Assimilating SST and Ocean Colour into ocean forecasting models Rosa Barciela, NCOF, Met Office
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Transcript of Assimilating SST and Ocean Colour into ocean forecasting models Rosa Barciela, NCOF, Met Office
www.ncof.gov.uk
Assimilating SST and Ocean Colour into ocean forecasting models
Rosa Barciela, NCOF, Met Office
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
Forecasting the open ocean: the FOAM system
• Operational real-time deep-ocean forecasting system
• Daily analyses and forecasts out to 6 days
• Low resolution global to high resolution nested configurations
• Relocatable system deployable in a few weeks
• Hindcast capability (back to 1997)
• Assimilates T and S profiles, SST, SSH, sea-ice concentration
FOAM = Forecasting Ocean Assimilation Model
Real-time data
Obs QC
Analysis
Forecast to T+144
NWP 6 hourly fluxes
Automatic verification Product
delivery
Input boundary
data
Output boundary
data
www.ncof.gov.uk
Operational configurations
12km (1/9º) Mediterranean
6km (1/20º) North East Atlantic
36km (1/3º) North Atlantic and Arctic
12km (1/9º) North Atlantic1º Global
36km (1/3º) Indian Ocean
12km (1/9º) Arabian Sea
27km (1/4º) Antarctic
• All configurations run daily in the operational suite
www.ncof.gov.uk
Hadley Centre Ocean Carbon Cycle Model (HadOCC)
Model description
- Variable C:Chl ratio
- Coupled to carbon and alkalinity
- Normally used for climate studies
- Transported around the ocean by physical processes
- ‘NPZD’ ecosystem model
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
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 improve the ocean temperature analysis by 0.1K RMS.
– Improvement not only at the surface but over the top 600 m
0
200
400
600
800
1000
0.7 0.8 0.9 1 1.1 1.2 1.3RMS Difference (K)
Dep
th (
m)
1/9° GHRSST1/9° control
www.ncof.gov.uk
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
Phytoplankton background error before the first analysis.
Phytoplanktonanalysis error after the first analysis, with data everywhere.
Phytoplankton errors (mmolN/m3)
Assimilation of Derived ChlorophyllR
esu
lts fr
om 3
-D tw
in
exp
erim
ent
s
www.ncof.gov.uk
Assimilation of Derived Chlorophyll
Total Dissolved Inorganic Carbon (mmolC/m3)
Control - truth
Assimilation - truth
Daily Mean RMS Errors in the North Atlantic from 3-D Twin Experiments
- 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 colour dataset
www.ncof.gov.uk
• 10-day test run
Free Run Chlorophyll DA
RMS error = 0.46 RMS error = 0.27Mean error = -0.28 Mean error = -0.11
Aim: Improvement of pCO2 estimation by assimilating ocean colour
Assimilation of Derived Chlorophyll
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%
- Extensive product quality control: include quantified errors and quality flags
- Validation against in situ data and across biogeochemical regions.
- Product format: WMO GRIB or netCDF
- Delivery method: FTP
- Large biases in the merged product corrected by in situ data
- Spatial resolution: 4 Km spacing (highest resolution models have)
- Bias information from individual sensors
www.ncof.gov.uk
GlobCOLOUR/Ocean ColourOperational User Requirements
• 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
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
• NW European Shelf (NOOS) user requirements may need to be gathered ([email protected])
www.ncof.gov.uk
Rosa [email protected]