The impact of vegetation and soil parameters in simulations of surface energy and water balance in the semi-arid sahel: A case study using SEBEX and HAPEX-Sahel data

2006 ◽  
Vol 320 (1-2) ◽  
pp. 238-259 ◽  
Author(s):  
Daniel S. Kahan ◽  
Yongkang Xue ◽  
Simon J. Allen
Keyword(s):  
Surface Energy ◽  
Water Balance ◽  
Soil Parameters ◽  
The Impact ◽  
Semi Arid

Investigating the possible measure to protect groundwater from polluted streams in Arid and Semi-Arid Regions: the Eastern Nile Delta case study

2021 ◽  
Author(s):  
Ismail Abd-Elaty ◽  
Martina Zelenakova ◽  
Salvatore Straface ◽  
Zuzana Vranayová ◽  
Mohamed Abu-hashim ◽  
...  
Keyword(s):  
Drinking Water ◽  
Arid Regions ◽  
Nile Delta ◽  
Total Dissolved Solids ◽  
Polluted Water ◽  
Deep Aquifer ◽  
Lower Permeability ◽  
The Impact ◽  
Semi Arid

<p>Groundwater is the main source of drinking water in the Nile Delta. Unfortunately, it might be polluted by seepage from polluted streams. This study was carried out to investigate the possible measures  to  protect groundwater  in the Nile delta aquifer using a numerical model (MT3DMS - Mass Transport 3-Dimension Multi-Species). The sources of groundwater contamination were identified and the total dissolved solids (TDS) was taken as an indicator for the contamination. Different strategies were investigated for mitigating the impact of polluted water: i) allocating polluted drains and canals in lower permeability layers; ii)  installing cut-off walls in the polluted drains, and finally, iii) using lining materials in polluted drains and canals. Results indicated these measures effective to mitigate the groundwater pollution. In particular, the cut-off wall was effective for contamination reduction in shallow aquifers, whereas it had no effect in the deep aquifer, while lining materials in polluted drains and canals were able to prevent contamination and to protect the freshwater in the aquifers.  It is worth mentioning that this study was partially supported by a bilateral project between ASRT (Egypt) and CNR (Italy).</p><p> </p><p> </p>

scholarly journals The aggregate description of semi-arid vegetation with precipitation-generated soil moisture heterogeneity

1997 ◽  
Vol 1 (1) ◽  
pp. 205-212 ◽  
Author(s):  
C. B. White ◽  
P. R. Houser ◽  
A. M. Arain ◽  
Z.-L. Yang ◽  
K. Syed ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Surface Energy ◽  
Meteorological Data ◽  
Surface Fluxes ◽  
Convective Precipitation ◽  
Soil Parameters ◽  
Energy Fluxes ◽  
Average Surface ◽  
Surface Energy Fluxes ◽  
Semi Arid

Abstract. Meteorological measurements in the Walnut Gulch catchment in Arizona were used to synthesize a distributed, hourly-average time series of data across a 26.9 by 12.5 km area with a grid resolution of 480 m for a continuous 18-month period which included two seasons of monsoonal rainfall. Coupled surface-atmosphere model runs established the acceptability (for modelling purposes) of assuming uniformity in all meteorological variables other than rainfall. Rainfall was interpolated onto the grid from an array of 82 recording rain gauges. These meteorological data were used as forcing variables for an equivalent array of stand-alone Biosphere-Atmosphere Transfer Scheme (BATS) models to describe the evolution of soil moisture and surface energy fluxes in response to the prevalent, heterogeneous pattern of convective precipitation. The calculated area-average behaviour was compared with that given by a single aggregate BATS simulation forced with area-average meteorological data. Heterogeneous rainfall gives rise to significant but partly compensating differences in the transpiration and the intercepted rainfall components of total evaporation during rain storms. However, the calculated area-average surface energy fluxes given by the two simulations in rain-free conditions with strong heterogeneity in soil moisture were always close to identical, a result which is independent of whether default or site-specific vegetation and soil parameters were used. Because the spatial variability in soil moisture throughout the catchment has the same order of magnitude as the amount of rain falling in a typical convective storm (commonly 10% of the vegetation's root zone saturation) in a semi-arid environment, non-linearity in the relationship between transpiration and the soil moisture available to the vegetation has limited influence on area-average surface fluxes.

