From the outside, it may have appeared that not much was happening with NEPTUNE Canada last fall. But those were busy days, as we worked through a plethora of tasks required to commission our infrastructure, instruments, security provisions and data products.
Observatory commissioning is an important period in the life cycle of any major project, when every element is thoroughly tested before being officially made available to users. More precisely, commissioning activities covered multiple areas such as underwater infrastructure verification (withAlcatel-Lucent), shore station equipment (Alcatel-Lucent and DMAS), national security checks by the navies, and of course all the data flow elements at the University of Victoria and at the University of Saskatchewan. The illustration below is a reminder of the various elements of the NEPTUNE data flow infrastructure.
By the end of September, Alcatel-Lucent had completed its part of the commissioning: making sure that our backbone cable with repeaters and branching units, science nodes and equipment in the shore station were fully functional. All components were found to be in working condition except the Middle Valley branching unit, which will be repaired this spring. Until that repair is done, our underwater backbone will continue to be configured as two independent cables–one from the shore station to ODP 889 (Clayoquot Slope) and the other from the shore station to ODP 1027 (Cascadia Basin)–rather than a single loop.
Our next commissioning step was to carefully review data flows. It was essential to make sure that all data coming from instruments made it safely into the archive. Conversely, it was also important to verify our ability to send commands to junction boxes, cameras, etc.
Data flow commissioning was quite challenging due to the varied nature of the instruments on the system and the complexity of the network. DMAS staff painstakingly traced everything from the nodes down: junction boxes, instruments and their various sensors. During this period, the University of Saskatchewan redundant data centre was also installed and certified. It now not only hosts a secondary copy of all NEPTUNE data but also shares the web access load.
Another commissioning task was a review of our overall system security. The Canadian and the US navies examined the sensitivity of some of our instruments (seismometers and hydrophones) and assessed their possible impact on naval operations and national security. When a detection possibility is suspected, data from those sensitive instruments will be temporarily filtered to remove the part of their response spectrum possibly containing traces of military vessel signatures.
A separate security audit of our installations indicated that our system has a high level of resilience to hacking and other acts of malevolence.
Our data commissioning process involved both internal quality checks and data reviews by Principal Investigators (PIs). Internally, a series of steps were undertaken to validate data:
- every raw data file was checked for proper format and completeness
- important metadata such as units, calibrations and configurations were verified
- data were plotted to ensure values made sense
- anomalies and data gaps were noted and investigated (We used a wiki to record findings and pass/fail status for every instrument each day data was acquired.)
- corrections and adjustments were made where necessary
Corrections and adjustments usually involved either changes in the data acquisition software or instrument configuration modifications. For example, we wrote additional software to minimize acoustic interference between two nearby instruments by interleaving pings. Without this adjustment, artifacts like vertical lines in the ADCP’s velocity magnitude would appear. In the data segment below, the last 20 minutes (75 pings) indicate the detection of pulses from an echosounder.
As a result of our efforts, about 30 instruments successfully passed their initial evaluation:
- Acoustic Doppler Current Profilers
- Bottom Pressure Recorders
- video cameras
- methane sensor
- oxygen sensors
Data products for the above-listed instruments are accessible by anyone using Data Search, and more will become available during the Spring. Another 30+ instruments are still in commissioning phase, as we fine-tune drivers, develop data products and work out file management protocols. Data from these will also be coming online gradually over the coming months.