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351.
Modelling blue and green water availability under climate change in the Beninese Basin of the Niger River Basin,West Africa
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Djigbo Félicien Badou Bernd Diekkrüger Evison Kapangaziwiri Mamadou L. Mbaye Yacouba Yira Emmanuel A. Lawin Ganiyu T. Oyerinde Abel Afouda 《水文研究》2018,32(16):2526-2542
The aim of this study was to quantify climate change impact on future blue water (BW) and green water (GW) resources as well as the associated uncertainties for 4 subbasins of the Beninese part of the Niger River Basin. The outputs of 3 regional climate models (HIRHAM5, RCSM, and RCA4) under 2 emission scenarios (RCP4.5 and RCP8.5) were downscaled for the historical period (1976–2005) and for the future (2021–2050) using the Statistical DownScaling Model (SDSM). Comparison of climate variables between these 2 periods suggests that rainfall will increase (1.7% to 23.4%) for HIRHAM5 and RCSM under both RCPs but shows mixed trends (?8.5% to 17.3%) for RCA4. Mean temperature will also increase up to 0.48 °C for HIRHAM5 and RCSM but decrease for RCA4 up to ?0.37 °C. Driven by the downscaled climate data, future BW and GW were evaluated with hydrological models validated with streamflow and soil moisture, respectively. The results indicate that GW will increase in all the 4 investigated subbasins, whereas BW will only increase in one subbasin. The overall uncertainty associated with the evaluation of the future BW and GW was quantified through the computation of the interquartile range of the total number of model realizations (combinations of regional climate models and selected hydrological models) for each subbasin. The results show larger uncertainty for the quantification of BW than GW. To cope with the projected decrease in BW that could adversely impact the livelihoods and food security of the local population, recommendations for the development of adequate adaptation strategies are briefly discussed. 相似文献
352.
Controls on mineral deposit occurrence inferred from analysis of their spatial pattern and spatial association with geological features 总被引:4,自引:0,他引:4
In this paper, point pattern analysis, fractal analysis and Fry analysis were employed to study the spatial pattern of known occurrences of mineral deposits of the type sought, whereas distance distribution method was applied to study the spatial associations between various geological features and known occurrences of mineral deposits of the type sought. In the Aroroy district (Philippines), the results of the applications of these spatial analytical techniques support a conceptual model of district-scale mechanism of geologic controls on low-sulphidation epithermal Au mineralization, which involves a more-or-less regular mesh of interlinked zones of extension faults/fractures at and/or around intersections of NNW- and NW-trending strike-slip faults/fractures. Integration of spatial evidential data layers representing these structural controls and surficial geochemical anomalies, via knowledge-guided application of data-driven evidential belief functions, results in delineation of prospective areas occupying about 25% of the district, in which there is about 70% likelihood of undiscovered occurrences of low-sulphidation epithermal Au deposits. 相似文献
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355.
Joseph Labuz Emmanuel Detournay Will Pettitt 《Rock Mechanics and Rock Engineering》2015,48(6):2495-2495
356.
Post‐processing of medium‐range probabilistic hydrological forecasting: impact of forcing,initial conditions and model errors
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The impact of errors in the forcing, errors in the model structure and parameters, and errors in the initial conditions is investigated in a simple hydrological ensemble prediction system. The hydrological model is based on an input nonlinearity connected with a linear transfer function and forced by precipitation forecasts from the European Centre for Medium‐Range Weather Forecast (ECMWF) Ensemble Prediction System (EPS). The post‐processing of the precipitation and/or the streamflow using information from the reforecasts performed by ECMWF is tested. For this purpose, hydrological reforecasts are obtained by forcing the hydrological model with the precipitation from the reforecast data. In the present case study, it is found that the post‐processing of the hydrological ensembles with a statistical model fitted on the hydrological reforecasts improves the verification scores better than the use of post‐processed precipitation ensembles. In the case of large biases in the precipitation, combining the post‐processing of both precipitation and streamflow allows for further improvements. During the winter, errors in the initial conditions have a larger impact on the scores than errors in the model structure as designed in the experiments. Errors in the parameter values are largely corrected with the post‐processing. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
357.
