Review of "Joint analysis of coastal altimetry and HF radar data: observability of seasonal and mesoscale ocean dynamics in the Bay of Biscay"

Abstract. Coastal HF radar systems provide operational measurements of coastal surface currents with high spatial (~ 1–5 km) and temporal (~ hourly) sampling resolution while the near continuous altimetry missions afford, from 1993 to nowadays, information of geostrophic currents in the global ocean with typical along-track and temporal sampling resolutions of > 7 km and > 9 days, respectively. During the last years, the altimetry community has made a step forward in improving these data in the coastal area, where the data present lower quality than in the open ocean. The combination of HF radar and altimetry measurements arises as a promising strategy to improve the continuous monitoring of the coastal area (e.g. by expanding the measurements made by HF radars to adjacent areas covered by the altimetry, or by validating/confirming improvements brought by specific coastal algorithms or new altimeter missions). A first step towards this combination is the comparison of both datasets in the overlapping areas. In this study, a HF radar system and two Jason-2 satellite altimetry products with different processing (CTOH and CMEMS) are compared over the period from 1 January 2009 to 24 July 2015. The results provide an evaluation of the performance of different coastal altimetry datasets within the study area and a better understanding of the ocean variability contained in the HF radar and both altimetry data sets. The variability of the radar and altimetry measurements is higher near the coast, and both observing systems detect the Iberian Poleward Current and eddies, which are the main mesoscale processes within the study area. The highest correlations between radar and altimetry (up to 0.64) take place in the slope, where the Iberian Poleward Current represents a significant part of the mesoscale variability. Besides, the use of a simple Ekman model to add the wind-induced current component to the to the altimetry-derived geostrophic currents increases the agreement between both data sets (increasing the correlation in around 10 %).

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

2013 MTS/IEEE OCEANS - Bergen ◽

10.1109/oceans-bergen.2013.6608039 ◽

2013 ◽

Cited By ~ 3

Author(s):

Anna Rubio ◽

Lohitzune Solabarrieta ◽

Manuel Gonzalez ◽

Julien Mader ◽

Sonia Castanedo ◽

...

Keyword(s):

Radar Data ◽

Hf Radar ◽

Bay Of Biscay ◽

Lagrangian Transport ◽

Surface Circulation

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

Ocean Science ◽

10.5194/os-9-399-2013 ◽

2013 ◽

Vol 9 (2) ◽

pp. 399-410 ◽

Cited By ~ 6

Author(s):

A. Fontán ◽

G. Esnaola ◽

J. Sáenz ◽

M. González

Keyword(s):

Radar Data ◽

Hf Radar ◽

Bay Of Biscay ◽

Interaction Patterns ◽

The South ◽

South Eastern ◽

Continental Shelves ◽

Surface Circulation ◽

Spatial Coverage ◽

Current Interaction

Abstract. Two high-frequency (HF) radar stations were installed on the coast of the south-eastern Bay of Biscay in 2009, providing high spatial and temporal resolution and large spatial coverage of currents in the area for the first time. This has made it possible to quantitatively assess the air–sea interaction patterns and timescales for the period 2009–2010. The analysis was conducted using the Barnett–Preisendorfer approach to canonical correlation analysis (CCA) of reanalysis surface winds and HF radar-derived surface currents. The CCA yields two canonical patterns: the first wind–current interaction pattern corresponds to the classical Ekman drift at the sea surface, whilst the second describes an anticyclonic/cyclonic surface circulation. The results obtained demonstrate that local winds play an important role in driving the upper water circulation. The wind–current interaction timescales are mainly related to diurnal breezes and synoptic variability. In particular, the breezes force diurnal currents in waters of the continental shelf and slope of the south-eastern Bay. It is concluded that the breezes may force diurnal currents over considerably wider areas than that covered by the HF radar, considering that the northern and southern continental shelves of the Bay exhibit stronger diurnal than annual wind amplitudes.

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Joint analysis of coastal altimetry and high-frequency (HF) radar data: observability of seasonal and mesoscale ocean dynamics in the Bay of Biscay

Ocean Science ◽

10.5194/os-14-1265-2018 ◽

2018 ◽

Vol 14 (5) ◽

pp. 1265-1281 ◽

Cited By ~ 4

Author(s):

Ivan Manso-Narvarte ◽

Ainhoa Caballero ◽

Anna Rubio ◽

Claire Dufau ◽

Florence Birol

Keyword(s):

Coastal Area ◽

High Frequency ◽

Ocean Dynamics ◽

Hf Radar ◽

Global Ocean ◽

Joint Analysis ◽

Data Sets ◽

Altimetry Data ◽

Geostrophic Currents ◽

Temporal Sampling

Abstract. Land-based coastal high-frequency (HF) radar systems provide operational measurements of coastal surface currents (within 1–3 m depth) with high spatial (300 m–10 km) and temporal (≤1 h) sampling resolutions, while the near-continuous altimetry missions provide information, from 1993 until today, on geostrophic currents in the global ocean with typical along-track and temporal sampling resolutions of >7 km and >9 days, respectively. During the last years, the altimetry community has made a step forward in improving these data in the coastal area, where the data present lower quality than in the open ocean. The combination of HF radar and altimetry measurements arises as a promising strategy to improve the continuous monitoring of the coastal area (e.g. by expanding the measurements made by HF radars to adjacent areas covered by the altimetry or by validating/confirming improvements brought by specific coastal algorithms or new altimeter missions). A first step towards this combination is the comparison of both data sets in overlapping areas. In this study, a HF radar system and two Jason-2 satellite altimetry products with different processing are compared over the period from 1 January 2009 to 24 July 2015. The results provide an evaluation of the performance of different coastal altimetry data sets within the study area and a better understanding of the ocean variability contained in the HF radar and altimetry data sets. Both observing systems detect the main mesoscale processes within the study area (the Iberian Poleward Current and mesoscale eddies), and the highest correlations between radar and altimetry (up to 0.64) occur in the slope where the Iberian Poleward Current represents a significant part of the variability in the circulation. Besides, the use of an Ekman model, to add the wind-induced current component to the altimetry-derived geostrophic currents, increases the agreement between both data sets (increasing the correlation by around 10 %).

