievals are crucial for producing an accurate wind atlas, and intercalibration of the SAR observations is therefore applied. Wind retrievals from the intercalibrated SAR observations show biases in the range of to -0.2 to 0.0ms -1, while at the same time improving the root-mean-squared error from 1.67 to 1.46ms -1. The intercalibrated SAR observations are, for the first time, aggregated to create a wind atlas at the height 10ma.s.l. (above sea level). The SAR wind atlas is used as a reference to study wind resources derived from the Wind Integration National Dataset Toolkit (WTK), which is based on 7 years of modelling output from the Weather Research and Forecasting (WRF) model. Comparisons focus on the spatial variation in wind resources and show that model outputs lead to lower coastal wind speed gradients than those derived from SAR. Areas designated for offshore wind development by the Bureau of Ocean Energy Management are investigated in more detail; the wind resources in terms of the mean wind speed show spatial variations within each designated area between 0.3 and 0.5ms -1 for SAR and less than 0.2ms -1 for the WTK. Our findings indicate that wind speed gradients and variations might be underestimated in mesoscale model outputs along the US East Coast.

Original languageAmerican English
Pages (from-to)1191-1210
Number of pages20
JournalWind Energy Science
Volume5
Issue number3
DOIs
StatePublished - 2020

Bibliographical note

See NREL/JA-5000-77002 for article as published in Wind Energy Science Discussions

NREL Publication Number

  • NREL/JA-5000-77935

Keywords

  • offshore wind energy
  • synthetic aperture radar
  • wind atlas
  • WIND Toolkit

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