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Publication Open Access Accuracy of methods for field assessment of rill and ephemeral gully erosion(Elsevier, 2006) Casalí Sarasíbar, Javier; Loizu Maeztu, Javier; Campo-Bescós, Miguel; Santisteban Comino, Luisa María de; Álvarez Mozos, Jesús; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakTo properly assess soil erosion in agricultural areas, it is necessary to determine precisely the volume of ephemeral gullies and rills in the field by using direct measurement procedures. However, little information is available on the accuracy of the different methods used. The main purpose of this paper is to provide information for a suitable assessment of rill and ephemeral gully erosion with such direct measurement methods. To achieve this objective: a) the measurement errors associated to three methods used for field assessment of channel cross sectional areas are explored; b) the influence of the number of cross sections used per unit channel length on the assessment accuracy, is analysed and; c) the effect of the channel size and shape on measurement errors is examined. The three methods considered to determine the cross sectional areas were: micro-topographic profile meter (1); detailed measurement of section characteristic lengths with a tape (2); measurement of cross section width and depth with a tape (3). Five reaches of different ephemeral gully types 14.0 or 30.0 m long and a set of six 20.4 to 29.4 m long rill reaches were selected. On each gully reach, the cross sectional areas were measured using the three above mentioned methods, with a separation (s) between cross sections of 1 m. For rills, the cross sectional areas were measured with methods 1 and 3, with s= 2 m. Then, the corresponding total erosion volumes were computed. The volume calculated with method 1 with s= 1 m for gullies and s= 2 m for rills was taken as the reference method. For each channel, and for each one of the possible combinations of s and measurement method (m), the relative measurement error and the absolute value of the relative measurement error (Ersm and |Ersm| ), defined with respect to the reference one, was calculated. |Ersm| much higher than 10% were obtained very easily, even for small s values and for apparently quasi prismatic channels. Channel size and shape had a great influence on measurement errors. In fact, the selection of the more suitable method for a certain gully shape and size seemed to be much more important than s, at least when s< 10 m. Method 1 always provided the most precise measurements, and its results were the less dependent on s. However, s must be <5 m to guarantee an error smaller than 10%. Method 2 is not recommended, because it is difficult, time consuming and can lead to large errors. Method 3 seems to be enough for small, wide and shallow gullies, and for small rills, but only if s is shorter than 5 m. Results obtained after the analysis of rill measurement errors were similar to those of gullies. The analysis of Ersm and |Ersm| when calculating channel volumes using a unique representative cross section highlighted the importance of correctly selecting the adequate cross section. Due to the high error values that this method can entail, it is not considered as advisable whenever accurate erosion measurements are pursued.Publication Open Access The added value of stratified topographic correction of multispectral images(MDPI, 2016) Sola Torralba, Ion; González de Audícana Amenábar, María; Álvarez Mozos, Jesús; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaSatellite images in mountainous areas are strongly affected by topography. Different studies demonstrated that the results of semi-empirical topographic correction algorithms improved when a stratification of land covers was carried out first. However, differences in the stratification strategies proposed and also in the evaluation of the results obtained make it unclear how to implement them. The objective of this study was to compare different stratification strategies with a non-stratified approach using several evaluation criteria. For that purpose, Statistic-Empirical and Sun-Canopy-Sensor + C algorithms were applied and six different stratification approaches, based on vegetation indices and land cover maps, were implemented and compared with the non-stratified traditional option. Overall, this study demonstrates that for this particular case study the six stratification approaches can give results similar to applying a traditional topographic correction with no previous stratification. Therefore, the non-stratified correction approach could potentially aid in removing the topographic effect, because it does not require any ancillary information and it is easier to implement in automatic image processing chains. The findings also suggest that the Statistic-Empirical method performs slightly better than the Sun-Canopy-Sensor + C correction, regardless of