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THOR
Presented by Doug Smith (MET OFFICE)Project coordinator: Detlef Quadfasel (UHAM)
Arctic Ice Cover during Winter
3000 km
< 1000 km
Winter ice boundaries
Population in the North
~ 400 Mio
~ 40 Mio
~ 4 Mio
Seasonal Ice Cover
Decadal Variability - Trends
?
Ocean Circulation carries Heat to the North
… and returns fresh water south
Shallow Circulation
Deep Circulation
North Atlantic Thermohaline Ocean Circulation and its Impact on Climate: Thermohaline Overturning – at Risk ?
Facts and Figures
FP 7 Collaborative Project – Large Scale
Project lifetime: 4 years, December 2008 – November 2012
Research focus: Stability of the ThermoHaline Circulation
Participants: 20 participating institutions from 9 European countries
5 Core Themes, 12 Work Packages
Project cost: 12.95 million Euro
EU Funding: 9.27 million Euro
Core Theme 1MOC Variability
Core Theme 3 Observations
Core Theme 2Model Uncertainty
Core Theme 5Technological Advancements
Core Theme 4Prediction & Predictability
What is it all about? THOR and its 5 core themes
NADW – North Atlantic Deep Water1 Sv = 106 m3/s
Project Management and Coordination (UHAM)
CT 1: Quantifying and modelling THC variability using palaeoclimate observations and simulations (MPI-M, MetO, UPMC, UiB, IFM-GEOMAR, NERSC, CNRS)
CT 2: Assessing sources of uncertainty in ocean analyses and forecasts(DMI, MPI-M, MetO, UPMC, UiB, IFM-GEOMAR, NERSC)
CT 3: Observations of the North Atlantic THC(UiB, UHAM, IFM-GEOMAR, HAV, MRI, NIOZ, NERC, SAMS, MPI-M)
CT 4: Predictability of the Meridional Overturning Circulation(KNMI, MPI-M, MetO, ECMWF, UREAD, IFM-GEOMAR)
CT 5: Technological Advancements for Improved near-real-time data transmission and Coupled Ocean-Atmosphere Data Assimilation (IFM-GEOMAR, UHAM, UiB, NERC, ECMWF, KNMI)
Gov
erni
ng B
oard
(GB
)
Sci
entif
ic S
teer
ing
and
Exe
cutiv
e C
omm
ittee
(SS
EC
)
International Advisory P
anel
Gender P
anel
Project Structure
Core Theme 1: Understanding Variability
Analysis of Millennium-scale numerical experiments and paleo-records
Atlantic inflow into the Nordic Seas
The observations and the model simulation show predominantly multidecadal-scale variability and a similar long-term evolution
Otterå, Bentsen, Drange & Suo, 2010
Core Theme 1: On-going Work
The figure shows how the vigor of Iceland-Scotland Overflow Water (ISOW) (, in red) (Mjell et al. in prep) and basin wide temperature (AMO in blue, after Gray et al., 2004) have co-varied over the past 400 years.
i.e. Relation between newly observed overflow strength and the basin-wide temperature changes:
Core Theme 2: Assessing Model Uncertainties
i.e. melting of the Greenland Ice Sheet, impact on the Ocean fresh water – salinity distribution after 30 years
Input of 0.1 Sv around Greenlandeast & west
west only
east only
Biastoch, 2010
Ocean reanalyses and observations, sensitivity experiments
Core Theme 2: On-going Work
Passive tracer release along the coast of Greenland
Working hypothesis: The effect of additional runoff on the convective activity in the interior Labrador Sea is weaker in models which resolves eddies. Coarser resolution models applying parameterizations which tend to cap the area with freshwater from the sides
After 3.5 years
Collapse of convection in the LS
The coarse simulation is less effected by additional freshwater due to lower initial overturning and lack of initial deep convection in the Labrador Sea
Core Theme 2: On-going Work
Core Theme 3: Observing the AMOC
Volume transport for deep western boundary current at the exit of the Labrador Sea (1997-2009);J. Fischer (IFM-GEOMAR)
Heat content of central Labrador Sea from K1 T time series (1997-2009);J. Fischer (IFM-GEOMAR)
Volume fluxes of MOC and mooring profiles of T,S at 26.50N (2004 - ongoing); S. Cunningham (NOCS/NERC)
Volume fluxes of FBC overflow (1995-2010), IFR inflow (1997-2010) and CTD standard sections;B. Hansen (FFL)
Volume fluxes of inflow of Atlantic waters in FSC (1994-2008), overflows at FSC and WTR (2003-2008) and CTD standard sections ; T. Sherwin (SAMS)
Volume transport of DSOW from Angmag-ssalik array and T,S time series (1994-2009);D. Quadfasel (IFM-UHAM),S. Dye (CEFAS)
Volume fluxes and T,S time series for Central Irminger Sea (2002-2009);J. Fischer and J. Karstensen (IFM-GEOMAR)
Volume fluxes in the IrmingerSea and CTD sectionsBetween Greenland andIreland (2003-2008);H. van Aken (NIOZ)
1/1/04 1/1/05 1/1/06 1/1/07Da te
-20
-10
0
10
20
30
Nor
th c
ompo
nent
(cm
/s)
21 0 m28 90 m
Volume and heat fluxes of Atlantic waters at Hornbanki section (1994-2009);S. Jónsson (MRI)
Transport data setsHydrography data sets
Datasets regularly updated, accessible through project homepage
Volume transport of DSOW and EGC at Denmark Strait sill section (1995-2011);D. Quadfasel (IFM-UHAM)
Core Theme 4: Prediction and Predictability
+
Data
Model
Synthesis
=
Hindcasts – ocean only Forecasts
initialisatio
n
PREDICATE: Sutton, 2004Köhl pers. con. 2010
Core Theme 4: On-going work – your input?
Core Theme 5: Technological Advancements
Real true data transmission from moorings: the Bergen and Kiel system
Data assimilation in coupled models: THOR
Core Theme 5: On-going
1. Real true data transmission from moorings
The Bergen System (accomplished)
Core Theme 5: On-going
1. Real true data transmission from moorings
The Kiel System (testing)
Core Theme 5: On-going
2. Data assimilation in THOR coupled model
• coupling: replacement of seaice- and ocean- compartments of the PlanetSimulator by MITogcm plus seaice
• configuration: coarse resolution setup with an atmosphere on a T21 grid and 5 sigma levels, and the MITogcm on a 5.625º grid having the North Pole shifted to Greenland, using 15 vertical levels
• testing: coupled system with single CPU on a notebook, performance is approx. 30 model years/day