Better understanding of urban microclimate and bioclimate of any city is imperative today when the world is constrained by both urbanisation and global climate change. Urbanisation generally triggers changes in land cover and hence influencing the urban local climate. Dar es Salaam city in Tanzania is one of the fast growing cities. Assessment of its urban climate and the human biometeorological conditions was done using the easily available synoptic meteorological data covering the period 2001–2011. In particular, the physiologically equivalent temperature (PET) was calculated using the RayMan software and results reveal that the afternoon period from December to February (DJF season) is relatively the most thermal stressful period to human beings in Dar es Salaam where PET values of above 35 °C were found. Additionally, the diurnal cycle of the individual meteorological elements that influence the PET index were analysed and found that air temperature of 30–35 °C dominate the afternoon period from 12:00 to 15:00 hours local standard time at about 60 % of occurrence. The current results, though considered as preliminary to the ongoing urban climate study in the city, provide an insight on how urban climate research is of significant importance in providing useful climatic information for ensuring quality of life and wellbeing of city dwellers. 相似文献
358.
People’s livelihood in several Himalayan regions largely depends on collection, use, and trade of medicinal plants. Traditional
use is generally not a problem, but commercial gathering of selected species to meet increasing national and international
demand can result in over-exploitation. Sustainable management of medicinal plants requires a clear understanding of the respective
roles, responsibilities and viewpoints of the various stakeholders involved. Through personal interviews and group discussions,
this study aimed at investigating the views of two stakeholder groups on use, trade and conservation of medicinal plants in
the Rasuwa district of Nepal. Local people and district and national organizations agreed that medicinal plants are collected
for a combination of commercial and personal uses. Perceptions on market availability differed significantly: 100 % of the
respondents from district and national organizations saw markets as easily available, against only 36 % for local people.
This could explain why medicinal plants were perceived by local people to contribute less to income generation than to livelihood
improvement. Different viewpoints were also expressed concerning the status of medicinal plants in the district: 81 % of the
respondents from district and national organizations considered that medicinal plants were threatened, compared to only 28
% for local people. Despite this disparity, both stakeholder groups agreed upon potential threats to medicinal plants: over-harvesting;
habitat loss due to land-use change and deforestation; and over-grazing by livestock. Several challenges were identified regarding
sustainable management of medicinal plants, such as ambiguous policies; lack of resources, information and infrastructures;
habitat degradation; and over-exploitation. Despite these challenges, respondents agreed that the medicinal plants sector
offers huge opportunities in the Rasuwa district, given resource availability, community awareness and motivation, and the
priority given to the sector by governments and other agencies. Proper collaboration, communication and coordination among
stakeholders are needed to grab these opportunities. 相似文献
359.
Christina L. De La Rocha Pierre Bescont Emmanuel Ponzevera 《Geochimica et cosmochimica acta》2011,75(18):5283-5295
We report here the silicon isotopic composition (δ30Si) of dissolved silicon (DSi) from 42 surface water samples from the Drake Passage, the Weddell Gyre, other areas south of the Southern Boundary of the Antarctic Circumpolar Current (ACC), and the ACC near the Kerguelen Plateau, taken between the beginning of February and the end of March 2007. From the beginning to end of the cruise (ANTXXIII/9), DSi diminished in the Antarctic by 50 μmol L−1 while concentrations of nitrate + nitrite and phosphate showed no net decline, indicating that the high seasonal Si/N removal ratios well known for the Southern Ocean may be more related to the strength of the silicate pump in the Southern Ocean than to the instantaneous Si/N uptake ratio of diatoms. The δ30Si of DSi in samples containing more than 20 μM DSi were strongly negatively correlated to DSi concentrations, supporting the use of δ30Si as a proxy for DSi removal. The “open system” fractionation observed, ε = −1.2 ± 0.11‰, agrees well with results from previous work in other areas, and the estimate of the initial δ30Si of DSi of +1.4‰ is not far off observations of the δ30Si of DSi in Winter Water (WW) in this area. Results were used to model DSi draw down in the past from the δ30Si of sediment cores, although isotopic fractionation during silica dissolution appeared to influence the δ30Si of some surface water samples, inviting further study of this phenomenon. 相似文献
360.