the stratification approach. In any case, further research is necessary to evaluate other stratification strategies and confirm these results.Publication Open Access Assessing hillslope-channel connectivity in an agricultural catchment using rare-earth oxide tracers and random forests models(Universidad de la Rioja, 2017) Masselink, Rens Hein; Temme, A.J.A.M.; Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Keesstra, Saskia D.; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Institute on Innovation and Sustainable Development in Food Chain - ISFOODSoil erosion from agricultural areas is a large problem because of off-site effects like the rapid filling of reservoirs. To mitigate the problem of sediments from agricultural areas reaching the channel, reservoirs and other surface areas it is important to understand hillslope-channel connectivity and catchment connectivity. To determine the functioning of hillslope-channel connectivity and the continuation of transport of these sediments in the channel, it is necessary to obtain data on sediment transport from the hillslopes to the channels. Simultaneously, the factors that influence sediment export out of the catchment need to be studied. For measuring hillslope-channel sediment connectivity, rare-earth oxide (REO) tracers were applied to a hillslope in an agricultural catchment in Navarre, Spain, preceding the winter of 2014-2015. The results showed that during the winter no sediment transport from the hillslope to the channel was detected. To test the implication of the REO results at the catchment scale, two contrasting conceptual models for sediment connectivity were assessed using a random forest (RF) machine learning method. The RF method was applied using a 15-year period of measured sediment output at the catchment scale. One model proposes that small events provide sediment for large events, while the other proposes that only large events cause sediment detachment and small events subsequently remove these sediments from near and in the channel. For sediment yield prediction of small events, variables related to large preceding events were the most important. The model for large events underperformed and, therefore, we could not draw any immediate conclusions whether small events influence the amount of sediment exported during large events. Both REO tracers and RF method showed that low intensity events do not contribute any sediments from the hillslopes to the channel in Latxaga catchment. Sediment dynamics are dominated by sediment mobilization during large (high intensity) events. Sediments are for a large part exported during those events, but the system shows a memory of the occurrence of these large events, suggesting that large amounts of sediments are deposited in and near the channel after these events. These sediments are gradually removed by small events. To better understand the delivery if sediments to the channel and how large and small events influence each other, more field data on hillslope-channel connectivity and within-channel sediment dynamics is necessary.Publication Open Access Assessing soil properties controlling interrill erosion: an empirical approach under Mediterranean conditions(Wiley, 2017) Ollobarren del Barrio, Paul; Giménez Díaz, Rafael; Campo-Bescós, Miguel; Landa Ingeniaritza eta Proiektuak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Proyectos e Ingeniería Rural; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaSoil erodibility is a complex phenomenon that comprises a number of different soil properties. However, most current (empirical) erodibility indices are based on only a few soil properties. A feasible soil characterization of interrill erosion (IE) prediction at large scale should be based on simple, quick and inexpensive tests to perform. The objective of this work was to identify and assess those soil properties that best reflect soil vulnerability to IE. Twenty‐three agricultural soil samples located in Spain and Italy were studied. Forty‐nine different physical and chemical soil properties that presumably underpin IE were defined. Experiments were carried out in the field (in microplots using simulated rainfall) and in the lab. The most relevant variables were detected using multivariate analysis. Six key variables were finally identified: RUSLE K factor, a granulometric/organic matter content index, exchangeable sodium percentage, shear strength, penetration resistance and permeability of soil seal. The latter is proposed as a useful technique to evaluate soil susceptibility to crusting even when the crust is not present at the time of the field survey. The selected variables represented a wide range of soil properties, and they could also be successfully applied to different soils with different characteristics than those evaluated in our experiments.Publication Open Access Assessment of soil factors controlling ephemeral gully erosion on agricultural fields(Wiley, 