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• Recalls a pioneering industrial use and modelling of bifacial photovoltaic modules. • Presents a two-dimensional view factor model for large bifacial photovoltaic plants. • Rear irradiance non-uniformity based on experimental bifacial-module observations. • Rear irradiance average at three points are used to predict the rear energy yield. • Energy yield gain for two photovoltaic plants, varying height and row spacing. Open questions remain regarding the use of bifacial photovoltaic (PV) modules, such as how to link the energy-yield modelling of large bifacial PV plants with further on-site measurements campaigns, the effect of the non-uniformity of the rear irradiance, as well as the convenience of varying the geometry of the plants to enhance the bifacial contribution. A simplified two-dimensional view factor model for bifacial PV plants is presented in this paper, as well as a specific definition of performance ratio (PR) for this type of installations. This model has been implemented in SISIFO --an open simulation tool --for static structures and horizontal single-axis trackers. Yearly energy yield has been simulated for two representative static and tracker PV plants located in Madrid with an albedo of 0.3 and a bifacial power coefficient of 0.7, resulting in yield increases driven by rear irradiation of 8% and 7%, respectively. In general, the influence of varying structure height is lower than that of row-to-row spacing. The model also reveals a non-homogeneous rear irradiance. This question of non-uniformity of rear irradiance is analyzed in light of experimental 10-month observations in a 6.6 kWp PV system. The average of the rear irradiance observed at the center and at the two borders of the PV array is an adequate predictor for DC power estimations. A pioneering chapter of bifacial PV modules industrialization that took place between 1984 and 1989 in Spain, and probably the first application of view factor to model bifacial PV modules, are also presented. [ABSTRACT FROM AUTHOR]

Abstract: Demand response resources management is one of the most investigated solutions oriented to improve the efficiency in electricity markets. In this paper, the capability of customers to participate in short term markets is analyzed. An available methodology to analyze the daily and monthly energy consumptions of large customers is used to create energy offers and bids. This allows customers to participate in energy markets in order to buy, as first step, the usual electricity consumption and, additionally, to offer demand reductions in the short term electricity markets. Additionally, this paper shows the customer potential to participate in the Spanish electricity markets. [Copyright &y& Elsevier]

Abstract: This paper presents the implementation of the Barcelona Basic Model (BBM) into the TOUGH–FLAC simulator analyzing the geomechanical behavior of unsaturated soils. We implemented the BBM into TOUGH–FLAC by (1) extending an existing FLAC3D module for the Modified Cam-Clay (MCC) model in FLAC3D and (2) adding computational routines for suction-dependent strain and net stress (i.e., total stress minus gas pressure) for unsaturated soils. We implemented a thermo-elasto-plastic version of the BBM, wherein the soil strength depends on both suction and temperature. The implementation of the BBM into TOUGH–FLAC was verified and tested against several published numerical model simulations and laboratory experiments involving the coupled thermal–hydrological–mechanical (THM) behavior of unsaturated soils. The simulation tests included modeling the mechanical behavior of bentonite-sand mixtures, which are being considered as back-fill and buffer materials for geological disposal of spent nuclear fuel. We also tested and demonstrated the use of the BBM and TOUGH–FLAC for a problem involving the coupled THM processes within a bentonite-backfilled nuclear waste emplacement tunnel. The simulation results indicated complex geomechanical behavior of the bentonite backfill, including a nonuniform distribution of buffer porosity and density that could not be captured in an alternative, simplified, linear-elastic swelling model. As a result of the work presented in this paper, TOUGH–FLAC with BBM is now fully operational and ready to be applied to problems associated with nuclear waste disposal in bentonite-backfilled tunnels, as well as other scientific and engineering problems related to the mechanical behavior of unsaturated soils. [Copyright &y& Elsevier]

