To assess climate change impact on the hydrology of Izmit Bay, a coupled model chain using the results of four combinations of Global Climate Models (GCMs) and Regional Climate Models (RCMs) and ...consisting two hydrological models (mGROWA and PROMET) and one hydrodynamic model (MIKE 3HD) was established. Climate model data of the 4 GCM-RCM combinations were applied to both hydrological models. The resulting 8 streamflow data of the hydrological models were then applied to the MIKE 3HD to assess possible hydrodynamic situations in Izmit Bay. Related model results indicate a range of possible future streamflow regimes suitable for the analysis of climate change impact on Izmit Bay. In order to evaluate the effects of the hydrological changes only on the bay, the bay was considered as closed in terms of hydrodynamics. There is a clear indication that the climate change induced impacts on streamflow may influence the sea level in the Bay to a minor extent. However, climate change induced water exchange processes in the Bay may have a much bigger influence. Hence, it is suggested that further simulations should be run once the hydrologic regime of the Marmara Sea has been assessed in a broader macro-scale study.
The implementation process of the EU water legislation (EU WFD, EU GWD) has put pressure on environmental managers to create, analyse and disseminate hydrological data in recent years. In this ...context, distributed hydrological model results at the macro scale (>10,000 km²) have gained importance for the Environment Agency of the Republic of Slovenia, too. Within a joint project the distributed water balance model GROWA, developed for Germany, has been adapted to Slovenia by re-calibrating the routine for determining the average annual groundwater recharge rate. This routine consists mainly of a base flow index approach (BFI). This BFI is based on 41 different site conditions in Slovenia, whereas lithology dominates the recharge process. This paper outlines the general GROWA approach, the required input data, and the calibration process. Validated model results for the period 1971–2000, especially total runoff and base flow, are presented and discussed. These results have been used already for practical water management issues in Slovenia on European, national and regional level. It is shown that Slovenian groundwater resources exhibit high regional and seasonal variability. Tendencies of more frequent and more pronounced droughts have been detected. As demonstrated by the results GROWA is a valuable tool for the spatially distributed assessment of groundwater recharge in Slovenia.
The Far-North region of Cameroon is threatened by extreme water shortage. Over the years groundwater has increasingly been used as the main source of domestic water supply. In spite of the increased, ...groundwater exploitation has been done without adequate planning. One of the key parameters of a sustainable groundwater management is the regional groundwater recharge rate, which defines the upper limit for which groundwater abstraction should not exceed. This paper summarizes the results of transferring the water balance model GROWA to the Far-North region of Cameroon. The main aim was to assess the spatial distributed groundwater recharge rate through rainfall. Due to the lack of adequate regional data bases, international data sources, e.g. the World soil map in scale of 1: 3,000,000 were used to derive the input parameters needed to run GROWA model. The simulated GROWA results show a satisfying agreement with existing groundwater recharge rate assessments for most areas of the study region. Against this background, it was concluded that GROWA model results represent reliable reference values for groundwater recharge through rainfall even though the input parameters were derived from small-scale generalized international maps. This approach provides a relevant initial step for a more detailed groundwater recharge estimate. A more accurate estimation for groundwater recharge should be carried out once the input data for the study area are available in higher spatial resolution including runoff records for a plausibility check of the modeled water quantities for groundwater recharge.
Hydrological modelling of mesoscale catchments is often adversely affected by a lack of adequate information about specific site conditions. In particular, digital land cover data are available from ...data sets which were acquired on a European or a national scale. These data sets do not only exhibit a restricted spatial resolution but also a differentiation of crops and impervious areas which is not appropriate to the needs of mesoscale hydrological models. In this paper, the impact of remote sensing data on the reliability of a water balance model is investigated and compared to model results determined on the basis of CORINE (Coordination of Information on the Environment) Land Cover as a reference. The aim is to quantify the improved model performance achieved by an enhanced land cover representation and corresponding model modifications. Making use of medium resolution satellite imagery from SPOT, LANDSAT ETM+ and ASTER, detailed information on land cover, especially agricultural crops and impervious surfaces, was extracted over a 5-year period (2000–2004). Crop-specific evapotranspiration coefficients were derived by using remote sensing data to replace grass reference evapotranspiration necessitated by the use of CORINE land cover for rural areas. For regions classified as settlement or industrial areas, degrees of imperviousness were derived. The data were incorporated into the hydrological model GROWA (large-scale water balance model), which uses an empirical approach combining distributed meteorological data with distributed site parameters to calculate the annual runoff components. Using satellite imagery in combination with runoff data from gauging stations for the years 2000–2004, the actual evapotranspiration calculation in GROWA was methodologically extended by including empirical crop coefficients for actual evapotranspiration calculations. While GROWA originally treated agricultural areas as homogeneous, now a consideration and differentiation of the main crops is possible. The accuracy was determined by runoff measurements from gauging stations. Differences in water balances resulting from the use of remote sensing data as opposed to CORINE were analysed in this study using a representative subcatchment. Resulting Nash–Sutcliff model efficiencies improved from 0.372 to 0.775 and indicate that the enhanced model can produce thematically more accurate and spatially more detailed local water balances. However, the proposed model enhancements by satellite imagery have not exhausted the full potential of water balance modelling, for which a higher temporal resolution is required.