2017) Ollobarren del Barrio, Paul; Campo-Bescós, Miguel; Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Landa Ingeniaritza eta Proiektuak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Proyectos e Ingeniería Rural; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaThe soil factor is crucial in controlling and properly modeling the initiation and development of ephemeral gullies (EGs). Usually, EG initiation has been related to various soil properties (i.e. sealing, critical shear stress, moisture, texture, etc.); meanwhile, the total growth of each EG (erosion rate) has been linked with proper soil erodibility. But, despite the studies to determine the influence of soil erodibility on (ephemeral) gully erosion, a universal approach is still lacking. This is due to the complex relationship and interactions between soil properties and the erosive process. A feasible soil characterization of EG erosion prediction on a large scale should be based on simple, quick and inexpensive tests to perform. The objective of this study was to identify and assess the soil properties – easily and quickly to determine – which best reflect soil erodibility on EG erosion. Forty‐nine different physical–chemical soil properties that may participate in establishing soil erodibility were determined on agricultural soils affected by the formation of EGs in Spain and Italy. Experiments were conducted in the laboratory and in the field (in the vicinity of the erosion paths). Because of its importance in controlling EG erosion, five variables related to antecedent moisture prior to the event that generated the gullies and two properties related to landscape topography were obtained for each situation. The most relevant variables were detected using multivariate analysis. The results defined 13 key variables: water content before the initiation of EGs, organic matter content, cation exchange capacity, relative sealing index, two granulometric and organic matter indices, seal permeability, aggregates stability (three index), crust penetration resistance, shear strength and an erodibility index obtained from the Jet Test erosion apparatus. The latter is proposed as a useful technique to evaluate and predict soil loss caused by EG erosion.Publication Open Access Assessment of the adequacy of EN ISO 15927-4 reference years for photovoltaic systems(Wiley, 2015) García Ruiz, Ignacio; Torres Escribano, José Luis; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakThe long-term performance prediction of photovoltaic systems requires representative meteorological data from a particular location. Among the numerous proposals in the field of solar energy, most of them include procedures oriented towards the generation of test reference years (TRYs). These synthetic years are composed of the concatenation of 12 actual months of the time series of meteorological measurements. Using TRYs to simulate the performance of different types of solar energy systems reduces the computational effort of the simulation and simplifies the analysis of the results. In this sense, the technical standard EN ISO 15927-4 describes a procedure for constructing a reference year suitable for evaluation of the annual heating and cooling long-term needs in buildings. In this work, the adequacy of the EN ISO 15927-4 reference year for photovoltaic systems was studied. The electricity production obtained by simulation with this TRY was compared with that obtained by the Weather Year for Solar Systems. This latter reference year only uses the monthly thermal energy collected by the system as a selection parameter of typical months. This comparison was performed for seven locations in the USA considering two 5.6 kWp grid-connected photovoltaic systems that only differ in the solar tracking system. The suitability of the EN ISO 15927-4 reference year for the estimation of the electrical energy generated by a photovoltaic system has been proved, showing good results in the annual and daily predictions in most of the cases studied.Publication Open Access Automatic detection of uprooted orchards based on orthophoto texture analysis(MDPI, 2017) Ciriza Labiano, Raquel; Sola Torralba, Ion; Albizua, Lourdes; Álvarez Mozos, Jesús; González de Audícana Amenábar, María; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakPermanent crops, such as olive groves, vineyards and fruit trees, are important in European agriculture because of their spatial and economic relevance. Agricultural geographical databases (AGDBs) are commonly used by public bodies to gain knowledge of the extension covered by these crops and to manage related agricultural subsidies and inspections. However, the updating of these databases is mostly based on photointerpretation, and thus keeping this information up-to-date is very costly in terms of time and money. This paper describes a methodology for automatic detection of uprooted orchards (parcels where fruit trees have been eliminated) based