Identifying and quantifying the impact of non-climatic effects on the water cycle in a semi-arid environment 

2021 ◽  
Author(s):  
Julie Collignan ◽  
Jan Polcher ◽  
Pere Quintana Seguí
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Water Balance ◽  
Human Activities ◽  
River Discharge ◽  
Water Cycle ◽  
Land Cover Changes ◽  
Anthropogenic Changes ◽  
The Impact ◽  
Semi Arid

<p>In a context of climate change, the stakes surrounding water availability and use are getting higher, especially in semi-arid climates. Human activities such as irrigation and land cover changes impact the water cycle, raising questions around the effects it could have on regional atmospheric circulation and how to separate the impact of climate change from the impact of anthropogenic activities to better understand their role in the historical records. The ORCHIDEE Land Surface Model from Institut Pierre Simon Laplace (IPSL) simulates global carbon cycle and aims at quantifying terrestrial water and energy balance. It is being developed at regional scale but does not include satisfying hypothesis to account for human activities such as irrigation at such scale so far.</p><p>We <span>propose</span> a methodology to semi-empirically separate the effect of climate from the impact of the changing catchment characteristics on river discharge. <span>It is based on</span> the Budyko framework and <span>allows to characterise the</span> annual river discharge of over 363 river monitoring stations in Spain. The Budyko parameter is estimated for each basin and <span>represents</span> its hydrological characteristics. Precipitations and potential evapotranspiration are derived from the forcing dataset GSWP3 (Global Soil Wetness Project Phase 3) – from 1901 to 2010 –. Two methods are used to estimate evapotranspiration : the first uses evapotranspiration from the ORCHIDEE LSM outputs while the second deduced evapotranspiration from river discharge observations and the water balance equation. The first method only accounts for the effects of atmospheric forcing while the other combines, through the observations, <span>climatic and non-climatic processes</span> over the watersheds. We then study the evolution over the <span>Budyko</span> parameter fitted with these two <span>estimates of evaporation</span>. Studying the watershed parameter allows us to free ourselves from some of the climate interannual variability compared to directly looking at changes in the river discharge and better separate anthropogenic changes from the effect of climatic forcing.</p><p>Our results show that for most basins tested over Spain, there is an increasing trend in the <span>Budyko parameter representing increasing evaporation efficiency</span> of the watershed which <span>can not be</span> explained by the climate forcing. This trend is consistent with changes in irrigation equipment and land cover changes over the studied period. However changes of the basin characteristics can not be fully quantified by this variables. Other factors as glaciers melting which derails the water balance over our time of study.</p><p>The methodology needs to be extended to other areas such as Northern Europe to see if the differences in response of the catchments to anthropogenic changes quantified by our methodology corresponds to known contrasts. Balance between climatic and anthropogenic changes of basin characteristics are different in semi-arid climate than in northern more humid regions.</p>

scholarly journals PROJECTION OF THE IMPACT OF CLIMATE CHANGE ON THE SURFACE ENERGY AND WATER BALANCE IN THE SEYHAN RIVER BASIN TURKEY

2006 ◽  
Vol 50 ◽  
pp. 31-36 ◽  
Author(s):  
Kenji TANAKA ◽  
Yoichi FUJIHARA ◽  
Tsugihiro WATANABE ◽  
Toshiharu KOJIRI ◽  
Shuichi IKEBUCHI
Keyword(s):  
Climate Change ◽  
Surface Energy ◽  
Water Balance ◽  
River Basin ◽  
Impact Of Climate Change ◽  
The Impact

scholarly journals Impact assessment of climate change on hydro-climatic conditions of arid and semi-arid watersheds (case study: Zoshk-Abardeh watershed, Iran)

2020 ◽  
Author(s):  
Mohadese Rahimpour ◽  
Mohamad Tajbakhsh ◽  
Hadi Memarian ◽  
Amirhosein Aghakhani Afshar
Keyword(s):  
Climate Change ◽  
Assessment Tool ◽  
Climatic Conditions ◽  
Future Period ◽  
Eastern Iran ◽  
Temperature Component ◽  
The Impact ◽  
Semi Arid ◽  
Far Future

Abstract The hydrologic cycle in the river basins of semi-arid regions is severely influenced by climate change. The aim of this study is to assess the impact of climate change on the hydro-climatic condition in Zoshk-Abardeh watershed in eastern Iran. The Soil and Water Assessment Tool (SWAT) was calibrated using the Sequential Uncertainty Fitting – Version 2 (SUFI-2) algorithm to improve the simulation results of the runoff. The Model for Interdisciplinary Research on Climate-Earth System Models (MIROC-ESM) was used to investigate the effects of climate change on hydro-climatic components under the representative concentration pathway scenarios (RCPs: 2.6, 4.5, 6.0, and 8.5) and in near- (2014–2042), mid- (2042–2071), and far- (2072–2100) futures. The temperature component under the RCP4.5 and RCP6.0 during the near- and mid-future intervals and the far-future period (for RCP6.0) indicated a significant rising trend. The rainfall parameter in all RCPs and future intervals showed an insignificant descending trend. Runoff alterations under the RCP4.5 amid the mid- to far-future intervals and under the RCP8.5 throughout the far-future period trailed a significant descending trend. The results determined that the temperature will track an upward tendency, while precipitation and runoff will follow a descending trend in this watershed by the end of the 21st century.

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