This paper details the design and implementation of a participatory modelling process in the Baixo Guadiana River Basin, in Portugal. A group of stakeholders was involved in a causal mapping exercise that lead to the development of a shared view of the problems, pressures and impacts characterizing the river basin. A simulation model was also developed to support experimentation with alternative management scenarios for the area. The paper looks critically at the evaluation of the participatory modelling outcomes, both at the individual and group levels, discussing the role of this approach in supporting the scoping stages of river basin planning and management processes. On the downside, the unstable group composition seems to have hindered the chances of producing a higher impact in the functioning of the group, and subsequently the capacity to sustain the level of collaboration required to achieve the strategic river basin objectives established during the participatory modelling process. The paper discusses the issue of group stability as well as some options to overcome the limitations of unstable participant groups. The strengths of participatory modelling, as underlined by the Baixo Guadiana experience, include the flexibility to adapt the method to different contexts and participatory designs and the capacity to structure the active involvement of stakeholders, providing an open and shared language for collaborative policy design, fostering learning and knowledge integration. [Copyright &y& Elsevier]

• Evaluation of the most recent Spanish grid code requirements. • A new tool to speed up the commissioning of new solar PV power plants is presented. • The accuracy of the aggregated PV power plant dynamic model proposed is demonstrated. • The aggregated model is shown to be ten times faster than the detailed equivalent. • The aggregated solar PV power plant simulation model approved by the Spanish TSO. Renewable energy and, in particular, solar PV power, will play a crucial role in achieving net-zero emissions scenarios over the coming decades. Increasing the share of renewables in countries' energy mixes is therefore a major challenge that must be urgently addressed. Within this context, the present work proposes an innovative tool that may accelerate the commissioning process of new solar PV power plants, in the form of an aggregated simulation model to assess a power plant's responses under the technical requirements established in the Spanish grid code. Our analyses, based on the comparison of the proposed model with a detailed model -both representing the same installation, show, from a quantitative and qualitative viewpoint, the accuracy and usefulness of the dynamic simulation model proposed. The aggregated model is shown to be ten times faster than the detailed equivalent, while the errors encountered in the simulation responses of both models are below 0.1% in all cases. It must also be noted that the present paper has allowed for the introduction, in the most recent version of the Spanish grid code and following approval of the Spanish Transmission System Operator (TSO), Red Eléctrica de España (REE), of this new and advantageous PV power plant model. Finally, it is worth mentioning that this study could form the basis for encouraging other countries to also adopt this model in their grid codes as a new tool to help integrate PV power into power grids. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The assessment of the technical impact of photovoltaic-distributed generation (PV-DG) units on radial distribution systems (RDSs) is complex because of the probabilistic nature of their output power and the diversity of potential sites where they can be installed. This type of evaluation thus requires a multivariate probabilistic analysis involving non-Gaussian correlated random variables. In a previous study, we applied an analytical technique to assess this technical impact for a single 10-min period. In the research presented in this paper, this technique was improved so that it could be applied during a full year, assuming 10-min intervals for PV and load profiles. This is the time period required to accurately assess the effects of stochastic PV inputs, and to determine the improvement of power quality (PQ) parameters, based on current regulations. This article describes a case study for a rural RDS located in the region of Andalusia in the south of Spain with spatially correlated PV-DG units. Our objective was to improve the analytical technique and also the accuracy of probabilistic methods. In our opinion, this can enhance the operation and planning of PV-DG in RDSs and provides a better understanding of the effects of spatial PV dependence structures. [Copyright &y& Elsevier]

Abstract: The use of intelligent optimization systems has been a major topic of research in the last few years for improving the existing urban infrastructure, the traffic optimization and the mobility of citizens. These techniques are of great importance in the analysis and optimization of transportation networks, as well as their re-organization to improve users’ mobility. In this paper we focus on the reconfiguration of one-way roads in a city after the occurrence of a major problem (e.g. a long-term road cut) in order to provide alternative routes that guarantee the mobility of citizens. In this manuscript a novel definition of this problem is formulated, for whose efficient resolution a novel two-objective approach based on the harmony search (HS) algorithm is proposed. The effectiveness of this proposal is tested in several synthetic instances, along with a real scenario in a city near Madrid, Spain. Extensive simulation results have been analyzed to verify that our proposal obtains excellent results in all the considered scenarios. [Copyright &y& Elsevier]