on the textural classification of orthophotos with a spatial resolution of 0.25 m. The textural features used for this classification were derived from the grey level co-occurrence matrix (GLCM) and wavelet transform, and were selected through principal components (PCA) and separability analyses. Next, a Discriminant Analysis classification algorithm was used to detect uprooted orchards. Entropy, contrast and correlation were found to be the most informative textural features obtained from the co-occurrence matrix. The minimum and standard deviation in plane 3 were the selected features based on wavelet transform. The classification based on these features achieved a true positive rate (TPR) of over 80% and an accuracy (A) of over 88%. As a result, this methodology enabled reducing the number of fields to photointerpret by 60–85%, depending on the membership threshold value selected. The proposed approach could be easily adopted by different stakeholders and could increase significantly the efficiency of agricultural database updating tasks.Publication Open Access Ayer y hoy de la estela discoidea en Navarra(Gobierno de Navarra. Institución Príncipe de Viana, 1994) Ukar Muruzábal, Jesús; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakEl presente trabajo analiza y cataloga las estelas discoideales en Navarra.Publication Open Access Bean moisture diffusivity and drying kinetics: a comparison of the liquid diffusion model when taking into account and neglecting grain shrinkage(Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 2007) Resende, O.; Correa, P. C.; Jarén Ceballos, Carmen; Moure Gil, José; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Tecnología de Alimentos; Elikagaien TeknologiaEl objetivo de este trabajo fue ajustar el modelo de difusión líquida para predecir las pérdidas de volumen de grano en el secado de judía (Phaseolus vulgaris L.). Se recolectaron granos de judía con una humedad del 0,92 y se sometieron a un proceso de secado, bajo condiciones controladas, a diferentes temperaturas entre 25 y 55°C y humedades relativas entre 20 y 75%. El volumen de cada grano, considerado como una esfera, fue obtenido utilizando como diámetro el promedio de las tres diagonales principales durante el proceso del secado. Las pérdidas de volumen de grano se determinaron por la relación entre el contenido de agua inicial y final. A partir de los resultados obtenidos, se concluye que el modelo de difusión representa satisfactoriamente la cinética del secado de la judía, y que tiene en cuenta las pérdidas de volumen del grano. El coeficiente de difusión, con valores comprendidos entre 10,8 × 10(-10) y 67,0 × 10(-10) m(2) s(-1), aumenta con la temperatura. La variación del coeficiente de difusión con la temperatura puede ser descrita por la expresión de Arrhenius, con una energía de activación de 40,08 kJ mol(-1).Publication Open Access Beyond precipitation: physiographic gradients dictate the relative importance of environmental drivers on savanna vegetation(Public Library of Science, 2013) Campo-Bescós, Miguel; Muñoz Carpena, Rafael; Kaplan, David A.; Southworth, Jane; Zhu, Likai; Waylen, Peter; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakBackground: Understanding the drivers of large-scale vegetation change is critical to managing landscapes and key to predicting how projected climate and land use changes will affect regional vegetation patterns. This study aimed to improve our understanding of the role, magnitude and spatial distribution of the key environmental factors driving vegetation change in southern African savanna, and how they vary across physiographic gradients. Methodology/Principal Findings: We applied Dynamic Factor Analysis (DFA), a multivariate times series dimension reduction technique to ten years of monthly remote sensing data (MODIS-derived normalized difference vegetation index, NDVI) and a suite of environmental covariates: precipitation, mean and maximum temperature, soil moisture, relative humidity, fire and potential evapotranspiration. Monthly NDVI was described by cyclic seasonal variation with distinct spatiotemporal patterns in different physiographic regions. Results support existing work emphasizing the importance of precipitation, soil moisture and fire on NDVI, but also reveal overlooked effects of temperature and evapotranspiration, particularly in regions with higher mean annual precipitation. Critically, spatial distributions of the weights of environmental covariates point to a transition in the importance of precipitation and soil moisture (strongest in grass-dominated regions with precipitation,750 mm) to fire, potential evapotranspiration, and temperature (strongest in tree-dominated regions with precipitation.950 mm). Conclusions/Significance: We quantified the combined spatiotemporal effects of an available suite of environmental drivers on NDVI across a large and diverse savanna region. The analysis supports known drivers of