In arid and semi-arid stream-dominated systems,the temporal variability in groundwater recharge has not been widely addressed.Various questions remain about the sources of groundwater recharge,its patterns,and the app...In arid and semi-arid stream-dominated systems,the temporal variability in groundwater recharge has not been widely addressed.Various questions remain about the sources of groundwater recharge,its patterns,and the appropriate measuring techniques.Hence,the main objective of the present study was to assess the changes that might affect the pattern of groundwater recharge under wetter than normal surface water availability.Therefore,the groundwater depth was monitored near a semi-arid Mediterranean intermittent stream on the piedmont of the High Atlas Mountains in the mountain catchment of the Wadi Rheraya over two hydrological years(2014-2016)with different climate conditions:extreme wet and normal conditions.Groundwater recharge was assessed using the episodic master recession algorithm.During the two years,the pattern of groundwater recharge was dominated by episodic events and by a high seasonality from wet seasons to dry seasons.In the wet year(2014-2015),the highest groundwater recharge was recorded following an extreme flood,which deeply replenished groundwater.Furthermore,an exceptional steady state of the groundwater depth was induced by a steady groundwater recharge rate.For several groundwater recharge events,the assessed recharge had multiple sources,mainly from streamflow at the local scale,but possibly from precipitation,underflow,deep percolation or irrigation return from the upstream part of the catchment.Local recharge by streamflow was likely to be short-lived,and lateral recharge was likely to last longer.Consequently,the episodic master recession algorithm estimated the total groundwater recharge that could encompass various sources.In the future,more studies and multidisciplinary approaches should be carried out to partition these sources and determine their specific contributions.In semi-arid stream-dominated systems,different groundwater recharge patterns induced by extreme hydrological events(e.g.,wet events)and various potential sources of groundwater recharge should be considered when assessing and predicting groundwater recharge.展开更多
The normalization of LST relative to environmental parameters is of great importance in various environmental applications. The purpose of this study was to develop a new approach for LST normalization relative to env...The normalization of LST relative to environmental parameters is of great importance in various environmental applications. The purpose of this study was to develop a new approach for LST normalization relative to environmental variables. These included topographic variables (i.e. solar irradiance and near-surface temperature lapse rate (NSTLR)) as well as biophysical properties (i.e. vegetation,wetness,and albedo). The study was conducted in two phases,namely (1) using global and (2) local optimization strategies to calculate the regression coefficients of environmental variables in the partial least squares regression (PLSR) and build the non-linear linking model in the random forest regression (RFR). The RMSEs between actual LST and modeled LST based on the global and local optimization strategies using PLSR (RFR) were 2.202 (0.935) and 0.939 (0.835) °C,respectively. The results showed that RFR had higher efficiency than PLSR in normalizing LST. Moreover,the local optimization method outperformed the global optimization method in terms of normalization accuracy. The results of this study could be very useful in many environmental applications such as identifying thermal anomalies,and surface anthropogenic heat island modeling.展开更多
基金supported by the projects SAGESSE-Decision Support System for Water Resources Management(Priority Projects of Scientific Research and Technological Development PPR Type B/2015/48,2016–2021)CHAAMS-Global Change:Assessment and Adaptation to Mediterranean Region Water Scarcity(ERANETMED3-062,2017–2022)ALTOS-Managing Water Resources within Mediterranean Agrosystems by accounting for Spatial Structures and Connectivities(PRIMA-S2,2020–2023)
文摘In arid and semi-arid stream-dominated systems,the temporal variability in groundwater recharge has not been widely addressed.Various questions remain about the sources of groundwater recharge,its patterns,and the appropriate measuring techniques.Hence,the main objective of the present study was to assess the changes that might affect the pattern of groundwater recharge under wetter than normal surface water availability.Therefore,the groundwater depth was monitored near a semi-arid Mediterranean intermittent stream on the piedmont of the High Atlas Mountains in the mountain catchment of the Wadi Rheraya over two hydrological years(2014-2016)with different climate conditions:extreme wet and normal conditions.Groundwater recharge was assessed using the episodic master recession algorithm.During the two years,the pattern of groundwater recharge was dominated by episodic events and by a high seasonality from wet seasons to dry seasons.In the wet year(2014-2015),the highest groundwater recharge was recorded following an extreme flood,which deeply replenished groundwater.Furthermore,an exceptional steady state of the groundwater depth was induced by a steady groundwater recharge rate.For several groundwater recharge events,the assessed recharge had multiple sources,mainly from streamflow at the local scale,but possibly from precipitation,underflow,deep percolation or irrigation return from the upstream part of the catchment.Local recharge by streamflow was likely to be short-lived,and lateral recharge was likely to last longer.Consequently,the episodic master recession algorithm estimated the total groundwater recharge that could encompass various sources.In the future,more studies and multidisciplinary approaches should be carried out to partition these sources and determine their specific contributions.In semi-arid stream-dominated systems,different groundwater recharge patterns induced by extreme hydrological events(e.g.,wet events)and various potential sources of groundwater recharge should be considered when assessing and predicting groundwater recharge.
文摘The normalization of LST relative to environmental parameters is of great importance in various environmental applications. The purpose of this study was to develop a new approach for LST normalization relative to environmental variables. These included topographic variables (i.e. solar irradiance and near-surface temperature lapse rate (NSTLR)) as well as biophysical properties (i.e. vegetation,wetness,and albedo). The study was conducted in two phases,namely (1) using global and (2) local optimization strategies to calculate the regression coefficients of environmental variables in the partial least squares regression (PLSR) and build the non-linear linking model in the random forest regression (RFR). The RMSEs between actual LST and modeled LST based on the global and local optimization strategies using PLSR (RFR) were 2.202 (0.935) and 0.939 (0.835) °C,respectively. The results showed that RFR had higher efficiency than PLSR in normalizing LST. Moreover,the local optimization method outperformed the global optimization method in terms of normalization accuracy. The results of this study could be very useful in many environmental applications such as identifying thermal anomalies,and surface anthropogenic heat island modeling.
