Dissertation•
Optimal land and water allocation to agriculture and hydropower in the Upper Blue Nile basin
01 Jan 2017-
TL;DR: In this paper, a framework for optimal allocation of land and water resources to agriculture and hydropower production in the upper Blue Nile (UBN) basin is developed, which contributes about 60 percent of the Nile river flow.
Abstract: The Nile basin is an ecosystem under stress due to
rapid population growth, urgent needs for more efficient
utilization of natural resources, potential impacts of climate
change, and persistent conflicts between riparian countries on the
limited set of resources. This thesis develops a framework for
optimal allocation of land and water resources to agriculture and
hydropower production in the upper Blue Nile (UBN) basin, which
contributes about 60 percent of the Nile river flow. The framework
consists of three optimization models that aim to: (a) provide
accurate estimates of the basin water budget components, (b)
allocate land and water resources optimally to rain-fed, and
irrigated agriculture, and (c) allocate water to agriculture and
hydropower production, and investigate trade-offs between them.
This thesis makes two methodological contributions.
Citations
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TL;DR: In this paper, the sensitivity of crop yield and production to initial soil moisture conditions in the Upper Blue Nile Basin (UBNB) of Ethiopia making use of a process-based spatially distributed crop model (DSSAT) linked to a hydrologic model (CREST), and assess the potential of soil moisture management in promoting agricultural outcome.
30 citations
Journal Article•
TL;DR: In this paper, the authors discuss the existing hydropolitcal positions of the Nile riparian states from an Ethiopian perspective and propose some win-win solutions that could pave the way for ending the stalemate.
Abstract: This paper discusses the existing hydropolitcal positions of the Nile riparian states from an Ethiopian perspective. It argues that Egyptian protectionist water security policy coupled with Sudan's hydropolitical dilemma, Ethiopia's grievances, and the complacency of White Nile riparian states to water redistribution have blocked the major venues to the formation of a multilateral agreement that would be acceptable to all the stakeholders. The formation of Nile-based organizations in the past thirty years has also failed to make a breakthrough because it failed to address the vital question of the fair and equitable distribution of the Nile waters. Some recent developments in this direction, particularly the formation of the Nile Basin Initiative in 1999, indicate some glimmer of hope in the basin. The author of this paper argues that an effective basin-wide organization could be implemented if and only if the outstanding problem of water redistribution is solved. The paper has, by way of conclusion, proposed some win-win solutions that could pave the way for ending the stalemate. These include, among others, the revision and re-negotiation of the 1959 bilateral treaty between Egypt and the Sudan to accommodate the natural rights of the other riparian states, the import of virtual water, the transfer of all or some of the Nile storage upstream to minimize evapotranspiration and the application of drip irrigation to save water.
5 citations
References
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European Centre for Medium-Range Weather Forecasts1, Lawrence Livermore National Laboratory2, Chinese Academy of Sciences3, Japan Meteorological Agency4, University of Reading5, Met Office6, Max Planck Society7, Royal Netherlands Meteorological Institute8, National Center for Atmospheric Research9, National Oceanic and Atmospheric Administration10
TL;DR: ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions as mentioned in this paper.
Abstract: ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions. The observing system changed considerably over this re-analysis period, with assimilable data provided by a succession of satellite-borne instruments from the 1970s onwards, supplemented by increasing numbers of observations from aircraft, ocean-buoys and other surface platforms, but with a declining number of radiosonde ascents since the late 1980s. The observations used in ERA-40 were accumulated from many sources. The first part of this paper describes the data acquisition and the principal changes in data type and coverage over the period. It also describes the data assimilation system used for ERA-40. This benefited from many of the changes introduced into operational forecasting since the mid-1990s, when the systems used for the 15-year ECMWF re-analysis (ERA-15) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) re-analysis were implemented. Several of the improvements are discussed. General aspects of the production of the analyses are also summarized.
A number of results indicative of the overall performance of the data assimilation system, and implicitly of the observing system, are presented and discussed. The comparison of background (short-range) forecasts and analyses with observations, the consistency of the global mass budget, the magnitude of differences between analysis and background fields and the accuracy of medium-range forecasts run from the ERA-40 analyses are illustrated. Several results demonstrate the marked improvement that was made to the observing system for the southern hemisphere in the 1970s, particularly towards the end of the decade. In contrast, the synoptic quality of the analysis for the northern hemisphere is sufficient to provide forecasts that remain skilful well into the medium range for all years. Two particular problems are also examined: excessive precipitation over tropical oceans and a too strong Brewer-Dobson circulation, both of which are pronounced in later years. Several other aspects of the quality of the re-analyses revealed by monitoring and validation studies are summarized. Expectations that the ‘second-generation’ ERA-40 re-analysis would provide products that are better than those from the firstgeneration ERA-15 and NCEP/NCAR re-analyses are found to have been met in most cases. © Royal Meteorological Society, 2005. The contributions of N. A. Rayner and R. W. Saunders are Crown copyright.