savanna vegetation but also uncovers important roles of temperature and evapotranspiration. Results highlight the utility of applying the DFA approach to remote sensing products for regional analyses of landscape change in the context of global environmental change. With the dramatic increase in global change research, this methodology augurs well for further development and application of spatially explicit time series modeling to studies at the intersection of ecology and remote sensing.Publication Open Access Bulk optical of potato flesh in the 500 – 1900 nm range(Springer US, 2015) López Maestresalas, Ainara; Aernouts, Ben; Van Beers, Robbe; Arazuri Garín, Silvia; Jarén Ceballos, Carmen; Baerdemaeker, Josse de; Saeys, Wouter; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn this study, the optical properties of potato flesh tissue were estimated using double-integrating sphere (DIS) measurements combined with an inverse adding-doubling (IAD) light propagation model. Total reflectance, total transmittance, and unscattered transmittance were measured for the wavelength range 500– 1900 nm with 5-nm resolution. From these measurements, the bulk optical properties (absorption coefficient, scattering coefficient, and anisotropy factor) of 53 potato tubers of the Hermes cultivar were estimated. The estimated absorption coefficient spectra were dominated by water and starch absorption bands, the main chemical components of potato tissue. Comparison of these values to those reported in literature for similar products showed comparable absorption profiles. The obtained scattering coefficient spectra showed a smooth decrease from 166 to 160 cm−1 in the near-infrared (NIR) spectral range with increasing wavelength, which is common for biological tissues. The anisotropy factor spectra obtained for the full wavelength range studied ranged between 0.949 and 0.959 with a maximum variability of 0.009 among the set of samples used. The information obtained in this study is essential to understand the effects of absorption and scattering on the propagation of light through the potato tubers in order to design more efficient sensors for non-destructive quality evaluation.Publication Open Access Caracterización del modelo HEC-HMS en la cuenca de río Arga en Pamplona y su aplicación a cinco avenidas significativas(Universidad Católica de la Santísima Concepción (Chile), 2012) López Rodríguez, José Javier; González Moreno, Miguel Ángel; Scaini, Anna; Goñi Garatea, Mikel; Valdenebro García, José Vicente; Gimena Ramos, Faustino; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakPamplona es una ciudad que es atravesada por el río Arga a lo largo de una llanura aluvial, que es susceptible de inundaciones cuando se producen avenidas de cierta magnitud. Ante esta situación es importante contar con un modelo hidrológico que permita simular los caudales del río que atraviesa el núcleo urbano, a partir de los datos de los distintos pluviómetros existentes en la cuenca, y que sirva para alimentar a modelos hidráulicos que permitan definir las zonas inundables asociadas a distintos niveles de probabilidad. Con esta finalidad, se ha montado y caracterizado el modelo HEC-HMS de la cuenca del río Arga en Pamplona, y posteriormente, se ha aplicado a las cinco avenidas más significativas de los últimos años, de las que se disponen de los mínimos datos de caudal y precipitación necesarios. HEC-HMS es un modelo lluviaescorrentía que se basa en estructurar la cuenca origen en subcuencas asociadas a los cauces de la red fluvial. El flujo base en los hidrogramas observados se ha estimado mediante el filtro de Eckhardt. Después de realizar un análisis de sensibilidad de los parámetros inciertos del modelo, en el que se ha observado que el más sensible es el CN, se ha aplicado el modelo con los datos de las series de precipitación de las estaciones automáticas, y con los datos de las automáticas más las manuales, en este segundo caso los resultados han mejorado significativamente obteniéndose resultados satisfactorios.Publication Open Access Challenges in Life Cycle Assessment (LCA) of stabilised clay-based construction materials(Elsevier, 2017) Marcelino Sádaba, Sara; Kinuthia, John; Oti, Jonathan; Seco Meneses, Andrés; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakThe preference of clay-based materials for sustainable construction is well-established. The establishment ofsustainability credentials of emergent construction materials is very subjective, and most available tools are notfully equipped to deal with individual material systems, such as composite cement- or lime-based cementitioussystems, including clay-based blocks and bricks. The main problem emanates from the challenges of the audit ofeach aspect of the material processing, and especially the quantification of the most relevant inputs into thecomposite product. The variability in material ingredients, and lack of data for each aspect of the manufacturingprocesses