123 research outputs found

    Adquisición de las interrogativas qu

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    Emergence of Cooperation in a Model for Agricultural Production

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    The emergence of cooperation in a model for an artificial farming society is studied here by the use of an agent-based model. The system is composed of an ensemble of N agents assumed to have equal access to water, whose availability fluctuates randomly in time. Each agent makes two decisions every sowing season regarding: (1) the type of crop mix to plant and (2) whether s/he joins, or not, a cooperative group that allocates water amongst farmers to maximize the production and share revenues equally. Results show that the degree to which farmers choose to cooperate has a strong dependency on the mean water availability. Cooperation seems to emerge as a way of adaptation to uncertain environments by which individual risk is minimized

    Improving Operational Short- to Medium-Range (SR2MR) Streamflow Forecasts in the Upper Zambezi Basin and Its Sub-Basins Using Variational Ensemble Forecasting

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    The combination of Hydrological Models and high-resolution Satellite Precipitation Products (SPPs) or regional Climatological Models (RCMs), has provided the means to establish baselines for the quantification, propagation, and reduction in hydrological uncertainty when generating streamflow forecasts. This study aimed to improve operational real-time streamflow forecasts for the Upper Zambezi River Basin (UZRB), in Africa, utilizing the novel Variational Ensemble Forecasting (VEF) approach. In this regard, we describe and discuss the main steps required to implement, calibrate, and validate an operational hydrologic forecasting system (HFS) using VEF and Hydrologic Processing Strategies (HPS). The operational HFS was constructed to monitor daily streamflow and forecast them up to eight days in the future. The forecasting process called short- to medium-range (SR2MR) streamflow forecasting was implemented using real-time rainfall data from three Satellite Precipitation Products or SPPs (The real-time TRMM Multisatellite Precipitation Analysis TMPA-RT, the NOAA CPC Morphing Technique CMORPH, and the Precipitation Estimation from Remotely Sensed data using Artificial Neural Networks, PERSIANN) and rainfall forecasts from the Global Forecasting System (GFS). The hydrologic preprocessing (HPR) strategy considered using all raw and bias corrected rainfall estimates to calibrate three distributed hydrological models (HYMOD_DS, HBV_DS, and VIC 4.2.b). The hydrologic processing (HP) strategy considered using all optimal parameter sets estimated during the calibration process to increase the number of ensembles available for operational forecasting. Finally, inference-based approaches were evaluated during the application of a hydrological postprocessing (HPP) strategy. The final evaluation and reduction in uncertainty from multiple sources, i.e., multiple precipitation products, hydrologic models, and optimal parameter sets, was significantly achieved through a fully operational implementation of VEF combined with several HPS. Finally, the main challenges and opportunities associated with operational SR2MR streamflow forecasting using VEF are evaluated and discussed

    Rising water levels at Lake Enriquillo, Dominican Republic : advice on potential causes and pathways forward

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    This short report summarizes the results of a five-day mission (September 26-30, 2011) by a fourperson, multidisciplinary, bilingual team to the Dominican Republic (Santo Domingo and Lake Enriquillo). The mission was undertaken in response to a request from the Instituto Nacional de Recursos Hidráulicos (INDRHI), an agency of the Government of the Dominican Republic charged with wise use and preservation of water resources, to the Institute for Water Resources, U.S. Army Corps of Engineers. A 2011 agreement links the two institutions and their respective UNESCO “category 2” centers, the Centre for the Sustainable Management of Water Resources in the Caribbean Island States (CEHICA) and the International Center for Integrated Water Resources Management (ICIWaRM). The purpose of the mission was: to provide feedback to INDRHI with respect to the many hypotheses proposed to account for the rising surface elevation of Lake Enriquillo in the southwestern part of the country; and: to provide general advice concerning future pathways to prevent, adapt to, or mitigate this rise

    Modeling vadose zone hydrological processes in naturally-occurring piezometric depressions. The Chari-Baguirmi region, southeastern of the Lake Chad Basin, Republic of Chad

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    The Chari-Baguirmi region, southeastern of the Lake Chad (Africa), has a wide naturally occurring piezometric depression with values deeper than the expected regional groundwater level. To date, the most widely accepted hypotheses to explain its origin and dynamics are based on lack of rainwater infiltration and exfiltration processes. The code HYDRUS-1D is applied to numerically simulate the hydrological flow processes along the unsaturated zone in two soil profiles located in the central part and on the boundary of this piezometric depression under bare and vegetated soil coverage. The simulated time period is 2004–2015 with 715 mm annual rainfall average. The computed recharge with respect to total precipitation accounts for 21% on the boundary and 12% in the central part, which is limited by thick silty low permeability layer on the top surface. Considering modelling uncertainty and limitations under the simulated climatic conditions, the rainfall effect is observed only at upper soil layers, which leads to low aquifer recharge, while the upward water flux causing water table evaporation is very low. Past climate conditions, capable of developing a drying front to reach the water table after thousands of years of drying and geological structural constraints, may explain the current depressed area.Peer ReviewedPostprint (published version