► An interdisciplinary model approach coupled one agro-economic and two hydrological models. ► Current nutrient emissions into ground- and surface waters were quantified. ► The future impact of ...agro-political measures and global economics for 2015 were estimated. ► Best fitting measures were designed on base on a comprehensive literature research coupled with expert opinions. ► Measure packages including the cost efficiency analyses were located in the respective communities in dependence of the respective regional natural conditions.
The European Water Framework Directive (WFD) requires a good chemical and ecological status of water and groundwater resources in the EU member countries by 2015. However, for some river basins, the good status cannot be achieved by 2015, and therefore measures have to be taken to reduce the unacceptably high nutrient input. Therefore, a new approach was developed by using an interdisciplinary model network, consisting of the regionalized agricultural economic model RAUMIS and two hydro(geo)logical models GROWA/WEKU and MONERIS. For the 49,000km2 Weser river basin, in Germany we: (1) analysed nitrogen surplus on agricultural land for 2003 and nitrogen emissions into ground and surface waters in an area-differentiated manner, (2) quantified the future impact of agro-political measures and global economics for 2015 and its effect on nitrogen emissions (baseline scenario), (3) identified reduction targets to reach the goals of the WFD and (4) designed comprehensive measure packages including cost efficiency. In 2003, high nitrogen balances lead to nitrogen emissions of 91,000tyr−1, which were mainly realized via the pathways groundwater flow, tile drainages and point sources. In 2015 the baseline scenario shows a mean reduction of nitrogen balances of ∼10kgha−1yr−1. Consequently, nitrogen emissions into surface waters are predicted to drop to 75,700kgha−1yr−1 for the whole catchment, and sitespecific emissions will remain under 30kgha−1yr−1. However, despite this reduction, additional measures will be needed in order for agriculture to reach the targets for the good ground and surface water quality. Therefore, seven conventional agricultural measures were chosen based on a comprehensive literature research and expert opinions. Results show, that in 6% of the regions the targets are not attained by conventional measures. This interdisciplinary model network provides an appropriate tool for a sustainable river basin management for large scales.
We used the interdisciplinary model network REGFLUD to predict the actual mean nitrate concentration in percolation water at the scale of the Weser river basin (Germany) using an area--differentiated ...(100 m x 100 m) approach. REGFLUD combines the agro-economic model RAUMIS for estimating nitrogen surpluses and the hydrological models GROWA/DENUZ for assessing the nitrate leaching from the soil. The areas showing predicted nitrate concentrations in percolation water above the EU groundwater quality standard of 50 mg NO₃/l, have been identified as priority areas for implementing nitrogen reduction measures. For these “hot spot” areas a backward modelling approach was used to quantify the maximal permissible nitrogen surplus levels in agriculture to guarantee a mean long-term nitrate concentration in percolation water below 50 mg NO₃/l. Research work will directly support the implementation of the EU-Water Framework Directive in the Weser basin, e.g. by using the maximal permissible nitrogen surplus levels as a framework for the derivation of regionally adapted and hence effective nitrogen reduction measures.