involved creates major challenges. Incorporation of materials with long and complex recyclingprocesses further exacerbate the challenge. These incorporations create problems in terms of accurate materialtrails and data for input in a robust Life Cycle Assessment (LCA) of individual products. This paper reports on asimplified approach towards full LCA of seven clay-based brick products developed in UK (4) and Spain (3), based on known material data and estimated energy inputs in the manufacturing processes. The UK-based brickscomprise of Lower Oxford Clay (LOC), stabilised using combinations of hydrated lime, Ground Granulated Blast-furnace Slag (GGBS) and Portland cement (PC). In order to test the robustness of the proposed approach, resultson UK-based bricks are compared with a parallel LCA on clay-based product developed in Spain. Finally, theclay-based products are compared with a typical Portland cement-based concrete block andfired clay brick. Inthe LCA, boundary conditions includefixed transport, thus attempting to factor only the material ingredients,their known atmospheric emissions, and estimated energy inputs during processing. Results suggest that themost challenging aspect in the undertaking of LCA is the availability of reliable input data. Results also show thatthere are numerous parameters that can reliably and corroboratively facilitate the comparison of performance, besides carbon dioxide emissions.Publication Open Access Clasificación de cultivos en la zona media de Navarra mediante imágenes radar polarimétricas(Universidad Politécnica de Valencia, 2010) Larrañaga Urien, Arantzazu; Albizua, Lourdes; Álvarez Mozos, Jesús; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakNavarra lleva años empleando la técnica de clasificación supervisada de imágenes multiespectrales de satélite para la realización de la estadística agraria. La cubierta nubosa, muy habitual en esta zona, limita e incluso imposibilita el uso de imágenes ópticas para este fin. Los sensores radar representan una alternativa interesante, dado que a las longitudes de onda que trabajan, la cobertura nubosa es transparente, por lo que la nubosidad no supone ningún tipo de limitación para su empleo. Por otro lado, los sensores radar de nueva generación (por ejemplo ALOS/PALSAR o RADARSAT- 2), incorporan mejoras importantes respecto a sus predecesores (ERS-1/-2 o RADARSAT-1). En lo que respecta a la clasificación de cultivos, los sensores radar que adquieren imágenes en múltiples polarizaciones resultan especialmente interesantes. El principal objetivo de este trabajo es evaluar la viabilidad del empleo de observaciones de teledetección radar de polarización múltiple en la clasificación de cultivos de la zona media de Navarra. Para ello, se han utilizado dos imágenes ALOS/PALSAR. Una vez realizado un detallado análisis polarimétrico, se han obtenido las firmas o signaturas de los distintos cultivos de secano y de regadío por separado y se ha realizado una clasificación supervisada. La clasificación obtenida se ha comparado con la verdad campo resultando en un índice Kappa y fiabilidad global de 0,52 y 85% respectivamente.Publication Open Access Combined spatial and temporal effects of environmental controls on long-term monthly NDVI in the Southern Africa savanna(MDPI, 2013) Campo-Bescós, Miguel; Muñoz Carpena, Rafael; Southworth, Jane; Zhu, Likai; Waylen, Peter; Bunting, Erin; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakDeconstructing the drivers of large-scale vegetation change is critical to predicting and managing projected climate and land use changes that will affect regional vegetation cover in degraded or threated ecosystems. We investigate the shared dynamics of spatially variable vegetation across three large watersheds in the southern Africa savanna. Dynamic Factor Analysis (DFA), a multivariate time-series dimension reduction technique, was used to identify the most important physical drivers of regional vegetation change. We first evaluated the Advanced Very High Resolution Radiometer (AVHRR)- vs. the Moderate Resolution Imaging Spectroradiometer (MODIS)-based Normalized Difference Vegetation Index (NDVI) datasets across their overlapping period (2001–2010). NDVI follows a general pattern of cyclic seasonal variation, with distinct spatio-temporal patterns across physio-geographic regions. Both NDVI products produced similar DFA models, although MODIS was simulated better. Soil moisture and precipitation controlled NDVI for mean annual precipitation (MAP) < 750 mm, and above this, evaporation and mean temperature dominated. A second DFA with the full AVHRR (1982–2010) data found that for MAP < 750 mm, soil moisture and actual evapotranspiration control NDVI dynamics, followed by mean and maximum temperatures. Above 950 mm, actual evapotranspiration and precipitation dominate. The quantification of the combined spatio-temporal environmental drivers of NDVI expands our ability to understand