Abstract: Most worldwide fish stocks are overexploited, and so exploited beyond the Maximum Sustainable Yield (MSY) and the Maximum Economic Yield (MEY). Not exploiting fisheries resources at MSY or MEY leads to the loss of production and rents from the fisheries. A large part of the EU fisheries are managed based on single species stock assessments; however, in reality, most species are caught together with other species and by different fleets. In multi-species and multi-fleet fisheries, single species assessments, and consequently MSY and MEY reference points, are often not valid, and so the catch recommendations. In this paper it is investigated the MSY and MEY estimation in multi-species and multi-fleet fisheries in comparison to single species assessments. Analyses are applied to the Bay of Biscay demersal fishery using the IAM bio-economic model. The impact of exploiting at MSY and MEY on the optimal effort allocation between fleets with different exploitation patterns and economic structures is analyzed. When accounting for the multi-species nature of the fishery, MSY landings are 0.4% to 2.7% lower than the single species simulations estimates. When accounting for the multi-fleet nature of the fishery, MSY landings are 27.2% to 30.2% higher than the single-fleet estimates. When considering the multi-fleet characteristics, MEY landings are 6.6% higher and profits are 66.5% higher than in the single-fleet simulation. Optimal effort at MEY is lower than at MSY, but when accounting for multi-fleet the optimal effort decreases for some fleets while increases for gillnetters. The results also provide an estimation of the profits at MEY (or costs of not being at MEY). Profits can be then up to 10.7 times larger than the current profits (256 million Euros compared to the current 24 million Euros). [Copyright &y& Elsevier]

Abstract: Issues concerning the use of baby carriages in public buses are still pendant of international legislation that could contribute to unify provisions around accessibility and safety on this type of transportation. There is actually a lack of knowledge around the dynamic behavior and forces involved in the movement of baby carriages when on board in public transportation services. This paper focuses on an analysis of the forces transmitted to the baby carriages and their behavior during normal operation and critical maneuvers by public buses. The article presents partially the results obtained from a research project conducted by the Institute of Design and Manufacturing (IDF) of the Universitat Politècnica de València (Spain) in cooperation with the Institute for Automobile Research (INSIA) of the Universidad Politécnica de Madrid (Spain). The aim was to establish the technical requirements for accessibility and safety of baby carriages (US) or prams (UK) in public buses that could help national and international community to develop standards and provisions on this type of people mobility. A series of tests with different types of baby carriages were carried out in public transportation buses in closed tracks and open roads to simulate the behavior of critical maneuvers in urban traffic. From an analysis of the testing results it was possible to identify situations where restraint systems should be used, as well as the safest orientation and location within a bus for baby carriages, and enabled the development of a ‘Code of Good Practice’ for bus operators, users, and baby carriage manufacturers. Furthermore, the analysis of the dynamic forces allowed the development of a new restraint device for securing carriages inside the vehicle’s passenger compartment. [Copyright &y& Elsevier]

Abstract: This paper describes the calibration (year 2005) and validation (year 2003) processes for the simulation of an onion crop (Himalaya cultivar) in a two-year field test under deficit irrigation conditions in Castilla-La Mancha (Spain) using the MOPECO model. Results show that MOPECO is suitable for simulating the yield versus total water use under the climatic and soil conditions in this study (RMSE=7462kgha−1, and relative error=10.1%, between observed and simulated yields). Growing-degree-days (GDD) for the whole growth cycle is around 2283.4°C, while the crop coefficient (K c: 0.65, 1.20, and 0.75) and calibrated crop yield response (K y: 0.45, 0.8, and 0.2) values for the growth stages proposed by FAO are similar to those presented in the literature. The electrical conductivity of the irrigation water in the area (0.85dSm−1) can be neglected when simulating the yield response of onion to water (over-estimations up to 7% without considering the effect of salinity). Under the current harvest sale price scenarios (0.12€kg−1 if onions are sold after harvest and up to 0.20€kg−1 if onions are stored to sell at a higher price later), this crop is one of the most profitable in the area, reaching a gross margin between 1750 and 2620€ha−1, respectively, for an average yield (70,000kgha−1). Even though optimized regulated deficit irrigation (ORDI) may slightly increase yield by 3–7%, the gross margin may significantly raise up to 30% compared with an irrigation strategy where the stress levels remain constant during the whole growth cycle. Hence, for medium and high water deficit conditions it is of interest to guarantee nascence and to favor the bulb formation stage as much as possible. For low and medium-low water deficit scenarios, nascence and establishment are guaranteed, and the model assigns more water to vegetative development than to ripening. [Copyright &y& Elsevier]

