scholarly journals Estimation des réserves en eau souterraine régulatrices dans la partie moyen-atlasique du fleuve Sebou (Maroc)

2021 ◽  
Vol 384 ◽  
pp. 169-173
Author(s):  
Sébastien Lebaut ◽  
Abdelghani Qadem ◽  
Brahim Akdim ◽  
Emmanuel Gille ◽  
Mohamed Laaouane
Keyword(s):  
Agricultural Sector ◽  
Groundwater Resource ◽  
Monthly Scale ◽  
Recession Curves ◽  
Middle Atlas ◽  
Eau Souterraine ◽  
Annual Scale

Abstract. L'estimation de la ressource en eau souterraine dans le Moyen-Atlas est investiguée à partir des débits mesurés dans l'oued Sebou à la station d'Azzaba, sur la période 1959–2015. Pour cela presqu'une centaine de phases de tarissement a été individualisé pour construire des courbes maîtresses de tarissement à partir desquelles le calcul des volumes des nappes est possible. Il est calculé mensuellement à partir du débit modal dont nous posons l'hypothèse qu'il représente la limite entre ruissellement et alimentation uniquement par les nappes. Les calculs donnent un volume de la réserve régulatrice moyen de 54 hm3, mais extrêmement variable à l'échelle interannuelle et intra-annuelle. Ces résultats démontrent la faible inertie des aquifères du Moyen Atlas et soulignent la vulnérabilité du secteur agricole vis-à-vis de cette ressource même lors de courte période de sécheresse. The estimate of the groundwater resource in the Middle Atlas is investigated from the runoff measured in the Sebou wadi at the Azzaba station, over the period 1959–2015. Almost a hundred recession curves have been individualized to build the master recession curves from which the calculation of the volumes of groundwater is possible. It was calculated at a monthly scale from the modal flow, which we assume is the limit between runoff and flow supply only by the aquifers. The results indicated a volume of the average regulatory reserve of 54 hm3, but extremely variable on an inter-annual and intra-annual scale. These results demonstrate the low inertia of the Middle Atlas aquifers and underline the vulnerability of the agricultural sector to this resource even during short periods of drought.

scholarly journals Evaluating the Performance of Satellite-Derived Vegetation Indices for Estimating Gross Primary Productivity Using FLUXNET Observations across the Globe

2019 ◽  
Vol 11 (15) ◽  
pp. 1823 ◽  
Author(s):  
Xiaojuan Huang ◽  
Jingfeng Xiao ◽  
Mingguo Ma
Keyword(s):  
Primary Productivity ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Vegetation Indices ◽  
Gross Primary Productivity ◽  
Surface Reflectance ◽  
Monthly Scale ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Annual Scale

Satellite-derived vegetation indices (VIs) have been widely used to approximate or estimate gross primary productivity (GPP). However, it remains unclear how the VI-GPP relationship varies with indices, biomes, timescales, and the bidirectional reflectance distribution function (BRDF) effect. We examined the relationship between VIs and GPP for 121 FLUXNET sites across the globe and assessed how the VI-GPP relationship varied among a variety of biomes at both monthly and annual timescales. We used three widely-used VIs: normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and 2-band EVI (EVI2) as well as a new VI - NIRV and used surface reflectance both with and without BRDF correction from the moderate resolution imaging spectroradiometer (MODIS) to calculate these indices. The resulting traditional (NDVI, EVI, EVI2, and NIRV) and BRDF-corrected (NDVIBRDF, EVIBRDF, EVI2BRDF, and NIRV, BRDF) VIs were used to examine the VI-GPP relationship. At the monthly scale, all VIs were moderate or strong predictors of GPP, and the BRDF correction improved their performance. EVI2BRDF and NIRV, BRDF had similar performance in capturing the variations in tower GPP as did the MODIS GPP product. The VIs explained lower variance in tower GPP at the annual scale than at the monthly scale. The BRDF-correction of surface reflectance did not improve the VI-GPP relationship at the annual scale. The VIs had similar capability in capturing the interannual variability in tower GPP as MODIS GPP. VIs were influenced by temperature and water stresses and were more sensitive to temperature stress than to water stress. VIs in combination with environmental factors could improve the prediction of GPP than VIs alone. Our findings can help us better understand how the VI-GPP relationship varies among indices, biomes, and timescales and how the BRDF effect influences the VI-GPP relationship.

