Publication Date:
2016-07-19
Description:
The marine boundary layer of the northeastern U.S. is studied with focus on wind speed, atmospheric stability, and turbulent kinetic energy (TKE), the three most relevant properties in the context of offshore wind power development. Two long-term observational datasets are analyzed. The first one consists of multi-level meteorological variables measured during 2003-2011 at the offshore Cape Wind tower up to 60 m, located near the center of the Nantucket Sound. The second dataset comes from the 2013-2014 IMPOWR campaign (Improving the Modeling and Prediction of Offshore Wind Resources), in which wind and wave data were collected with new instruments on the Cape Wind platform, in addition to meteorological data measured during 19 flight missions offshore of New York, Connecticut, Rhode Island, and Massachusetts. It is found that in this region: 1) the offshore wind resource is remarkable, with monthly-average wind speeds at 60 m exceeding 7 m s -1 all year round, highest winds in winter (10.1 m s -1 ) and lowest in summer (7.1 m s -1 ), and a relatively weak diurnal modulation on average; 2) the marine boundary layer is predominantly unstable, meaning that mixing is strong, heat fluxes are positive, and the wind speed profile is often non-logarithmic (~40% of the time); and 3) the shape of the wind speed profile (log versus non-log) is an effective qualitative proxy for atmospheric stability, whereas TKE alone is not.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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