This work aims to evaluate regional climate models of Ensemble project to reproduce the seasonal ... more This work aims to evaluate regional climate models of Ensemble project to reproduce the seasonal rainfall variability of Northern Algeria (coastal basins). Models are firstly validated over the reference period 1961-1990 and then future seasonal rainfall variability is analyzed over two projection periods: 2021-2050and 2070-2099. Simulated data have been extracted from 10 regional models and compared to the observed data using the “bias method”. It is the difference between simulated and observed data. This method gives an overview of percentage of overestimation (underestimation) of models to the observed data. Kolmogorov-Smirnov test has been used to test the significance of the difference between simulated and observed data.Generally, it appears that models underestimate the wet season and overestimate the dry season over the control period 1961-1990. Only four models have been validated to be used in projection as regional models, namely: CNRM, CHMI, GKSS and ETHZ regional model...
The work presented here focuses on the inter-annual variability of annual rainfall in Northern Al... more The work presented here focuses on the inter-annual variability of annual rainfall in Northern Algeria. This work is carried out by using the coefficient of variation (the ratio between the standard deviation and the average). We will try to show areas of low, medium and high variations in Northern Algeria. In order to do this, we use 333 rainfall stations spread over the entire study area, with a measurement period of 37 years (1968/2004). The contrast of rainfall spatial and temporal distribution has been demonstrated by studying the sixteen basins, as adopted by the National Agency of Water Resources. The high spatial variability characterizes the basins of the High Plateaus of Constantine and Chot El Hodna.
Maximum rain quantiles estimate has always been of great importance to hydrologists and water res... more Maximum rain quantiles estimate has always been of great importance to hydrologists and water resource managers. This information is essential for planning emergency situations related to hazardous weather conditions and the design of water supply engineering structures. In many instances, it is vital to estimate the extreme values relevant to the few frequencies for sites where there are few measures or even almost non-existent. The regionalization approach is the most used in such cases. The regionalization procedure, based on the L-moments coupled with the rain index method has been both applied to rainfall data of two hundred and thirty (230) stations spread at random across northern Algeria and is the goal of this work. L-moments method confirmed the homogeneity of the twelve (12) regions that make up the study area. Rain indexes, combined with the regional growth curves developed in this study may logically estimate maximum rains quantiles at the stations by using the mean max...
This work aims to identify the potential groundwater recharge zones in the Mitidja plain (north A... more This work aims to identify the potential groundwater recharge zones in the Mitidja plain (north Algeria) using the multi-criteria approach. The analysis was based on the use of a geographical information system (GIS) and remote sensing to establish eight thematic maps, weighted, categorized and inserted, that allowed us to establish the potential zones’ map for groundwater recharge. Three potential groundwater recharge classes were defined corresponding, respectively, to low (26%), moderate (47%) and high (27%). The best groundwater potential zones are situated in the piedmont of the Blidean Atlas (the south of the study area), precisely, upstream near to wadis (wadi El Harrach, wadi Djemaa, wadi Mazafran) and the western aquifer limit, where the hydrogeological units are formed by the alluvium formation which is characterized by high hydraulic conductivity, high water flow, low slope, low drainage, low quantity transported sediments and good water quality. The obtained results, in ...
Climate and anthropogenic changes impact on the erosion and sediment transport processes in river... more Climate and anthropogenic changes impact on the erosion and sediment transport processes in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes from natural areas to cultivated areas, and then from degraded areas to desertification. Such areas, under the effect of anthropogenic activities, are more sensitive to erosion, and are therefore prone to erosion. On the other hand, with an increase in the number of dams in watersheds, a great portion of sediment fluxes is trapped in the reservoirs, which do not reach the sea in the same amount nor at the same quality, and thus have consequences for coastal geomorphodynamics. The Special Issue “Modeling and Practice of Erosion and Sediment Transport under Change” is focused on a number of keywords: erosion and sediment transport, model and practice, and change. The keywords are brief...
Many studies have highlighted breaks in mean values of temperature and precipitation time series ... more Many studies have highlighted breaks in mean values of temperature and precipitation time series since the 1970s. Given that temperatures have continued to increase following that decade, the first question addressed in this study is whether other breaks in mean values have occurred since that time. The second question is to determine which climate indices influence temperature and rainfall in the coastal region of Northern Algeria. To address these two questions, we analyzed the temporal variability of temperature and annual and seasonal rainfall as they relate to four climate indices at seven coastal stations in Algeria during the 1972–2013 period using the Mann–Kendall, Lombard, and canonical correlation (CC) analysis methods.The annual and seasonal maximum, minimum and mean temperatures increased significantly over that time period. Most of these increases are gradual, implying a slow warming trend. In contrast, total annual and seasonal rainfall did not show any significant cha...