7,110 citations
TL;DR: The Global Precipitation Climatology Project (GPCP) version 2 Monthly Precise Analysis as discussed by the authors is a merged analysis that incorporates precipitation estimates from low-orbit satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations.
Abstract: The Global Precipitation Climatology Project (GPCP) Version 2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.5 degrees x 2.5 degrees latitude-longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The data set is extended back into the premicrowave era (before 1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the raingauge analysis. This monthly analysis is the foundation for the GPCP suite of products including those at finer temporal resolution, satellite estimate, and error estimates for each field. The 23-year GPCP climatology is characterized, along with time and space variations of precipitation.
4,951 citations
TL;DR: The Modern-Era Retrospective Analysis for Research and Applications (MERRA) was undertaken by NASA's Global Modeling and Assimilation Office with two primary objectives: to place observations from NASA's Earth Observing System satellites into a climate context and to improve upon the hydrologic cycle represented in earlier generations of reanalyses as mentioned in this paper.
Abstract: The Modern-Era Retrospective Analysis for Research and Applications (MERRA) was undertaken by NASA’s Global Modeling and Assimilation Office with two primary objectives: to place observations from NASA’s Earth Observing System satellites into a climate context and to improve upon the hydrologic cycle represented in earlier generations of reanalyses. Focusing on the satellite era, from 1979 to the present, MERRA has achieved its goals with significant improvements in precipitation and water vapor climatology. Here, a brief overview of the system and some aspects of its performance, including quality assessment diagnostics from innovation and residual statistics, is given.By comparing MERRA with other updated reanalyses [the interim version of the next ECMWF Re-Analysis (ERA-Interim) and the Climate Forecast System Reanalysis (CFSR)], advances made in this new generation of reanalyses, as well as remaining deficiencies, are identified. Although there is little difference between the new reanalyses i...
4,572 citations
01 Oct 2000
TL;DR: The most complete digital topographic map of Earth was made by the Shuttle Radar Topography Mission (SRTM) as discussed by the authors, which used a single-pass radar interferometer to produce a digital elevation model (DEM) of the Earth's land surface between about 60 deg north and 56 deg south latitude.
Abstract: On February 22, 2000 Space Shuttle Endeavour landed at Kennedy Space Center, completing the highly successful 11-day flight of the Shuttle Radar Topography Mission (SRTM). Onboard were over 300 high-density tapes containing data for the highest resolution, most complete digital topographic map of Earth ever made. SRTM is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense. The mission was designed to use a single-pass radar interferometer to produce a digital elevation model (DEM) of the Earth's land surface between about 60 deg north and 56 deg south latitude. When completed, the DEM will have 30 m pixel spacing and about 15 m vertical accuracy. Two orthorectified image mosaics (one from the ascending passes with illumination from the southeast and one from descending passes with illumination from the southwest) will also be produced.
3,137 citations
TL;DR: The Climate Forecast System (CFS) as discussed by the authors is a fully coupled ocean-land-atmosphere dynamical seasonal prediction system, which became operational at NCEP in August 2004.
Abstract: The Climate Forecast System (CFS), the fully coupled ocean–land–atmosphere dynamical seasonal prediction system, which became operational at NCEP in August 2004, is described and evaluated in this paper. The CFS provides important advances in operational seasonal prediction on a number of fronts. For the first time in the history of U.S. operational seasonal prediction, a dynamical modeling system has demonstrated a level of skill in forecasting U.S. surface temperature and precipitation that is comparable to the skill of the statistical methods used by the NCEP Climate Prediction Center (CPC). This represents a significant improvement over the previous dynamical modeling system used at NCEP. Furthermore, the skill provided by the CFS spatially and temporally complements the skill provided by the statistical tools. The availability of a dynamical modeling tool with demonstrated skill should result in overall improvement in the operational seasonal forecasts produced by CPC. The atmospheric compon...
1,220 citations
Additional excerpts
..., 2007; Uppala et aL, 2008); the NCEP-CFSR released in 2010 (Saha et al., 2010) and the modern-era reanalysis (MERRA) available for the period 1979-current (Rienecker et al....
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