C A S I XC A S I XCentre for observation of Air-Sea

Interactions and fluXes(A NERC Centre of Excellence in Earth Observation)

Nick Hardman-Mountford, Jim Aiken

CASIX Project Office, Plymouth Marine Laboratorycasix_dir@pml.ac.uk

& the CASIX TeamPML, SOC/SOES, POL,

UEA, UWB, U.Ply, U.Leics, U.Edi, U.Read,

Met Office

CASIX: Open-Ocean Modelling of Air-sea Carbon Dioxide Fluxes

Example• The model captures the

spring bloom signature in the SeaWiFS chlorophyll data in early March 2000

• The model can extrapolate under cloud and to other quantities not remotely observable

HadOCC HadOCC• 4 compartment ecosystem

model plus carbon cycling

FOAM• Operational ocean models

using data assimilation to forecast 5 days ahead

• Driven by 6-hourly fluxes from Met Office Numerical Weather Prediction (NWP) system

+

FOAM

.

Vertical structure, salinity

CASIX purpose: to exploit EO data to derive air-sea interactions, focus on CO2 fluxes

NOAA-AVHRR Terra & AquaMODIS AIRS

SeastarSeaWiFS

TOPEX-Poseidon,JASON, Altimeters

ERS-1 & 2 SARQuickscat-SeaWinds

EnvisatMERIS, AATSR

ASAR, RA-2SCIAMACHY

ADEOS IINSCAT, SeaWinds

OCTS, Polder

To exploit these complex, diverse data & address the global problem of CO2 fluxes, we need integration and modelling: 1-D & 3-D Ocean and Shelf circulation models with coupled biology, the C-cycle. Primary focus will be on N Atlantic & N W European

Shelf Seas with the assimilation of EO data into models

Atmospheric aerosols and gases, CO2

Air-seaexchange

Surface roughness/ Surface height

Ocean colour Plankton Marine

Biogeochemistry

Physical StructureTemperature

.

Vertical structure, salinity

CASIX purpose: to exploit EO data to derive air-sea interactions, focus on CO2 fluxes

NOAA-AVHRR Terra & AquaMODIS AIRS

SeastarSeaWiFS

TOPEX-Poseidon,JASON, Altimeters

ERS-1 & 2 SARQuickscat-SeaWinds

EnvisatMERIS, AATSR

ASAR, RA-2SCIAMACHY

ADEOS IINSCAT, SeaWinds

OCTS, Polder

To exploit these complex, diverse data & address the global problem of CO2 fluxes, we need integration and modelling: 1-D & 3-D Ocean and Shelf circulation models with coupled biology, the C-cycle. Primary focus will be on N Atlantic & N W European

Shelf Seas with the assimilation of EO data into models

Atmospheric aerosols and gases, CO2

Air-seaexchange

Surface roughness/ Surface height

Ocean colour Plankton Marine

Biogeochemistry

Physical StructureTemperature

CASIX: Aims & RationaleCASIX Purpose The purpose of CASIX is:

to exploit new-generation Earth Observation (EO) data, to advance the science of air-sea interactions and reduce the errors in the prediction of environmental change. The primary goal is to quantify accurately the global air-sea fluxes of CO2, other gases and particles, using state-of-the-art, error-budgeted models.

This is a crucial element in furthering understanding the role of the ocean carbon cycle in the global carbon cycle and their role in climate change.

To do this, novel EO data sources and algorithms will be developed and integrated with 3-D coupled physical-ecosystem ocean models to produce new error-quantified climatologies of air-sea gas fluxes.

Geographical range Primary focus will be the N Atlantic & NW European Shelf Seas (validation data available) We will provide results for the global ocean with lower confidence Integration of shelf & ocean is a unique feature of CASIX

CASIX Time Frame Quantification and understanding of air-sea CO2 fluxes - 5 yrs Quantification and understanding of air-sea fluxes for a wider range of climatically important

gases - 10 yrs

4: Integration (climatology and analysis) Wider

application

CASIX science elements and their interaction

CASIX science elements and their interaction

1: Physical controls on surface exchange 2: Biogeochemistry

and bio-optics

3a: 3-D N. Atlantic ocean model for CO2

3b: 3-D N.W. European shelf model

for CO2

3c: Interface modelling

Experiment with parameterisations and process models

Define flux parameterisationusing EO input Optimise input from EO colour

CO2 flux climatologyIn situ flux data

Satellite data

10 year hind-cast of CO2 fluxes

SSTAATSR, NPOES

MSG, AMSR, TMI

Wave heightJASON, ALT-2

Surface topographyTOPEX, JASON, ALT-2

CASIX will exploit a wide array of data sources

CASIX will exploit a wide array of data sources

Surface roughnessSea-Winds, N-SCAT

ASAR, Radarsat, AMSR, Windsat TOPEX, JASON, ALT-2

Wind stressSurface films

Air-sea fluxparameterisations

Air-sea gas flux (CO2)climatologyAtmospheric CO2

Atmos. SensorsSciamachy, AIRS

Ocean colour SeaWiFS, MERIS,

MODIS, GLI

ChlorophyllPrimary production

processes controlling upper ocean pCO2

Ocean circulation models with bio-geo-chemistry and air-sea interface processes

Coupled modelling in CASIX

Example• The model captures the

spring bloom signature in the SeaWiFS chlorophyll data in early March 2000

• The model can extrapolate under cloud and to other quantities not remotely observable

HadOCC Ecosystem Models• Hadley Centre Ocean Carbon

Cycle Model (HadOCC)• PML European Regional Seas

Model (ERSEM)

Physical• Met Office Operational

Forecasting Ocean Assimilation Model (FOAM)

• POL Coastal Ocean Modelling System (POLCOMS) Regional Seas Model.

+

FOAM

FOAM/HadOCC model output & data assimilationFOAM/HadOCC output fields Model fields that contribute to

estimation of chlorophyll and primary production

Ocean colour data assimilation Weekly chlorophyll fields from FOAM/HadOCC

with corresponding SeaWiFS images The challenge is to assimilate ocean colour

data to correct and nudge the model for operational forecasting

Moving towards CO2 fluxes The revised output field improves

estimates of derived fields (e.g. primary production, CO2 flux)

This is the goal of CASIX!

Shelf Seas Modelling with POLCOMS & ERSEMPOLCOMS• 3-D shelf-sea physical circulation model

(incl. waves, tides, turbulence, benthic resuspension, spm)

• 6km & 1.8km horizontal resolution

ERSEM• Complex ecosystem model (benthic &

pelagic)• Coupled to POLCOMS 3-D ecosystem

fields

Importance of Shelf Seas• Continental shelf waters = 10% of

the global ocean area• 30% of global ocean production

occurs in shelf seas making them a sink for atmospheric CO2

• Shelf seas can also be a source of CO2 to the atmosphere – origin terrestrially exported carbon

• Net flux is unknown

New CASIX CO2 flux climatologies

CO2 flux maps Global estimates of CO2 flux for January (top) and July (bottom) 2002 Hindcast CO2 fluxes 20 year hindcast estimates

of CO2 flux for global areas shown as coloured panels on map.

Optimal interpolation techniques are used to combine parameters influencing air-sea gas exchange: wind speed and wind speed variability, sea surface temperature, sea surface salinity, sea surface roughness and the gradient of CO2 partial pressure across the air-sea interface

http://www.soc.soton.ac.uk/lso/casix/prelim/

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