(Sub‐)inertial wave boundary turbulence in the Gulf of Valencia. Issue 4 (25th April 2013)

• Record Type: Journal Article
• Authors: van Haren, Hans; Ribó, Marta; Puig, Pere
• Is Part Of: Journal of geophysical research. Volume 118:Issue 4(2013:Apr.)
• Page Start: 2067
• Page End: 2073
• Publication Date: 2013-04-25
• Subjects: 50‐m high K‐H billows -- inertial wave turbulence -- Gulf of Valencia; Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/jgrc.20168
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract : [1] The bottom boundary layer above sloping topography can be highly turbulent, even in deep seas. This is demonstrated here using high‐resolution 1‐Hz sampling temperature sensors that were moored for 5 months every 0.5 m between 6.5 and 61 m above a 572 m deep seafloor promontory on the continental slope off Valencia, Spain. Using these data, turbulence parameters have been estimated. With time and in the vertical, values vary over four orders of magnitude. They have a dominant local inertial period which is modulated by an about 11 day periodicity associated with variations in a baroclinic unstable boundary current. When this current is strong and Eastward, the upslope phase of inertial wave generates convective turbulence which reaches closest to the bottom and therefore can effect sediment dispersal. In late winter, equally strong shear‐induced turbulence in 50 m high Kelvin‐Helmholtz (K‐H) overturns is forced by 0.2 m s −1 off/downslope motions, which are preceded by periods of warming of a few 0.01°C before the cooler near‐bottom water is suddenly flushed over the promontory into the basin. Such anomalously large K‐H overturns occurred 6 times in the investigated winter period. Key Points: high‐resolution observations of two types of turbulence in Mediterranean Driving mechanisms are a boundary flow and near‐inertial internal waves In late winter, these cause flushing of cool near‐bottom water into the basin