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Chapter 4 Observing platforms

Chapter 4 Observing platforms When planning an experiment, project, measurement, first think of the requirements/needs you have ! Not enough to say „I want to measure currents in a such and such a location“.

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Chapter 4 Observing platforms

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  1. Chapter 4 Observing platforms When planning an experiment, project, measurement, first think of the requirements/needs you have ! Not enough to say „I want to measure currents in a such and such a location“. The platform is usually dictated by a variety of needs and the respective capabilities and cost ! Have to consider: • Cost • range (horizontal and vertical) • endurance (time, power, storage) • payload • real-time capability • sampling resolution in space/time • power availability typical requirements shown in following….

  2. a: Reaching remote ocean regions

  3. b: Useage of heavy equipment

  4. c: Taking of samples

  5. d1: Measurements in the deep ocean

  6. d2: Measurements at the seafloor d3: Measurements at the sea surface are actually very tricky..... and require special efforts/techniques

  7. wave motion Ship heave Minimum depth to first measurement 5-10m Near-surface and near-bottom CTD data missing or extrapolated !!! Safety distance from bottom 10-20m (weight with alarm or acoustic pinger)

  8. ADCP‘s (acoustic doppler current profilers), vessel or buoy or bottom-mounted, also miss surface and bottom Installation depth plus blank-out region plus first 1-2 bins not useable (3-10m) Last 10% of profile before bottom (or surface) reflection not useable due to sidelobe reflections (see ADCP chapter)

  9. e: Measurements of (vertical) profiles CTD profile Free-fall current profile

  10. f: Continuous observations (timeseries)

  11. Net CO2 flux (Takahashi et al 1995) g: Large-scale coverage

  12. h1: Remote sensing of the sea surface (for better coverage or because of inaccessability) Remote sensing of surface Remote sensing of surface Remote sensing of surface

  13. h2: Remote sensing of the interior (for better coverage or because of inaccessability)

  14. i: Stable platforms (no or little motion)

  15. j: High accuracy (versus cheap, expendable, large numbers…)

  16. k: Data telemetry

  17. l: Following of water masses

  18. Research vessels

  19. Things to consider when planning useage of a research vessel: • availability of ship • size (capable to reach location, do the work, not too big) • equipment - cranes, winches - echo sounders, ADCP, pingers, - navigation, communication systems, - installation of own equipment like pingers, - power connections) • positioning system • weather and ice limitations • deck space, container spaces (above and below deck) • weight of equipment (on and below deck) • lab space • cost • speed • safety restrictions (hazardous chemicals and procedures) • ability to work at night • does work need to be done over stern/side/from bow, etc.

  20. US vessels: www.unols.org SIO vessels: http://shipsked.ucsd.edu French vessels: http://www.ifremer.fr/fleet/ German vessels (partially in German): www.ifm.zmaw.de/leitstelle/ www.briese.de/forschungsschifffahrt-briese.html?&L=1 www.awi.de/en/infrastructure/ships/ Atalante „live“ (German and French): http://www.ifremer.fr/move/

  21. Typical research vessel costs: Sproul: $12,000 /day New Horizon: $22,000 /day Melville, Meteor, Atalante: $35,000 /day Polarstern $50.000 /day Student funding is available for shiptime,and has the highest priority with UC ship funds. Sproul and New Horizon have frequent holes inthe schedules.

  22. Ship (hydrographic data) from http://cchdo.ucsd.edu/ (actual data plots/sections can be found at http://sam.ucsd.edu/vertical_sections/.index.html)

  23. Volunteer Observing Ships (VOS) or Ships Of Opportunity (SOO) Commercial ships (ferries, container vessels, etc) which carry out various observations on the way, or deploy probes/instruments Main requirement: • must be able to do this at full speed • should take minimum effort/attendance by crew • modifications to ship should be small Advantages: • Cheap • frequent trans-basin coverages Disadvantages: • startup effort is large • limited sensors • speed • ships may be moved

  24. Thermosalinograph: Problem: calibration needs taking samples and analyzing them (i.e. shipping them maybe from distant ports)

  25. Many other variables can be analyzed from engine intake water, example „Ferrybox project“: Sampled on some lines: water temperature,salinity,turbidity,dissolved oxygen,fluorescence,ammonium,nitrate/nitrite,phosphate,silicate, different algae groups Project which coordinated many European lines and institutions finished in 2006. Now have to go to single country websites to get data and plot…. www.gkss.de/institute/coastal_research/structure/operational_systems/KOI/projects/ferrybox/001919/index_0001919.html http://ferrydata.gkss.de

  26. XBT temperature probes launched from VOS Hi-resolution XBT network Biases due to manufacturing changes and fall-rate issues are still an active and hot discussion/research topic… Sensor good to 0.05C but fallrate random error can give 0.1-0.2C, and fall-rate biases can be the same (that needs to be resolved)

  27. ADCP observations from VOS: Oleander ADCP sections across the Gulf Stream: www.po.gso.uri.edu/rafos/research/ole/index.html Nuka Arctica ADCP sections 1999-2002 (mean)

  28. Underway CO2 observing network www.ioccp.org/then go to  Underway CO2

  29. Continuous Plankton Recorder (CPR) www.sahfos.ac.uk/about-us/cpr-survey/the-cpr-survey.aspx

  30. Underway data project offices / data centers: www.jcommops.org/soopip/ www.coriolis.eu.org/Data-Services-Products/View-Download tthere go to “data selection” and after selection “refresh”

  31. Observation towers www.whoi.edu/science/AOPE/dept/CBLAST/ASIT.html

  32. Tower in the Baltic Sea http://www.bsh.de/en/Marine_data/Observations/MARNET_monitoring_network/Stationen/dars.jsp then go to “detailed drawing”

  33. SPAR buoys www.mpl.ucsd.edu/resources/flip.intro.html

  34. Moorings

  35. Mooring technologies Available now or in near future: surface and subsurface moorings, winched systems, cabled moorings, high-latitude spar buoys, virtual moorings, under-ice moorings,...

  36. Animation of a typical subsurface mooring

  37. Mooring design (subsurface)

  38. depth component S/N rope# distance incl. &length from stretch lower end

  39. Residual buoyancy (kg)

  40. Modelling of mooring subduction

  41. Mooring shape model fitted to some pressure data

  42. Diagnostic output Horizontal displacement Vertical subduction Line tension Launch tension is another important factor, should not exceed 50% of breaking strength

  43. Loading/packing list generated

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