Groundwater discharge mechanism in semi‐arid regions and the role of evapotranspiration

2008 ◽  
Vol 22 (16) ◽  
pp. 2993-3009 ◽  
Author(s):  
Osman A. E. Abdalla
Keyword(s):  
Arid Regions ◽  
Groundwater Discharge ◽  
Discharge Mechanism ◽  
Semi Arid

Social networks in arid Australia: a review of concepts and evidence

2008 ◽  
Vol 30 (1) ◽  
pp. 167 ◽  
Author(s):  
R. R. J. McAllister ◽  
B. Cheers ◽  
T. Darbas ◽  
J. Davies ◽  
C. Richards ◽  
...  
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Natural Resources ◽  
Social Structure ◽  
West Coast ◽  
Arid Regions ◽  
Weak Links ◽  
Network Data ◽  
Semi Arid

Arid systems are markedly different from non-arid systems. This distinctiveness extends to arid-social networks, by which we mean social networks which are influenced by the suite of factors driving arid and semi-arid regions. Neither the process of how aridity interacts with social structure, nor what happens as a result of this interaction, is adequately understood. This paper postulates three relative characteristics which make arid-social networks distinct: that they are tightly bound, are hierarchical in structure and, hence, prone to power abuses, and contain a relatively higher proportion of weak links, making them reactive to crisis. These ideas were modified from workshop discussions during 2006. Although they are neither tested nor presented as strong beliefs, they are based on the anecdotal observations of arid-system scientists with many years of experience. This paper does not test the ideas, but rather examines them in the context of five arid-social network case studies with the aim of hypotheses building. Our cases are networks related to pastoralism, Aboriginal outstations, the ‘Far West Coast Aboriginal Enterprise Network’ and natural resources in both the Lake-Eyre basin and the Murray–Darling catchment. Our cases highlight that (1) social networks do not have clear boundaries, and that how participants perceive their network boundaries may differ from what network data imply, (2) although network structures are important determinants of system behaviour, the role of participants as individuals is still pivotal, (3) and while in certain arid cases weak links are engaged in crisis, the exact structure of all weak links in terms of how they place participants in relation to other communities is what matters.

scholarly journals Cellulose δ18O of Tree Rings Reflects Vapour Pressure Variations in the Ordos Plateau

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 788
Author(s):  
Wentai Liu ◽  
Qiang Li ◽  
Huiming Song ◽  
Ruolan Deng ◽  
Yu Liu
Keyword(s):  
Vapour Pressure ◽  
Arid Regions ◽  
Southern Oscillation ◽  
Ensemble Empirical Mode Decomposition ◽  
Ordos Plateau ◽  
Mode Decomposition ◽  
Ecological Conservation ◽  
Semi Arid ◽  
Main Factor

In arid and semi-arid regions, a better understanding of the effect of climate change mechanisms on environmental evolution can be used to guide regional ecological conservation and to improve water resource availability. Increased aridity in arid and semi-arid regions considerably affects the physiological functions of plants and the exchange of carbon and water with the environment. We collected Pinus tabuliformis Carr. samples from Ordos, Inner Mongolia, and measured their δ18O variations. Vapour pressure (VP) was the main factor dominating δ18O variations from July to August, indicating the regulatory role of plant leaf stomata. Based on the δ18O series in the Ordos region, we reconstructed VP variations for July–August (VPJA) for the past 205 years. Spatial analysis showed the reconstruction as spatially highly representative. VP variations in the Ordos region mainly reflected precipitation variations and did not show a significant correlation with temperature. Since the late 1950s, VP has been decreasing, which is related to the weakening of the Asian monsoon. The results of reconstruction decomposed using ensemble empirical mode decomposition showed that El Niño–Southern Oscillation may affect VP in the study area, and the effect of sea surface temperature on the central and eastern Pacific Ocean in the Ordos region may lead to an increase in the drought.

