Space Technology for Global Water Resources Observations

Author(s):  
Jérôme Benveniste
2016 ◽  
Vol 20 (7) ◽  
pp. 2877-2898 ◽  
Author(s):  
Hannes Müller Schmied ◽  
Linda Adam ◽  
Stephanie Eisner ◽  
Gabriel Fink ◽  
Martina Flörke ◽  
...  

Abstract. When assessing global water resources with hydrological models, it is essential to know about methodological uncertainties. The values of simulated water balance components may vary due to different spatial and temporal aggregations, reference periods, and applied climate forcings, as well as due to the consideration of human water use, or the lack thereof. We analyzed these variations over the period 1901–2010 by forcing the global hydrological model WaterGAP 2.2 (ISIMIP2a) with five state-of-the-art climate data sets, including a homogenized version of the concatenated WFD/WFDEI data set. Absolute values and temporal variations of global water balance components are strongly affected by the uncertainty in the climate forcing, and no temporal trends of the global water balance components are detected for the four homogeneous climate forcings considered (except for human water abstractions). The calibration of WaterGAP against observed long-term average river discharge Q significantly reduces the impact of climate forcing uncertainty on estimated Q and renewable water resources. For the homogeneous forcings, Q of the calibrated and non-calibrated regions of the globe varies by 1.6 and 18.5 %, respectively, for 1971–2000. On the continental scale, most differences for long-term average precipitation P and Q estimates occur in Africa and, due to snow undercatch of rain gauges, also in the data-rich continents Europe and North America. Variations of Q at the grid-cell scale are large, except in a few grid cells upstream and downstream of calibration stations, with an average variation of 37 and 74 % among the four homogeneous forcings in calibrated and non-calibrated regions, respectively. Considering only the forcings GSWP3 and WFDEI_hom, i.e., excluding the forcing without undercatch correction (PGFv2.1) and the one with a much lower shortwave downward radiation SWD than the others (WFD), Q variations are reduced to 16 and 31 % in calibrated and non-calibrated regions, respectively. These simulation results support the need for extended Q measurements and data sharing for better constraining global water balance assessments. Over the 20th century, the human footprint on natural water resources has become larger. For 11–18% of the global land area, the change of Q between 1941–1970 and 1971–2000 was driven more strongly by change of human water use including dam construction than by change in precipitation, while this was true for only 9–13 % of the land area from 1911–1940 to 1941–1970.


2011 ◽  
Vol 21 (2) ◽  
pp. 592-603 ◽  
Author(s):  
Nigel W. Arnell ◽  
Detlef P. van Vuuren ◽  
Morna Isaac

2013 ◽  
Vol 129 ◽  
pp. 456-462 ◽  
Author(s):  
Elizabeth Curmi ◽  
Keith Richards ◽  
Richard Fenner ◽  
Julian. M. Allwood ◽  
Grant M. Kopec ◽  
...  
Keyword(s):  

2006 ◽  
Vol 10 (3) ◽  
pp. 455-468 ◽  
Author(s):  
A. K. Chapagain ◽  
A. Y. Hoekstra ◽  
H. H. G. Savenije

Abstract. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm3/yr. These products are however being produced with only 1253 Gm3/yr in the exporting countries, saving global water resources by 352 Gm3/yr. This saving is 28 per cent of the international virtual water flows related to the trade of agricultural products and 6 per cent of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm3/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm3/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.


Author(s):  
P. Pallavi ◽  
Shaik Salam

Water is an important, but often ignored element in sustainable development by now it has been clear that urgent action is needed to avoid global water crisis. Water resource management is the activity of planning, developing, distributing and managing the optimum use of water resources. Successful management of water resources requires accurate knowledge of their resource distribution to meet up the competing demands and mechanisms to make good decisions using advanced recent technologies.Towards evolving comprehensive management plan in suitable conservation and utilization of water resources space technology plays a crucial role in managing country’s available water resources. Systematic approaches involving judicious combination of conventional server side scripting programming and remote sensing techniques pave way for achieving optimum planning and operational of water resources projects.   new methodologies and 24/7 accessible system need to be built, these by reducing the dependency on complex infrastructure an specialist domain Open source web GIS systems have proven their rich in application of server side scripting and easy to use client application tools. Present study and implementation aims to provide wizard based or easily driven tools online for command area management practices. In this large endeavour modules for handling remote sensing data, online raster processing, statistics and indices generation will be developed.


2021 ◽  
Author(s):  
Cecilia Tortajada ◽  
Eduardo Araral
Keyword(s):  

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