scholarly journals Quantifying Groundwater Resources for Municipal Water Use in a Data-Scarce Region

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 184
Author(s):  
Iolanda Borzì ◽  
Brunella Bonaccorso
Keyword(s):  
Groundwater Recharge ◽  
Groundwater Resources ◽  
Aridity Index ◽  
Water Sampling ◽  
Aquifer Recharge ◽  
Water Abstraction ◽  
Monthly Scale ◽  
Annual Scale ◽  
The City ◽  
Resources Planning

Groundwater is a major source of drinking water worldwide, often considered more reliable than surface water and more accessible. Nowadays, there is wide recognition by the scientific community that groundwater resources are under threat from overexploitation and pollution. Furthermore, frequent and prolonged drought periods due to climate change can seriously affect groundwater recharge. For an appropriate and sustainable management of water systems supplied by springs and/or groundwater withdrawn from aquifers through drilling wells or drainage galleries, the need arises to properly quantify groundwater resources availability, mainly at the monthly scale, as groundwater recharge is influenced by seasonality, especially in the Mediterranean areas. Such evaluation is particularly important for ungauged groundwater bodies. This is the case of the aquifer supplying the Santissima Aqueduct, the oldest water supply infrastructure of the city of Messina in Sicily (Southern Italy), whose groundwater flows are measured only occasionally through spring water sampling at the water abstraction plants. Moreover, these plants are barely maintained because they are difficult to reach. In this study, groundwater recharge assessment for the Santissima Aqueduct is carried out through a GIS-based inverse hydrogeological balance methodology. Although this approach was originally designed to assess aquifer recharge at the annual scale, wherever a model conceptualization of the groundwater system was hindered by the lack of data, in the present study some changes are proposed to adjust the model to the monthly scale. In particular, the procedure for evapotranspiration assessment is based on the Global Aridity Index within the Budyko framework. The application of the proposed methodology shows satisfactory results, suggesting that it can be successfully applied for groundwater resources estimation in a context where monthly information is relevant for water resources planning and management.

DAMPAK KEBIJAKAN FISKAL TERHADAP KINERJA SEKTOR PERTANIAN DI SULAWESI TENGGARA

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
La Ode Jabuddin ◽  
Ayub M Padangaran ◽  
Azhar Bafadal Bafadal
Keyword(s):  
Fiscal Policy ◽  
Interest Rates ◽  
Agricultural Sector ◽  
Simultaneous Equations ◽  
Poor People ◽  
Land Area ◽  
Factors Affecting ◽  
Historical Simulation ◽  
The Impact ◽  
Direct Expenditure

This study aims to: (1) Knowing the dynamics of fiscal policy and the performance of the agricultural sector, (2) Analyze the factors that influence fiscal policy and the performance                   of the agricultural sector, and (3) Analyzing the impact of fiscal policy on the performance of the agricultural sector. The data used in this study were pooled 2005-2013 data in the aggregate. Econometric model the impact of fiscal policy on the performance of the agricultural sector is built in the form of simultaneous equations, consisting of 7 equations with 25 total variables in the model, 7 endogenous variables, 12 exogenous variables, and 6 variables lag. The model is estimated by 2SLS method SYSLIN procedures and historical simulation with SIMNLIN procedure.The results showed that: (1) The development of fiscal policy in Southeast Sulawesi from year to year tends to increase, (2) The performance of the agricultural sector from the aspect of GDP has decreased, from the aspect of labor is still consistent, in terms of investment to grow positively, and assign roles which means to decrease the number of poor people, (3) factors affecting fiscal policy is local revenues, equalization funds, other revenues, as well as the lag fiscal policy, (4) the factors that affect the performance of the agricultural sector from the aspect GDP is labor, direct expenditure and GDP lag; from the aspect of labor is the total labor force, investment, land area, direct expenditure, as well as the lag of labor; from the aspect of investment is influenced by GDP per capita, land area, interest rates and investment lag; as well as from the aspect of poor people, are affected by population, investments, direct expenditure and poverty lag, (5). Fiscal policy impact on the agricultural sector GDP increase, a decrease in the number of poor, declining agricultural laborers, and a decrease in the amount of investment in the agricultural sector.Keywords: Fiscal policy, the performance of the agricultural sector, the simultaneous equations

Sign in / Sign up

Export Citation Format

Share Document