Abstract: This paper presents the results of the acoustic simulation of the Manuel de Falla Auditorium (MFA), Granada, Spain, carried out in CATT-Acoustic and CATT–TUCT. The 3D geometrical acoustic model created for this purpose is tuned by adjusting the absorption and scattering coefficients of the convex reflector ceiling of the auditorium through an iterative process aimed at rendering differences between simulated and measured values for reverberation time in each octave frequency band lower than 5%. The model is validated by comparing simulated and measured figures for the most significant monaural and binaural room acoustic parameters assessed at multiple locations both on the stage and within the audience areas, then by performing both spectral and spatial analyses of their behaviour, and ultimately studying dissimilarities between the two sets of data in terms of just noticeable difference (JND). The influence of the degree of detail of the geometric model on the outcome is also considered by incorporating the 44 iconic lamps specifically designed for this enclosure, into the model. Likewise, the acoustic effect of an already executed seating replacement in the performance space is analyzed in relation to the degree of occupancy of the room. The simulated results confirm the appropriateness of the choice of the new seating for the refurbishment of the concert hall. [Copyright &y& Elsevier]

Abstract: Urban growth models developed in the second half of the 20th century have allowed for a better understanding of the dynamics of urban growth. Among these models, cellular automata (CA) have become particularly relevant because of their ability to reproduce complex spatial and temporal dynamics at a global scale using local and simple rules. In the last three decades, many urban CA models that proved useful in the simulation of urban growth in large cities have been implemented. This paper analyzes the ability of some of the main urban CA models to simulate growth in a study area with different characteristics from those in which these models have been commonly applied, such as slow and low urban growth. The comparison of simulation results has allowed us to analyze the strengths and weaknesses of each model and to identify the models that are best suited to the characteristics of the study area. Results suggest that models which simulate several land uses can capture better land use dynamics in the study area but need more objective and reliable calibration methods. [Copyright &y& Elsevier]

Abstract: A wide variety of flood simulation models are available nowadays. Some of them use a 1D approach and others a 2D one, but there are also some which allow the performance of integrated 1D–2D simulations. These latter models, which have important advantages in optimizing computational costs, commonly use the 1D approach in river channels and the 2D one in floodplains. The coupling of 1D and 2D flows usually ensures mass conservation and makes use of simplified weir-type or friction slope equations, but neglects momentum transfer between the two domains. This paper presents a fully conservative method for the coupling of 1D and 2D domains to be used in numerical schemes based on finite volumes. The method, based on a discretization of the numerical fluxes which ensures the conservation of mass and momentum, is verified with simple test cases. The proposed scheme is compared with the standard method based on the source term of the equations and is applied to the hydrodynamic characterization of a river-reservoir system situated in the River Ebro in Spain. [Copyright &y& Elsevier]

Abstract: Energy consumption in buildings accounts for a significant percentage of total world energy utilization. Great efforts have been made in order to reduce fossil energy consumption and mitigate its depletion by means of energy efficiency directives. The national transposition of such directives generates regional regulations that might be counterproductive if it is not clear which one is more restrictive. The main goal of this paper is to evaluate the potential of energetic savings of the dwellings in Catalonia and its economic impact, according to different scenarios of efficiency that have been defined according to current regulations at state and autonomic level. To achieve this objective, thirteen typologies of dwellings have been defined in order to categorize the stock of buildings in Catalonia. Simulations with LIDER software have been carried out in order to obtain the heating and cooling demand for each typology of dwelling in different climatic zones and orientations. The economic impact of each scenario has been stated as well. We show that the best normative scenario is not the regional but the national one, and only when full limitations imposed by the state regulations are fulfilled. Following the latter 6.4% reduction in CO2 emissions would be achieved, whereas following the former gives us only 2.8% reduction for year 2015. These results have been obtained considering a base case scenario without any energetic measures implemented for the same time line. [Copyright &y& Elsevier]

