Biogeography ; Classification ; Lake ; Mathematical model ; Model ; Neural network ; Stream
Modelling of cyanobacteria in freshwaters is an important tool for understanding their population dynamics and predicting bloom occurence in lakes and rivers. In this paper existing key models of cyanobacteria are reviewed, evaluated and classified
. Two major groups emerge : deterministic mathematical and artificial neural network models.
A conceptual model for meander initiation in bedload-dominated streams
Cours d'eau ; Erosion des berges ; Géométrie hydraulique ; Modèle ; Modèle conceptuel ; Méandre ; Transport sédimentaire
Bank erosion ; Channel geometry ; Conceptual model ; Meander ; Model ; Sediment transport ; Stream
A simple analytic model is presented relating local sediment transport capacity to variance in the transverse shear stress distribution in a stream channel. The model is used to develop a physically based conceptual model for the initiation
Input-output model ; Matrix analysis ; Methodology ; Model ; Multiplicator ; Price ; Regional economy ; Structural stability
Le modèle de Ghosh considère en général que les changements physiques des outputs sont causés par des changements physiques dans les inputs des facteurs primaires. Une fois qu'il est interprété comme un modèle de prix, l'A. montre que le modèle
d'entrée-sortie combinant offre et demande devient plausible. Position du modèle de Leontief par rapport à celui de Ghosh.
Dynamic models of shopping behaviour: testing the linear learning model and some alternatives
Commerce de détail ; Comportement des consommateurs ; Généralités sur la géographie ; Modèle ; Modèle de Bernoulli ; Modèle dynamique ; Modèle linéaire d'apprentissage ; Modèle stochastique ; Suède ; Uppsala
Une nouvelle analyse du comportement des consommateurs à partir de données recueillies à Uppsala (Suède) illustre les difficultés pratiques de l'application de modèles aléatoires. Le modèle hétérogène de Bernoulli s'est montré supérieur au modèle
Glacier melt : a review of processes and their modelling
Albédo ; Bibliographie ; Bilan énergétique ; Eau de fonte ; Glacier ; Modèle ; Radiation ; Température de l'air
Air temperature ; Albedo ; Bibliography ; Energy balance ; Glacier ; Meltwater ; Model ; Radiation
During the last few decades, a large variety of melt models have been developed, ranging from simple temperature-index to sophisticated energy-balance models. There is a recent trend towards modelling with both high temporal and spatial resolution
, the latter accomplished by fully distributed models. This review discusses the relevant processes at the surface-atmosphere interface, and their representation in melt models. While modelling of incoming radiation in mountain terrain is relatively accurate
, modelling of turbulent fluxes and spatial and temporal variability in albedo constitute major uncertainties in current energy-balance models, and thus need further research.
An integrated metropolitan model incorporating demographic-economic, land-use and transport models
Interaction spatiale ; Modèle ; Modèle d'entrée-sortie ; Modèle démo-économique ; Modèle urbain ; Multiplicateur ; Réseau de transports ; Utilisation du sol ; Ville
Demographic-economic model ; Input-output model ; Land use ; Model ; Multiplicator ; Spatial interaction ; Town ; Transport network ; Urban model
Le modèle proposé renferme trois composantes : les liens multi-zones d'entrée-sortie, les modèles de prévision foncière, les modèles de prévision de la demande en transports. De par sa structure, le modèle proposé peut estimer les impacts
Alluvial cone ; Fluvial processes ; Hydrology ; Mathematical model ; Model ; Sedimentology
A mathematical model which estimates the scale-independent sediment surface profile of alluvial fans has been developed. This model utilizes a diffusive sediment transport model and an unsteady, radial flow, conservation relationship. The model
suggests that the overall dimensionless morphology of alluvial fans is governed more by fundamental diffusion principles in sediment deposition than by individual environmental or basin characteristics. A preliminary comparison indicates that this model
Energy balance ; Meltwater ; Meteorology ; Model ; Precipitation ; Rill wash ; Snow ; Spatial variation ; Temperature
This article reviews the nature of meltwater runoff models and the variety of ways in which key functional tasks necessary in any such model have been implemented by different modellers. Modelling issues and alternative solutions are exemplified
with reference to 2 widely used but contrasting models (HBV and SRM). This review therefore attempts not just to describe meltwater models but also to show how their variety reflects wider debates in environmental modelling. The emphasis is on seasonal snowmelt
Aeolian features ; Aeolian transport ; Dune ; Model ; Numerical model ; Sand ; Wind
The derivation and history of the frequently cited aeolian transport model of White are considered in light of the continued replication of an error in the original expression. The error may have escaped notice because the expression is still
dimensionally correct and it yields predictions that appear reasonable in comparison with both the predictions of other models and with field data. The incorrect expression has come to be identified as a distinct model. However, the correct formulation
of the White model is, in fact, a rearrangement of the Kawamura model with a slightly smaller empirical coefficient.