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….

a: Reaching remote ocean regions

b: Useage of heavy equipment

c: Taking of samples

d1: Measurements in the deep ocean

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

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

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) ADCP‘s (acoustic doppler current profilers), vessel or buoy or bottom-mounted, also miss surface and bottom

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

f: Continuous observations (timeseries)

(Takahashi et al 1995) Net CO 2 flux g: Large-scale coverage

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

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

i: Stable platforms (no or little motion)

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

k: Data telemetry

l: Following of water masses

Research vessels

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.

US vessels: SIO vessels: French vessels: German vessels (partially in German): Atalante „live“ (German and French):

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

Ship (hydrographic data) from (actual data plots/sections can be found at )

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

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

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 Now have to go to single country websites to get data and plot…. x/001919/index_ html

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 C, and fall-rate biases can be the same (that needs to be resolved)

ADCP observations from VOS: Oleander ADCP sections across the Gulf Stream: Nuka Arctica ADCP sections (mean)

Underway CO 2 observing network then go to  Underway CO2

Continuous Plankton Recorder (CPR)

Underway data project offices / data centers: tthere go to “data selection” and after selection “refresh”

Observation towers

Tower in the Baltic Sea ata/Observations/MARNET_mo nitoring_network/Stationen/dar s.jsp then go to “detailed drawing”

SPAR buoys

Moorings

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,...

Animation of a typical subsurface mooring

Mooring design (subsurface)

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

Residual buoyancy (kg)

Modelling of mooring subduction

Mooring shape model fitted to some pressure data

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

Loading/packing list generated

Typical component costs… Wire termination: $ Anchor $1000 glass balls $450 ea. foam floats: 45" - $14,000 49" - $16,000 51" - $23,000 57" - $29,000 62" - $35,000 76" - $46,000

Example cost for 100m mooring

See also movies of SeaCycler spinning in lab….

Relevant links: OceanSITES OOI project (NSF) SeaCycler project

Some ongoing moorings….

Possible, cost-effective configuration....

Developed and deployed 2 moorings with full inductive capability, controller and acoustic modem each.

quarterly sampling misses much variability and events  moorings are an ideal (and necessary) complement moored sensors NEED ship samples for calibration/ground truth, e.g inorganic carbon, net tows with EK60 for moored sonar all moorings are open and flexible and real-time; collaborations and partnerships are sought CCE-2 and Del Mar currently unfunded, need endorsements, expressions of support, especially for critical SWFSC/Demer component O 2 /Chl, pH/CO 2 O 2, Chl 35m T/S, O 2 90m Del Mar mooring on shelf since 2006, CalCOFI line 93 More cool things at oxygen at 35m

Geodetic mooring system to observe seafloor motion with cm-accuracy

“Often the physical and chemical measurements needed to link ecosystem variability to environmental variability do not exist.” (OceanObs09 Community Statement)  Showcase ??? CCE-1 co-funded by unique NOAA climate&NMFS sharing (S.Murawski/M.Johnson) - NOAA climate with NOAA NMFS - SIO with NOAA SWFSC and NOAA PMEL - Send & Ohman with Demer, Sabine, Dickson, Hildebrand, Martz meteor., 7-ch radiation pCO 2, T/S pH, O 2 ADCP T/S, Chl-a turbidity T/S, Chl-a NO 3, turbidity pH, O 2 T/S 7-ch radiation acoust.zooplankt passive mammal 0m 0-500m 20m 40m 80m 0-300m 1000m CCE-1 Many sensors, collaborators, institutions (CCE-1)  real-time inductive telemetry and control  Powerful and compelling due to its unique setting within CalCOFI and LTER

California Current Ecosystem (CCE) moorings Pt.Conception Gliders (CORC, LTER, Moore) CalCOFI/ LTER CCE-1 (SIO/ SWFSC/PMEL) CCE-2 Complementary with ship surveys and glider sections - Ships sample many variables and provide ground truth - Gliders provide cross-shelf sampling with a few variables - Moorings give full time sampling, wide range of variables CalCOFI line 80