AST-12 meeting report posted - Argo

closes on command. The board was designed by D. Swift and 100 units were built
commercially in Seattle. This fix has been added to all UW and PMEL floats since February
2011. Individual floats can be tested for this problem by connecting a laptop prior to deployment
and inflating the bladder. Teledyne/Webb has been notified of this problem and the suggested
remedy. As of March 2011, they have not instituted the remedy and they continue to build and
ship floats with this potential problem. It is not clear whether or not they intend to add the
auxiliary PCB in their production process.
UW has developed a prototype float that uses a Kenwood PMT to communicate with ARGOS-3
satellites. There were a couple of reasons for doing this. The first being that ARGOS-3 will
someday provide bidirectional communications and could be a possible alternative to Iridium.
The second being that the Seimac PTT used in Apex floats is no longer being manufactured so
alternative communication methods for Apex ARGOS floats need to be explored. The first tests
of the Kenwood PMT have shown that energy use is larger than with present ARGOS-2 PTTs.
The PMT float has been running on a simulator at UW for several months and the PMT
consumes more than twice the energy per transmission of the present ARGOS-2 Seimac PTT
or Telonics PTT units.
Finally, S. Riser presented on SeaBird CTD issues. SBE claims the microleak problem is now
understood and fixed at the Druck factory. The glass/metal seals that caused the problem have
been re-engineered and will be installed in SBE float CTDs beginning in July 2011. Until then,
SBE is screening all Druck pressure sensors that are installed in float CTD units (possibly
resulting in continued reduced production of CTD units). Some groups have tried the Kistler
pressure sensors with good results so far in a limited number of floats for a limited time. SBE
claims lab tests show the Kistler sensor to be as good or better than the new Druck sensors.
Both Jamstec and PMEL have noted floats with unacceptable conductivity drift after deployment
(> 0.01 PSU equivalent). This problem was traced to erosion of the platinum in the CTD
electrodes. The cause of the problem has been found and new QC procedures have been
installed at SBE. It is believed that this problem occurred in an isolated group of floats (CTDs
built in late 2010) but all groups should check for this.
Action item 26: S. Riser to draft a statement concerning solenoid problems on APEX
floats to be posted on AST website and sent out on Argo email lists. S. Riser, M. Scanderbeg
Action item 27: Ask SBE for serial numbers of CTDs having difficulty with conductivity
sensor drift immediately after deployment and for serial numbers of CTDs with new, improved
Druck sensor. S. Riser
SOLO-II
D. Roemmich updated everyone on the SOLO-II which is the newly redesigned SOLO float that
is now commercially available through MRV Systems (http://www.mrvsys.com). The SOLO-II is
engineered to complete around 300 dives anywhere in the world ocean using Iridium. It weighs
less and is shorter than the SOLO making it easier to deploy.
The first prototype SOLO-II was deployed in September 2009 and completed 20 three day
cycles before being recovered. It was redeployed in February 2010 (WMO 4901242) and ran
until its batteries were depleted in September 2010. During that time, it completed 324 deep
cycles to 1750m with a 2 dbar sampling scheme on the rise all the way up to 3 dbar when the
pump was turned off. The rise rate was around 13 cm/s. The second SOLO-II prototype had a
new antenna and a redesigned bottom hemisphere and bladder. This one was deployed in
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