Abstract: This paper presents and tests a method to design high-performance transit networks. The method produces conceptual plans for geometric idealizations of a particular city that are later adapted to the real conditions. These conceptual plans are generalizations of the hybrid network concept proposed in . The best plan for a specific application is chosen via optimization. The objective function is composed of analytic formulae for a concept’s agency cost and user level of service. These formulae include as parameters key demand-side attributes of the city, assumed to be rectangular, and supply-side attributes of the transit technology. They also include as decision variables the system’s line and stop spacings, the degree to which it focuses passenger trips on the city center, and the service headway. These decision variables are sufficient to define an idealized geometric layout of the system and an operating plan. This layout-operating plan is then used as a design target when developing the real, detailed master plan. Ultimately, the latter is simulated to obtain more accurate cost and level of service estimates. This process has been applied to design a high performance bus (HPB) network for Barcelona (Spain). The idealized solution for Barcelona includes 182km of one-way infrastructure, uses 250 vehicles and costs 42,489€/h to build and run. These figures only amount to about one third of the agency resources and cost currently used to provide bus service. A detailed design that resembles this target and conforms to the peculiarities of the city is also presented and simulated. The agency cost and user level of service metrics of the simulated system differ from those of the idealized model by less than 10%. Although the designed and simulated HPB systems provide sub-optimal spatial coverage because Barcelona lacks suitable streets, the level of service is good. Simulations suggest that if the proposed system was implemented side-by-side with the current one, it would capture most of the demand. [Copyright &y& Elsevier]

Abstract: This paper describes a simulation model that reproduces the performance of parabolic trough solar thermal power plants with a thermal storage system. The aim of this model is to facilitate the prediction of the electricity output of these plants during the various stages of their planning, design, construction and operation. Model results for a 50MWe power plant are presented and compared to real data from an equivalent power plant currently operated by the ACS Industrial Group in Spain. [Copyright &y& Elsevier]

Abstract: This paper focuses on the validation of a dynamic simulation model used to describe the performance of an existing solar cooling installation located in Zaragoza (Spain). The dynamic model has been developed under the simulation environment TRNSYS. The aim of this simulation model is to dispose of a tool in order to use it to evaluate different energy improvement actions in a real solar cooling installation. This solar cooling installation has been monitored and analyzed since 2007. The COP of this experimental solar cooling system presents a great influence from its heat rejection sink, a dry cooling tower. Once the model was validated with the experimental data obtained from the real installation, it was used to predict the chiller performance with a new geothermal sink, which started to operate in 2009. The present work describes the design and validation model process, as well as the comparison between the model results and the monitoring ones with the geothermal heat rejection system. [Copyright &y& Elsevier]

Abstract: Energy supply concepts for zero energy residential building (ZERB) in Shanghai (humid) and Madrid (dry) are discussed in this paper. Simulation is employed as the main research method. Two typical housing models are designed according to the real occupancy condition, the life schedule, the thermostats settings, etc., for the two cities. An energy analysis considering the annual balance of input from the grid and output from renewable power systems is made. Indoor comfortable comparisons between the two models are presented to show optimal design strategies for HVAC under different weather conditions. Also performed is the analysis on the primary energy payback time and the CO2 equivalent saving in order to evaluate the performance of novel energy systems to verify the feasibility. [Copyright &y& Elsevier]

Abstract: This short communication paper presents recommendations for developing scale-appropriate monitoring and modelling strategies to assist decision making in natural resource management (NRM). These ideas presented here were discussed in the session (S5) ‘Monitoring strategies and scale-appropriate hydrologic and biogeochemical modelling for natural resource management’ session at the 2008 International Environmental Modelling and Simulation Society conference, Barcelona, Spain. The outcomes of the session and recent international studies exemplify the need for a stronger collaboration and communication between researcher and model developer on the one side, and natural resource managers and the model users on the other side to increase knowledge in: 1) the limitations and uncertainties of current monitoring and modelling strategies, 2) scale-dependent linkages between monitoring and modelling techniques, and 3) representation of hydrologic and biogeochemical phenomena in model development and practical application for natural resource management. [ABSTRACT FROM AUTHOR]

Abstract: Over the last few years electronic commerce, e-commerce for short, has become one of the most accepted purchasing systems this having became the easiest way of accessing a large variety of goods. E-commerce provides: the possibility of comparing costs and bids without going to outlets and therefore, saving time and money; the availability of detailed characteristics of goods; the possibility of acquiring new goods available abroad. Moreover, the form of payments are getting progressively safer and more reliable on the Internet. In this paper we develop a mathematical model to study future short-term trends of e-commerce in Spain. To do this, we divide the total population into age groups and each age group into two subgroups: the first one consists of people adopting this technology and the second one who do not. Then, we consider a nonlinear diffusion model whose parameters are the innovation coefficients associated with each age group and related to advertising, and the imitation coefficients related to the influence of an adopting technology group on non-adopting group. These parameters are estimated by fitting the available real data from the Spanish Statistic Institute. Finally, an analysis of statistic sensitivity is included. [ABSTRACT FROM AUTHOR]

