Technological developments

Ifremer/Coriolis, AWI

EURO-ARGO/ESFRI

ARVOR float• Arvor : new float dedicated to CTD measurements for Argo

• Deployment facilitated (smaller, lighter weight <20 kg) and to reduce manufacturing costs.

• 10 instruments manufactured in May + intensive tests done in 2008

• 2 Arvor were successfully deployed in southern ocean; they are cycling every 2 days to assess their performance and have performed 5 cycles; 8 more will be deployed in Atlantic this summer

Transmission through Bi-directional communication

Iridium transmission implemented on ProvCarbon and ProvBio which are Argo floats (Provor) fitted with extra optical sensors.

2 ProvCarbon have been deployed in February 2008 and have performed more than 50 cycles today ( 5 days period)

Surface times could be reduced to 30 minutes; the surface time is allocated to increasing the buoyancy of the float to sufficiently rise the antenna (about 5 min), the iridium transmission (around 5 min), and finally to reduce buoyancy.

12 ProvBio have been manufactured and most of them have been deployed (http://www.obs-vlfr.fr/OAO/).

Iridium/GPS antenna developed and tested for 2000 dbar operations.

Iridium satellite downlink capability successfully tested

Development of an Arvor equipped with an Iridium antenna

Use of ARGOS-3 transmission ?

new modem PMT from CLS Argos tested

Implementation on Arvor and deployment in 2009

Transmission through Bi-directional communication

PROVOR-DO • Provor + dissolved oxygen sensor (optode)• Change the sensor position: top bottom

– Optode closer to the CTD– No temperature bias induced by the float– Calibration possibilities in moist air

• Correction of two bugs in the software Two floats are currently tested

• Lifetime of float: Extra power for sensor – ~8% of total provor energy (for optode), lifetime is maintained beyond 3

years. – cost of optode sensor: ~5900€.

PROVOR-DO

New developments

• CTD Improvements: less energy consuming for new 2009 model (180mW vs 300mW today).

• Investigation for deep measurements

• Higher pressure operation to 3500 dbars: available with titanium pump impeller housing rather than plastic, and Druck Pressure sensor (about same price than 2000 dbars model). 7000 dbars expected in 2009.

• Further sensor investigations on the CTD accuracy

Ice sensing

Initially, Argo was intended to observe deep ice-free ocean in real time, but the ice-resilience of floats has been increased.

• Nemo (optimare) is fitted with 3 main features:

– Ice Sensing Algorithm (ISA) to improve endurance in ice-covered seas,

– Interim Storage of aborted profile data in presence of ice at surface,

– Subsurface RAFOS navigation to locate profile/ float under the sea ice.

– Development of a new ISA algorithm for deployment in the Arctic

• A non Argo model of Provor (NKE) exists for ice thickness assessment. It uses the subsurface RAFOS navigation (Provor-A) coupled with an upward looking acoustic sounder.

Under-ice floats in Antarctica : 5 years of experience