Core measurements:
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menu with table listings of Level I, II, III measurements by cruise.
Three levels
of observations are included in the CO2/CLIVAR hydrographic section program
with selection criteria listed in parentheses:
- Level I core measurements (mandatory on all
cruises; suggested standard for international collaborators; measured at
highest spatial resolution practical; funded through the omnibus proposal
across all cruises).
- Level II recommended measurements (highly
desirable on subset of US cruises; may be collected on coarser station
spacing; coordinated with the core effort but funded by separate proposals
either on a cruise by cruise basis of by specific measurement).
- Level III ancillary measurements (on
opportunity and space available basis; not to significantly interfere with
Level I or II effort; may be regional or specific to individual cruise;
extramural funding).
Level I:
rationale based on measurements required to directly quantify change in ocean
carbon inventory, estimate anthropogenic CO2 empirically, characterize
large-scale water mass ventilation rates, constrain horizontal heat, freshwater, C, N, and O2 transports and/or
net divergence, and provide
on-going basis for model evaluation.
DIC dissolved
inorganic carbon (DIC)
Total
Alkalinity (TAlk)
CTD pressure,
temperature, conductivity (salinity)
CTD oxygen
(sensor)
Bottle
salinity
Nutrients by
standard auto analyzer (NO3/NO2, PO4, SiO3)
Dissolved
oxygen (O2)
Chlorofluoro
carbon tracers CFC-11, -12, -113
Tritium-3He
Total organic
carbon (TOC, DOC and/or POC)
Total organic
nitrogen
Surface
underway system: T, S, pCO2
ADCP shipboard
ADCP lowered
Level II:
related to large-scale carbon cycle and/or ventilation; specific rationale
listed after measurement; possibly on coarser spatial resolution than Level I
but on all cruises
pH
(internal carbonate system consistency)
discrete pCO2
(internal
carbonate system consistency)
14C by AMS
(bomb penetration; southern ocean circulation changes; may need to repeat only
on 20 year time-scale)
CCl4 and SF6
(to extend
range of age tracers further back
in time (CCl4) and into the future
(SF6 )
del 13C of DIC
(independent
measure of anthropogenic CO2 uptake and inventory changes)
Fe/trace
metals
(others? Zn?
Al for dust? There are three sampling approaches
-on
"regular" rosette
-Teflon/plastic
water sampler hanging below CTD
-Separate
Kevlar wire; separate casts)
CTD
transmissometer
(POC
distribution; ambiguity as to calibration; regional?)
More complete
surface underway system: nutrients, O2, Chl, DIC, surface skin temperature
Level III:
focus on upper ocean biogeochemistry and cycling
Chlorophyll
Primary
production (on deck incubations)
HPLC pigments (phytoplankton community composition)
PIC
HCFC
Experimental
continuous analyzers (as they develop and can go full depth)
del 15N NO3
(nutrient utilization)
32Si
18O of H2O
NH4
Low level
nutrients
Total organic
phosphorus (difficult to measure??)
Upper ocean
optical profile (similar to AMT line; algorithm development/validation; short
cast; needs to be coherent with
biological sampling)
del 17O of
O2 (gross primary production)
methyl halides
(linkages to SOLAS)
DMS (linkages
to SOLAS)
ADCP
(multibeam) (optimized for (biological) particle enumeration)