The great success of the Tropical Rainfall Measuring Mission (TRMM) and its successor Global Precipitation Measurement (GPM) has accelerated the development of global high-resolution satellite-based ...precipitation products (SPP). However, the quantitative accuracy of SPPs has to be evaluated before using these datasets in water resource applications. This study evaluates the following GPM-era and TRMM-era SPPs based on two years (2014–2015) of reference daily precipitation data from rain gauge networks in ten mountainous regions: Integrated Multi-SatellitE Retrievals for GPM (IMERG, version 05B and version 06B), National Oceanic and Atmospheric Administration (NOAA)/Climate Prediction Center Morphing Method (CMORPH), Global Satellite Mapping of Precipitation (GSMaP), and Multi-Source Weighted-Ensemble Precipitation (MSWEP), which represents a global precipitation data-blending product. The evaluation is performed at daily and annual temporal scales, and at 0.1 deg grid resolution. It is shown that GSMaPV07 surpass the performance of IMERGV06B Final for almost all regions in terms of systematic and random error metrics. The new orographic rainfall classification in the GSMaPV07 algorithm is able to improve the detection of orographic rainfall, the rainfall amounts, and error metrics. Moreover, IMERGV05B showed significantly better performance, capturing the lighter and heavier precipitation values compared to IMERGV06B for almost all regions due to changes conducted to the morphing, where motion vectors are derived using total column water vapor for IMERGV06B.
In this study, HSPF (Hydrologic Simulation Program-FORTRAN) was used to analyze the potential impact of climate change on the streamflow of four major river basins in Ethiopia: Awash, Baro, Genale, ...and Tekeze. The calibrated and validated HSPF model was forced with daily climate data of 10 CMIP5 (Coupled Model Intercomparison Project phase 5) Global Climate Models (GCMs) for the 1971–2000 control period and the RCP4.5 and RCP8.5 climate projections of 2041–2070 (2050s) and 2071–2100 (2080s). The ensemble median of these 10 GCMs projects the temperature in the four study areas to increase by about 2.3 °C (3.3 °C) in 2050s (2080s), whereas the mean annual precipitation is projected to increase by about 6% (9%) in 2050s (2080s). This results in about 3% (6%) increase in the projected annual streamflow in Awash, Baro, and Tekeze rivers whereas the annual streamflow of Genale river is projected to increase by about 18% (33%) in the 2050s (2080s). However, such projected increase in the mean annual streamflow due to increasing precipitation over Ethiopia contradicts the decreasing trends in mean annual precipitation observed in recent decades. Regional climate models of high resolutions could provide more realistic climate projections for Ethiopia’s complex topography, thus reducing the uncertainties in future streamflow projections.
The aim of this study is to assess the performance of various global precipitation products for water resources application in the Upper Blue Nile basin, Ethiopia. Three precipitation products of ...gauge-adjusted (corrected) CMORPH, (TRMM) TMPA 3B42v7 and ECMWF reanalysis products are evaluated. A Coupled Routing and Excess Storage (CREST) distributed hydrological model is calibrated and used for the evaluation. The model is calibrated for 2000–2005 and validated for 2006–2011 periods using daily observed rainfall and discharge datasets. The results indicate the precipitation products consistently provide a better performance of runoff estimation when they are independently calibrated than simulation modes of the products. We conclude as long as each product is calibrated independently, global precipitation products can provide enough information for water resource management in data-scarce regions of upper Blue Nile Basin. Further analysis is underway to understand the response characteristics of the precipitation products at larger spatio-temporal scales.
The increasing availability of global observation datasets, both from in situ and remote sensors, and advancements in earth system models and data assimilation algorithms have generated a number of ...water resources reanalysis products that are available at global scale and high spatial and temporal resolutions. These products hold great potential for water resources applications, but their levels of uncertainty need to be evaluated at local scale. In this work, we evaluate the runoff product from two multi-model global water resources reanalyses (WRRs), available at 0.5° (WRR1) and 0.25° (WRR2) grid resolutions, which were produced within the framework of a European Union project (eartH2Observe) in the upper Blue Nile basin. Analysis indicates that the recently released WRR2 UniK product exhibits consistently better performance statistics than the earlier coarser-resolution WRR1 and the rest of the WRR2 products at all ranges of temporal and spatial scale evaluated. Streamflow simulations based on gauged rainfall forcing and the locally set hydrological model CREST outperforms all the other products, including UniK. Global hydrological products can be a data source for various water resources planning and management applications in data-scarce areas of Africa. This study cautions against using available global hydrological products without prior uncertainty evaluation.
Abstract
This study aims to understand the long-term (2020–2050) urban water–energy–food (WEF) resources access and sustainability in Addis Ababa city through a nexus modeling approach. Several ...feasible scenarios in line with improving WEF resources supply and access through conservation, system rehabilitation and technology input are explored. The water system scenarios include rehabilitation and conservation scenario, water supply enhancement scenario, technology input scenario and integrated water improvement scenario. The energy scenario includes energy conservation scenario and new renewable supply enhancement scenarios and integration of both scenarios as integrated energy scenario. The food system scenarios include crop yield productivity and irrigation water use efficiency scenarios of urban agricultural system. The integrated WEF nexus scenario is the integration of all scenarios under one nexus framework. The results are evaluated against baseline scenario. At a system level, the integrated water scenario result provides a water saving potential of 26 and 52% from the baseline scenario by 2030 and 2050, respectively, whereas the integrated energy use scenario saves energy by as much as 22 and 48%. For respective years, under the integrated WEF nexus scenario, the integrated water use scenario for low energy intensity reduces the energy use for urban water system by 23 and 72% from the baseline scenario. Similarly, urban food production have also shown enhancement. Urban food production system in Addis Ababa city is relatively small and does not significantly affect the food import from other parts of the country. Overall, the results WEF nexus modeling approach revealed the importance of exploring integrated nexus approach to sustainable urban water energy and food development and management as a first attempt at the urban scale.