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Variability in the air–sea interaction patterns and time-scales within the Southeastern Bay of Biscay, as observed by HF radar data

Ocean Science Discussions ◽

10.5194/osd-9-2793-2012 ◽

2012 ◽

Vol 9 (4) ◽

pp. 2793-2815

Author(s):

A. Fontán ◽

G. Esnaola ◽

J. Sáenz ◽

M. González

Keyword(s):

Time Scales ◽

Radar Data ◽

Hf Radar ◽

Bay Of Biscay ◽

Interaction Patterns ◽

Synoptic Variability ◽

Continental Shelves ◽

Surface Circulation ◽

Spatial Coverage ◽

Current Interaction

Abstract. Two high frequency (HF) radar stations were installed on the Southeastern Bay of Biscay in 2009, providing high spatial and temporal resolution and large spatial coverage currents for the first time in the area. This has enabled to determine quantitatively the air–sea interaction patterns and time-scales for the period 2009–2010. The analysis was conducted by using the Barnett-Preisendorfer approach to canonical correlation analysis (CCA) of reanalysis surface winds and HF radar-derived currents. The results reveal that the CCA yields two canonical patterns. The first wind-current interaction pattern corresponds to the classical Ekman drift at sea surface, whilst the second describes an anticyclonic/cyclonic surface circulation. The results obtained demonstrate that the local winds play an important role in driving the upper water circulation. The wind-current interaction time-scales are mainly related to diurnal breezes and synoptic variability. In particular, the breezes force diurnal currents in the continental shelf and slope of the Southeastern Bay. It is concluded that the breezes may force diurnal currents over considerably wider areas than that covered by the HF radar, considering that the northern and southern continental shelves of the Bay exhibit stronger diurnal than annual wind amplitudes.

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Surface water circulation patterns in the southeastern Bay of Biscay: New evidences from HF radar data

Continental Shelf Research ◽

10.1016/j.csr.2013.11.022 ◽

2014 ◽

Vol 74 ◽

pp. 60-76 ◽

Cited By ~ 37

Author(s):

Lohitzune Solabarrieta ◽

Anna Rubio ◽

Sonia Castanedo ◽

Raúl Medina ◽

Guillaume Charria ◽

...

Keyword(s):

Surface Water ◽

Radar Data ◽

Water Circulation ◽

Hf Radar ◽

Bay Of Biscay ◽

Circulation Patterns

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

Geophysical Research Letters ◽

10.1029/2011gl048783 ◽

2011 ◽

Vol 38 (19) ◽

pp. n/a-n/a ◽

Cited By ~ 22

Author(s):

A. Rubio ◽

G. Reverdin ◽

A. Fontán ◽

M. González ◽

J. Mader

Keyword(s):

Radar Data ◽

Hf Radar ◽

Bay Of Biscay

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Updating IRI Model Using Vertical Sounding and GIM TEC Data and Its Application for the Ekaterinburg HF Radar Data Simulation

2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science ◽

10.23919/ursigass49373.2020.9232229 ◽

2020 ◽

Author(s):

Alexey V. Oinats ◽

Ilya K. Edemsky ◽

Denis D. Rogov

Keyword(s):

Radar Data ◽

Hf Radar ◽

Data Simulation ◽

Iri Model

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Gap Filling of the CALYPSO HF Radar Sea Surface Current Data through Past Measurements and Satellite Wind Observations

International Journal of Navigation and Observation ◽

10.1155/2016/2605198 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Adam Gauci ◽

Aldo Drago ◽

John Abela

Keyword(s):

Oil Spills ◽

Surface Current ◽

Radar Data ◽

Current Data ◽

Hf Radar ◽

Sea Surface ◽

Machine Learning Techniques ◽

Learning Techniques ◽

Spatial Coverage ◽

Essential Components

High frequency (HF) radar installations are becoming essential components of operational real-time marine monitoring systems. The underlying technology is being further enhanced to fully exploit the potential of mapping sea surface currents and wave fields over wide areas with high spatial and temporal resolution, even in adverse meteo-marine conditions. Data applications are opening to many different sectors, reaching out beyond research and monitoring, targeting downstream services in support to key national and regional stakeholders. In the CALYPSO project, the HF radar system composed of CODAR SeaSonde stations installed in the Malta Channel is specifically serving to assist in the response against marine oil spills and to support search and rescue at sea. One key drawback concerns the sporadic inconsistency in the spatial coverage of radar data which is dictated by the sea state as well as by interference from unknown sources that may be competing with transmissions in the same frequency band. This work investigates the use of Machine Learning techniques to fill in missing data in a high resolution grid. Past radar data and wind vectors obtained from satellites are used to predict missing information and provide a more consistent dataset.

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