scholarly journals A Maximum Entropy Production Hypothesis for Time Varying Climate Problems: Illustration on a Conceptual Model for the Seasonal Cycle

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 966
Author(s):  
Vincent Labarre ◽  
Didier Paillard ◽  
Bérengère Dubrulle
Keyword(s):  
Energy Balance ◽  
Entropy Production ◽  
Conceptual Model ◽  
Maximum Entropy ◽  
Seasonal Cycle ◽  
Ground Temperature ◽  
Time Varying ◽  
Energy Fluxes ◽  
Maximum Entropy Production ◽  
Energy Balance Models

We investigated the applicability of the maximum entropy production hypothesis to time-varying problems, in particular, the seasonal cycle using a conceptual model. Contrarily to existing models, only the advective part of the energy fluxes is optimized, while conductive energy fluxes that store energy in the ground are represented by a diffusive law. We observed that this distinction between energy fluxes allows for a more realistic response of the system. In particular, a lag is naturally observed for the ground temperature. This study therefore shows that not all energy fluxes should be optimized in energy balance models using the maximum entropy production hypothesis, but only the fast convective (turbulent) part.

Exploring the possible meridional temperature gradient of Early Eocene Climatic Optimum with an energy balance model

2021 ◽  
Author(s):  
Fanni Dora Kelemen ◽  
Bodo Ahrens
Keyword(s):  
Energy Balance ◽  
Temperature Gradient ◽  
Entropy Production ◽  
Maximum Entropy ◽  
Early Eocene ◽  
Meridional Temperature Gradient ◽  
Proxy Data ◽  
Maximum Entropy Production ◽  
Early Eocene Climatic Optimum ◽  
Climatic Optimum

<p>Early Eocene Climatic Optimum (EECO, ~53-51 million years) is one of the past warm periods, associated with high CO<sub>2</sub> concentrations (~900-2500 ppmv), which can serve as an analogue for our possible future, high C0<sub>2 </sub>climate. One notable feature of this hothouse climate state is the weaker meridional temperature gradient relative to pre-industrial values. This have been confirmed by both proxies and models, but the extent of the temperature gradient still requires more research. Models are challenged to reproduce the stronger than present day polar amplification signal, and it is also shown that high latitude proxy data are often influenced by seasonal bias. Thus, there is an uncertainty regarding both the observed and modelled meridional gradient and the mentioned issues complicate also the comparison between modeled and proxy data.</p><p>In our work we aim to investigate the EECO period with a simple energy balance box model and apply the maximum entropy production principle to explore the possible scenarios of meridional temperature gradients. We find that the maximum entropy production principle could be beneficial in the paleoclimate context since it has the utility to give an accurate prediction for non-equilibrium systems with the minimal amount of information. We also assess the heat transport signaled by proxy data and by state-of-the-art model outputs in accordance to our theoretical constrains based on the idealized test case.</p>

scholarly journals A Radiative Convective Model based on constrained Maximum Entropy Production

2018 ◽  
Author(s):  
Vincent Labarre ◽  
Didier Paillard ◽  
Bérengère Dubrulle
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Energy Flux ◽  
Radiative Forcing ◽  
Climate Models ◽  
Carbon Dioxide Concentration ◽  
Atmospheric Composition ◽  
Energy Fluxes ◽  
Maximum Entropy Production ◽  
Energy Transfers

Abstract. The representation of atmospheric convection induced by radiative forcing is a longstanding question mainly because turbulence plays a key role in the transport of energy as sensible heat, geopotential and latent heat. Recent works have tried to use Maximum Entropy Production as a closure hypothesis in Simple Climate Models in order to compute implicitly temperatures and vertical energy flux. However, these models failed to compute realistic profiles. To solve this problem, we prescribe a simplified 1D mass scheme transport which ensures energy fluxes. The later appears as a mechanical constraint which imposes the direction and/or limits the amplitudes of energy fluxes. This leads to a different MEP steady state which depends on the considered energy transfers in the model. Results using such model are improved with respect to another model, not including such effect: temperature and energy flux are closer to the observations and we naturally reproduce stratification when we consider geopotential. Variations of the atmospheric composition, such as doubling of the carbon dioxide concentration, is also investigated.