Drought is one of the least understood and complex natural hazards often characterized by a significant decrease in water availability for a prolonged period. It can be manifested in one or more ...forms as meteorological, agricultural, hydrological, and/or socio-economic drought. The overarching objective of this study is to demonstrate and characterize the different forms of droughts and to assess the multidimensional nature of drought in the Abbay/ Upper Blue Nile River (UBN) basin and its national and regional scale implications. In this study, multiple drought indices derived from in situ and earth observation-based hydro-climatic variables were used. The meteorological drought was characterized using the Standardized Precipitation Index (SPI) computed from the earth observation-based gridded CHIRPS (Climate Hazards Group InfraRed Precipitation with Station) rainfall data. Agricultural and hydrological droughts were characterized by using the Soil Moisture Deficit Index (SMDI) and Standardized Runoff-discharge Index (SRI), respectively. The monthly time series of SMDI was derived from model-based gridded soil moisture and SRI from observed streamflow data from 1982 to 2019. The preliminary result illustrates the good performance of the drought indices in capturing the historic severe drought events (e.g., 1984 and 2002) and the spatial extents across the basin. The results further indicated that all forms of droughts (i.e., meteorological, agricultural, and hydrological) occurred concurrently in Abbay/Upper Blue Nile basin with a Pearson correlation coefficient ranges from 0.5 to 0.85 both Kiremt and annual aggregate periods. The concurrent nature of drought is leading to a multi-dimensional socio-economic crisis as indicated by rainfall, and soil moisture deficits, and drying of small streams. Multi-dimensional drought mitigation necessitates regional cooperation and watershed management to protect both the common water sources of the Abbay/Upper Blue Nile basin and the socio-economic activities of the society in the basin. This study also underlines the need for multi-scale drought monitoring and management practices in the basin.
Urban water-energy demand is an important basic data for urban engineering planning, design and management. Making full use of multi-source data and prior knowledge to quickly and economically obtain ...high-precision urban water-energy demand are of great significance to the optimal allocation of sustainable urban water-energy supply. In order to accurately forecast the future urban water-energy demand, this study took Addis Ababa City as a research area to forecast the water-energy demand of the city from 2020 to 2050. Aiming at the oscillating characteristics of the urban water-energy demand sequence and the over-fitting problem of prediction models, this study proposed the linear mathematical regression algorithm model. Urbanization drivers such as population (POP), gross domestic product (GDP) and per capita income (PCI) were explored to determine the water-energy consumption, or demand. Technologies based water-energy delivery efficiency, which is one of urbanization driver, was also considered to forecast the electric energy and water demand. This study adopted a linear model using data-mining approach, which is used to associate the historical water-energy consumption with the POP, GDP and PCI growth scenarios in order to address the water-energy consumptions. Overall, the total water-energy demand is projected to increase by 65% for water supply and 120% energy in 2030 and by 365% for water supply and 700% energy in 2050 from the baseline period of 2020 because the increase in the water-energy urbanization drivers mainly the POP, GDP, and PCI. For the water-energy demand forecast, the model's performance was assessed in order to correctly pinpoint the most significant urbanization drivers. This has been done to help planners and policymakers think about sustainable water-energy supply with a better understanding and more thorough insights.
Ethiopia unveiled homegrown economic reform agenda aimed to achieve a lower-middle status by 2030 and sustain its economic growth to achieve medium-middle and higher-middle status by 2040 and 2050 ...respectively. In this study, we evaluated the optimal renewable energy mix for power generation and associated investment costs for the country to progressively achieve upper-middle-income countries by 2050. Two economic scenarios: business as usual and Ethiopia's homegrown reform agenda scenario were considered. The study used an Open Source energy Modeling System. The model results suggest: if projected power demand increases as anticipated in the homegrown reform agenda scenario, Ethiopia requires to expand the installed power capacity to 31.22GW, 112.45GW and 334.27GW to cover the current unmet and achieve lower, medium and higher middle-income status by 2030, 2040 and 2050 respectively. The Ethiopian energy mix continues to be dominated by hydropower and starts gradually shifting to solar and wind energy development towards 2050 as a least-cost energy supply option. The results also indicate Ethiopia needs to invest about 70 billion US$ on power plant investments for the period 2021-2030 to achieve the lower-middle-income electricity per capita consumption target by 2030 and staggering cumulative investment in the order of 750 billion US$ from 2031 to 2050 inclusive to achieve upper-middle-income electricity consumption rates by 2050. Ethiopia has enough renewable energy potential to achieve its economic target. Investment and financial sourcing remain a priority challenge. The findings could be useful in supporting decision-making concerning socio-economic development and investment pathways in the country.
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