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					Assimilating SST and Ocean Colour into ocean
forecasting models
Rosa Barciela, NCOF, Met Office




                                        www.ncof.gov.uk
      rosa.barciela@metoffice.gov.uk
Contents



    • Introduction
       – Operational FOAM
       – Biogeochemical modelling
    • Satellite data assimilation in FOAM
       – Medspiration SST
       – SeaWiFS Ocean Colour
       – Future plans
    • Operational Requirements - GlobCOLOUR




                                            www.ncof.gov.uk
Forecasting the open ocean: the FOAM system


               FOAM = Forecasting Ocean Assimilation Model

• Operational real-time deep-                         NWP 6                   Input
  ocean forecasting system                             hourly               boundary
• Daily analyses and forecasts                         fluxes                  data
  out to 6 days
• Low resolution global to high
  resolution nested




                                                           Analysis
  configurations                              Obs                     Forecast to
                                              QC                        T+144
• Relocatable system
  deployable in a few weeks
• Hindcast capability (back to
  1997)
                                  Real-time                              Output
• Assimilates T and S profiles,     data
                                                    Automatic           boundary       Product
                                                    verification
  SST, SSH, sea-ice                                                       data         delivery
  concentration



                                                                      www.ncof.gov.uk
Operational configurations




                            36km (1/3º) North        12km (1/9º) North Atlantic
       1º Global
                            Atlantic and Arctic

                                                                                  6km (1/20º) North
                                                                                    East Atlantic



 36km (1/3º) Indian Ocean

                             27km (1/4º) Antarctic                         12km (1/9º) Mediterranean




  12km (1/9º) Arabian Sea   • All configurations run daily in the operational suite

                                                                          www.ncof.gov.uk
Hadley Centre Ocean Carbon Cycle Model
(HadOCC)
Model description
- ‘NPZD’ ecosystem model
- Coupled to carbon and alkalinity
- Variable C:Chl ratio
- Transported around the ocean by
    physical processes
- Normally used for climate studies
Aims
- Air-sea fluxes of CO2 using high-
resolution GCM (1º go, 1/3º & 1/9º NA)
- Assimilation of Ocean Colour & EO
data to improve these fluxes
- 10 year hindcast (1997-2006)
with/without data assimilation
                                         www.ncof.gov.uk
Contents



    • Introduction
       – Operational FOAM
       – Biogeochemical modelling
    • Satellite data assimilation in FOAM
       – Medspiration SST
       – SeaWiFS Ocean Colour
       – Future plans
    • Operational Requirements - GlobCOLOUR




                                            www.ncof.gov.uk
Operational FOAM assimilation of GHRSST-PP products


Assimilation of Medspiration data


   – FOAM adapted to use GHRSST obs
   – 3-month hindcast run with/without
     assimilation of Medspiration data
   – Main differences in Gulf stream
     region
   – Assimilation of Medspiration obs                                     RMS Di ffe re n ce (K)
     improve the ocean temperature                            0.7   0.8     0.9    1       1.1   1.2      1.3
     analysis by 0.1K RMS.                                0

   – Improvement not only at the surface                200
                                           Depth (m)

     but over the top 600 m                             400

                                                        600

                                                        800

                                                       1000

                                                                                               1/9° GHRSST
                                                                                               1/9° control
Future Plans




      To use GHRSST-PP data operationally from next year
                 (development work required)




                                               www.ncof.gov.uk
Contents



    • Introduction
       – Operational FOAM
       – Biogeochemical modelling
    • Satellite data assimilation in FOAM
       – Medspiration SST
       – SeaWiFS Ocean Colour
       – Future plans
    • Operational Requirements - GlobCOLOUR




                                            www.ncof.gov.uk
Assimilation of Derived Chlorophyll
   Results from 3-D twin experiments




                                                                         Phytoplankton
                                                                         background error
                                                                         before the first
                                                                         analysis.




                                                                         Phytoplankton
                                                                         analysis error after
                                                                         the first analysis,
                                                                         with data
                                                                         everywhere.


                                                                         www.ncof.gov.uk
                                       Phytoplankton errors (mmolN/m3)
Assimilation of Derived Chlorophyll

 Daily Mean RMS Errors in the North Atlantic from 3-D Twin Experiments

     Total Dissolved Inorganic Carbon (mmolC/m3)
                                                            - Air-sea exchange of CO2
                                                            significantly improved after
                                                            assimilating ocean colour data

                                                            - Joint assimilation of Medspiration
                                                            SST and ocean colour is desirable
                                                            as carbon solubility is strongly
                                                            dependent on temperature

                                                            - 10 year hindcast will benefit from
                                                            using a long-term SST, ocean
                                     Control - truth        colour dataset
                                     Assimilation - truth


                                                                       www.ncof.gov.uk
Assimilation of Derived Chlorophyll


  Aim: Improvement of pCO2 estimation by assimilating ocean colour
         Free Run                         Chlorophyll DA

• 10-day test run




Mean error = -0.28   RMS error = 0.46   Mean error = -0.11      RMS error = 0.27



                                                             www.ncof.gov.uk
Future plans




   To transition the FOAM-HadOCC system into pre-operational
                           state by 2008
                  (assimilation of ocean colour products)




                                                        www.ncof.gov.uk
Contents



    • Introduction
       – Operational FOAM
       – Biogeochemical modelling
    • Satellite data assimilation in FOAM
       – Medspiration SST
       – SeaWiFS Ocean Colour
       – Future plans
    • Operational Requirements - GlobCOLOUR




                                            www.ncof.gov.uk
GlobCOLOUR/Ocean Colour
Operational User Requirements

 • Specific requirements for GlobCOLOUR
  - L2 Global Area Coverage of chl a plus quantified errors from
   merged and individual sensors
  - Best possible accuracy: essential to decrease errors in derived chl below 35%
  - Spatial resolution: 4 Km spacing (highest resolution models have)
  - Extensive product quality control: include quantified errors and quality flags
  - Validation against in situ data and across biogeochemical regions.
  - Large biases in the merged product corrected by in situ data
  - Bias information from individual sensors
  - Product format: WMO GRIB or netCDF
  - Delivery method: FTP
                                                                   www.ncof.gov.uk
GlobCOLOUR/Ocean Colour
Operational User Requirements

For operational purposes …

   • Long-term provision of quality-controlled products in a timely (within 1 day)
   manner.
       - sustainability is key as lots of investment required to use the data
       - stable formats and delivery: (very) high availability and reliability

   • Joint GlobCOLOUR/Medspiration products would be an advantage:
        - single file format
        - single file delivery
        - reduced data processing time
        - diagnostic data set applied to GlobCOLOUR data
   • NW European Shelf (NOOS) user requirements may need to be gathered
    (martin.holt@metoffice.gov.uk)


                                                                www.ncof.gov.uk
     Rosa Barciela
rosa.barciela@metoffice.gov.uk




                                 www.ncof.gov.uk

				
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posted:11/4/2012
language:English
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