Abstract: Live fuel moisture content (FMC) is a key factor required to evaluate fire risk and its operative and accurate estimation is essential for allocating pre-fire resources as a part of fire prevention. This paper presents an operative and accurate procedure to estimate FMC though MODIS (moderate resolution imaging spectrometer) data and simulation models. The new aspects of the method are its consideration of several ecological criteria to parameterize the models and consistently avoid simulating unrealistic spectra which might produce indetermination (ill-posed) problems when inverting the model. The methodology was operatively applicable to 12 shrubland plots located in different provinces of the Mediterranean region of Spain and tested with field data collected in those areas. The results showed that the proposed method efficiently tracks changes of FMC with average errors around 15%. However the model under-estimates FMC values higher than 135.68% since those situations were not included in the simulation scheme and the inversion precision is also dependent on an accurate estimation of LAI. These limitations will be overcome in future work mainly by including spectral signatures of vegetation with FMC values higher than 135.68% in the simulations, and by exploring new methods for LAI retrieval. Further efforts will also be devoted to extend this approach to other ecosystems. [Copyright &y& Elsevier]

Abstract: DAHAN, the pioneer 1MWe CRS (central receiver system) funded by Ministry of Sciences and Technology (MOST), which can be regarded as the milestone in solar thermal power development in China, is now under construction at the foot of The Great Wall nearby Beijing. The major objective of the design and construction of DAHAN is to demonstrate the operation of CRS in China. A software tool HFLD is developed for heliostat field layout design and performance calculation. The simulation results from HFLD approximately agree very well with the published heliostat field efficiency data from Spain PS10. Based on that, the heliostat field layout of DAHAN is designed using HFLD and the whole CRS performance is simulated in the TRNSYS plant model. The modeling and simulation of this plant is presented in this paper. [Copyright &y& Elsevier]

Abstract: This paper presents an application of probabilistic methodologies to evaluate the reserve requirements of generating systems with a large penetration of renewable energy sources. The idea is to investigate the behavior of reliability indices, including those from the well-being analysis, when the major portion of the renewable sources comes from wind power and other intermittent sources. A new simulation process to address operating reserve adequacy is introduced, and the correspondent reliability indices are observed. Case studies on the Portuguese and Spanish generating systems are presented and discussed. [Copyright &y& Elsevier]

Abstract: In this paper, we study the dynamics of the transmission of respiratory syncytial virus (RSV) in the population using stochastic models. The stochastic models are developed introducing stochastic perturbations on the demographic parameter as well as on the transmission rate of the RSV. Numerical simulations of the deterministic and stochastic models are performed in order to understand the effect of fluctuating birth rate and transmission rate of the RSV on the population dynamics. The numerical solutions of stochastic models are calculated using Euler-Maruyama and Milstein schemes, and confidence intervals for stochastic solutions are given using Monte-Carlo method. Analysis of the numerical results reveals that perturbations on the transmission rate are more decisive in the dynamics of RSV than perturbations on demographic parameters. In addition, the stochastic models show the advantage of reproducing more effectively the noisy RSV hospitalization data. It is concluded that these stochastic models are a viable option to provide a realistic modeling of the RSV dynamics on the population. [Copyright &y& Elsevier]

Abstract: Distributed crop simulation models are typically confronted with considerable uncertainty in weather variables. In this paper the use of MeteoSat-derived meteorological products to replace weather variables interpolated from weather stations (temperature, reference evapotranspiration and radiation) is explored. Simulations for winter-wheat were carried for Spain, Poland and Belgium using both interpolated and MeteoSat-derived weather variables. The results were spatially aggregated to national and regional level and were evaluated by comparing the simulation results of both approaches and by assessing the relationships with crop yield statistics over the periods 1995–2003 from EUROSTAT. The results indicate that potential crop yield can be simulated well using MeteoSat-derived meteorological variables, but that water-stress hardly occurs in the water-limited simulations. This is caused by a difference in reference evapotranspiration which was 20–30% smaller in case of MeteoSat. As a result, the simulations using MeteoSat-derived meteorological variables performed considerably poorer in a regression analyses with crop yield statistics on national and regional level. Our results indicate that a recalibration of the model parameters is necessary before the MeteoSat-derived meteorological variables can be used operationally in the system. [Copyright &y& Elsevier]