Groundwater recharge rates calculated with the GROWA model have been applied as the recharge boundary condition for the regional groundwater model Rurscholle. This model simulates groundwater ...dynamics in the Pleistocene aquifers of the Lower Rhine lignite mining area (Germany). GROWA uses an area-differentiated approach to calculate recharge rates depending on runoff-relevant site characteristics, which are represented by a set of baseflow indices. The regional accuracy of the coupled groundwater and GROWA models has been checked using groundwater hydrographs as validation criteria. The results suggest that the current (unadjusted) version of GROWA underestimates the regional groundwater recharge rate by 10-20 mm/yr. The comparative analysis identified areas where recharge calculations could be improved by adjusting the baseflow indices for areas where runoff is dominated by slope, low water-logging and a low degree of sealing. Using the adjusted set of baseflow indices, the mean groundwater recharge rate of the Rurscholle region was modelled as approx. 170 mm/yr. This study highlights the benefit of using a coupled approach and being able to independently calibrate and validate groundwater recharge boundary conditions in regional groundwater models.
Digital spatial data always imply some kind of uncertainty. The source of this uncertainty can be found in their compilation as well as the conceptual design that causes a more or less exact ...abstraction of the real world, depending on the scale under consideration. Within the framework of hydrological modelling, in which numerous data sets from diverse sources of uneven quality are combined, the various uncertainties are accumulated. In this study, the GROWA model is taken as an example to examine the effects of different types of uncertainties on the calculated groundwater recharge. Distributed input errors are determined for the parameters' slope and aspect using a Monte Carlo approach. Landcover classification uncertainties are analysed by using the conditional probabilities of a remote sensing classification procedure. The uncertainties of data ensembles at different scales and study areas are discussed. The present uncertainty analysis showed that the Gaussian error propagation method is a useful technique for analysing the influence of input data on the simulated groundwater recharge. The uncertainties involved in the land use classification procedure and the digital elevation model can be significant in some parts of the study area. However, for the specific model used in this study it was shown that the precipitation uncertainties have the greatest impact on the total groundwater recharge error.
LEDs for energy efficient greenhouse lighting Singh, Devesh; Basu, Chandrajit; Meinhardt-Wollweber, Merve ...
Renewable & sustainable energy reviews,
September 2015, 2015-09-00, Letnik:
49
Journal Article
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Light energy is an important factor for plant growth. In regions where the natural light source (solar radiation) is not sufficient for growth optimization, additional light sources are being used. ...Traditional light sources such as high pressure sodium lamps and other metal halide lamps are not very efficient and generate high radiant heat. Therefore, new sustainable solutions should be developed for energy efficient greenhouse lighting. Recent developments in the field of light source technologies have opened up new perspectives for sustainable and highly efficient light sources in the form of LEDs (light-emitting diodes) for greenhouse lighting. This review focuses on the potential of LEDs to replace traditional light sources in the greenhouse. In a comparative economic analysis of traditional vs. LED lighting, we show that the introduction of LEDs allows reduction of the production cost of vegetables in the long-run (several years), due to the LEDs׳ high energy efficiency, low maintenance cost and longevity. In order to evaluate LEDs as an alternative to current lighting sources, species specific plant response to different wavelengths is discussed in a comparative study. However, more detailed scientific studies are necessary to understand the effect of different spectra (using LEDs) on plants physiology. Technical innovations are required to design and realize an energy efficient light source with a spectrum tailored for optimal plant growth in specific plant species.
O presente artigo foi descrito tendo como premissa compreender os conceitos acerca dos temas Coaching e Mentoring na gestão de carreira e sob o contexto empresarial. A pesquisa objetivou compreender ...a aplicabilidade da ferramenta GROW segundo as perspectivas de Vilhena (2014) no âmbito organizacional. A ferramenta GROW consiste em uma compreensão acerca de suas respectivas fases, caracterizadas como: Goals, Reality, Options e Will (WHITMORE, 2012). Tais fases são responsáveis por deliberar atitudes, competências e melhores desempenhos, direcionadas aos colaboradores. A pesquisa foi conduzida sob uma ótica exploratória, ampliando as compreensões acerca dos conceitos de coaching e mentoring no âmbito organizacional e delineada acerca da aplicação da ferramenta GROW (WHITMORE, 2012), sendo complementada pelas contribuições de Vilhena (2014). A utilização da ferramenta GROW pode ser caracterizada como a introdução de melhorias por meio da deliberação de posições, atitudes, competências e desempenhos perante os empregados, proporcionando melhorias para fins individuais ou melhorando o trabalho em equipe. A utilização da ferramenta GROW pode ser caracterizada como a introdução de melhorias deliberando posicionamentos, atitudes, competências e performances diante dos colaboradores, proporcionando melhorias para fins individuais ou aperfeiçoando o trabalho em equipes.
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