1. 5th Workshop on "SMART Cable Systems: Latest Developments and Designing the Wet Demonstrator Project" (Dubai, UAE, April 2016)
Contribution of SMART cable systems to Ocean and Climate Science Jerome Aucan, Research Scientist, IRD France

2. Contribution of initial sensors
Spatial and temporal variability of deep-ocean temperatures.
Temporal variability of tides, which impacts tidal corrections for satellite missions.
Ocean circulation response to wind forcing.
Impact of infragravity waves on high-precision altimetry missions.

3. Contributions to existing earth observing systems : space/time coverage

4. Initial sensors : Temperature Pressure Accelerometers
Initial accuracy : ±0.001ºC; Stability: 0.002ºC / year.
Pressure
Accuracy : ±1mm H2O relative to recent measurements; Maximum allowable drift after a settling-in period : 0.2m H2O/year (much better can be achieved ?).
Accelerometers
Accuracy and stability value from functional requirement (

5. Contributions to existing earth observing systems Deep ocean temperatures
SMART cable temperature measurements could detect current deep warming trends ( ºC / year.) within several years :
Much higher temporal sampling (thus, less aliasing problems) than other arrays
Much higher spatial sampling as well (20,000 nodes at 50 km spacing, compared to projected 1,000 deep global ARGO floats)

6. Contributions to existing earth observing systems Deep ocean temperatures
SMART temperature measurements will also allow unprecedented exploration of temporal variability of deep ocean temperatures due to tides, eddies, mixing, etc.

7. Contributions to existing earth observing systems Sea level
Sea level, a fundamental property of the ocean, is measured by satellite altimetry.
Bottom pressure measurements along cables provide ground truth for models of tides and other high-frequency motions that must be subtracted accurately from altimeter records.

8. Contributions to existing earth observing systems Gravity
Bottom pressure observations
Proportional to total water mass above.
Will be valuable ground truth for remotely sensed gravity missions.
Could provide an alternative ground truth method for wind-stress measurements and large-scale ocean circulation.
From Landerer et al. 2016

9. Contributions to existing earth observing systems Long surface waves
Infragravity waves are expected to be a significant source of error in the planned NASA/CNES SWOT mission.
SMART cable bottom pressure data combined with modeling will improve our ability to remove errors due to infragravity waves.
Mean seasonal IG wave height from the DART network
(Aucan& Ardhuin 2014)

10. What happens when repeater is buried :
Temperature data will have to be corrected for sediment heat flux.
Pressure data should be unaffected.
What happens if repeater sinks :
Effect on temperature will need to be accounted for.
Induced pressure signal will be monotonic (increasing). It will need correction for long-term trends but not for high-frequency and short-term signals.
Wave-induced sinking of a pressure sensor in the sand.

11. Thank you