Autonomous Flow Through Instrument (AFT)
The AFT-CO2 and AFT-pH are benchtop instruments based on the same technology as the SAMIs. They measure either pCO2 (carbon dioxide) or pH from a stream of water pumped through the unit. They are typically used on research vessels or ships of opportunity to measure surface water but can also be used for benchtop measurements of discrete samples.
The AFT can also support 3 external instruments, including GPS. If connected to a computer, real-time data can be obtained. If preferred, AFT data can be dowloaded later from the internal data logger. Programming, download and display of the data are performed by the same client software used for the SAMIs.
Built around a LI-COR 850 CO2/H2O Analyzer, the SuperCO2 uses either a showerhead equilibrator or a membrane contactor to equilibrate a gas stream to a flowing sample stream. The unit uses a Windows based tablet running custom developed software for control, display and data collection. Once running the unit requires minimal oversight. Because it is built around an NDIR (non-dispersive infrared) gas analyzer, it has a very fast response time and can measure every 2 seconds if desired.
Using gas standards (user-supplied), the SuperCO2 self-calibrates periodically and can also take periodic samples of ambient air.
The SuperCO2 can log data from a Seabird thermosalinograph (TSG) and also has capability of monitoring other analog output sensors by special order.
Submersible Autonomous Moored Instrument (SAMI)
Ocean pH and CO2 Sensors
Developed by Dr. Mike DeGrandpre at Woods Hole in the mid 90's, the Submerisble Autonomous Moored Instrument for carbon dioxide (SAMI-CO2) uses patented technology (US Patent 7,026,165) to measure pCO2. Sunburst Sensors has exclusive license to this technology and has been producing the instrument since 1999. The SAMI-pH joined the product line in 2007 utilizing similar technology. Both instruments were completely redesigned in 2010.
The SAMIs are deployable to 600 m and can run for over a year taking hourly measurements*. They can support up to 3 external instruments such as PAR, dissolved O2, chlorophyll fluorometer or CTD. Though they log their own data, the SAMIs can be configured to communicate with the Seabird Inductive Modem system or external data loggers.
A titanium-housed SAMI-pH won first place in the accuracy category for the Wendy Schmidt Ocean Health XPRIZE
*The SAMI-pH requires a supplemental battery pack for this number of measurements