NEMO Floats : Recent Technology and Upcoming Features
by OPTIMARE MMS Company
OPTIMARE has developed the Navigating European Marine Observer (NEMO)-Float for the research programme ARGO. NEMO has been further developed on the basis of the SOLO-Float from Scripps Institute of Oceanography, La Jolla, Califiornia. The goal was to develop floats which can be deployed in ice covered areas with ice detection during the upcast. Of the years many floats have been launched in the ice covered Weddle Sea in corporation with the Alfred Wegener Institute (AWI) in Bremerhaven.
Figure 1 : Standard Iridium NEMO Float © OPTIMARE
- Increase the maximum operation depth to 2000 dbar.
- Deploy floats in ice covered regions with operation under ice and delayed mode data transfer
- Increase the payload for larger sensor packages
- Have the possibility to integrate more sensors
- Create a highly modular system concerning the mission software and sensor integration
The NEMO-Float has been further improved to allow the deployment under ice, positioning through GPS and RAFOS, as well as the integration of new sensors (oxygen) and telemetries. Data transfer to a land-base is available via satellite communication. Twelve batches of NEMO floats have been build since 2002.
Figure 2 : 141 Platforms of NEMO types deployed by the Argo Programme, majority of German ones (80%).
Total of 10498 cycles (6434 profiles) - Mean of 73 cycles per float (45 profiles). © AIC July 2012
- more than 150 standard profiles
- bi-directional communication via Iridium
- modular software architecture allows easy to customize the mission cycle modes e.g. park and profile (with user defined park depth) mode, ISA (Ice Sensing Algorithm) mode, first profile without parking option (for comparison of vessel sensors)
- mission cycle and parameter modification after deployment
- on-board firmware updates via serial interface
- Compact Flash mass storage (practically unlimited profile storage)
- improved ice detection
- recovery feature
- RAFOS on board for underwater location during parking
CNEMO : special floats for special projects
The CNEMO-Float is a special float with a CO2 sensor by Contros, Bi-directional Iridium and ARGOS telemetry, GPS and recovery function for applications in the upper 400 meters. The instrument was deployed by Ifm-Geomar in 2010/2011 off Cape Verde for several missions.
Figure 3 : CNEMO Float with Contros Sensor © Fiedler et al., under review ( GEOMAR Kiel)
- Multi mission cycle mode
- Embedding new sensors
- Grounding detection
- Easy mission configuration via ini-file