Abstract: Transportation, energy and environmental tax reforms represent an ongoing debate in contemporary policy. The main aim of this paper is to shed some light on this debate using micro-simulation tools to analyse consumer response and welfare effects of environmental policy consisting of an increment of the indirect taxes on fuels to finance the elimination of VAT on the public means of transport. In order to do so, we first estimate an Almost Ideal Demand System for 16 different groups of goods in the Spanish economy, for the purpose of evaluating expenditure and price elasticities. Using this information, we then micro-simulate the abolition of VAT on public transport services and a simultaneous increment on fuel taxes, so that total revenue remains unchanged. The welfare effects of this revenue-neutral tax reform are evaluated. The aim of this simulation is to define a public policy that increases public transportation availability and use in order to bring about decreases in pollution and congestion. [Copyright &y& Elsevier]

Population models have played a chief role informing management decisions for the endangered Bonelli’s eagle (Aquila fasciata) in Spain. In this paper, we incorporate spatial structure and stochasticity in the construction of individual-based metapopulation models, and use these models to explore the effects of possible management actions on the persistence of the species in Spain. To build the models we used data on seven sub-populations that have experienced different trends in the last decades, and we introduced new estimates of pre-adult survival rate. The elasticity analysis of our models showed that when the interchange of individuals among sub-populations is taken into account, pre-adult mortality plays the key role in determining the overall population trend. This is in contrast to what it has been suggested by previous demographic models that modelled local populations as isolated. Specifically, a 20% decrease in pre-adult mortality during the first two years of life was enough for the stabilization of the metapopulation (i.e., λ ⩾1.0). However, neither a similar decrease in the values of adult mortality, nor an increase in the percentage of breeders, modified the declining trend of our model metapopulation. This reinforces the idea that to ensure the long-term persistence of the species in Spain, management actions should aim at minimizing pre-adult mortality. These include locating and protecting the areas used by juvenile Bonelli’s eagles (e.g., temporary settlements), minimizing the risk of electrocution in power lines, and preventing human persecution. [Copyright &y& Elsevier]

Modelling species distributions with presence data from atlases, museum collections and databases is challenging. In this paper, we compare seven procedures to generate pseudo-absence data, which in turn are used to generate GLM-logistic regressed models when reliable absence data are not available. We use pseudo-absences selected randomly or by means of presence-only methods (ENFA and MDE) to model the distribution of a threatened endemic Iberian moth species (Graellsia isabelae). The results show that the pseudo-absence selection method greatly influences the percentage of explained variability, the scores of the accuracy measures and, most importantly, the degree of constraint in the distribution estimated. As we extract pseudo-absences from environmental regions further from the optimum established by presence data, the models generated obtain better accuracy scores, and over-prediction increases. When variables other than environmental ones influence the distribution of the species (i.e., non-equilibrium state) and precise information on absences is non-existent, the random selection of pseudo-absences or their selection from environmental localities similar to those of species presence data generates the most constrained predictive distribution maps, because pseudo-absences can be located within environmentally suitable areas. This study shows that if we do not have reliable absence data, the method of pseudo-absence selection strongly conditions the obtained model, generating different model predictions in the gradient between potential and realized distributions. [Copyright &y& Elsevier]

Burn severity is a key factor in post-fire assessment and its estimation is traditionally restricted to field work and empirical fitting from remotely sensed data. However, the first method is limited in terms of spatial coverage and cost effectiveness and the second is site-and data-specific. Since alternative approaches based on radiative transfer models (RTM) have been usefully applied in retrieving several biophysical plant parameters (leaf area index, water and dry matter content, chlorophyll), this paper has applied the inversion of a simulation model to estimate burn severity in terms of the Composite Burn Index (CBI). The performance of the model inversion method was compared to standard empirical techniques. The study area chosen was a large forest fire in central Spain which occurred in July 2005. The model inversion showed the most accurate estimation for high severity levels (for CBI>2.7, RMSE=0.30) and for unburned areas (CBI<0.5, RMSE=0). In both methodologies, the error associated to CBI from 0.5 to 2.7 was not acceptable (RMSE>0.7), because it is higher than 25% of the total range of the index. Finally, burn severity maps from both methods were compared. [Copyright &y& Elsevier]

