Ocean monitoring using GNSS-R techniques and microwave radiometry: The pau instrument concept

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El uso de señales de oportunidad GPS para observación de la Tierra

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New Passive Instruments Developed for Ocean Monitoring at the Remote Sensing Lab—Universitat Politècnica de Catalunya

Lack of frequent and global observations from space is currently a limiting factor in many Earth Observation (EO) missions. Two potential techniques that have been proposed nowadays are: (1) the use of satellite constellations, and (2) the use of Global Navigation Satellite Signals (GNSS) as signals of opportunity (no transmitter required). Reflectometry using GNSS opportunity signals (GNSS-R) was originally proposed in 1993 by Martin-Neira (ESA-ESTEC) for altimetry applications, but later its use for wind speed determination has been proposed, and more recently to perform the sea state correction required in sea surface salinity retrievals by means of L-band microwave radiometry (TB). At present, two EO space-borne missions are currently planned to be launched in the near future: (1) ESA's SMOS mission, using a Y-shaped synthetic aperture radiometer, launch date November 2nd, 2009, and (2) NASA-CONAE AQUARIUS/SAC-D mission, using a three beam push-broom radiometer. In the SMOS mission, the multi-angle observation capabilities allow to simultaneously retrieve not only the surface salinity, but also the surface temperature and an “effective” wind speed that minimizes the differences between observations and models. In AQUARIUS, an L-band scatterometer measuring the radar backscatter (σ0) will be used to perform the necessary sea state corrections. However, none of these approaches are fully satisfactory, since the effective wind speed captures some sea surface roughness effects, at the expense of introducing another variable to be retrieved, and on the other hand the plots (TB-σ0) present a large scattering. In 2003, the Passive Advance Unit for ocean monitoring (PAU) project was proposed to the European Science Foundation in the frame of the EUropean Young Investigator Awards (EURYI) to test the feasibility of GNSS-R over the sea surface to make sea state measurements and perform the correction of the L-band brightness temperature. This paper: (1) provides an overview of the Physics of the L-band radiometric and GNSS reflectometric observations over the ocean, (2) describes the instrumentation that has been (is being) developed in the frame of the EURYI-funded PAU project, (3) the ground-based measurements carried out so far, and their interpretation in view of placing a GNSS-reflectometer as secondary payload in future SMOS follow-on missions

Calibration of Correlation Radiometers Using Pseudo-Random Noise Signals

The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers’ outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called “baseline errors” associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN) signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver’s output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network

The proof of concept for 3-cm Altimetry using the Paris Interferometric Technique

© 2010 IEEE. Reprinted, with permission, from Nogués, O., Ribó, S., Arco, J. C., Cardellach, E., Rius, A., València, E., A. Camps, van der Marel, H., Martín-Neira, M., The proof of concept for 3-cm altimetry using the PARIS interferometric technique, Proceedings of IEEE International Geoscience and Remote Sensing Symposium (IEEE IGARSS), and july/2010. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of CSIC products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.Peer reviewe

De campañas de medidas a productos de salinidad: un tributo a las contribuciones de Jordi Font a la mision SMOS

Camps, Adriano ... et al.-- Special volume: Planet Ocean. Scientia Marina 80(Suppl.1) 2016.-- 14 pages, 20 figures[EN] This article summarizes some of the activities in which Jordi Font, research professor and head of the Department of Physical and Technological Oceanography, Institut de Ciències del Mar (CSIC, Spanish National Research Council) in Barcelona, has been involved as co-Principal Investigator for Ocean Salinity of the European Space Agency Soil Moisture and Ocean Salinity (SMOS) Earth Explorer Mission from the perspective of the Remote Sensing Lab at the Universitat Politècnica de Catalunya. We have probably left out some of his many contributions to salinity remote sensing, but we hope that this review will give an idea of the importance of his work. We focus on the following issues: 1) the new accurate measurements of the sea water dielectric constant, 2) the WISE and EuroSTARRS field experiments that helped to define the geophysical model function relating brightness temperature to sea state, 3) the FROG 2003 field experiment that helped to understand the emission of sea foam, 4) GNSS-R techniques for improving sea surface salinity retrieval, 5) instrument characterization campaigns, and 6) the operational implementation of the Processing Centre of Levels 3 and 4 at the SMOS Barcelona Expert Centre[ES] Este artículo resume algunas de las actividades en las que Jordi Font, profesor de investigación y jefe del Departamento de Física y Tecnología Oceanográfica, del Institut de Ciències del Mar (CSIC) en Barcelona, ha estado desarrollando como co-Investigador Principal de la parte de la misión SMOS de la ESA, una misión Earth Explorer, desde la perspectiva del Remote Sensing Lab, de la Universitat Politècnica de Catalunya. Seguramente, estamos olvidando algunas de sus muchas contribuciones a la teledetección de la salinidad, pero esperamos que esta revisión dé una idea de la importancia de su trabajo. Este artículo se focaliza en los siguientes puntos: 1) las medidas de alta calidad de la constante dieléctrica del agua marina, 2) las campañas de medidas WISE y EuroSTARRS que ayudaron a la definición del modelo geofísico relacionando la temperatura de brillo con el estado del mar, 3) la campaña de medidas FROG 2003 que ayudó a entender la emisión de la espuma marina 4) presentación de las técnicas de GNSS-R para la mejora de la recuperación de la salinidad superficial 5) campañas para la caracterización del instrumento y 6) la implantación del centro de procesado operacional de niveles 3 y 4 en el SMOS Barcelona Expert CentreThis work has been performed under research grants TEC2005-06863-C02-01/TCM, ESP2005-06823-C05 and ESP2007-65667-C04, AYA2008-05906-C02-01/ESP, AYA2010-22062-C05 and ESP2015-70014-C2-1-R, and EURYI 2004 awardPeer Reviewe

