Geothermal heating : the unsung diva of abyssal dynamics Julien Emile-Geay Lamont-Doherty Earth Observatory, Palisades, NY, USA Gurvan Madec LODYC, Paris,

Slides:

Advertisements

Similar presentations

1 Dynamical Polar Warming Amplification and a New Climate Feedback Analysis Framework Ming Cai Florida State University Tallahassee, FL 32306

Advertisements

The Global Salinity Budget From before, salinity is mass salts per mass seawater (S = 1000 * kg salts / kg SW) There is a riverine source …BUT… salinity.

Introduction to the Lagrangian Isopycnal Dispersion Experiment in the North Atlantic Long Zhou.

The ocean and the global hydrologic cycle Jim Carton (University of Maryland) Paulo Nobre (INPE) São Paulo Summer School on Global Climate Modeling October,

Modeling the MOC Ronald J Stouffer Geophysical Fluid Dynamics Laboratory NOAA The views described here are solely those of the presenter and not of GFDL/NOAA/DOC.

4. Ocean Temperature The equilibrated ocean surface temperature anomalies in EPR0 and EPR2 are shown below ( o C). The responses at low latitudes, where.

Thermohaline circulation ●The concept of meridional overturning ●Deep water formation and property Antarctic Bottom Water North Atlantic Deep Water Antarctic.

Preliminary results on Formation and variability of North Atlantic sea surface salinity maximum in a global GCM Tangdong Qu International Pacific Research.

Published in 2007 Cited 15 times Keywords: North Pacific, PDO-related air forcing, Eddy permitting model, Model heat/SST budget analysis.

Climatic impacts of stochastic fluctuations in air–sea fluxes Paul Williams Department of Meteorology, University of Reading, UK.

Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009 Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009.

Diagnosing Eddy Mixing in the Southern Ocean from SOSE Ryan Abernathey With John Marshall, Matt Mazzloff and Emily Shuckburgh.

Response of the Atmosphere to Climate Variability in the Tropical Atlantic By Alfredo Ruiz–Barradas 1, James A. Carton, and Sumant Nigam University of.

Oceanography & Climate Synthesis Question: If all of the oceans currents changed direction, would they then heat the equator and cool the poles?

Sea-ice & the cryosphere

Thermohaline Circulation

Thermohaline Circulation (THC) By Ross Alter. What is it? “…that part of the ocean circulation which is driven by fluxes of heat and freshwater across.

Ocean Response to Global Warming William Curry Woods Hole Oceanographic Institution Wallace Stegner Center March 3, 2006.

=(S,,0); 4=(S,,4000).

The Atmosphere: Part 5: Large-scale motions Composition / Structure Radiative transfer Vertical and latitudinal heat transport Atmospheric circulation.

EVAT 554 OCEAN-ATMOSPHERE DYNAMICS THERMOHALINE CIRCULATION (CONTINUED) LECTURE 20.

Potential temperature ( o C, Levitus 1994) Surface Global zonal mean.

© Imperial College LondonPage 1 Solar Influence on Stratosphere-Troposphere Dynamical Coupling Isla Simpson, Joanna D. Haigh, Space and Atmospheric Physics,

1 Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009.

Evaporation Slides prepared by Daene C. McKinney and Venkatesh Merwade

General Circulation of the Atmosphere Lisa Goddard 19 September 2006.

Subsurface Currents The Oceans in Motion. Subsurface Currents 1.Mechanics 2.Deep water formation 3.The Importance of the Global Conveyer Belt.

Water masses of the Southern Ocean: Their formation, circulation and global role Igor V. Kamenkovich University of Washington, Seattle.

Atmospheric TU Delft Stephan de Roode, Harm Jonker clouds, climate and weather air quality in the urban environmentenergy.

Are Tropical Cyclones Changing the Meridional Overturning Circulation? Gino.

1.Introduction 2.Description of model 3.Experimental design 4.Ocean ciruculation on an aquaplanet represented in the model depth latitude depth latitude.

1-Slide Summary Explicit Southern Ocean eddies respond to forcing differently than parameterizations.  We need eddy resolving ocean climate models. Spurious.

