The HF Radar System in the Basque Country

First validation and data analysis results

Anna Rubio, Julien Mader, Manuel González, Almudena Fontán, Vicente

Fernandez (QUALITAS REMOS), J.A. Aranda (Euskalmet)

REF: HYDROLOGICAL STUDIES AND SURFACE CURRENTS IN THE COASTAL AREA OF THE BAY OF BISCA Y. Miguel Ibañez Artica.Instituto Geográfico Vasco. Lurralde :inv. espac. N. 2 (1979) p. 37-75 ISSN 1697-3070, extracted from: http://www.ingeba.org/lurralde/lurranet/lur02/iba02/iba02.htm

Surface currents in the SE of the Bay of Biscay during 1978

15,000 plastic drift cards thrown into the sea from different coastal points

Outline

1. Introduction: Description of the Basque and some observations over the slope

2. The HF Radar System

3. Data Availability and Quality Control

4. Validation and first results

5. Perspectives

Introduction: the OO System

S. SEBASTIANDONOSTIABILBAO

MATXITXAKO

Deep water buoy

Coastal station

HF radar antenna

MATXITAKODONOSTIA

http://www.euskalmet.euskadi.net http://www.ibi-roos.eu/

Data available at:

Variability of currents over the SLOPEOffshore buoys; over 450 and 550 m depth

2008

WELL-MIXED STRATIFIED

MatxitxakoDonostia

SD SD

f f

Lomb-Scargle peridogram 120 days, 60days-overlapping segments. Vertically averaged

Processes governing the variability

U componentV component

D

Variability of currents over the SLOPEOffshore buoys; over 450 and 550 m depth

2008

Variability of currents over the SLOPE

D2

D2

f

f

Lomb-Scargle peridogram 60 days, 30days-overlapping segments.

Processes governing the variability at high frequencies, seasons and depth

U+V COMPONENTS

10-40 m

100-140 m

D1

D2f

D1

Offshore buoys; over 450 and 550 m depth2008

Variability of currents over the SLOPE

M2 M2f f

VERTICAL SHEARU+V COMPONENTS

Lomb-Scargle power spectra from the vertical gradients of the horizontal velocity components.

Contribution to the shear-induced mixingat high frequencies, seasons and depth

10-40 m

100-140 m

Offshore buoys; over 450 and 550 m depth2008

Introduction: the HF RADAR System

Matxitxako Antenna (transmitter and receiver) and electronics.

Two radial site stations: Higer and MatxitxakoCentral combine

site in Vitoria

WORKING SINCE 2009

MAIN CARACTERISTICS of the BASQUE SYSTEM

RadarFrequency

(MHz)

RadarWavelength

(m)

OceanWavelength

(m)

Depth ofCurrent1

(m)

TypicalRange2

(km)

TypicalResolution3

(km)

4.86 60 30 2-3 ~150 ~ 5

Upper H1/3

Limit4

(m)

25

TypicalBandwidth

(kHz)

30

Introduction: the HF RADAR System

FROM CROSS SPECTRA TO RADIAL VELOCITIES

MUSIC (MUltiple SIgnal Classification) Algorithm[Schmidt, R.O., (1986), IEEE Trans. Antennas Propagat., vol. AP-34, pp. 276-280]

•Linear solutions based on eigen-analysis of averaged spectral covariances•Capable of more than two solutions with little added numerical burden•Chooses number of bearings based on both eigenvalue & amplitude ratios•Capable of incorporating measured, distorted antenna patterns

OUTPUT: Vectors in polar coordinate system centered at receive antenna:

1 radial map per averaged cross spectra fileTypically, seven radial maps “merged” into one hourly map

(3-hours running average)Angular resolutions is 5˚

Introduction: the HF RADAR System

FROM RADIAL TO TOTAL RADIAL VELOCITIES

Several radials from each site contribute to each total vector, being resolved into orthogonal components (U, V)