Study of maize plants effects in the retrieval of soil moisture using the interefence Ppttern GNSS-R technique

The use of Global Navigation Satellite Signals Reflections (GNSS-R) techniques to retrieve geophysical parameters from surfaces has been increased in the recent years. These techniques have resulted in suitable tools to obtain information about the sea state of oceans, which is very useful to improve the ocean salinity retrieval, and also, information about the soil moisture of lands. The present work focuses on the use of the Interference Pattern Technique (IPT), a particular type of GNSS-R technique, to study vegetation-covered soils. The IPT consists mainly of the measurement of the interference pattern between the GPS direct and reflected signals (the interference power), after they impinge over the ensemble soil surface and vegetation layer. The measured interference signal provides information on the soil moisture of the surface and also, on the vegetation height.Peer ReviewedPostprint (published version

Diversificación de itinerarios de evaluación en Educación Superior. Una propuesta colaborativa de innovación educativa

La sociedad en general y la educación en particular demandan nuevas formas de plantear el proceso de enseñanza y aprendizaje que deben estar en consonancia con los actuales paradigmas educativos y con las demandas sociales. Una estrategia de cambio a adoptar es la implementación de innovaciones educativas de forma colaborativa. En este caso, se describe un sistema de evaluación dividido en tres itinerarios en función del grado de asistencia del alumnado: formativo, mixto y final. Esta experiencia ha supuesto una excelente oportunidad para tomar conciencia sobre la evaluación y para reflexionar de forma crítica y colaborativa sobre nuestra labor docente

The effect of feeder system and diet on welfare, performance and meat quality, of growing-finishing Iberian × Duroc pigs under high environmental temperatures

The present study investigated the replacement of 5% of starch (ST) by 5% of sunflower oil (SO), with or without feed restriction, in the diet of growing-finishing Iberian × Duroc pigs exposed to heat stress conditions. The effects of these strategies on the welfare, performance and meat quality of the animals were evaluated. Seventy-two crossbred males [51.00 ± 6.29 kg body weight (BW)] were housed in collective pens and randomly distributed according to their initial BW in climate-controlled rooms under heat stress conditions (30–32 °C; 35%–50% humidity). The experiment was carried out in a randomized block design, in a 2 × 2 factorial design composed of two diets (control or oil) and two feed management (ad-libitum and restriction) types. The investigated treatments were: 1) control diet (5% ST × 0% SO) with ad-libitum feed intake, 2) oil diet (replacement of 5% of ST by 5% SO) with ad-libitum feed intake, 3) control diet with restriction feed intake, and 4) oil diet with restriction feed intake. The pigs’ behavior and dirtiness score were observed daily, and their performance was assessed weekly. Furthermore, three blood samples were collected from each animal for hemogram analysis during the period of study. The analysis of meat and carcass quality was performed 24 h post-mortem once the animals had reached an average BW of 130–140 kg. Statistical analyses were performed using the PROC MIXED and PROC GENMOD procedures of the Statistical Analysis System (SAS). The diet-regimen interaction produced no effects (P > 0.05) on the analyzed variables, except for behavior. Animals on the control diet associated with ad-libitum feed management spent more time in the lateral decubitus position and showed reduced activity. In addition, pigs fed ad-libitum and those that received the control diet displayed the highest level of dirtiness during the experiment. Evaluation of performance revealed that pigs receiving the oil diet showed reduced feed intake (P < 0.05) with no difference in average daily gain and consequently presented better feed conversion values compared to animals on the control diet. Furthermore, the oil diet resulted in a higher (P < 0.05) carcass yield as well as a higher oleic fat content in the meat. Pigs on restricted feeding management with lower body and carcass weights produced higher values of leanness percentage and carcass compared to animals in the ad-libitum group. In conclusion, the replacement of 5% of starch by 5% of sunflower oil in the pigs’ diet during high ambient temperatures improved the animals’ welfare, feed efficiency, and carcass characteristics.info:eu-repo/semantics/acceptedVersio