1. Year-long measurement of surface currents in the Malta- Sicily Channel: Lessons learned and implications Malta, August 29 th, 2013 Simone Cosoli Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Trieste

2. Year-long measurement of surface currents in the Malta- Sicily Channel: Lessons learned and implications Malta, August 29 th, 2013 Simone Cosoli Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Trieste

3. Motivations-1: Marine traffic in the Malta – Sicily Channel Oil spill density map (source: Policy research Corporation,JJoint Research Centre, European Commission: http://serac.jrc.it CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

4. Motivations-2: Fishing activities in the Malta – Sicily Channel (1)Direzione generale delle politiche interne dell’unione Unita’ tematica B Politiche strutturali e di coesione – Pesca: la pesca in Sicilia – Parlamento Europeo (2) GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta Some numbers and facts(1,2): -greatest fishing fleet in Italy as for : - number of boats (3323 boats - 24.4% national fleet @2010), - size of boats (19.3 tons avg – 14tons avg in Italy) - boat power (86.6 KW avg – 83.8 avg in Italy) -fishing fleet: - 12-24m boats operating on a short-distance basis (1 to 2 days trips) - >24m boats employed on long fishing trips (3–4 weeks) in offshore waters

5. Motivations-2: Fishing activities in the Malta – Sicily Channel Some numbers and facts (1,2) : -43 301 tons of captures in 2008: - 69% pelagic fishes: small-sized big-sized - 10% mollusc - 21% crustacean large amount of targeted species and over-fishing problems (1) Direzione generale delle politiche interne dell’unione Unita’ tematica B Politiche strutturali e di coesione – Pesca: la pesca in Sicilia – Parlamento Europeo (2) GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN Engraulis encrasicolus Sardina pilchardus Xiphias gladius Thunnus thynnus Todarodes sagittatusSepia officinalis Parapenaeus longirostris Aristeus antennatus Nephrops norvegicus CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

6. Motivations (yes, more): currents – ocean structures impact fish distribution and fishing activity A conceptual model for Sardine in the Sicily Channel (*)Lafuente et al., Influence of the surface circulation in the spawning strategy of the Sicilian Channel anchovy, ICES 2000 Annual Science Conference Remote Ocean Sensing Workshop ROS 2013March 13 – 14, 2013 Engraulis encrasicolus Modification in AIS path: along-shore transport of fish-larvae (depletion and enrichment) Offshore advection from AIS branches – upwelling or northern winds – ageostrophic processes increase mortality risks Larvae entrapment in persistent vortices favors fish growth

7. Background ABV = Adventure Bank Vortex MCC = Maltese Channel Crest ISV = Ionian Shelfbreak Vortex CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

8. Background CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

9. Background CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

10. Drifter tracks in the Sicily Channel (1992 – 2010) Why not simple buoys? Problems: Sub-optimal temporal and spatial coverage in certain areas – oversampling in other areas CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

11. Why not models? Circulation Models: 3-D momentum eqtn. continuity eqtn. eqtn. of state Problems: Complicated set of Differential Equations – not easy to solve Tuning required – not always possible die to lack of data Cannot account for ALL processes: Parametrisation of fine-scale physical processes often needed No matter what or how complicated one makes it….some process will be missing (always)… CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

12. Combned TX-RX element 2 orthogonal crossed-loops >180˚ coverage combine d TX-RX antenna integrat ed in the support mast Why HF radars? Italy Compact, non invasive systems Safe for population (avg.TX Pw. 35W) Working continuously independently of weather conditions and sea-state Unique spatial-temporal high-resolution not achievable with conventional instrumentation CALYPSO Project Final Meeting, August 29, 2013, University of Malta, Valletta Campus, Valletta

13. Tunisia Algeria Libya Sicily Grecia Albania France Italy HF radar coverage

14. HF radar maps: how do they look like?

15. Seasonal variability in the AI-Stream as for position and extension Persistent gyre moves and stretches in time, predominant in winter August 2012 September 2012 October 2012 Surface current regimes in the Malta Channel December 2012

16. Persistent channel-wide cyclonic gyre (R~30 km) and less-evident anti-cyclonic gyre (R~10 km): impacts DEPEND on release location 16-12-2012 18-01-2013 20-02-2013

17. Persistent channel-wide cyclonic gyre (R~30 km) and less-evident anti-cyclonic gyre (R~10 km): impacts DEPEND on release location

19. Importance for SAR activities

20. Importance for spill tracking

21. Periodic increase of NF levels @13MHz Strongest activity at afternoon-night Lasting several hours Affecting 1 st order Bragg region  interferences with radar currents Common problem @13MHz HF radar in the Med.Sea RFI – removal algorithms exist – actually testing some @OGS Filtering? Identification required first ITU rules: HF radars can exist, but with a secondary license --license Theoretical Noise Level (~-130dBm) Up to 20-30 dBm fluctuations due to ? Importance of measuring reliable current data: periodic RFI issue

22. Thanks for your attention!

23. Importance for SAR activities