Rossby Wave Two-layer model with rigid lid η=0, p s ≠0 The pressures for the upper and lower layers are The perturbations are 

Modelling the evolution of the Siple Coast ice streams. Tony Payne 1*, Andreas Vieli 1 and Garry Clarke 2 1 Centre for Polar Observation and Modelling,

The Gent-McWilliams parameterization of ocean eddies in climate models Peter Gent National Center for Atmospheric Research.

Impact of freshwater release in the Southern Ocean on the Atlantic Didier Swingedouw.

The Influence of the Indonesian Throughflow on the Eastern Pacific Biogeochimical Conditions Fig.1 The last year of the two runs is used to force offline.

Thermohaline Ocean Circulation Stefan Rahmstorf. What is Thermohaline Circulation? Part of the ocean circulation which is driven by fluxes of heat and.

Ocean Currents Ocean Density. Energy in = energy out Half of solar radiation reaches Earth The atmosphere is transparent to shortwave but absorbs longwave.

Snowball oceanography. What is Snowball Earth? Most extreme climate event in Earth history. Characteristics: Occurred at least twice between Ma.

Typical Distributions of Water Characteristics in the Oceans.

Thermohaline Circulation Lecture Outline 1)What is thermohaline circulation 2)History of understanding 3)Key water masses 4)Formation of deep water 5)Theory.

Class 8. Oceans Figure: Ocean Depth (mean = 3.7 km)

Current state of ECHAM5/NEMO coupled model Wonsun Park, Noel Keenlyside, Mojib Latif (IFM-GEOMAR) René Redler (NEC C&C Research Laboratories) DRAKKAR meeting.

Ocean Response to Global Warming/Global Change William Curry Woods Hole Oceanographic Institution Environmental Defense May 12, 2005 Possible changes in.

The CHIME coupled climate model Alex Megann, SOC 26 January 2005 (with Adrian New, Bablu Sinha, SOC; Shan Sun, NASA GISS; Rainer Bleck, LANL)  Introduction.

 p and  surfaces are parallel =>  =  (p) Given a barotropic and hydrostatic conditions, is geostrophic current. For a barotropic flow, we have and.

On the effect of the Greenland Scotland Ridge on the dense water formation in the Nordic Seas Dorotea Iovino NoClim/ProClim meeting 4-6 September 2006.

Nansen Environmental and Remote Sensing Center Modifications of the MICOM version used in the Bergen Climate Model Mats Bentsen and Helge Drange Nansen.

A. Laurian S. Drijfhout W. Hazeleger B. van den Hurk Response of the western European climate to a THC collapse Koninklijk Nederlands Meteorologisch Instituut,

Forces and accelerations in a fluid: (a) acceleration, (b) advection, (c) pressure gradient force, (d) gravity, and (e) acceleration associated with viscosity.

Tropical Atlantic SST in coupled models; sensitivity to vertical mixing Wilco Hazeleger Rein Haarsma KNMI Oceanographic Research The Netherlands.

How Convection Currents Affect Weather and Climate.

The Greenhouse Effect Solar Radiation, Earth's Atmosphere, and the Greenhouse Effect. Martin Visbeck DEES, Lamont-Doherty Earth Observatory

Gent-McWilliams parameterization: 20/20 Hindsight Peter R. Gent Senior Scientist National Center for Atmospheric Research.

For a barotropic flow, we have is geostrophic current.

Our water planet and our water hemisphere

Trevor J McDougall, Raf Ferrari & Ryan Holmes

Wind-driven circulation

Two stable equilibria of the Atlantic subpolar gyre

OCEAN RESPONSE TO AIR-SEA FLUXES Oceanic and atmospheric mixed

Mark A. Bourassa and Qi Shi

Ocean Currents & Climate

Ocean circulation: key questions

TALLEY Copyright © 2011 Elsevier Inc. All rights reserved

Investigating Dansgaard-Oeschger events via a 2-D ocean model

Impacts of Air-Sea Interaction on Tropical Cyclone Track and Intensity

Oceans and Internal Climate Variability

Numerical Mixing in the COSIMA Models

Surface Wave Enhanced Turbulence as an important source energy maintaining/regulating Thermohaline Circulation Rui Xin Huang Woods Hole Oceanographic.

