EGU25-17062, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-17062
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Bottom dynamics and turbulence estimates from a fleet of landers in north/northwest Spanish shelf and slope
Antonio Márquez García, César Manuel González-Pola Muñiz, and Rocío Fernández Graña
Antonio Márquez García et al.
  • CSIC - Consejo Superior de Investigaciones Científicas, IEO - Instituto Español de Oceanografía, Gijón, Spain

Landers are structures designed to be deployed directly at the bottom of the sea, hosting scientific equipment to operate autonomously for long periods of time. The recent development of a remote-operated towed vehicle designed to cost-effectively deploy and recover oceanographic landers (the LanderPick vehicle) allows the design of experiments based on the massive deployment of low-cost landers.

In July 2023, 21 landers equipped with tilt current meters (Lowell TCM) and high-frequency thermistors (RBR SoloT) were deployed across the north and northwest Spanish shelves and upper slopes. The array was designed as five cross-shelf sections with four units each, at nominal depths of 50, 100, 200 and 500 meters, spanning across more than 350 nautical miles. Landers were recovered (most units) in September 2024, thus providing nearly 14 months of near-bed high-frequency environmental data. Records evidence seasonal circulation patterns and strong oscillations at tidal and inertial frequencies that vary according to location.

With a recording frequency of 5 seconds, the thermistors provide insights on turbulence intensity. In this study, we follow the methodology proposed by Cimatoribus et al. (2014) to estimate the turbulent dissipation rate from Eulerian high-frequency time-series. The procedure requires estimates of local background Brunt-Väisälä frequency, which are derived from climatologies of density profiles provided by a regional long-term observational program of essential ocean variables in the region (Radiales project). Near-bed turbulence shows a substantial increase after the arrival at seabed of the mixed layer development in autumn.

Additionally, the spatial and temporal variability of near-bed turbulence across the continental shelf observed by the fleet of landers is analysed in combination with results from additional landers located at intricate topography sites, such as canyons and seamounts. Low-cost lander structures are being further developed, pursuing to consolidate lander swarms or arrays as a tool for surveying near-bottom conditions and allowing the monitorization of a wider set of essential ocean variables.

How to cite: Márquez García, A., González-Pola Muñiz, C. M., and Fernández Graña, R.: Bottom dynamics and turbulence estimates from a fleet of landers in north/northwest Spanish shelf and slope, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17062, https://doi.org/10.5194/egusphere-egu25-17062, 2025.

Supplementary materials

Comments on the supplementary material

AC: Author Comment | CC: Community Comment | Report abuse

supplementary materials version 1 – uploaded on 26 Apr 2025, no comments