The Ocean’s role in the climate system Rein Haarsma, Dewi Le Bars and Will de Ruijter USPC 2016

From NASA: http://data.giss.nasa.gov

From NASA: http://data.giss.nasa.gov Climate “hiatus”: The global temperature reached a plateau From NASA: http://data.giss.nasa.gov

Did the incoming energy decrease? Hansen et al. 2011 No, the energy imbalance is maximum Where did the heat go?

The ARGO program

Fast warming of the deep ocean since 2000 Ocean Heat Content Balmaseda et al. 2013 Fast warming of the deep ocean since 2000

Outlines Horizontal ocean circulation 3D ocean circulation Modes of climate variability

Horizontal ocean circulation

Wind driven ocean gyres Very schematic representation!

Poleward heat transport Atmosphere Ocean NCEP Czaja and Marshall, 2006 ECMWF

Western intensification Sea surface temperature from satellite data: Red = Warm Blue = cold

Some other western boundary currents Kuroshio Current Agulhas Current East Australian Current

Upwelling and global overturning circulation 3D Ocean circulation Upwelling and global overturning circulation

North-South temperature section in the Pacific

Ekman spiral

Equatorial upwelling Chlorophyll contents

Coastal and equatorial upwellings

Meridional heat transport Poleward heat flux except in the South Atlantic ocean

Sea surface salinity (Levitus) What is the peculiarity of the Atlantic Ocean?

North-South salinity cross section of the Atlantic Ocean revealing its meridional overturning circulation

Conductivity, Temperature, Depth (CTD) measurements

Labrador sea convection

Sites of deep convection Marshall and Schott, 1999

Global Overturning Circulation Marshall and Speer, 2012

Vellinga, Hadley center, UK What if it stops? Vellinga, Hadley center, UK

Bryden et al. 2005: strength of the overturning has decreased by about 30%...

Measuring the Atlantic Meridional Overturning Circulation (AMOC) The RAPID array since 2004

Important time variability but no trend this Srokosz et al. 2012 Important time variability but no trend

Not exactly true, now we see a trend, important? Roberts et al. 2014 Not exactly true, now we see a trend, important?

Modes of climate variability El Nino-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Madden Julian Oscillation (MJO)...

ENSO

El Nino impact on the ocean heat content ENSO El Nino impact on the ocean heat content Balmaseda et al. 2013

Tipping points The term “tipping point” commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system

Potential tipping elements Lenton et al. 2008

Importance of the Ocean for climate Heat storage Heat transport from the equator to the poles Inter-annual modes of climate variability Nutrients availability, CO2 storage...