Mapping near-inertial variability in the SE Bay of Biscay from HF radar data and two offshore moored buoys

Abstract

.[1] HF radar surface current data together with data from two operational offshore oceanographic buoys located over the slope are used to map the variability associated with the near-inertial waves, during a target year (2009), in the SE Bay of Biscay. The results obtained show the complex 4D distribution of inertial oscillations in this area. We find a very pronounced horizontal structure across the area with ranges of a factor 5 in near-inertial kinetic energy. This pattern presents also strong seasonal variability, with a peak in KE closer to the shelf-break in summer, whereas winter maximum is weaker and located further to the north-east. The mooring data indicate more trapping near the surface in summer. These patterns are discussed in relation to the known seasonal differences in atmospheric/ buoyancy forcing and the characteristics of the sub-inertial surface velocity field. Citation: Rubio, A., G. Reverdin, A. Fontán, M. González, and J. Mader (2011), Mapping nearinertial variability in the SE Bay of Biscay from HF radar data and two offshore moored buoys, Geophys.

Surface circulation and Lagrangian transport in the SE Bay of Biscay from HF radar data

“…In addition, parameters related to errors due to the geometrical dilution of the precision are calculated and controlled when deriving total velocities from radials. Eulerian comparison between the HF radar data and other available in-situ data in the SE Bay of Biscay has been performed in previous work [14,15,16]. The comparison between radar data and the currents at 1.…”

“…At shorter time-scales, the variability is dominated by inertial oscillations and tides (mainly semidiurnal), although energy contents around the main tidal peaks are lower than in other areas of the Bay [13]. Reference [14] discussed on the contribution of inertial oscillations to the shear-induced vertical mixing in this area [3] and, from HF radar data in 2009, showed that the distribution of kinetic energy around the inertial band was highly variable in time and space [14].…”

“…During the last years, several comparison exercises of HF radar data with other existing measures in the area, from the in-situ network and other available data, have proved the performances of the Basque HF radar system from a Eulerian point of view [14, 15 16]. Previous work has shown its potential for the study of the ocean processes and the complex spatial patterns at different time scales governing the surface circulation in the area [14,15,16,17].…”

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

“…A growing number of European studies have been developed on the use of HFR data toward a better understanding of the surface ocean coastal dynamics (Shrira et al, 2001;Rubio et al, 2011;Schaeffer et al, 2011;Uttieri et al, 2011;Sentchev et al, 2013;Berta et al, 2014a;Shrira and Forget, 2015;Stanev et al, 2015;Falco et al, 2016). Moreover, since HFR data provide measurements of currents with a relatively wide spatial coverage and high spatial and temporal resolution in near real time (there are systems with lags of just 20 min, after generating the data), they have become invaluable tools in the field of operational oceanography.…”

Variability in the air–sea interaction patterns and timescales within the south-eastern Bay of Biscay, as observed by HF radar data

“…Standard quality control procedures were applied to radial and total velocities (Rubio et al, 2011). The HF radar currents were validated by Rubio et al (2011); these authors concluded that the HF radar currents agree well with in situ measurements in the area.The wind components at 10 m a.s.l. of the Climate Forecast System Reanalysis (CFSR), provided by the National Centers for Environmental Prediction (NCEP), were also analysed in this study (Saha et al, 2010).…”