scholarly journals Multiple solutions and numerical analysis to the dynamic and stationary models coupling a delayed energy balance model involving latent heat and discontinuous albedo with a deep ocean

2014 ◽  
Vol 470 (2170) ◽  
pp. 20140376 ◽  
Author(s):  
J. I. Díaz ◽  
A. Hidalgo ◽  
L. Tello
Keyword(s):  
Energy Balance ◽  
Latent Heat ◽  
Deep Ocean ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Ocean Model ◽  
Energy Balance Model ◽  
Balance Model ◽  
Finite Volume Scheme ◽  
Two Phase

We study a climatologically important interaction of two of the main components of the geophysical system by adding an energy balance model for the averaged atmospheric temperature as dynamic boundary condition to a diagnostic ocean model having an additional spatial dimension. In this work, we give deeper insight than previous papers in the literature, mainly with respect to the 1990 pioneering model by Watts and Morantine. We are taking into consideration the latent heat for the two phase ocean as well as a possible delayed term. Non-uniqueness for the initial boundary value problem, uniqueness under a non-degeneracy condition and the existence of multiple stationary solutions are proved here. These multiplicity results suggest that an S-shaped bifurcation diagram should be expected to occur in this class of models generalizing previous energy balance models. The numerical method applied to the model is based on a finite volume scheme with nonlinear weighted essentially non-oscillatory reconstruction and Runge–Kutta total variation diminishing for time integration.

scholarly journals Debris-covered energy balance model for Imja-Lhotse Shar Glacier in the Everest region of Nepal

2015 ◽  
Vol 9 (3) ◽  
pp. 3503-3540 ◽  
Author(s):  
D. R. Rounce ◽  
D. J. Quincey ◽  
D. C. McKinney
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Roughness ◽  
Energy Balance ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Energy Balance Model ◽  
Balance Model ◽  
Glacier Surface ◽  
Supraglacial Lakes

Abstract. Debris thickness plays an important role in regulating ablation rates on debris-covered glaciers as well as controlling the likely size and location of supraglacial lakes. Despite its importance, lack of knowledge about debris properties and associated energy fluxes prevents the robust inclusion of the effects of a debris layer into most glacier surface energy balance models. This study combines fieldwork with a debris-covered energy balance model to estimate debris temperatures and ablation rates on Imja-Lhotse Shar glacier located in the Everest region of Nepal. The debris properties that significantly influence the energy balance model are thermal conductivity, albedo, and surface roughness. Fieldwork was conducted to measure thermal conductivity and a method was developed using Structure from Motion to estimate surface roughness. Debris temperatures measured during the 2014 melt season were used to calibrate and validate a debris-covered energy balance model by optimizing the albedo, thermal conductivity, and surface roughness at 10 debris-covered sites. Furthermore, three methods for estimating the latent heat flux were investigated. Model calibration and validation found the three methods had similar performance; however, comparison of modeled and measured ablation rates revealed that assuming a zero latent heat flux may overestimate ablation. Results also suggest that where debris moisture is unknown, measurements of the relative humidity or precipitation may be used to estimate wet debris periods, i.e., the latent heat flux is non-zero. The effect of temporal resolution on the model was also assessed and results showed that both 6 h data and daily average data slightly underestimate debris temperatures and ablation rates, thus these should only be used to estimate rough ablation rates when no other data are available.

scholarly journals Transient Climate Response in a Two-Layer Energy-Balance Model. Part I: Analytical Solution and Parameter Calibration Using CMIP5 AOGCM Experiments

2013 ◽  
Vol 26 (6) ◽  
pp. 1841-1857 ◽  
Author(s):  
O. Geoffroy ◽  
D. Saint-Martin ◽  
D. J. L. Olivié ◽  
A. Voldoire ◽  
G. Bellon ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Energy Balance ◽  
Analytical Solution ◽  
Deep Ocean ◽  
Energy Balance Model ◽  
Balance Model ◽  
Model Parameters ◽  
Climate Change Scenarios ◽  
Ocean Heat Uptake ◽  
Transient Climate Response

Abstract This is the first part of a series of two articles analyzing the global thermal properties of atmosphere–ocean coupled general circulation models (AOGCMs) within the framework of a two-layer energy-balance model (EBM). In this part, the general analytical solution of the system is given and two idealized climate change scenarios, one with a step forcing and one with a linear forcing, are discussed. These solutions give a didactic description of the contributions from the equilibrium response and of the fast and slow transient responses during a climate transition. Based on these analytical solutions, a simple and physically based procedure to calibrate the two-layer model parameters using an AOGCM step-forcing experiment is introduced. Using this procedure, the global thermal properties of 16 AOGCMs participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5) are determined. It is shown that, for a given AOGCM, the EBM tuned with only the abrupt 4×CO2 experiment is able to reproduce with a very good accuracy the temperature evolution in both a step-forcing and a linear-forcing experiment. The role of the upper-ocean and deep-ocean heat uptakes in the fast and slow responses is also discussed. One of the main weaknesses of the simple EBM discussed in this part is its ability to represent the evolution of the top-of-the-atmosphere radiative imbalance in the transient regime. This issue is addressed in Part II by taking into account the efficacy factor of deep-ocean heat uptake.