Abstract: The Port of Seville is an inland port located in the Guadalquivir River in the south of Spain and it is the unique Spanish inland port. Our research is focused on the simulation of the freight transport process beginning with the movement through the whole estuary of the river and finishing with the vessels arriving to the port dependencies, where the logistic operators’ load and unload processes take place. The simulation presented in the paper is carried out with Arena software and considers all the types of cargo existing in the Seville Port: containers, cereals, cements, scrap, iron and steel and fertilizers. We have simulated the navigation through the Guadalquivir estuary, the lock, the basins and the docks of the port, as well as the logistic activities in the berths. After testing several scenarios, we can state that the facilities of the Port of Seville allow to deal with the incoming logistic flows, except for momentary difficulties in the container traffic. So the improvement measures for the logistic activity must come from other alternative key actions. [Copyright &y& Elsevier]

Abstract: Several methods for sizing stand alone photovoltaic (pv) systems has been developed. The more simplistic are called intuitive methods. They are a useful tool for a first approach in sizing stand alone photovoltaic systems. Nevertheless they are very inaccurate. Analytical methods use equations to describe the pv system size as a function of reliability. These ones are more accurate than the previous ones but they are also not accurate enough for sizing of high reliability. In a third group there are methods which use system simulations. These ones are called numerical methods. Many of the analytical methods employ the concept of reliability of the system or the complementary term: loss of load probability (LOLP). In this paper an improvement for obtaining LOLP curves based on the neural network called Multilayer Perceptron (MLP) is presented. A unique MLP for many locations of Spain has been trained and after the training, the MLP is able to generate LOLP curves for any value and location. [Copyright &y& Elsevier]

Agrometeorological crop simulation models are used increasingly in spatial applications like regional crop monitoring and yield forecasting. The spatial application of these models involves gathering spatially representative values of meteorological input variables (temperature, radiation and precipitation). This is usually accomplished by interpolating meteorological variables measured at point locations. This paper explores the use of advanced very high resolution radiometer (AVHRR)-derived surface temperature as a replacement for interpolated maximum air temperature in a spatial crop monitoring and yield forecasting system.A 2-year set of daily National Oceanic And Atmospheric Administration (NOAA)–AVHRR images over western Europe was used to derive estimates of daily surface temperature aggregated over 50 km × 50 km gridcells, a land cover database was used to select only pixels that were classified as ‘arable land’. On days that did not yield data due to cloud cover, the monthly average surface temperature was substituted.The AVHRR-derived surface temperature is usually higher than the maximum air temperature measured at a weather station. To account for this difference, an empirical model was used that relates surface temperature to maximum air temperature. The model parameters were obtained using calibration with the maximum air temperature measured at five weather stations. Next, it was applied to the entire AVHRR data set in order to convert AVHRR surface temperature into a simulated maximum air temperature. Finally, a case study was carried out by using the WOrld FOod Studies (WOFOST) crop model to simulate growth of winter-wheat and sunflower for Spain using both the simulated maximum air temperature and the interpolated maximum air temperature from weather stations.Our results demonstrate that the spatial patterns of the yearly temperature sums over Spain are similar for both sources of temperature. Therefore, it can be concluded that the AVHRR-derived temperature can be used to obtain realistic spatial patterns of the yearly temperature sums. Nevertheless, the AVHRR-derived temperature sums are too large, particularly in the southern parts of Spain. As the model that was applied to correct for the difference between surface temperature and maximum air temperature does not fully correct for this difference in the southern parts of Spain.The effects on the simulation of winter-wheat and sunflower are predictable. For both crops the overestimation of the temperature sums causes a shortening of the growing season and consequently a lower accumulation of biomass at the end of the season. This effect is more pronounced for sunflower because this crop is grown later in the crop growing season.It was demonstrated that AVHRR-derived surface temperature has good potential for use in regional agrometeorological systems but more attention should be paid to the correction of AVHRR-derived surface temperature to maximum air temperature. For example, by applying the correction for the different climatic regions instead of one correction for the entire study area. [Copyright &y& Elsevier]