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ArticleUS East Coast lidar measurements show offshore wind turbines will encounter very low atmospheric turbulence(American Geophysical Union, 2019-05-01) Bodini, Nicola ; Lundquist, Julie K. ; Kirincich, Anthony R.The rapid growth of offshore wind energy requires accurate modeling of the wind resource, which can be depleted by wind farm wakes. Turbulence dissipation rate (ϵ) governs the accuracy of model predictions of hub‐height wind speed and the development and erosion of wakes. Here we assess the variability of turbulence kinetic energy and ϵ using 13 months of observations from a profiling lidar deployed on a platform off the Massachusetts coast. Offshore, ϵ is 2 orders of magnitude smaller than onshore, with a subtle diurnal cycle. Wind direction influences the annual cycle of turbulence, with larger values in winter when the wind flows from the land, and smaller values in summer, when the wind flows from open ocean. Because of the weak turbulence, wind plant wakes will be stronger and persist farther downwind in summer.
Technical ReportStratus Ocean Reference Station (20˚S, 85˚W), mooring recovery and deployment cruise R/V Ronald H. Brown cruise 05-05, September 26, 2005–October 21, 2005(Woods Hole Oceanographic Institution, 2006-02) Hutto, Lara ; Weller, Robert A. ; Lord, Jeffrey ; Smith, Jason C. ; Bouchard, Paul R. ; Fairall, Christopher W. ; Pezoa, Sergio ; Bariteau, Ludovic ; Lundquist, Jessica ; Ghate, Virendra P. ; Castro, Rodrigo ; Cisternas, CarolinaThe Ocean Reference Station at 20°S, 85°W under the stratus clouds west of northern Chile is being maintained to provide ongoing, climate-quality records of surface meteorology, of air-sea fluxes of heat, freshwater, and momentum, and of upper ocean temperature, salinity, and velocity variability. The Stratus Ocean Reference Station (ORS Stratus) is supported by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Observation Program. It is recovered and redeployed annually, with cruises that have come between October and December. During the October 2005 cruise of NOAA’s R/V Ronald H. Brown to the ORS Stratus site, the primary activities were recovery of the WHOI surface mooring that had been deployed in December 2004, deployment of a new WHOI surface mooring at that site, in-situ calibration of the buoy meteorological sensors by comparison with instrumentation put on board by staff of the NOAA Environmental Technology Laboratory (ETL), and observations of the stratus clouds and lower atmosphere by NOAA ETL. The ORS Stratus buoys are equipped with two Improved Meteorological (IMET) systems, which provide surface wind speed and direction, air temperature, relative humidity, barometric pressure, incoming shortwave radiation, incoming longwave radiation, precipitation rate, and sea surface temperature. The IMET data are made available in near real time using satellite telemetry. The mooring line carries instruments to measure ocean salinity, temperature, and currents. The ETL instrumentation used during the 2005 cruise included cloud radar, radiosonde ballons, and sensors for mean and turbulent surface meteorology. In addition, two technicians from the University of Concepcion collected water samples for chemical analysis. Finally, the cruise hosted a teacher participating in NOAA’s Teacher at Sea Program.