Presentation transcript:

Geothermal heating : the unsung diva of abyssal dynamics Julien Emile-Geay Lamont-Doherty Earth Observatory, Palisades, NY, USA Gurvan Madec LODYC, Paris, France

Solid Earth cooling in the abyss Solid Earth cooling in the abyss

The spatial structure

Introduction “Q geo ~ 100 mW.m -2 / Solar is ~100 W.m -2 ” Why is geothermal heating generally neglected in dynamical oceanography ? (except by Scott, Adcroft and Marotzke, JGR, 2001) AABW

Outline 1.Analytical balance 2.Density-binning 3.Numerical approach Geothermal Heating is a Driving force of the MOC

Heat Equation 2 ways of comparing : 1.Plot downward heat flux 2.“Equivalent K z ” Bryan, 1987 : MOC is controlled by the heat supplied to the abyss How big is geothermal heating in the heat budget ? DiffusionGeothermal Heatflow Measured K z : ~0.1 cm 2.s -1 Implied K z : ~1 cm 2.s -1 (advection-diffusion balance) Munk, 1966

Geothermal Heating vs Diapycnal Mixing (2) (z=-3500m)

A simple scaling law

Results BasinAtlanticIndianPacificGlobal Area (10 14 m 2 )  T ( C) Scaling(Sv) Geothermal circulation is commensurable to the Stommel-Arons circulation

Density-binning the abyssal ocean (Steady-state) Transformation equation :Formation equation : Geothermal Circulation

Results : A Q F Transformation of ~6.5 Sv Centered on  = Transformation of ~6 Sv Shifted towards  = Uniform Heatflow Realistic Heatflow

A numerical approach OPA model v8.1 (Madec et al, 1998): Primitive equation model, non-linear equation of state Horizontal physics : Isopycnal mixing with Gent & McWilliams Conservation of haline content (Roullet and Madec 2000) ORCA2 configuration  x*  y=2 * [0.5(Tropics) ; 2] - 31 vertical levels ( 15 in upper 200m) Coupled to LIM (LLN sea-ice model) Equilibrium runs from Levitus (1998) forced by climatological fluxes Geothermal Heat flux passed like a surface flux

Control runs K z =0.1cm 2.s -1 Cold bottom water K z =0.1 K z =1 Hadley center

Effect of a uniform heatflow(CBW)

Effect of a uniform heatflow (STD) Transformation (Sv)

Effect of vertical physics

Conclusions Q geo ~ K z = 1.2 cm 2.s -1 (at 3500m) Three independent approaches predict a circulation of 5-6 Sv, inversely proportional to deep temperature gradients (modulated by mixing) Changes the thermal structure to first order (cf Scott et al.), in particular the meridional temperature gradient Geothermal Heating is a major AABW consumer Major forcing of the abyssal circulation

Summary (continued) Details of the spatial structure are secondary : Circulation is weakened by ~ 20% (STD) Warming enhanced in the NADW depth range weakened on abyssal plains (by ~10-20%)

Conclusion “Viewed as a heat engine, the ocean circulation is extraordinarily inefficient. Viewed as a mechanically-driven system, it is a remarkably effective transporter of the energy” Walter Munk and Carl Wunsch, 1998 Geothermal Heating is a major actor of abyssal dynamics Influences mostly PE, not KE Provides 1/3 of APE for deep mixing May help resolve the “diffusivity dilemna” Does it have a role in climate change ? (Little Ice Age ? Glacial THC ?)

Geothermal Heating vs Diapycnal mixing (1) Downward Heat Flux =

What happens to the Sverdrup balance ? If, then : (Sverdrup balance) Now, then : Integrating : (Joyce et al. [1986])

Life cycle of AABW Formation Transformation Consumption Deep convection, cabelling Entrainment, Downhill mixing, Diapycnal mixing Upwelling (NADW) Getohermal Heating

Density-binning the abyssal ocean (Steady-state) Transformation equation :

Effect of a spatially variable heatflow

Impact on the circulation

Impact on the thermal structure

Three views of the problem 1.Geothermal Heating as a source of mixing Gordon and Gerard (1970) Huang (1999) 2.Localized hydrothermal venting Stommel (1983) Helfrich and Speer (1995) 3.The new wave Adcroft et al (2001), Scott et al (2001) This study

Three sets of experiments Set Experiments Q geo (mW.m -2 ) K z (cm 2.s -1 ) CBW CBWCBW_Q_uni STD STDSTD_Q_uniSTD_Q_var086.4 Q geo (x,y) MIX MIXMIX_Q_var0 1 (Hadley)