Efecto de la recurrencia de los incendios sobre la resiliencia post-incendio de las comunidades vegetales de Cataluña a partir de imágenes de satélite.

La recuperación post-incendio de la vegetación ha sido estudiada sobre todo a nivel de parcela. A escala regional diferentes factores pueden determinar la variabilidad en la capacidad de regeneración vegetal. El empleo de la teledetección permite efectuar un seguimiento de la regeneración a gran escala. En este trabajo se muestra como la recurrencia de incendios a lo largo del periodo de estudio (1975-1998) provocó una disminución significativa de la resiliencia de los bosques y matorrales mediterráneos de Cataluña. En las zonas quemadas una vez se encontró mayor resiliencia en las formaciones dominadas por especies rebrotadoras.Peer Reviewe

Efecto de la recurrencia de los incendios sobre la resiliencia post-incendio de las comunidades vegetales de Cataluña a partir de imágenes de satélite

La recuperación post-incendio de la vegetación ha sido estudiada sobre todo a nivel de parcela. A escala regional diferentes factores pueden determinar la variabilidad en la capacidad de regeneración vegetal. El empleo de la teledetección permite efectuar un seguimiento de la regeneración a gran escala. En este trabajo se muestra como la recurrencia de incendios a lo largo del periodo de estudio (1975-1998) provocó una disminución significativa de la resiliencia de los bosques y matorrales mediterráneos de Cataluña. En las zonas quemadas una vez se encontró mayor resiliencia en las formaciones dominadas por especies rebrotadoras

Long-Term Monitoring of the Flooding Regime and Hydroperiod of Doñana Marshes with Landsat Time Series (1974–2014)

This paper presents a semi-automatic procedure to discriminate seasonally flooded areas in the shallow temporary marshes of Doñana National Park (SW Spain) by using a radiommetrically normalized long time series of Landsat MSS, TM, and ETM+ images (1974–2014). Extensive field campaigns for ground truth data retrieval were carried out simultaneous to Landsat overpasses. Ground truth was used as training and testing areas to check the performance of the method. Simple thresholds on TM and ETM band 5 (1.55–1.75 μm) worked significantly better than other empirical modeling techniques and supervised classification methods to delineate flooded areas at Doñana marshes. A classification tree was applied to band 5 reflectance values to classify flooded versus non-flooded pixels for every scene. Inter-scene cross-validation identified the most accurate threshold on band 5 reflectance (ρ < 0.186) to classify flooded areas (Kappa = 0.65). A joint TM-MSS acquisition was used to find the MSS band 4 (0.8 a 1.1 μm) threshold. The TM flooded area was identical to the results from MSS 4 band threshold ρ < 0.10 despite spectral and spatial resolution differences. Band slicing was retrospectively applied to the complete time series of MSS and TM images. About 391 flood masks were used to reconstruct historical spatial and temporal patterns of Doñana marshes flooding, including hydroperiod. Hydroperiod historical trends were used as a baseline to understand Doñana’s flooding regime, test hydrodynamic models, and give an assessment of relevant management and restoration decisions. The historical trends in the hydroperiod of Doñana marshes show two opposite spatial patterns. While the north-western part of the marsh is increasing its hydroperiod, the southwestern part shows a steady decline. Anomalies in each flooding cycle allowed us to assess recent management decisions and monitor their hydrological effects.: This study was funded by the Spanish Ministry of Science and Innovation through the research projects HYDRA (#CGL2006-02247/BOS) and HYDRA2 (CGL2009-09801/BOS), and by funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 641762 to ECOPOTENTIAL project. The Espacio Natural de Doñana provided permits for fieldwork in protected areas with restricted access and historical data from water column readings. We are grateful to many MSc students who helped in image processing and field sampling. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

A semiautomatic methodology to detect fire scars in shrubs and evergreen forests with Landsat MSS time series.

