Measurements available for the assessment of off-shore wind energy resource from remote sensors: lidar and scatterometer

Brandi McCarty (1), James Churnside (2), Tim Lang (3) and Yelena Pichugina (1)

Abstract
Many satellite based wind speed estimates depend on the sea surface roughness measurements of scatterometers. The neutral-equivalent, 10-m wind speed estimate, as well as, wind direction estimates are satellite products from the ASCAT and OSCAT sensors. The data are available nearly daily for the world’s oceans. The High Resolution Doppler Lidar, HRDL, has been deployed on research ships measuring wind profiles of speed and direction from near surface to 2 km for periods of time ranging from weeks to months. This study compares the satellite estimates of near surface wind speed with that of in-situ Doppler lidar measurements in the Indian Ocean. Vertical profiles of speed and direction are used to demonstrate the skill of lidar in measuring fine scale off shore wind features. The lidar data is also used to validate near surface satellite wind products using statistical analysis. The 12.5 m range gate of the lidar profile was compared to the 10 m satellite estimate for both speed and direction matched both temporally and spatially. The near surface wind speed comparison, between the lidar and 2 satellite based scatterometers, over the time period 01-Sept-2011 to 06-Dec-2011 in the Indian Ocean show good statistical agreement and little or no bias. The lidar demonstrates great skill in fine scale structure in wind speed and direction. The measurements may be useful in predicting hourly or daily resource assessment in a limited spatial domain of ~4 km2. The near surface satellite wind speed estimates may be useful in assessing monthly or annual wind resources on a global area scale.