Some mathematical problems associated with the development and use of marine models

Deleersnijder, Éric; Beckers, Jean-Marie; Campin, Jean‐Michel; Mohajir, Mohammed El; Fichefet, Thierry; Luyten, Patrick

doi:10.1007/978-3-642-60603-8_2

Cited by 25 publications

(14 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CLIO (Coupled Large-scale Ice Ocean) model (Goosse et al, 1997Goosse and Fichefet, 1999;Tartinville et al, 2001) results from the coupling of a comprehensive sea-ice model Morales Maqueda, 1997, 1999) and an ocean general circulation model (Deleersnijder and Campin, 1995;Deleersnijder et al, 1997, Campin and) both developed at the Institut d'Astronomie et de Géophysique G. Lemaître, Louvain-la-Neuve (ASTR) of the UCL.…”

Section: Clio: the Sea-ice And Ocean Componentmentioning

confidence: 99%

Description of the Earth system model of intermediate complexity LOVECLIM version 1.2

et al. 2010

View full text Add to dashboard Cite

Abstract. The main characteristics of the new version 1.2 of the three-dimensional Earth system model of intermediate complexity LOVECLIM are briefly described. LOVE-CLIM 1.2 includes representations of the atmosphere, the ocean and sea ice, the land surface (including vegetation), the ice sheets, the icebergs and the carbon cycle. The atmospheric component is ECBilt2, a T21, 3-level quasigeostrophic model. The ocean component is CLIO3, which consists of an ocean general circulation model coupled to a comprehensive thermodynamic-dynamic sea-ice model. Its horizontal resolution is of 3 • by 3 • , and there are 20 levels in the ocean. ECBilt-CLIO is coupled to VECODE, a vegetation model that simulates the dynamics of two main terrestrial plant functional types, trees and grasses, as well as desert. VECODE also simulates the evolution of the carbon cycle over land while the ocean carbon cycle is represented by LOCH, a comprehensive model that takes into acCorrespondence to: H. Goosse (hugues.goosse@uclouvain.be) count both the solubility and biological pumps. The ice sheet component AGISM is made up of a three-dimensional thermomechanical model of the ice sheet flow, a visco-elastic bedrock model and a model of the mass balance at the iceatmosphere and ice-ocean interfaces. For both the Greenland and Antarctic ice sheets, calculations are made on a 10 km by 10 km resolution grid with 31 sigma levels. LOVECLIM1.2 reproduces well the major characteristics of the observed climate both for present-day conditions and for key past periods such as the last millennium, the mid-Holocene and the Last Glacial Maximum. However, despite some improvements compared to earlier versions, some biases are still present in the model. The most serious ones are mainly located at low latitudes with an overestimation of the temperature there, a too symmetric distribution of precipitation between the two hemispheres, and an overestimation of precipitation and vegetation cover in the subtropics. In addition, the atmospheric circulation is too weak. The model also tends to underestimate the surface temperature changes (mainly at low latitudes) and to overestimate the ocean heat uptake observed over the last decades.

show abstract

Section: Clio: the Sea-ice And Ocean Componentmentioning

confidence: 99%

Description of the Earth system model of intermediate complexity LOVECLIM version 1.2

et al. 2010

View full text Add to dashboard Cite

show abstract

“…This threshold is defined by 0.83 times the vertically integrated saturated specific humidity, assuming constant relative humidity within the layer (Goosse et al, 2010). The oceanic component (CLIO) is a primitive-equation, free-surface general ocean circulation model (Deleersnijder and Campin, 1995;Deleersnijder et al, 1997) coupled to a thermodynamic-dynamic sea-ice model Morales Maqueda, 1997, 1999), and has a resolution of 3 • × 3 • latitude-longitude and realistic bathymetry. The vegetation component (VECODE) is a reduced-form dynamic global vegetation model, and is capable of simulating the dynamics of two plant functional types, trees and grasses, as well as desert as a dummy type (Brovkin et al, 2002).…”

Section: Modelmentioning

confidence: 99%

The impact of Sahara desertification on Arctic cooling during the Holocene

et al. 2015

View full text Add to dashboard Cite

Abstract. Since the start of the Holocene, temperatures in the Arctic have steadily declined. This has been accredited to the orbitally forced decrease in summer insolation reconstructed over the same period. However, here we present climate modelling results from an Earth model of intermediate complexity (EMIC) that indicate that 17-40 % of the cooling in the Arctic, over the period 9-0 ka, was a direct result of the desertification that occurred in the Sahara after the termination of the African Humid Period. We have performed a suite of sensitivity experiments to analyse the impact of different combinations of forcings, including various vegetation covers in the Sahara. Our simulations suggest that over the course of the Holocene, a strong increase in surface albedo in the Sahara as a result of desertification led to a regional increase in surface pressure, a weakening of the trade winds, the westerlies and the polar easterlies, which in turn reduced the meridional heat transported by the atmosphere to the Arctic. We conclude that during interglacials, the climate of the Northern Hemisphere is sensitive to changes in Sahara vegetation type.

show abstract

“…23), are not unconditionally positivity preserving, see Burchard et al (2003). The remedy for positivity preservation, the quasi-implicit Patankar-type schemes [motivated by the work of Patankar (1980), see also Deleersnijder et al (1997)] are not conservative, since source and sink terms are numerically treated in a different way. For this type of schemes, the first-order Patankar-Euler scheme PE1 (Eq.…”

Section: Vertical Discretisation and Ode Solversmentioning

confidence: 98%

Application of modified Patankar schemes to stiff biogeochemical models for the water column

2005

Self Cite

View full text Add to dashboard Cite

In this paper, we apply recently developed positivity preserving and conservative Modified Patankar-type solvers for ordinary differential equations to a simple stiff biogeochemical model for the water column. The performance of this scheme is compared to schemes which are not unconditionally positivity preserving (the first-order Euler and the second-and fourth-order Runge-Kutta schemes) and to schemes which are not conservative (the first-and second-order Patankar schemes). The biogeochemical model chosen as a test ground is a standard nutrient-phytoplankton-zooplankton-detritus (NPZD) model, which has been made stiff by substantially decreasing the half saturation concentration for nutrients. For evaluating the stiffness of the biogeochemical model, so-called numerical time scales are defined which are obtained empirically by applying high-resolution numerical schemes. For all ODE solvers under investigation, the temporal error is analysed for a simple exponential decay law. The performance of all schemes is compared to a high-resolution high-order reference solution. As a result, the second-order modified Patankar-Runge-Kutta scheme gives a good agreement with the reference solution even for time steps 10 times longer than the shortest numerical time scale of the problem. Other schemes do either compute negative values for non-negative state variables (fully explicit schemes), violate conservation (the Patankar schemes) or show low accuracy (all first-order schemes).

show abstract

Some mathematical problems associated with the development and use of marine models

Cited by 25 publications

References 71 publications

Description of the Earth system model of intermediate complexity LOVECLIM version 1.2

Description of the Earth system model of intermediate complexity LOVECLIM version 1.2

The impact of Sahara desertification on Arctic cooling during the Holocene

Application of modified Patankar schemes to stiff biogeochemical models for the water column

Contact Info

Product

Resources

About