    Integrating knowledge exchange and the assessment of dryland management alternatives – A learning-centered participatory approach

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    The adoption of sustainable land management strategies and practices that respond to current climate and human pressures requires both assessment tools that can lead to better informed decision-making and effective knowledge-exchange mechanisms that facilitate new learning and behavior change. We propose a learning-centered participatory approach that links land management assessment and knowledge exchange and integrates science-based data and stakeholder perspectives on both biophysical and socio-economic attributes. We outline a structured procedure for a transparent assessment of land management alternatives, tailored to dryland management, that is based on (1) principles of constructivism and social learning, (2) the participation of stakeholders throughout the whole assessment process, from design to implementation, and (3) the combination of site-specific indicators, identified by local stakeholders as relevant to their particular objectives and context conditions, and science-based indicators that represent ecosystem services of drylands worldwide. The proposed procedure follows a pattern of eliciting, challenging, and self-reviewing stakeholder perspectives that aims to facilitate learning. The difference between the initial baseline perspectives and the final self-reviewed stakeholder perspectives is used as a proxy of learning. We illustrate the potential of this methodology by its application to the assessment of land uses in a Mediterranean fire-prone area in East Spain. The approach may be applied to a variety of socio-ecological systems and decision-making and governance scales.The PRACTICE protocol was developed in the framework of the project PRACTICE: Prevention and Restoration Actions to Combat Desertification. An integrated Assessment, funded by the European Commission (GA226818). This research was also funded by the European project CASCADE (GA283068), and the Marie Skłodowska-Curie Actions Fellowship of the European Union (GA 629677) “S4S, Science for Society Solutions”, awarded to B.J.O

    Hydrology and its role in water engineering

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    [ES] La Hidrología es una ciencia esencial en Ingeniería del Agua, la cual abarca un amplio abanico de temas de investigación que engloban los diversos estadios del agua en el ciclo Hidrológico, tanto en atmósfera, superficie y suelo. Con motivo del relanzamiento de la revista Ingeniería del Agua se presenta un breve artículo de carácter introductorio en el que se muestran algunas de la líneas de investigación actuales en Hidrología, dedicadas a lluvia, interceptación de agua por la vegetación, sensores en Hidrología, agua subterránea, entre otras. Dicha revisión no pretende ser exhaustiva, dado el tamaño limitado de este formato de publicación, sino motivar la publicación en Ingeniería del Agua de artículos dentro de la temática Hidrología.[EN] Hydrology is the basic science for water engineering, including a wide list of research topics ranging from atmospheric water and surface hydrology to groundwater hydraulics. To initiate the new publication period of the journal Ingeniería del Agua, we present here a brief review paper where the current state of research in many hydrologic fields is discussed. The aim of the paper is not to present a complete picture of current state-of-the-art research topics, but rather to provide a broad overview and stimulate new and innovative publication of Hydrology papers in the journal Ingeniería del Agua.García-Marín, A.; Roldán-Cañas, J.; Estévez, J.; Moreno-Pérez, F.; Serrat-Capdevila, A.; González, J.; Francés García, FR.... (2014). La hidrología y su papel en ingeniería del agua. Ingeniería del agua. 18(1):1-14. https://doi.org/10.4995/ia.2014.3048OJS11418

    Climate Change Impacts on Net Ecosystem Productivity in a Subtropical Shrubland of Northwestern México

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    The sensitivity of semiarid ecosystems to climate change is not well understood due to competing effects of soil and plantâ mediated carbon fluxes. Limited observations of net ecosystem productivity (NEP) under rising air temperature and CO2 and altered precipitation regimes also hinder climate change assessments. A promising avenue for addressing this challenge is through the application of numerical models. In this work, we combine a mechanistic ecohydrological model and a soil carbon model to simulate soil and plant processes in a subtropical shrubland of northwest México. Due to the influence of the North American monsoon, the site exhibits net carbon losses early in the summer and net carbon gains during the photosynthetically active season. After building confidence in the simulations through comparisons with eddy covariance flux data, we conduct a series of climate change experiments for nearâ future (2030â 2045) scenarios that test the impact of meteorological changes and CO2 fertilization relative to historical conditions (1990â 2005). Results indicate that reductions in NEP arising from warmer conditions are effectively offset by gains in NEP due to the impact of higher CO2 on water use efficiency. For cases with higher summer rainfall and CO2 fertilization, climate change impacts lead to an increase of ~25% in NEP relative to historical conditions (mean of 66 g C mâ 2). Net primary production and soil respiration derived from decomposition are shown to be important processes that interact to control NEP and, given the role of semiarid ecosystems in the global carbon budget, deserve attention in future simulation efforts of ecosystem fluxes.Key PointsModel simulation accurately captured the seasonality of vegetation activityNet ecosystem productivity decreased under reduced summer rainfall and increased temperature scenariosElevated CO2 scenarios offset the negative impacts of meteorological conditionsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142969/1/jgrg20992_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142969/2/jgrg20992.pd
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