Leo Maas
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Internal waves: Field observations
The internal tide in the Bay of Biscay is observed to constitute a beam whose structure is well-resolved with the help of a towed ADCP. A model predicts the beam to reflect from the bottom, and, depending on the presence and strength of a seasonal thermocline, to either reflect or scatter into a combination of thermocline waves and obliquely propagating internal waves. Observations deep down in the Bay of Biscay reveal 'clean' spectra, with lots of mixed harmonics being generated by both tides and inertial oscillations. On the shelf observations show the thermocline "attracts" high shear due to inertial oscillations.     Internal tide amplitude (left; m/s) and phase (right, degrees) in vertical cross-sections obtained from Bay of Biscay field observations (top) and a numerical model (bottom). The observed area in the top panels corresponds to that inside the dashed rectangle in the bottom panels. Horizontal and vertical distances are given in kilometers (see Lam et al 2004, and Gerkema et al 2004)
Publications:
Lam, F.-P. A., Maas, L.R.M., Gerkema, T. (2004) Spatial structure of tidal and residual currents as observed over the shelf break in the Bay of Biscay.  Deep-Sea Research I, in press. ( Download PDF-file )   Gerkema, T., Lam, F.-P. A., Maas, L.R.M. (2004) Internal tides in the Bay of Biscay: conversion rates and seasonal effects.  Deep Sea Research II, in press. ( Download PDF-file )   Haren, J.J.M. van, Maas, L.R.M., Aken, H.M. van (2002) On the nature of internal wave spectra near a continental slope.   Geophysical Research Letters, 29(12): 10-102. ( Download PDF-file ) See also corrigendum.   Haren, J.J.M. van, Maas, L.R.M., Zimmerman, J.T.F, Ridderinkhof, H., Malschaert, H. (1999) Strong inertial currents and marginal internal wave stability in the central North Sea.   Geophysical Research Letters, 26: 2993-2996. ( Download PDF-file )
Unpublished webscript:
Lam, F.-P.A., Gerkema, T., Maas, L.R.M. Preliminary Results from Observations of Internal Tides and Solitary Waves in the Bay of Biscay.