The relationship between altitude and hail frequency in the Transvaal
Afrique du Sud ; Altitude ; Climatologie ; Fréquence ; Grêle ; Géographie de l'Afrique ; Modèle non linéaire ; Précipitation ; Transvaal
An exponential function is developed to describe the relationship between Transvaal hail day frequency and altitude. Some anomalies are also explained.
Frequency isopleth diagram: a new way of presenting wind observations
Climatologie ; Diagramme isoplèthe de fréquence ; Direction ; Fréquence ; Géographie physique ; Représentation graphique ; Vent ; Vitesse
Présentation d'un nouveau diagramme isopléique appliqué à la fréquence du vent. Sur un graphe à coordonnées orthogonales, les directions sont portées en abcisses et les vitesses en ordonnées. Si le résultat est assez parlant, la construction du
This paper investigates the concept of frequency and magnitude firstly in the context of a range of important, frequently studied weathering processes (e.g. solution, fire, thermoclasty, haloclasty, frost, and biological weathering
) and their effectiveness in terms of rock breakdown, and secondly in terms of the totality of weathering and its effectiveness in terms of larger-scale geomorphological change.Finally, the importance of the ideas of frequency and magnitude as applied to weathering
Les modèles statistiques classiques sont assez décevants pour évaluer l'incertitude des fréquences de crue. Application des méthodes du maximum de vraisemblance et bayésienne pour évaluer la validité des modèles. Le modèle d'inférence bayésienne
Mean slope-angle frequency distribution and size frequency distribution of landslide masses in Higashikubiki area, Japan
Landslide mass size frequency distributions and mean slope-angle frequency distributions were calculated for slump, slide, and creep type landslides in the Higashikubiki area. Mean slope-angle frequency distributions closely approximated Weibull
distributions. Size frequency distributions show power-law dependencies. Both can be explained by modeling landslides as linked uniform blocks in tensile force.
Changing Late Holocene flooding frequencies on the Columbia River, Washington
Flood frequencies comparable to those of the twentieth century existed prior to 1020 A.D. and after 1390 A.D. Large floods were three to four times more common during the intervening centuries. Climatic conditions are the most probable factors
Wind pollution index and wind pollution frequency a climatological problem in urban planning.
Arguing from the bases that the frequencies of occurrence of weather conducive to air pollution with wind from different directions are more useful to the planning of industrial location than the prevailing wind principle, the author suggests two
equations the wind pollution index, and the wind pollution frequency measurement for consideration by urban planners. (TNC).
Nearest neighbour cumulative frequency distribution
Analyse spatiale ; Distance ; Forme ; Fréquence cumulée ; Généralités sur la géographie ; Méthode du plus proche voisin ; Semis de point ; Statistique spatiale
Utilise les distributions des fréquences cumulées des valeurs de distances aux plus proches voisins pour analyser la forme des semis de points| cette démarche est plus efficace que toute autre basée sur des caractéristiques statistiques
Modelling hail frequency using a generalised additive interactive technique
Relationships between hail day frequency, altitude and latitude in the summer rainfall region of South Africa are investigated by means of generalised additive models. - (AJC)
The objective of flood frequency analysis is to relate the magnitude of annual peak flow discharges to their frequency of occurrence through the use of probability distributions. In this study a time trend is investigated in the first two moments
, i.e. in the Mean value and the Standard Deviation (SD), and it is assumed to be a continuous function of time. Preliminary results of a flood frequency analysis for Polish rivers obtained with the IDT (Identification of Distribution and Trend) package
The parameters of frequency and magnitude and their relationship provide only a partial explanation of episodic process behaviour. Full characterization of episodic processes from a geomorphic perspective should include, initiating and ending
La relation fréquence-abondance. Aspects théoriques| application à un peuplement d'oiseaux
Dénombrement ; Ecologie ; Géographie physique ; Méthodologie ; Oiseau ; Population animale ; Relation fréquence-abondance ; Structure de peuplement
The frequency of a species (proportion of samples in which the species is recorded) is a non linear function of its abundance, which is modified by the pattern of distribution of the individuals and by the surface of the area sampled
on the relationship between frequency and abundance... The proposed models have been applied to a series of bird censuses performed by J. Blondel.
Frequency and magnitude of landsliding : fundamental research issues
Magnitude and frequency in geomorphology
Concept ; Distribution spatiale ; Fréquence et magnitude ; Glissement de terrain ; Modélisation ; Méthodologie ; North Island ; Nouvelle-Zélande ; Précipitation ; Risque naturel ; Statistique ; Versant
Some fundamental research issues related to the application of frequency-magnitude analysis to landslides are discussed. It is shown that there are marked differences between the hillslope system and the fluvial system. Methodological approaches
to the establishment of temporal and magnitude frequency are presented and illustrated. Both empirical and deterministic methods are discussed. In particular, advances in empirical modelling are used to show the extent to which the probability of landslide occurrence
can be determined with a regional context. Frequency-magnitude analysis can also be applied to the spatial distribution of landslides.
Innskotatidni kvikuholfa og gostidni eldstodvakerfa Intrusion frequencies of magma chambers and extrusion frequencies of volcanic systems
Réactualisation et développement d'un modèle antérieurement élaboré par l'A. sur les fréquences des phénomènes d'intrusion et d'extrusion le long des dorsales volcaniques actives. Parmi les conclusions, on note qu'à court terme la fréquence
d'extrusion d'un système volcanique peut être équivalente à la fréquence d'intrusion à partir du réservoir magmatique, ce qui veut dire que chaque dyke alimente une coulée subaérienne. A long terme, sur la durée de vie d'un volcan, le rapport est, en revanche
Frequency-magnitude distributions for soil erosion, runoff and rainfall - a comparative analysis
Magnitude and frequency in geomorphology
Belgique ; Bilan d'érosion ; Canada ; Concept ; Erosion des sols ; Etats-Unis ; Fréquence et magnitude ; Précipitation ; Royaume-Uni ; Ruissellement ; Régression linéaire ; Versant
This study analyses frequency-magnitude distributions of rainfall, runoff and erosion from sites in the UK, Belgium, Canada and the USA. Frequency-magnitude distributions of rainfall appear to be a poor predictor of distributions of runoff or soil
Changes in the tracks and frequencies of tropical cyclones in the Lesser Antilles from 1650 to 1975 and some geomorphological and ecological implications
Etude des variations dans la trajectoire et la fréquence des cyclones sur les petites Antilles de 1650 à 1975. Etude des conséquences sur l'érosion: les variations des taux d'érosion sont en relation avec la fréquence des cyclones| l'extension
spatiale de l'érosion a nettement changé en liaison avec les changements de trajectoire et de fréquence des cyclones. Ces faits semblent prédominants dans le déséquilibre permanent des caractères écologiques et géomorphologiques de ces îles.
Strong and very strong winds were recorded at 16 stations during the period 1956-1965. Poland's climate is characterised by rather small average frequency of strong and very strong wind. Nevertheless geographical and dynamical factors influence
the frequency of wind. Tha aim of this study is to estimate the influence of changes of the atmospheric circulation on the frequency of strong and very strong wind. - (DG)
Cartographie de la fréquence de la direction des vents
The aim of the study was to establish the method enabling the presentation of frequency of wind directions on maps using the isolines. Such maps concerning the mean annual frequency of winds from four sectors of 90° each, on Poland's territory have
The changing frequency of drought in India 1871-1985
L'A. étudie la fréquence de la sécheresse dans 10 macrorégions non montagneuses de l'Inde, en se basant sur les données de la mousson d'été - c'est-à-dire de juin à septembre - de 1871 à 1985.