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Observations of the trade wind wakes of Kauai and Oahu
Author(s) -
Yang Yang,
Ma Jian,
Xie ShangPing
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl031742
Subject(s) - wake , geology , sea breeze , diurnal cycle , shore , oceanography , wind shear , forcing (mathematics) , climatology , thermal wind , wind speed , atmospheric sciences , aerospace engineering , engineering
The Hawaiian islands of Kauai and Oahu stand in the path of the east‐northeasterly trade winds, creating wakes in the lee. For the first time, the structure of the wakes and their diurnal cycle were observed on a cruise during 18–20 December 2006. The dynamic wakes, characterized by reduced trades, extend about 1 km in height with strong wind shear at the top. Thermal forcing of these small islands also affects the wake circulations. Sea breezes develop in the afternoon turning the winds into westerly near the shore in the wakes. At night, land breezes advect cool air from the islands, creating a shallow cool layer between the sea surface and a capping inversion. The warming in the wake in the afternoon extends much deeper (1.4 km) than the cool layer (0.5 km) at night. The effect of diurnal changes on cloud formation in the wakes is discussed, and the sharp variations in wind velocity lee of the islands may affect ocean currents, waves and mixing.