Surface pressure PROVOR/ARVOR floats Coriolis DAC V. Thierry DMQC 4 – Toulouse – September 2009

downtimeuptime telemetry period A C B D Surface pressure for PROVOR/ARVOR floats  Psurf is measured just before the float dives  The Psurf value is taken into account for the next cycle and for the next profile (in general 10 days later) Psurf is simply substracted from the pressure measurements for CTF and CTS2 PROVOR floats A reset of the pressure sensor is done with the “RESETOFFSET” command of the SBE41CP sensor for the CTS3 PROVOR and ARVOR floats

Surface pressure for PROVOR/ARVOR floats  Data are then truncated (-0.3 → 0; 0.6 → 0 ) and transmitted with a 1 dbar resolution for the CTF, CTS3, CTS3 et ARVOR  With an Iridium transmission and for CTS3 deployed since June 2009, the data are transmitted with a 1cbar resolution  Those differences are significant when dealing with the microleak problem.

 Psurf measurements (1cbar resolution) subtracted to the pressure measurements  No reset of the pressure sensor  8% of the CTS2 affected by the micrloeak problem  The floats affected by the microleak problem have not been re-considered in D mode but the drift is corrected at each cycle PROVOR – CTS2

 Reset of the pressure sensor before each dive (RESETOFFSET command)  Transmission of a relative offset with a 1 dbar resolution  Statistics: 140 floats with Psurf = 0 6 floats with Psurf = ± 1 dbar 2 floats with |Psurf | > 1 dbar  Unknown percentage of the floats concerned by the microleak problem PROVOR CTS3 Surface pressure offset relative to the previous profile

PROVOR CTS3 Cumulative surface pressure offset  Reset of the pressure sensor before each dive (RESETOFFSET command)  Transmission of a relative offset with a 1 dbar resolution  Statistics: 140 floats with Psurf = 0 6 floats with Psurf = ± 1 dbar 1 floats with |Psurf | > 1 dbar  Unknown percentage of the floats concerned by the microleak problem

CTS3 Iridium  Reset of the pressure sensor before each dive (RESETOFFSET command)  Transmission of a relative offset with a 1 cbar resolution  73 % of the floats concerned by the microleak problem PROVOR CTS3 – cbar transmission

CTS3 Iridium  Reset of the pressure sensor before each dive (RESETOFFSET command)  Transmission of a relative offset with a 1 cbar resolution  73 % of the floats concerned by the microleak problem PROVOR CTS3 – cbar transmission