A geostatistical approach for areal rainfall statistics assessment

Lebel, Thierry; Laborde, Jean-Pierre

doi:10.1007/bf01544039

Cited by 42 publications

(29 citation statements)

References 8 publications

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“…Mais à l'échelle du bassin, elles sont fortement liées aux effets dynamiques introduits par les contrastes entre la plaine côtière et le golfe de Guinée ou encore entre les reliefs du Nord-Ouest (culminant vers 700 à 800 m d'altitude) et les zones plus basses du bassin. La répartition spatiale des précipitations moyennes annuelles montre que ce sont le Nord et le Centre Ouest qui enregistrent les fortes pluies, ce qui détermine la dynamique de l'écoulement dans le bassin (Amoussou 2010 (Lebel et al 1987, Lebel et Laborde 1988. Ici la portée du modèle ajusté est égale à 65 km, ce qui indique la distance « moyenne » de décorrélation des précipitations entre deux stations.…”

Section: Le Bassin Du Monounclassified

Dynamique et modélisation des crues dans le bassin du Mono à Nangbéto (Togo/Bénin)

Amoussou

Tramblay

Totin

et al. 2014

Hydrological Sciences Journal

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Reçu le 29 avril 2013; accepté le 28 octobre 2013; la discussion concernant cet article est ouverte jusqu'au 1er mai 2015Editeur Z.W. Kundzewicz; Editeur associé B. Touaibia Résumé Les inondations des dernières années en Afrique de l'Ouest rendent nécessaire la prévision hydrologique pour réduire la vulnérabilité des populations. Nous avons étudié la dynamique des crues dans le bassin du Mono en amont du barrage de Nangbéto (Togo et Bénin) par des méthodes statistiques et déterministes. L'augmentation des précipitations au cours de la décennie 1990 et la mise en eau du barrage de Nangbéto en 1988 ont modifié le régime du Mono, dont les débits d'étiages ont augmenté. Les débits entrants et sortants du barrage sont équivalents, même lors des crues. Les maximums annuels des débits entrants peuvent être modélisés par une distribution des valeurs extrêmes (GEV) de type Fréchet, tandis que ceux des débits sortants, suivent une loi GEV de type Weibull (bornée). Le mécanisme dominant de génération des crues dans le bassin est la montée progressive des eaux associée à l'augmentation de la saturation des sols. L'analyse des débits de crue entre 1988 et 2010 n'a pas montré d'augmentation de la magnitude ou de la fréquence des crues. Le modèle GR4J reproduit bien les débits de crues en période calage, mais ces critères de performance se dégradent lorsque l'on s'en éloigne. Dans ces conditions, l'utilisation de ce modèle pour évaluer les risques futurs de crues serait hasardeuse et il est nécessaire d'envisager d'autres types d'approches.Mots clefs Bénin-Togo ; bassin Mono ; barrage de Nangbéto ; crues ; GR4J ; statistiques ; extrêmes Dynamics and modelling of floods in the river basin of Mono in Nangbeto, Togo/Benin Abstract The devastating floods in recent years in West Africa call for improvement in hydrological forecasts to reduce the vulnerability of local communities. We studied flood dynamics in the Mono basin, in Togo and Benin, upstream of the Nangbeto Dam, using statistical methods. The increase in precipitation in the 23-year period from 1988 (following completion of the Nangbeto Dam) modified the regine of the Mono River, with an increase in stage discharge. There is little difference between the river discharge at the entrance and the exit of the Nangbeto Reservoir, at least at peak flow, which emphasizes that the dam, due to the small capacity of the reservoir, has a limited effect on flow regulation. The annual peak flows entering the reservoir can be modelled using a Frechet-type generalized extreme value (GEV) distribution, while those at the exit follow a Weibulltype GEV distribution. The main mechanism for peak flow generation in the basin is a steady rise of water as a result of increasing soil moisture saturation, rather than isolated rain spells. Peak flows between 1988 and 2010 do not show any change in magnitude and frequency. The GR4J hydrological model is shown to be effective in reproducing peak flows, but its skill decreases as we move away from the calibration period. Therefore, it may be risky t...