The role of dams in development

2002 ◽  
Vol 45 (8) ◽  
pp. 169-180 ◽  
Author(s):  
Doğan Altinbilek
Keyword(s):  
Economic Development ◽  
Environmental Impact ◽  
Sustainable Management ◽  
Arid Regions ◽  
The World ◽  
Displaced People ◽  
The Subject ◽  
Semi Arid ◽  
World Commission On Dams

Dams are a major issue in sustainable management of finite water resources; they have also become the subject of vigorous public debate. This article considers them in the light of the report of the World Commission on Dams and using the example of Turkey. It is argued that economic development and population growth, particularly in arid and semi-arid regions, make plain the need for dams for hydropower and irrigation. Environmental impact assessment is essential, as are effective programmes for resettlement to avoid the impoverishment of displaced people.

scholarly journals How to identify groundwater-caused thermal anomalies in lakes based on multi-temporal satellite data in semi-arid regions

2013 ◽  
Vol 10 (4) ◽  
pp. 4901-4949 ◽  
Author(s):  
U. Mallast ◽  
C. Siebert ◽  
R. Gloaguen ◽  
J. Friesen ◽  
T. Rödiger ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Arid Regions ◽  
Spatial Scales ◽  
Groundwater Discharge ◽  
High Gain ◽  
Dead Sea ◽  
Data Series ◽  
Statistical Measures ◽  
Multi Temporal ◽  
Semi Arid

Abstract. Information on groundwater discharge over large spatial scales are essential for groundwater management particularly in (semi-) arid regions. If discharge areas are known, direct measurements over larger spatial scales are complicated to obtain by conventional means, why thermal remote sensing is increasingly applied to localize and quantify groundwater discharge. In this context, mostly unconsidered is (i) the influence of surface-runoff that can negatively affect groundwater focused studies and (ii) the representativeness of remotely sensed groundwater discharge based on single thermal images, against the background of discharge intermittency. Addressing these issues we apply a multi-temporal SST data approach based on 19 Landsat ETM+ band 6.2 (high gain) data from the year 2000 until 2002 at the example of the (semi-)arid vicinity of Dead Sea. To be independent of auxiliary rain data we develop a novel approach to identify surface-runoff influenced images solely using image statistics. Compared to foregoing rain events the result reveals a general influence-time of at least two days, but also that a simple time-difference criterion to exclude possible surface-runoff is not advisable. In the second part of the study we evaluate the significance of six statistical measures calculated on a per-pixel basis on the remaining 12 surface-runoff uninfluenced sea-surface-temperature (SST) data using in situ discharge measurements of the Israel Hydrological Service (IHS). We found that the spatial patterns of the standard deviation and range on the SST data series best fit to the IHS observed discharge locations and hence are suitable for detecting groundwater discharge areas.

scholarly journals How to identify groundwater-caused thermal anomalies in lakes based on multi-temporal satellite data in semi-arid regions

2014 ◽  
Vol 18 (7) ◽  
pp. 2773-2787 ◽  
Author(s):  
U. Mallast ◽  
R. Gloaguen ◽  
J. Friesen ◽  
T. Rödiger ◽  
S. Geyer ◽  
...  
Keyword(s):  
Water Availability ◽  
Surface Runoff ◽  
Arid Regions ◽  
Groundwater Discharge ◽  
Quantitative Information ◽  
Data Series ◽  
Thermal Anomalies ◽  
Statistical Measures ◽  
Multi Temporal ◽  
Semi Arid

Abstract. The deduction by conventional means of qualitative and quantitative information about groundwater discharge into lakes is complicated. Nevertheless, at least for semi-arid regions with limited surface water availability, this information is crucial to ensure future water availability for drinking and irrigation purposes. Overcoming this lack of discharge information, we present a satellite-based multi-temporal sea-surface-temperature (SST) approach. It exploits the occurrence of thermal anomalies to outline groundwater discharge locations using the example of the Dead Sea. Based on a set of 19 Landsat Enhanced Thematic Mapper (ETM+) images 6.2 (high gain), recorded between 2000 and 2002, we developed a novel approach which includes (i) an objective exclusion of surface-runoff-influenced data which would otherwise lead to erroneous results and (ii) a temporal SST variability analysis based on six statistical measures amplifying thermal anomalies caused by groundwater. After excluding data influenced by surface runoff, we concluded that spatial anomaly patterns of the standard deviation and range of the SST data series spatially fit best to in situ observed discharge locations and, hence, are most suitable for detecting groundwater discharge sites.

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