landscape level changes in vegetation evaluated through remote sensing and improves the basis for the management of vulnerable regions, like the southern Africa savannas.Publication Open Access Comparison between capacitive and microstructured optical fiber soil moisture sensors(MDPI, 2018) López Aldaba, Aitor; López Torres, Diego; Campo-Bescós, Miguel; López Rodríguez, José Javier; Yerro Lizarazu, David; Elosúa Aguado, César; Arregui San Martín, Francisco Javier; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa eta Elektronikoa; Landa Ingeniaritza eta Proiektuak; Institute of Smart Cities - ISC; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ingeniería Eléctrica y Electrónica; Proyectos e Ingeniería RuralSoil moisture content has always been an important parameter to control because it is a deterministic factor for site-specific irrigation, seeding, transplanting, and compaction detection. In this work, a discrete sensor that is based on a SnO2–FP (Fabry-Pérot) cavity is presented and characterized in real soil conditions. As far as authors know, it is the first time that a microstructured optical fiber is used for real soil moisture measurements. Its performance is compared with a commercial capacitive soil moisture sensor in two different soil scenarios for two weeks. The optical sensor shows a great agreement with capacitive sensor’s response and gravimetric measurements, as well as a fast and reversible response; moreover, the interrogation technique allows for several sensors to be potentially multiplexed, which offers the possibility of local measurements instead of volumetric: it constitutes a great tool for real soil moisture monitoring.Publication Open Access Coupling hysteresis analysis with sediment and hydrological connectivity in three agricultural catchments in Navarre, Spain(Springer Verlag, 2019) Keesstra, Saskia D.; Davis, Jason; Masselink, Rens Hein; Casalí Sarasíbar, Javier; Peeters, Edwin T.H.M.; Dijksma, Roel; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakPurpose: Rain storm events mobilise large proportions of fine sediments in catchment systems. Sediments from agriculturalcatchments are often adsorbed by nutrients, heavy metals and other (in)organic pollutants that may impact downstream envi-ronments. To mitigate erosion, sediment transport and associated pollutant transport, it is crucial to know the origin of thesediment that is found in the drainage system, and therefore, it is important to understand catchment sediment dynamicsthroughout the continuity of runoff events. Materials and methods:To assess the impact of the state of a catchment on the transport of fine suspended sediment to catchmentoutlets, an algorithm has been developed which classifies rain storm events into simple (clockwise, counter-clockwise) andcompound (figure-of-eight; complex) events. This algorithm is the first tool that uses all available discharge and suspendedsediment data and analyses these data automatically. A total of 797 runoff events from three experimental watersheds in Navarre(Spain) were analysed with the help of long-term, high-resolution discharge and sediment data that was collected between 2000 and 2014. Results and discussion: Morphological complexity and in-stream vegetation structures acted as disconnecting landscape featureswhich caused storage of sediment along the transport cascade. The occurrence of sediment storage along transport paths wastherefore responsible for clockwise hysteresis due to the availability of in-stream sediment which could cause theBfirst flush^affect. Conversely, the catchment with steeper channel gradients and a lower stream density showed much more counter-clockwise hysteresis due to better downstream and lateral surface hydrological connectivity. In this research, hydrologicalconnectivity is defined as the actual and potential transfer paths in a catchment. The classification of event SSC-Q hysteresisprovided a seasonal benchmark value to which catchment managers can compare runoff events in order to understand the originand locations of suspended sediment in the catchment. Conclusions: A new algorithm uses all available discharge and suspended sediment data to assess catchment sediment dynamics.From these analyses, the catchment connectivity can be assessed which is useful to develop catchment land management.Publication Open Access Demonstrating correspondence between decision-support models and dynamics of real-world environmental systems(Elsevier, 2016) Huffaker, Ray; Muñoz Carpena, Rafael; Campo-Bescós, Miguel; Southworth, Jane; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakThere are increasing calls to audit decision-support models used for environmental policy to ensure that they correspond with the reality facing policy makers. Modelers can establish correspondence by providing empirical evidence of real-world behavior that their models skillfully simulate. Since real-world behavior—especially in environmental