This work aims to evaluate regional climate models of Ensemble project to reproduce the seasonal ... more This work aims to evaluate regional climate models of Ensemble project to reproduce the seasonal rainfall variability of Northern Algeria (coastal basins). Models are firstly validated over the reference period 1961-1990 and then future seasonal rainfall variability is analyzed over two projection periods: 2021-2050and 2070-2099. Simulated data have been extracted from 10 regional models and compared to the observed data using the “bias method”. It is the difference between simulated and observed data. This method gives an overview of percentage of overestimation (underestimation) of models to the observed data. Kolmogorov-Smirnov test has been used to test the significance of the difference between simulated and observed data.Generally, it appears that models underestimate the wet season and overestimate the dry season over the control period 1961-1990. Only four models have been validated to be used in projection as regional models, namely: CNRM, CHMI, GKSS and ETHZ regional model...
The work presented here focuses on the inter-annual variability of annual rainfall in Northern Al... more The work presented here focuses on the inter-annual variability of annual rainfall in Northern Algeria. This work is carried out by using the coefficient of variation (the ratio between the standard deviation and the average). We will try to show areas of low, medium and high variations in Northern Algeria. In order to do this, we use 333 rainfall stations spread over the entire study area, with a measurement period of 37 years (1968/2004). The contrast of rainfall spatial and temporal distribution has been demonstrated by studying the sixteen basins, as adopted by the National Agency of Water Resources. The high spatial variability characterizes the basins of the High Plateaus of Constantine and Chot El Hodna.
Maximum rain quantiles estimate has always been of great importance to hydrologists and water res... more Maximum rain quantiles estimate has always been of great importance to hydrologists and water resource managers. This information is essential for planning emergency situations related to hazardous weather conditions and the design of water supply engineering structures. In many instances, it is vital to estimate the extreme values relevant to the few frequencies for sites where there are few measures or even almost non-existent. The regionalization approach is the most used in such cases. The regionalization procedure, based on the L-moments coupled with the rain index method has been both applied to rainfall data of two hundred and thirty (230) stations spread at random across northern Algeria and is the goal of this work. L-moments method confirmed the homogeneity of the twelve (12) regions that make up the study area. Rain indexes, combined with the regional growth curves developed in this study may logically estimate maximum rains quantiles at the stations by using the mean max...
This work aims to identify the potential groundwater recharge zones in the Mitidja plain (north A... more This work aims to identify the potential groundwater recharge zones in the Mitidja plain (north Algeria) using the multi-criteria approach. The analysis was based on the use of a geographical information system (GIS) and remote sensing to establish eight thematic maps, weighted, categorized and inserted, that allowed us to establish the potential zones’ map for groundwater recharge. Three potential groundwater recharge classes were defined corresponding, respectively, to low (26%), moderate (47%) and high (27%). The best groundwater potential zones are situated in the piedmont of the Blidean Atlas (the south of the study area), precisely, upstream near to wadis (wadi El Harrach, wadi Djemaa, wadi Mazafran) and the western aquifer limit, where the hydrogeological units are formed by the alluvium formation which is characterized by high hydraulic conductivity, high water flow, low slope, low drainage, low quantity transported sediments and good water quality. The obtained results, in ...
Climate and anthropogenic changes impact on the erosion and sediment transport processes in river... more Climate and anthropogenic changes impact on the erosion and sediment transport processes in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes from natural areas to cultivated areas, and then from degraded areas to desertification. Such areas, under the effect of anthropogenic activities, are more sensitive to erosion, and are therefore prone to erosion. On the other hand, with an increase in the number of dams in watersheds, a great portion of sediment fluxes is trapped in the reservoirs, which do not reach the sea in the same amount nor at the same quality, and thus have consequences for coastal geomorphodynamics. The Special Issue “Modeling and Practice of Erosion and Sediment Transport under Change” is focused on a number of keywords: erosion and sediment transport, model and practice, and change. The keywords are brief...
Many studies have highlighted breaks in mean values of temperature and precipitation time series ... more Many studies have highlighted breaks in mean values of temperature and precipitation time series since the 1970s. Given that temperatures have continued to increase following that decade, the first question addressed in this study is whether other breaks in mean values have occurred since that time. The second question is to determine which climate indices influence temperature and rainfall in the coastal region of Northern Algeria. To address these two questions, we analyzed the temporal variability of temperature and annual and seasonal rainfall as they relate to four climate indices at seven coastal stations in Algeria during the 1972–2013 period using the Mann–Kendall, Lombard, and canonical correlation (CC) analysis methods.The annual and seasonal maximum, minimum and mean temperatures increased significantly over that time period. Most of these increases are gradual, implying a slow warming trend. In contrast, total annual and seasonal rainfall did not show any significant cha...
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Papers by mohamed meddi