PROVOR profiling float performance Gerard Loaec, Ifremer

PROVOR profiling float performanceGerard Loaec, Ifremer History and performances of PROVOR float IAST6 Meeting – Brest - GL

Provor - main features • FSI (Excell) or SeaBird CTD (SBE41 CP) packages • Self-ballasted, with active buoyancy control (hydraulic pump). More than 2000 cm3 of variable buoyancy, including surface emergence • Max profiling depth : 2000 m • Possibility of data acquisition on down-profile to parking depth and while drifting. CTD profile on the descent of the first cycle • Provor/ Apex format (variable / fixed number of samples) • ARGOS data transmission (28 bits ID) History and performances of PROVOR float IAST6 Meeting – Brest - GL

Marvor/Provor history • Developed by Ifremer since 1990: • Woce: Marvor multi-cycle Rafos float • Argo/Coriolis : Provor profiling float • Through industrial partnership with Martec company and its subsidiaries: • Martec-Serpe-Iesm is responsible for sales in Europe • Martec-Metocean is responsible for sales in other countries History and performances of PROVOR float IAST6 Meeting – Brest - GL

Martec Provor and Metocean Promet (between 2002 and 2004) • The same hydraulics, electronics, sensors, • the buoyancy is higher (bigger housing) • some differences in the software History and performances of PROVOR float IAST6 Meeting – Brest - GL

Gyroscope Float Status Overview- December 2003 (by Y. Desaubies) 7 Provor and 7 Apex have been lost since IAST-5 History and performances of PROVOR float IAST6 Meeting – Brest - GL

Technical improvements: stability at depth • Many Metocean floats deployed by Jamstec have shown ‘emergency ascent’; if the pressure is higher than the maximum allowed pressure, the floats pops up to the surface, without waiting for the end of the cycle. • The floats die between 70 and 90 cycles (Japanese National Report) with a parking depth of 2000 dbars. • Improvements: • The software has been updated on all floats to control the float at depth • It seems that the quality of the valve on the hydraulic engine is not stable and that low leakages inside the hydraulic circuit may happen. All floats have been fitted with a new valve (PSA) since the end of 2003. History and performances of PROVOR float IAST6 Meeting – Brest - GL

Gyroscope WMO 6900162 – parking & profiling 1750 dbar Hydac valve History and performances of PROVOR float IAST6 Meeting – Brest - GL

Gyroscope WMO 6900162 – parking & profiling 1750 dbar Hydac valve A depth control means the float is outside its target depth History and performances of PROVOR float IAST6 Meeting – Brest - GL

Provor WMO 1900081 parking depth=1500 dbars (PSA valve) profiling depth = 2000 dbars History and performances of PROVOR float IAST6 Meeting – Brest - GL

Provor WMO 1900081 parking depth=1500 dbars(PSA valve) profiling depth = 2000 dbars A depth control means the float is outside its target depth History and performances of PROVOR float IAST6 Meeting – Brest - GL

Technical improvements: grounding in surface cold water • Some Kordi and Pri floats don’t dive when the surface water temperature is low • Grounding detection: • When there is not water enough: • Either the floats stays on the sea floor waiting for the end of the cycle, • Or it moves away from the sea floor and drifts some meters higher • When the float is on the sea shore: • The mission is stopped and an Argos message is emitted every 100 seconds • By counting the number of valve actions and looking at the pressure; if the number of valve actions is higher than a given parameter and the pressure remains stable, grounding is detected History and performances of PROVOR float IAST6 Meeting – Brest - GL

Technical improvements: grounding in surface cold water • On these floats: • The flow is low (low temperature) • The buoyancy when the float is deployed is high • Grounding is detected because the number of openings of the valve to reduce buoyancy is too high History and performances of PROVOR float IAST6 Meeting – Brest - GL

Technical improvements: grounding in surface cold water • Improvements • by reducing the buoyancy when the float is deployed • by adjusting the grounding detection parameters 1°C 2°C 3°C Provor WMO 1900314 – 56° South History and performances of PROVOR float IAST6 Meeting – Brest - GL

FSI sensors • Jumps in salinity • High stability P/T sensors WMO 1900207 . Eastern Tropical Atlantic . 30 cycles . 6 acceptables T/S profiles History and performances of PROVOR float IAST6 Meeting – Brest - GL

FSI sensors • Possible reasons: • Breaking or rotation of the damping disk ? • Rotation of conductivity cell ? • Fouling ? • Corrections: • The damping disk is moved away from the sensors • Test of a new antifouling paint: unacceptable secondary effects • Remaining floats fitted with Fsi sensors are deployed in cold water • Most of Provor floats are now fitted with SBE sensors, but we are still working with FSI History and performances of PROVOR float IAST6 Meeting – Brest - GL

Conclusions • The most important point is the stabilization at depth. The new valve should improve this. • Some differences between floats delivered by Metocean and Serpe-Iesm • From the beginning of 2004, There will be only one Provor design : • All floats are produced in France by Martec-Serpe-Iesm that is responsible for sales in Europe. • Martec-Metocean is responsible for sales in other countries and provides technical support and customization • All Provor floats will be tested using Ifremer facilities before they are shipped History and performances of PROVOR float IAST6 Meeting – Brest - GL

A new CTD Profiling float • 19 Kgs • 100 cycles to 2000 m in all oceans • No ballasting • 800 cm3 variable buoyancy • SBE 41 CP sensors History and performances of PROVOR float IAST6 Meeting – Brest - GL

PROVOR profiling float performance Gerard Loaec, Ifremer