This paper presents a semi-automatic methodology for fire scars mapping from a long time series of remote sensing data. Approximately, a hundred MSS images from different Landsat satellites were employed over an area of 32 100 km2 in the north-east of the Iberian Peninsula. The analysed period was from 1975 to 1993. Results are a map series of fire history and frequencies. Omission errors are 23% for burned areas greater than 200 ha while commission errors are 8% for areas greater than 50 ha. Subsequent work based on the resultant fire scars will also help in describing fire regime and in monitoring post-fire regeneration dynamics.Peer Reviewe

Impact properties and water uptake behavior of old newspaper recycled fibers-reinforced polypropylene composites

Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of applications. Nonetheless, the impact strength and the water uptake behavior of such materials have been seen as drawbacks. In this work, the impact strength and the water uptake of composites made of polypropylene reinforced with fibers from recycled newspaper have been researched. The results show how the impact strength decreases with the percentage of reinforcement in a similar manner to that of glass fiber-reinforced polypropylene composites as a result of adding a fragile phase to the material. It was found that the water uptake increased with the increasing percentages of lignocellulosic fibers due to the hydrophilic nature of such reinforcements. The diffusion behavior was found to be Fickian. A maleic anhydride was added as a coupling agent in order to increase the strength of the interface between the matrix and the reinforcements. It was found that the presence of such a coupling agent increased the impact strength of the composites and decreased the water uptake. Impact strengths of 21.3 kJ/m3 were obtained for a coupled composite with 30 wt % reinforcement contents, which is a value higher than that obtained for glass fiber-based materials. The obtained composites reinforced with recycled fibers showed competitive impact strength and water uptake behaviors in comparison with materials reinforced with raw lignocellulosic fibers. The article increases the knowledge on newspaper fiber-reinforced polyolefin composite properties, showing the competitiveness of waste-based materialsPostprint (published version

Topography of the interfacial shear strength and the mean intrinsic tensile strength of hemp fibers as a reinforcement of polypropylene

The strength of the interphase between the reinforcements and the matrix has a major role in the mechanical properties of natural ¿ber reinforced polyole¿n composites. The creation of strong interphases is hindered by the hydrophobic and hydrophilic natures of the matrix and the reinforcements, respectively. Adding coupling agents has been a common strategy to solve this problem. Nonetheless, a correct dosage of such coupling agents is important to, on the one hand guarantee strong interphases and high tensile strengths, and on the other hand ensure a full exploitation of the strengthening capabilities of the reinforcements. The paper proposes using topographic pro¿le techniques to represent the e¿ect of reinforcement and coupling agent contents of the strength of the interphase and the exploitation of the reinforcements. This representation allowed identifying the areas that are more or less sensitive to coupling agent content. The research also helped by ¿nding that an excess of coupling agent had less impact than a lack of this componentPostprint (published version

Carbon footprint of lamb and Wool production at farm gate and the regional sale in southern Patagonia

Natural steppe grasslands are the principal food resource for sheep in the Patagonia region, reared for meat and wool. However, there is currently a concern about the relationship between ruminant livestock and climate change due to its contribution to anthropogenic greenhouse gas (GHG) emissions. The objective of this study was to determine the carbon footprints (CF) of sheep meat (lamb) and wool on a range of farms using empirical data collected on farm and then upscaled to the regional scale using models that use topographic, climatic, and vegetation indices as independent variables. At the regional level, the total CF of lamb and wool (the combination of emissions produced on farm, via transport, and via industrial processing) varied from 10.64 to 41.32 kg CO2-eq/kg for lamb meat (carcass) and from 7.83 to 18.70 kg CO2-eq/kg for fine-grade wool. For both, the predominant contribution was from primary production on-farm (75–90%), followed by industrial processing (2–15%), and transportation. We used multiple regression models to produce maps of lamb and wool CF at farm gate across Santa Cruz province. The model for variation of lamb CF explained 95% of the variance on the data and the most significant predictor variables were temperature seasonality and normalized difference vegetation index (NDVI, dimensionless). The most important variables for the model of CF of greasy wool production at farm gate were isothermality, temperature seasonality, and NDVI explained 98%. The lowest CF values of both products (lamb and wool) were located in more productive grasslands. The successful management of livestock GHG emissions becomes an important challenge to the scientific, commercial, and policy communities. The results of CF for lamb and wool production found in the present work assist in characterizing the greenhouse gas emissions profile of livestock products in Southern Patagonia by providing a baseline against which mitigation actions can be planned and progress monitoredEEA SANTA CRUZFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral (UNPA). Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Rosas, Yamina Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Austral de Investigaciones Científicas (CADIC). Ushuaia, Tierra del Fuego; Argentina.Fil: Ladd, Brenton. Universidad Científica del Sur. Escuela de Agroforestería. Lima; Perú.Fil: Díaz-Delgado, Ricardo. Estación Biológica de Doñana (CSIC). Laboratorio de SIG y Teledetección. Sevilla; España.Fil: Martínez Pastur, Guillermo J. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Austral de Investigaciones Científicas (CADIC).Ushuaia, Tierra del Fuego; Argentina