systems—is often complex, credibly modeling underlying dynamics is essential. We present a pre-modeling diagnostic framework based on Nonlinear Time Series (NLTS) methods for reconstructing real-world environmental dynamics from observed data. The framework is illustrated with a case study of saltwater intrusion into coastal wetlands in Everglades National Park, Florida, USA. We propose that environmental modelers test for systematic dynamic behavior in observed data before resorting to conventional stochastic exploratory approaches unable to detect this valuable information. Reconstructed data dynamics can be used, along with other expert information, as a rigorous benchmark to guide specification and testing of environmental decision-support models corresponding with real-world behavior.Publication Open Access Desarrollo de productos avanzados para la misión SEOSAT/Ingenio(Universitat Politecnica de Valencia, 2016) Sabater, N.; Ruiz Verdú, A.; Delegido, J.; Fernández Beltrán, R.; Latorre Carmona, P.; Pla, F.; González de Audícana Amenábar, María; Álvarez Mozos, Jesús; Sola Torralba, Ion; Villa, G.; Tejeiro, J. A.; Miguel, E. de; Jiménez, M.; Molina, S.; Moreno, J.; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakSEOSAT/Ingenio es la futura misión española de observación de la Tierra en el óptico en alta resolución espacial. Mientras que los productos de imagen a Nivel 1, radiancias geo-referenciadas a nivel de sensor, se encuentran en una fase avanzada de desarrollo existiendo para ello un contrato industrial, los productos de Nivel 2 deben ser desarrollados por los propios usuarios. Este hecho limita el uso de las imágenes a la comunidad científica, restringiendo sus posibles aplicaciones fuera de ésta. Así pues, bajo el marco de un proyecto coordinado y motivados por ofrecer productos de Ingenio/SEOSAT de Nivel 2 a disposición de cualquier usuario, se origina y desarrolla este trabajo. En este artículo se presentan los diferentes procesos desarrollados para la elaboración de productos a Nivel 2, desde reflectividades en superficie a la resolución nominal del sensor hasta imágenes con información espacial realzada y la posibilidad de crear mosaicos espaciales y compuestos temporales. Por una parte, en el caso de los productos de reflectividad en superficie se propone una técnica de corrección atmosférica basada en el uso de la información espacial, previo enmascaramiento de las nubes y una exhaustiva corrección de sombras morfológicas y/o topográficas. Por otra parte, para el realce de la información espacial, han sido evaluados diferentes métodos basados en la fusión de bandas multiespectrales con una banda pancromática así como la aplicación de técnicas llamadas de “Super-resolución”. Finalmente, se proporcionan las herramientas necesarias para la realización de mosaicos tanto espaciales como temporales para todo tipo de usuarios interesados en la explotación de las imágenes.Publication Open Access Diseño de un nuevo motor de explosión de dos tiempos con etanol como combustible(Publicaciones DYNA SL, 2012) Lostado Lorza, Rubén; Villanueva Roldán, Pedro; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta ProiektuakActualmente, el mecanismo en el cual están basados la mayoría de los motores de explosión mono o pluricilindricos y que montan los vehículos convencionales, es el tradicional mecanismo cigüeñal-biela-pistón. En este mecanismo, el pistón tiene la posibilidad de girar con respecto a la biela y de friccionar con las paredes del cilindro a medida que éste se desplaza por su interior. La fricción entre el pistón y las paredes del cilindro puede ocasionar un desgaste excesivo tanto del interior del cilindro como del propio pistón, y, en el peor de los casos, incluso un atascamiento (o gripaje) del pistón en su recorrido o carrera. Para reducir este desgaste y evitar los indeseables gripajes, los motores requieren de sofisticados circuitos de engrase, los cuales han de proporcionar una película lubricante homogénea y constante entre las paredes del cilindro y las paredes del pistón. En este artículo, se ha diseñado un nuevo motor de explosión reemplazando el mecanismo cigüeñalbiela- pistón tradicional, en el que el émbolo se desplaza con un movimiento alternativo rectilíneo, por un sistema en el que el émbolo describe un movimiento alternativo circular. En este nuevo sistema, el pistón está unido rígidamente a la biela mediante pasadores, suprimiendo el giro del pistón y evitando su contacto con las paredes interiores del cilindro. Esta restricción de giro, reduce tanto el desgaste del pistón y del cilindro como el consumo de aceite lubricante. El motor diseñado funciona con etanol, y su ciclo termodinámico es el de un motor de dos tiempos. En este motor, la admisión de la mezcla airecombustible se realiza mediante lumbreras laterales y el escape de los gases productos de la combustión a través de una válvula situada en la parte superior de la cámara de explosión hemisférica.