Introduction - Kannad PROVBIO-B Manuel Utilisateur

USER MANUAL / MANUEL UTILISATEUR

1. INTRODUCTION

PROVBIO-B is a subsurface profiling float developed jointly by IFREMER and KANNAD company.
The PROVBIO-B float has been developed on the basis of CTS-3 PROVOR float previously designed for
Argo program with the addition of optical sensors (transmittance, irradiance, backscattering, chlorophyll,
and Colored Dissolved Organic Matter CDOM
Note1: in all this manual, CDOM will refer to Colored Dissolved Organic Matter.
The addition of such sensors involves the use of the IRIDIUM satellites communication system.
After launch, PROVBIO-B's mission consists of a repeating cycle of descent, submerged drift, ascent and
data transmission. During these cycles, PROVBIO-B dynamically controls its buoyancy with a hydraulic
system. This hydraulic system adjusts the density of the float causing it to descend, ascend or hover at a
constant depth in the ocean.
The user selects the depth at which the system drifts between descent and ascent profiles. PROVBIO-B
continually samples the pressure at this drift depth and maintains that depth within approximately 30 m.
After the submerged drift portion of a cycle, the float proceeds to the depth at which the ascending profile
is to begin. The ascent profile starting depth (typically 1,000 m) is not necessarily the same as the drift
depth.
During its mission, PROVBIO-B collects measurements of three parameters «salinity, temperature, depth
(CTD)» as well as those of optical measurements (irradiance, transmittance and ECO Triplet sensor) then
save them in its memory. The CTD measurements can be made during the float descent (descent profile),
during the submerged drift period (Lagrangian operation) and during the ascent (ascent profile), the optical
measurements can be made only during the ascent.
Unlike ARGO float, the ascent is programmed to reach the surface at a pre-defined time (apparent noon by
default).
After each ascent, PROVBIO-B transmits its saved data to satellites of the IRIDIUMs system. The volume
of data is reduced using a compression algorithm in order to reduce the time needed for transmission. While
on surface thanks to a GPS receiver, an accurate position of the float can be obtained and the clock of the
float be updated.
This manual describes the PROVBIO-B float, how to use it and safety precautions to be observed during
handling.
Please read this manual carefully to ensure that PROVBIO-B functions as intended.
The descending and ascending profiles are almost identical, indicating that the float operation was in the
same water mass for the entire test.
PROVBIO-B
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PAGE : 1 / 72
DATE : 26/03/2008
INDEX : A
REF. : DOC08018