TOPAZ the Arctic TEP and the Arctic GOOS L. Bertino, G. Evensen, K.A. Lisæter, I. Keghouche Arctic GOOS opening, Bergen, 12 th Sept. 2006

Analysis 1 st Sept Google Earth

TOPAZ System Description Model components Assimilation method Upgrades

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)

The TOPAZ model system  TOPAZ: Atlantic and Arctic  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

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

Ice extent and ice volume Solid black line - ensemble mean Dashed black line - free run Grey - individual ensemble members

Barents Sea

TOPAZ2 (400x600x22) 20km resolution TOPAZ3 (800x880x22) 11km resolution

TOPAZ Upgrade Stronger W. Spitzberg Current TOPAZ3TOPAZ2

CERSAT - IFREMER

The Arctic TEP Thematic Portal Common Viewing Downloading Downscaling Validation Plan

Live Access Server

The MERSEA metrics

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

Top 3 m layer

100 m depths

Validation procedures against in-situ measurements and climatology Station at the North Pole TOPAZ profiles In-situ data from CORIOLIS (Argo, XBT, …)

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

Thank You

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]

Ensemble Kalman filtering a stochastic process ForecastAnalysis Observations 1.Initial uncertainty 2.Model uncertainty 3.Measurement uncertainty Member1 Member2 …… Member99 Member100

Surface temperature update Assimilation update - Summer Ice concentration update Surface salinity update

Results from TOPAZ and nested models

Validation Salinity

Validation Temperature

Results from a nested model VOLUME TRANSPORTS How good are the boundary conditions ? BIC AW NCC

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: -???

Bear Island - Svalbard Recirculation within the Bear Island Trough is relatively stable at ~ 1.0 Sv [Ingvaldsen et al., 2002]

Svalbard – Franz Josef Land In => 0.4 Sv Out => 0.1 Sv [Loeng et al., 1997] (used Russian literature)

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]

Kara Gate In = 0.1 Sv Out = 0.05 to 0.7 Sv [Loeng et al., 1997] (used Russian literature)

Planned upgrade - TOPAZ3

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. Norway Spitzberg Barents Sea opening TOPAZ2 TOPAZ3

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

The end

System Applications Nested systems in 1.North Sea (N. Winther/C. Hansen) 2.Gulf of Mexico (F. Counillon) 3.Barents Sea (I. Keghouche)

Illustr. I. Kerghouche