Essential Variables:
Central focus –variables are needed to constrain the Southern Ocean carbon cycle
To keep in mind:
 Variables will be collected across many different scales – remote sensing, Argos Floats,
using remote vehicles (Gliders; AUV), Shipboard-based spatial time series surveys (LTER
and AMLR) and process-oriented cruises
 Methodologies need to be comparable
 Tap into standard lists and methodologies adopted by NASA and large field programs
(will need to cull lists, not all variables amenable to all platforms)
o JGOFS
o CALCOFI
o LTER
o WOCE
o CLIVAR – will be developing a variables list useful to modelers later this fall
o NASA Ocean Optics technical manual has 30 essential variables
• Find synergies with ongoing programs
Needs:
 Improved bathymetry to constrain the volume of Southern Ocean; and links between
bathymetry and nutrient regime
 Improved sea state data - significant wave height
 Measures for stratification/ MLD/ Density- Biological mixed layer is not necessarily the
same as the physical - salinity is the main driver – the biology can respond rapidly…
 Improve quality of air-sea interface parameterizations
 Improve respiration/remineralization estimates

Biggest uncertainties:
 Lack of observations – SOCCOM input; work with SOCCOM to identify key variables to
fill gaps
 CLIVAR Modeler: Vertical diffusion profiles – turbulence; mixing… this has a temporal
component that is NOT considered. Understanding eddy kinetics and energy is
important for physics and can be determined with sea surface hiehgt with satellites
 How can we separate growth limitation of phytoplankton – iron/light/B12/ - is there a
simple way to parameterize these (light can be measured directly; iron or other
microelement limitation can be detected with transcriptomics/proteomics – and/or
experimental incubations)
 Uptake kinetics – nutrient specific across different organisms –
 Gas exchange – air sea interface
 Respiration terms – temperature dependence; quality of organic matter dependence;
loss term of zooplankton
 Iron where’s it coming from and how much
 Freshwater flux from glaciers
Environmental Variable Categories –
and Key Variables
How can we better constrain these
variables across interannual, seasonal and
regional contexts?
Sea Ice parameters and measurements
Carbon
Export – 100 and 500 m (Clivar)
Export (POC)
DOC
DIC
Alkalinity
Biological components of carbon
Respiration
Net Community Production (GPPRespiration) [at different depths]
New Production
Phytoplankton carbon
Zooplankton carbon
Bacterioplankton carbon
Biology
Size fractionated phytoplankton
Major microbial functional/biogeochemical
groups
Ecological and/or ecosystem drivers of
community structure (top down/bottom
up)
Biogeochemistry
Uptake – ideally.
Fe (other trace elements?)
NO3, NO2, NH4, Norg
Si
PO4, Porg
DO (and other dissolved gases)
Physics
MLD and water column structure
Salinity
Temperature
Remote Sensing
Sea surface height
Sea surface chlorophyll
SST
Wind
Sea ice
Ocean color
Heat flux
CO2
NASA – Echo2 model – Global circulation
model [ Mitchell/Manizza working with this
model with JPL – to apply this in the
Southern Ocean]
NASA – GIS model
PACE - hyperspectral – 7-8 nm UV and
Vis/IR + Altimeters.
Non-Carbon or Nutrient Chemistry
O2/AOU
Pigments
Chemotaxonomy
14C, 18O
Atmospheric Gases
O2
Ar
N 2O
NO
CH4
DMSO
CO2
Particles/Aerosols
Discussion Items and take home points
1. Export – To improve the understanding and input for models: Multiple depths, multiple
methods (Thorium, Oxygen etc.) are needed. Refer to the literature protocols to determine
these. Uncertainties large – take advantage of EXPORTS Science Plan.
2. Look at and utilize Southern Ocean Models (e.g. Oscar Scofield’s model he presented) as
checks for parameters in addition to facilitating constraining uncertainties.
Top down vs. bottom up control – and temporal changes?
3. Models:
 Need for coupling, put an atmospheric model on top of ecosystem models that consider
major drivers (limitation – light/Fe etc.).
 Focus on variables important in the Southern Ocean – wind, surface roughness, etc.
 SOCCOM –NO3, O2, Biooptics – will go towards utilizing inverse model. What can “we”
do to augment the floats?
 SOSE is large-scale. Modelers are not ready to deal with future influx of higherresolution satellite data.
4. Questions:
 What controls community structure? Use network models to associate structure across
different trophic levels; then link to remote sensing optical/hyperspectral data.
 How important are coastal vs. open ocean carbon cycling processes?
 What do we need for upscaling and downscaling?
5. Observation ideas:
 Transects across the fronts/ get to sea ice-shelf.
 Moorings
 Under- ice work (AUV/ROV/Glider)
 Enhance atmospheric observations at seasonal, regional scales – work to determine how
to do so possible to do economically, leveraging international collaboration, automated
observation