Handbook of best practices

Variables Drift Correction methods Reference
Nitrate yes Offset, pressure and drift
pCO2 yes Offset, pressure and drift
Johnson et al. (2013),
Sakamoto et al. (2009)
Atamanchuk et al.
(2015)
pH yes no information yet no information yet
Finally, pH and pCO2 data from recent sensors (CONTROS, Aanderaa, Seafet, …) are
evoked but the quality control procedures are not ready to be proposed as best practices
yet. So far taking water samples and analysing those for DIC and Alkalinity, using certified
reference material, and calculating pH and pCO2 appears to be the most robust. A
calibration coefficients fitting seems to be the best way to correct the data for accuracy offset
and drift.
6. Future directions (Univ. Aberdeen, 52North, UPC)
6.1 Sensor web enablement
Ocean observing systems use a wide variety of instruments and sensors types and there is
little standardisation of the protocols used to control, configure and retrieve the data from
these devices. To integrate these instruments into an observing system, a data management
and instrument control framework is required. This is usually achieved using a proprietary
framework, generally involving extensive manual configuration of specialised software
drivers to translate commands and data between the protocols of the individual instruments.
This highlights the need for the development of smart sensors to move towards the
standardisation of instruments. A smart, or ‘plug & play’, sensor would (i) allow for easy
integration into observing systems vis-à-vis connectors, power supplies, data formats,
protocols and data handling, (ii) provide retrievable information about the sensor itself and
(iii) be able to check for possible malfunction autonomously and report back to the
operations centre.
Protocol standards such as the Open Geospatial Consortium (OGC) PUCK 2 have been
developed in response to this need for standardisation between instruments. PUCK
addresses the installation and configuration challenges for sensors by defining a standard
instrument protocol to store and automatically retrieve metadata as well as other information
from the instrument itself. The protocol is suitable for RS232 and Ethernet connected
instruments. The PUCK commands do not replace existing instrument command sets, but
are added to the existing commands. The PUCK standard has been implemented by several
manufacturers, although it is not ubiquitous.
6.1.1 Sensor web
Integrating observations gathered by different sensors in mapping software, Web
applications, or computer models can be a cumbersome task requiring a lot of manual
interaction. In addition, structured metadata such as provenance information, which is
important for discovering sensor data within or between organizations or meaningfully using
2 http://www.opengeospatial.org/standards/puck
71