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Section: Le Bassin Du Monounclassified

Dynamique et modélisation des crues dans le bassin du Mono à Nangbéto (Togo/Bénin)

Amoussou

Tramblay

Totin

et al. 2014

Hydrological Sciences Journal

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“…The variogram allows quantifying the degree of spatial dependence of a field. precipitation kriging since it provides a value of the decorrelation distance, given by the value of the range parameter (Lebel and Laborde, 1988). The climatological variograms are presented in Fig.…”

Section: Serial and Cross Correlationsmentioning

confidence: 99%

Trends and variability in extreme precipitation indices over Maghreb countries

Tramblay

Adlouni

Servat

2013

Nat. Hazards Earth Syst. Sci.

141

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Abstract. Maghreb countries are highly vulnerable to extreme hydrological events, such as floods and droughts, driven by the strong variability of precipitation. While several studies have analyzed the presence of trends in precipitation records for the Euro-Mediterranean basin, this study provides a regional assessment of trends on its southernmost shores. A database of 22 stations located in Algeria, Morocco and Tunisia with between 33 and 59 yr of daily precipitation records is considered. The change points and trends are analyzed for eleven climate indices, describing several features of the precipitation regime. The issue of conducting multiple hypothesis tests is addressed through the implementation of a false discovery rate procedure. The spatial and interannual variability of the precipitation indices at the different stations are analyzed and compared with largescale atmospheric circulation patterns, including the North Atlantic Oscillation (NAO), western Mediterranean Oscillation (WEMO), Mediterranean Oscillation (MO) and El Niño-Southern Oscillation (ENSO). Results show a strong tendency towards a decrease of precipitation totals and wet days together with an increase in the duration of dry periods, mainly for Morocco and western Algeria. On the other hand, only a few significant trends are detected for heavy precipitation indices. The NAO and MO patterns are well correlated with precipitation indices describing precipitation amounts, the number of dry days and the length of wet and dry periods, whereas heavy precipitation indices exhibit a strong spatial variability and are only moderately correlated with large-scale atmospheric circulation patterns.

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“…According to the procedure proposed by Lebel and Laborde (1988), there are several applications of the scale parameter of the Gumbel distribution. Slimani and Lebel (1987) found that this distribution has a fit similar to that of an exponential distribution for the maximum monthly events.…”

Section: Estimation and Representation Of Hydrological Riskmentioning

confidence: 99%

Prediction of Hydrological Risk for Sustainable Use of Water in Northern Mexico

Gutiérrez-López

Lebel²,

Ruiz-González

et al. 2015

Sustainability of Integrated Water Resources Management

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Among surface hydrologic phenomena, it is common to find series of events of random occurrence in time. Poisson processes lead to probabilistic models that are appropriate to explain the number of events produced by certain phenomena. For instance, in surface hydrology, it is quite frequent to relate the Poisson distribution to the occurrence of rainfall events. The so-called leak distribution consists of the simultaneous use of a Poisson law to represent the probability of occurrence of an event and an exponential distribution applied to the mean magnitude of such event.Originally introduced to simulate gas leaks in distribution networks in France, from where it takes its name, the leak distribution has important applications in hydrology. In this paper, the theoretical basis of the law and the method for the estimation of its parameters are introduced. Some applications are included, such as further knowledge of the precipitation regime of hydrologic region No. 10 in Mexico. In this case, through the knowledge of the two parameters of this law, which can be associated to physical variables, it is possible to determine the temporal and spatial distribution of precipitation in detail. As an additional application, the use of this law in drought analysis is shown. Here, the distribution parameters are related to the Standardized Precipitation Index, SPI, allowing the construction of a modified SPI that much better represents the spatial variability of drought periods in the watershed. According to the

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A geostatistical approach for areal rainfall statistics assessment

Cited by 42 publications

References 8 publications

Dynamique et modélisation des crues dans le bassin du Mono à Nangbéto (Togo/Bénin)

Dynamique et modélisation des crues dans le bassin du Mono à Nangbéto (Togo/Bénin)

Trends and variability in extreme precipitation indices over Maghreb countries

Prediction of Hydrological Risk for Sustainable Use of Water in Northern Mexico

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