scholarly journals A radiative-convective model based on constrained maximum entropy production

2019 ◽  
Vol 10 (3) ◽  
pp. 365-378 ◽  
Author(s):  
Vincent Labarre ◽  
Didier Paillard ◽  
Bérengère Dubrulle
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Energy Flux ◽  
Radiative Forcing ◽  
Climate Models ◽  
Carbon Dioxide Concentration ◽  
Atmospheric Composition ◽  
Energy Fluxes ◽  
Maximum Entropy Production ◽  
Energy Gradient

Abstract. The representation of atmospheric convection induced by radiative forcing is a long-standing question mainly because turbulence plays a key role in the transport of energy as sensible heat, geopotential, and latent heat. Recent works have tried using the maximum entropy production (MEP) conjecture as a closure hypothesis in 1-D simple climate models to compute implicitly temperatures and the vertical energy flux. However, these models fail to reproduce realistic profiles. To solve the problem, we describe the energy fluxes as a product of a positive mass mixing coefficient with the corresponding energy gradient. This appears as a constraint which imposes the direction and/or limits the amplitude of the energy fluxes. It leads to a different MEP steady state which naturally depends on the considered energy terms in the model. Accounting for this additional constraint improves the results. Temperature and energy flux are closer to observations, and we reproduce stratification when we consider the geopotential. Variations in the atmospheric composition, such as a doubling of the carbon dioxide concentration, are also investigated.

The mechanics of granitoid systems and maximum entropy production rates

2010 ◽  
Vol 368 (1910) ◽  
pp. 53-93 ◽  
Author(s):  
Bruce E. Hobbs ◽  
Alison Ord
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Melt Inclusions ◽  
Selection Process ◽  
Finite Thickness ◽  
Control Valve ◽  
Entropy Production Rate ◽  
Constitutive Behaviour ◽  
Maximum Entropy Production ◽  
Physical Height

A model for the formation of granitoid systems is developed involving melt production spatially below a rising isotherm that defines melt initiation. Production of the melt volumes necessary to form granitoid complexes within 10 4 –10 7 years demands control of the isotherm velocity by melt advection. This velocity is one control on the melt flux generated spatially just above the melt isotherm, which is the control valve for the behaviour of the complete granitoid system. Melt transport occurs in conduits initiated as sheets or tubes comprising melt inclusions arising from Gurson–Tvergaard constitutive behaviour. Such conduits appear as leucosomes parallel to lineations and foliations, and ductile and brittle dykes. The melt flux generated at the melt isotherm controls the position of the melt solidus isotherm and hence the physical height of the Transport/Emplacement Zone. A conduit width-selection process, driven by changes in melt viscosity and constitutive behaviour, operates within the Transport Zone to progressively increase the width of apertures upwards. Melt can also be driven horizontally by gradients in topography; these horizontal fluxes can be similar in magnitude to vertical fluxes. Fluxes induced by deformation can compete with both buoyancy and topographic-driven flow over all length scales and results locally in transient ‘ponds’ of melt. Pluton emplacement is controlled by the transition in constitutive behaviour of the melt/magma from elastic–viscous at high temperatures to elastic–plastic–viscous approaching the melt solidus enabling finite thickness plutons to develop. The system involves coupled feedback processes that grow at the expense of heat supplied to the system and compete with melt advection. The result is that limits are placed on the size and time scale of the system. Optimal characteristics of the system coincide with a state of maximum entropy production rate.

scholarly journals Relaxation Processes and the Maximum Entropy Production Principle

Entropy ◽  
2010 ◽  
Vol 12 (3) ◽  
pp. 473-479 ◽  
Author(s):  
Paško Županović ◽  
Srećko Botrić ◽  
Davor Juretić ◽  
Domagoj Kuić
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Relaxation Processes ◽  
Maximum Entropy Production
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