S 1

CT1/CT3 Meeting 22-23 April 2013 Hamburg

WP 3.1 Suitability of the ocean observing system components for initialization

Wonsun ParkGEOMAR

http://www.argo.ucsd.edu/About_Argo.html

Core Theme 3: Initialization of prediction systems with ocean observations (Lead: Steffen Olsen, DMI)

WP 3.1 Suitability of the ocean observing system components for initialization (Lead: Mojib Latif, GEOMAR)

Wonsun Park, Fritz Krueger, Thomas Martin

WP 3.1 Suitability of the ocean observing system components for initialization

• Objectives– To investigate the benefit of the different ocean

observing system components for the initialization of decadal climate prediction systems

– To quantify the impact of the different observing system components in terms of decadal hindcast skill

– To identify the necessary enhancements and potential reductions of the present observing systems

22 ensemble runs with 1%/yr CO2 increaseNatural variability is important at least till 40 yrs

Latif and Park 2012

Observed multidecadal variability (ERSSTv3b)Pacific Decadal Variability vs. Atlantic Multidecadal Variability

Park and Latif 2012

Centennial/multicentennial variability in observation and KCM

Latif et al. 2013SSO index: SST averaged 50°-70°S

Internal modesMulticentennial/Quasicentennial/Multidecadal

SST

SSS

Park and Latif 2012

Salinity restored to model climatology in the subpolar North Atlantic

Ba et al. 2013

WP 3.1 Scientific work plan

• Perfect model approach• Initialization: sampling according to existing ocean

observing system components• Hindcasts with reduced set of initial conditions• Quantification contribution of different components

of ocean observing system• Investigate potential observational needs to enhance

decadal prediction• Comparison with other models (e.g. KCM with MPI-

ESM)

Description of work• Model setup and control run

– Set up the coupled model and perform long control integration.– Choose a suitable set of initial states from the control

integrations with regard to the Atlantic Meridional Overturning Circulation.

• Hindcast experiments and skill assessment– Do re-start experiments with truncated initial conditions that

correspond to the different ocean observing system components, and with the full system.

– Assess results in terms of hindcast skill.– Provide recommendations for a “suitable” observing system.

• Benefit of different Ocean regions– Do re-start experiments with truncated initial conditions which

correspond to the different ocean regions, and with the global initialization, and assess the hindcast skill. [MPI-M]

The research leading to these results has received funding from the European Union 7th Framework Programme (FP7 2007-2013), under grant agreement n.308299NACLIM www.naclim.eu