Preprints
https://doi.org/10.5194/os-2021-34
https://doi.org/10.5194/os-2021-34

  30 Apr 2021

30 Apr 2021

Review status: this preprint is currently under review for the journal OS.

Evaluating High-Frequency radar data assimilation impact in coastal ocean operational modelling

Jaime Hernandez-Lasheras1, Baptiste Mourre1, Alejandro Orfila2, Alex Santana1, Emma Reyes1, and Joaquín Tintoré1,2 Jaime Hernandez-Lasheras et al.
  • 1SOCIB - Balearic Islands Coastal Observing and Forecasting System. Palma, Mallorca, Spain
  • 2IMEDEA (CSIC-UIB) - Instituto Mediterraneo de Estudios Avanzados. Esporles, Mallorca, Spain

Abstract. The impact of the assimilation of HFR (High-Frequency Radar) observations in a high-resolution regional model is evaluated, focusing on the improvement of the mesoscale dynamics. The study area is the Ibiza Channel, located in the Western Mediterranean Sea. The resulting fields are tested against trajectories from 13 drifters. Six different assimilation experiments are compared to a control run (no assimilation). The experiments consists in assimilating (i) Sea surface temperature, sea level anomaly and Argo profiles (generic observation dataset); the generic observation dataset plus (ii) HFR total velocities and (iii) HFR radial velocities. Moreover, for each dataset two different initialization methods are assessed: a) restarting directly from the analysis after the assimilation or b) using an intermediate initialization step applying a strong nudging towards the analysis fields. The experiments assimilating generic observations plus HFR total velocities with the direct restart provides the best results, improving by 53 % the average separation distance between drifters and virtual particles after the first 48 hours of simulation in comparison to the control run. When using the nudging initialization step, the best results are found when assimilating HFR radial velocities, with a reduction of the mean separation distance by around 48 %. Results show the capability of the Ensemble Optimal Interpolation data-assimilative system to correct surface currents not only inside but also beyond the HFR coverage area. The assimilation of radial observations benefits from the smoothing effect associated with the application of the intermediate nudging step.

Jaime Hernandez-Lasheras et al.

Status: open (until 25 Jun 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Jaime Hernandez-Lasheras et al.

Jaime Hernandez-Lasheras et al.

Viewed

Total article views: 80 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
62 16 2 80 0 0
  • HTML: 62
  • PDF: 16
  • XML: 2
  • Total: 80
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 30 Apr 2021)
Cumulative views and downloads (calculated since 30 Apr 2021)

Viewed (geographical distribution)

Total article views: 81 (including HTML, PDF, and XML) Thereof 81 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 05 May 2021
Download
Short summary
Correct surface ocean circulation forecasts are highly relevant for search and rescue, oil-spill and ecological processes understanding, among others. High Frequency Radars (HFR) is a remote sensing technology that measure surface currents in coastal areas with high temporal and spatial resolution. We performed a series of experiments in which we use HFR observations from the Ibiza Channel to improve the forecasts provided by a Regional ocean model in the Western Mediterranean.