Detección de superficies forestales quemadas en Cataluña mediante imágenes de satélite durante el período 1975-1995 : aplicación para la caracterización del régimen de incendios y los procesos de regeneración de la vegetación

En este trabajo se presenta la metodología desarrollada para obtener las superficies forestales quemadas en Cataluña a partir de una serie temporal de imágenes MSS del satélite Landsat (periodo 1975-1993). A esta serie se han añadido dos años más a partir de imágenes TM (1994-1995). Los resultados obtenidos en forma de mapa conforman la historia de fuegos del área de estudio durante 21 años, asi como los niveles de recurrencia de incendio alcanzados. Los errores de omisión suponen un 23% para las áreas quemadas mayores de 200 ha, mientras que los de comisión están en tomo al 8% para superficies quemadas mayores de 50 ha. Los resultados fueron incorporados en un sistema de información geográfica con objeto de caracterizar el régimen de fuegos de la zona de estudio. Se analiza la distribución de tamaños de incendios y el número de focos secundarios de incendio originados por cada fuego, asi como la distancia máxima alcanzada con respecto al fuego principal. También, se muestran algunos aspectos del seguimiento de la regeneración a través del índice de vegetación de diferencia normalizada (NDVI).This paper presents a semiautomatic methodology for fire scars mapping from a time series of Landsat MSS images over the forest surface of Catalonia (1975- 1993). This series has been enlarged from two years of TM images (1994-1995). Results are a map series offire history during 21 years as well as fire recurrence level. Omission errors are 23 % for burned areas greater than 200 ha while commission errors are 8% for areas greater than 50 ha. Detected fire scars were incorporated into a geographic information system in order to characterise the fíre regime of the study area. Fire size distribution and the number of spot fires originated from each fire as well as the maximum distance reached from the main fire are analysed. Some aspects about post-fire regeneraron monitoring through normalised difference vegetation index (NDVI) are also shown

Effects of JPEG and JPEG2000 lossy compression on remote sensing image classification for mapping crops and forest areas

This study measures the effect of lossy image compression on the digital classification of crops and forest areas. A hybrid classification method using satellite images and other variables has been used. The results contribute interesting new data on the influence of compression on the quality of the produced cartography, both from a "by pixel" perspective and regarding the homogeneity of the obtained polygons. The classified area in classifications only carried out with radiometric variables or with NDVI and humidity (for crops) increases as image compression increases, although the increase is smaller for JPEG2000 formats and for crops. On the other hand, the classified area decreases in classifications which also take into account topoclimatic variables (for forests). Overall image accuracy diminishes at high compression ratios (CR), although the point of inflection occurs at different CR depending on the compression format. As a rule, the JPEG2000 format gives better results quantitatively for forests (accuracy and classified area) and visually (images with less "salt and pepper" effect) for both land covers

Low cost indoor ultrasonic positioning implemented in FPGA

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. A. Sánchez, S. Elvira, Á. de Castro, G. Gonzalez-de-Rivera, R. Ribalda, J. Garrido, "Low cost indoor ultrasonic positioning implemented in FPGA", 35th Annual Conference of IEEEIndustrial Electronics, 2009. IECON '09, Porto (Portugal), 2009, pp. 2709 - 2714This paper presents a low cost indoor ultrasonic-based positioning system. This system allows the mobile nodes of a Wireless Sensor Network to know their location using radiofrequency and ultrasonics. To achieve this goal, a matrix of transmitting anchor points is installed whereas the mobile nodes receive these transmitted signals and estimate the time-of-flight of the ultrasonic signals. Using two time-of-flight measurements and trilateration equations, the location of the mobile nodes can be inferred in a 2-D space.This work has been partially supported by the CCG08-UAM/TIC-4258 project of the Comunidad de Madrid and UAM