Linear least squares performed on U, V components separately

From radials with:• An angle of incidence greater than α

α min = 20-30 º•And total velocities < 100-120 cm/s

Defining a•GRID SPACING: 5km •AVERAGING RADIOUS: of 20 KM

Data Availability and Quality Control

MEAN COVERAGE AND STD OF TOTAL U, V COMPONENTS

DATA AVAILABILITY IN 2009

Large STDvalues

α min = 15º α min = 30º

radial velocities < 150 cm/s radial velocities < 100 cm/s

Data Availability and Quality Control

Data Availability and Quality ControlComparison with Slope buoys

ADCP 12m ADCP sup DONOSTIA HF RADAR 0.104 0.121 0.117 0.134 ADCP sup 0.119 0.115

MATXITXAKO HF RADAR 0.11 0.09

Data Availability and Quality Control

ADCP DATA RADAR DATA

SD

ff

D

SD fD

SD f

D

SD

Comparison with Slope buoys

SD fD

Data Availability and Quality Control

M2 ELLIPES - HARMONIC ANALYSIS - SVD (Press et al., 1989)

Comparison with Slope buoys

Data Availability and Quality ControlComparison with a drifter

COURTESY OF GILLES REVERDIN (LOCEAN)

Data Availability and Quality ControlQUALITATIVE Comparison with ADCP data

COURTESY OF MARIA SANTOS (AZTI)

Data Availability and Quality ControlQUALITATIVE Comparison with ADCP data

COURTESY OF MARIA SANTOS (AZTI)

Data Availability and Quality ControlComparison withSST IMAGES and WIND forcing….

Data Availability and Quality ControlComparison with SST IMAGES and WIND forcing….

Perspectives- Future work

• Use radial velocities for the comparison

• Validation of general patterns observed through the comparison with other in-situ data (drifting buoys) and satellite images

• Describe surface circulation:

– General patterns, seasonal and mesoscale variability (river plumes, eddies)

– Harmonic analysis of the data (in progress) to compare with in-situ data and existing models. Mapping current variability associated to f

• Reconstruct velocity series (e.g. DINEOF on radial components) to obtain a complete data set : use Lagrangian model to describe surface transport

Perspectives- Future work

IMPROVING THE SYSTEM WITH A THIRD ANTENNA IN COMTIS…

Perspectives- Future work

• Abstract sent to EOF2010: ‘ COASTAL HF RADAR FOR OPERATIONAL SURFACE CURRENT MONITORING AND MODEL VALIDATION IN THE SE BAY OF BISCAY’. Mader J1.; Rubio, A1.; Fernández, V. 2; González, M1.; Tarafa, N 2.; Fontán, A1.; Ferrer, L1.

1 AZTI-Tecnalia, Pasaia, Spain; 2 Qualitas Remos, Madrid, Spain

• FCT GRANT – PHD Student for 2011 ¿?

• Planning a workshop in OCTOBER at AZTI…

Thanks for your attention !

?

ADCP data – BIOMANADCP DATA ECOANCHOA MAYO 2008 a 15 m

30' 4oW 30' 3oW 30' 2oW 30'

30'

44oN

30'

45oN

30'

46oN

06May 12

08May 0408May 12 09May 0208May 19

17May 14 ADCP DATA ECOANCHOA MAYO 2008 a 15 m

30' 4oW 30' 3oW 30' 2oW 30' 12'

24'

36'

48'

44oN

12'

06May 12

08May 04 08May 12 09May 02

08May 19

11May 23

6-23 May 2008

4 – 25 May 2009

3 – 23 May 2010

3oW 40' 20' 2oW 40' 20' 12'

24'

36'

48'

44oN

DonostiaMatxitxako

+ Pasaia

-3000

-2500

-2000

-1500

-1000

-500

MOORINGS “ECOSISTEMA” in 2010

• 4 x RCM9• 1 x RCM7• 2 x acoustic release • 1 ADCP (workhorse ~300MHz ~100m rang)

upward looking

A B

AB

~350 m

~100 m

??

??

??

??