TOPAZ the Arctic TEP and the Arctic GOOS

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TOPAZ the Arctic TEPand the Arctic GOOS

• L. Bertino, G. Evensen, K.A. Lisæter, I. Keghouche

Arctic GOOS opening, Bergen, 12th Sept. 2006
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Analysis 1st Sept. 2006
Google Earth
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TOPAZ

• System Description
• Model components
• Assimilation method
• Upgrades

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Motivation

• Objective
• Provide short-term forecasts of physical and
  biogeochemical parameters targeted to users needs
  (primarily the offshore oil and gas industry)
• Strategy
• Focus on advanced data assimilation techniques
• Gradual increase of resolution
• Nesting on regions of higher interest
• Support
• TOPAZ is the Arctic component of MERSEA IP
• ESA, Industry, private donation (Frank Mohn AS,
  Bergen)

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The TOPAZ model system

• TOPAZ Atlantic and Arctic
• 18-35 km resolution
• 22 vertical layers
• Assimilates
• SLA (4 satellite altimeters),
• SST (from AVHRR),
• ice concentrations (SSM/I)
• Run weekly, ECMWF forcing
• Provides nesting conditions to high-res. models

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Ice concentration data

• Passive MW (NSIDC)
• Real-time data set (2-3 days delay)
• NORSEX algorithm (Svendsen et al 1983)
• 37GHz, 19GHz
• 25 km resolution

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Ice extent and ice volume
Solid black line - ensemble mean Dashed black
line - free run Grey - individual ensemble members
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Barents Sea
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TOPAZ2 (400x600x22) 20km resolution
TOPAZ3 (800x880x22) 11km resolution
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TOPAZ UpgradeStronger W. Spitzberg Current
TOPAZ3
TOPAZ2
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CERSAT - IFREMER
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The Arctic TEP Thematic Portal

• Common Viewing
• Downloading
• Downscaling
• Validation
• Plan

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(No Transcript)
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Live Access Server
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The MERSEA metrics
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The MERSEA metrics

• Class1 3D daily averages
• Class2 Sections and moorings
• Class3 derived quantities (fluxes)
• Class4 validation to observations

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Top 3 m layer
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100 m depths
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Validation proceduresagainst in-situ
measurements and climatology
Station at the North Pole TOPAZ profiles In-situ
data from CORIOLIS (Argo, XBT, )
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Status / Plan

• TOPAZ
• next upgrade (TOPAZ3) Apr. 2007
• Ice drift data assimilation
• Arctic TEP
• Started during the TOP1 period (Oct. 2005)
• Barents Sea model
• Downscaling from TOPAZ.
• Real-time since Sept. 2006.
• MERSEA TOP2 period (Apr. Sept. 07)
• Contributions from all Mersea V2 systems
• More validation metrics

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Thank You
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The ingredients

• Models
• HYCOM (U. Miami, USA)
• Ice model
• Biogeoch. model (AWI, D)
• Observations
• Altimetry, SST (CLS, F)
• Sea Ice (NSIDC, USA)
• Sea Ice drift (Cersat, F)
• In-situ (CORIOLIS, F)
• Data assimilation
• Ensemble Kalman Filter Evensen 1994, 2006

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Ensemble Kalman filteringa stochastic process
Forecast
Analysis
Member1
Member2
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Member99

• Initial uncertainty
• Model uncertainty
• Measurement uncertainty

Member100
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Observations
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Assimilation update - Summer
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Results from TOPAZ and nested models
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Validation Salinity
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Validation Temperature
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Results from a nested model VOLUME TRANSPORTS
How good are the boundary conditions ?
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Norway-Bear Island
Net transport AW 1.5 Sv/year (1.7 Sv in winter
and 1.3 Sv in Summer) Ingvaldsen et al.,
2004 Net transport NCC 0.5 Sv/year Blindheim,
1989 Net transport BIC -???
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Bear Island - Svalbard
Recirculation within the Bear Island Trough is
relatively stable at 1.0 Sv Ingvaldsen et
al., 2002
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Svalbard Franz Josef Land
In gt 0.4 Sv Out gt 0.1 Sv Loeng et al.,
1997 (used Russian literature)
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Frans Josef Land Novaya Zemlja
In 0 to 0.3 Sv in Summer Out 1.5 Sv
(between 0.6 Sv in Summer and 2.6 Sv in
Winter) Schauer et al., 2002
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Kara Gate
In 0.1 Sv Out 0.05 to 0.7 Sv Loeng et al.,
1997 (used Russian literature)
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Planned upgrade -TOPAZ3
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Expected improvements

• Improved dynamics
• Better resolution of shelf currents (esp. in the
  Nordic Seas)
• Better fluxes in/out of the Arctic Ocean
• More efficient assimilation of altimetry and
  hydrographic profiles.

TOPAZ2
Spitzberg
Norway
Barents Sea opening
TOPAZ3
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Future Perspectives

• Geographical extension
• Indian ocean (under development)
• Pacific Ocean / South China Sea (Nansen-Zhu,
  Beijing)
• Exhaustive model validation
• In collaboration with the MERSEA gang
• Real-time assimilation of more observations
• Temperature and salinity profiles (Argo program)
• Ice thicknesses (CRYOSAT)
• Sea surface salinity (SMOS / Aqua)
• New geoid and Mean Dynamic Topography (GOCE)
• Progresses in data assimilation
• Biases, non-linearity, parameter estimation
• Coupling to a global system
• Mercator

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The end
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System Applications

• Nested systems in
• North Sea (N. Winther/C. Hansen)
• Gulf of Mexico (F. Counillon)
• Barents Sea (I. Keghouche)

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Illustr. I. Kerghouche