scholarly journals Transient Climate Response in a Two-Layer Energy-Balance Model. Part II: Representation of the Efficacy of Deep-Ocean Heat Uptake and Validation for CMIP5 AOGCMs

2013 ◽  
Vol 26 (6) ◽  
pp. 1859-1876 ◽  
Author(s):  
O. Geoffroy ◽  
D. Saint-Martin ◽  
G. Bellon ◽  
A. Voldoire ◽  
D. J. L. Olivié ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Energy Balance ◽  
Surface Temperature ◽  
General Circulation ◽  
Deep Ocean ◽  
Energy Balance Model ◽  
Balance Model ◽  
Ocean Heat Uptake ◽  
Transient Climate Response ◽  
Heat Uptake

Abstract In this second part of a series of two articles analyzing the global thermal properties of atmosphere–ocean coupled general circulation models (AOGCMs) within the framework of a two-layer energy-balance model (EBM), the role of the efficacy of deep-ocean heat uptake is investigated. Taking into account such an efficacy factor is shown to amount to representing the effect of deep-ocean heat uptake on the local strength of the radiative feedback in the transient regime. It involves an additional term in the formulation of the radiative imbalance at the top of the atmosphere (TOA), which explains the nonlinearity between radiative imbalance and the mean surface temperature observed in some AOGCMs. An analytical solution of this system is given and this simple linear EBM is calibrated for the set of 16 AOGCMs of phase 5 of the Coupled Model Intercomparison Project (CMIP5) studied in Part I. It is shown that both the net radiative fluxes at TOA and the global surface temperature transient response are well represented by the simple EBM over the available period of simulations. Differences between this two-layer EBM and the previous version without an efficacy factor are analyzed and relationships between parameters are discussed. The simple model calibration applied to AOGCMs constitutes a new method for estimating their respective equilibrium climate sensitivity and adjusted radiative forcing amplitude from short-term step-forcing simulations and more generally a method to compute their global thermal properties.

scholarly journals Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal

2015 ◽  
Vol 9 (6) ◽  
pp. 2295-2310 ◽  
Author(s):  
D. R. Rounce ◽  
D. J. Quincey ◽  
D. C. McKinney
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Roughness ◽  
Energy Balance ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Energy Balance Model ◽  
Balance Model ◽  
Glacier Surface ◽  
Supraglacial Lakes

Abstract. Debris thickness plays an important role in regulating ablation rates on debris-covered glaciers as well as controlling the likely size and location of supraglacial lakes. Despite its importance, lack of knowledge about debris properties and associated energy fluxes prevents the robust inclusion of the effects of a debris layer into most glacier surface energy balance models. This study combines fieldwork with a debris-covered glacier energy balance model to estimate debris temperatures and ablation rates on Imja–Lhotse Shar Glacier located in the Everest region of Nepal. The debris properties that significantly influence the energy balance model are the thermal conductivity, albedo, and surface roughness. Fieldwork was conducted to measure thermal conductivity and a method was developed using Structure from Motion to estimate surface roughness. Debris temperatures measured during the 2014 melt season were used to calibrate and validate a debris-covered glacier energy balance model by optimizing the albedo, thermal conductivity, and surface roughness at 10 debris-covered sites. Furthermore, three methods for estimating the latent heat flux were investigated. Model calibration and validation found the three methods had similar performance; however, comparison of modeled and measured ablation rates revealed that assuming the latent heat flux is zero may overestimate ablation. Results also suggest that where debris moisture is unknown, measurements of the relative humidity or precipitation may be used to estimate wet debris periods, i.e., when the latent heat flux is non-zero. The effect of temporal resolution on the model was also assessed and results showed that both 6 h data and daily average data slightly underestimate debris temperatures and ablation rates; thus these should only be used to estimate rough ablation rates when no other data are available.

scholarly journals On the Use of the Eddy Covariance Latent Heat Flux and Sap Flow Transpiration for the Validation of a Surface Energy Balance Model

2018 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Antonino Maltese ◽  
Hassan Awada ◽  
Fulvio Capodici ◽  
Giuseppe Ciraolo ◽  
Goffredo La Loggia ◽  
...  
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Surface Energy ◽  
Eddy Covariance ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Sap Flow ◽  
Surface Energy Balance ◽  
Energy Balance Model ◽  
Balance Model

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

Estimation of mass and energy balance of glaciers using a distributed energy balance model over the Chandra river basin (Western Himalaya)

2021 ◽  
Vol 35 (2) ◽  
Author(s):  
Akansha Patel ◽  
Ajanta Goswami ◽  
Jaydeo K. Dharpure ◽  
Meloth Thamban ◽  
Parmanand Sharma ◽  
...  
Keyword(s):  
Energy Balance ◽  
River Basin ◽  
Western Himalaya ◽  
Energy Balance Model ◽  
Balance Model ◽  
Distributed Energy
Sign in / Sign up

Export Citation Format

Share Document