http://hdl.handle.net/2117/1443 webmaster.bupc@upc.edu Universitat Politècnica de Catalaunya. Servei de Biblioteques i Documentació no Search the Channel search http://upcommons.upc.edu/e-prints/simple-search http://hdl.handle.net/2117/14194 Title: Monitoring of the Eyjafjallajökull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations<br/><br/>Authors: Alados Arboledas, Lucas; Pujadas, Manuel; Wagner, F.; Rocadenbosch Burillo, Francisco; Sicard, Michaël; Guerrero Rascado, Juan Luis; Navas Guzmán, Francisco; Preissler, J.; Molero, Francisco; Tomás Martínez, Sergio; Bravo Aranda, J. A.; Comerón Tejero, Adolfo<br/><br/>Abstract: Lidar and sun-photometer measurements were performed intensively over the IberianPeninsula (IP) during the eruption of Eyjafjallaj ¨ okull volcano (Iceland) in April–May 2010. The volcanic plume hit all the IP stations for the first time on 5 May 2010. A thorough study of the event is conducted for the period 5–8 May. Firstly the spatial and temporal evolution of the plume is described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol layers observed over the IP were rather thin (< 1000 m) with a top height up to 11–12 km. The mean optical thicknesses associated to those layers were rather low (between 0.013 and 0.020 over the whole period). Punctually on 7 May the optical thickness reached peakvalues near 0.10. Secondly the volcanic aerosols are characterized in terms of extinction and backscatter coefficients, lidar ratios, A° ngstro¨m exponents and linear particle depolarization ratio. Lidar ratios at different sites varied between 30 and 50 sr without a marked spectral dependency. Similar extinction-related A° ngstro¨m exponents varying between 0.6 and 0.8 were observed at different sites. The temporal evolution of the backscatter-related A° ngstro¨m exponents points out a possible decrease of the volcanicparticle size as the plume moves from west to east. Particle depolarization ratioson the order of 0.06–0.08 confirmed the coexistence of both ash and non-ash particles. Additionally profiles of mass concentration were obtained with a method using the opposite depolarizing effects of ash particles (strongly depolarizing) and non-ash particles (very weakly depolarizing), and sun-photometer observations. In Granada the ash mass concentration was found approximately 1.5 higher than that of non-ash particles, and probably did not exceed the value of 200 μgm−3 during the whole event. Wed, 07 Dec 2011 19:44:42 GMT Alados Arboledas, Lucas; Pujadas, Manuel; Wagner, F.; Rocadenbosch Burillo, Francisco; Sicard, Michaël; Guerrero Rascado, Juan Luis; Navas Guzmán, Francisco; Preissler, J.; Molero, Francisco; Tomás Martínez, Sergio; Bravo Aranda, J. A.; Comerón Tejero, Adolfo no Lidar and sun-photometer measurements were performed intensively over the Iberian Peninsula (IP) during the eruption of Eyjafjallaj ¨ okull volcano (Iceland) in April–May 2010. The volcanic plume hit all the IP stations for the first time on 5 May 2010. A thorough study of the event is conducted for the period 5–8 May. Firstly the spatial and temporal evolution of the plume is described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol layers observed over the IP were rather thin (< 1000 m) with a top height up to 11–12 km. The mean optical thicknesses associated to those layers were rather low (between 0.013 and 0.020 over the whole period). Punctually on 7 May the optical thickness reached peak values near 0.10. Secondly the volcanic aerosols are characterized in terms of extinction and backscatter coefficients, lidar ratios, A° ngstro¨m exponents and linear particle depolarization ratio. Lidar ratios at different sites varied between 30 and 50 sr without a marked spectral dependency. Similar extinction-related A° ngstro¨m exponents varying between 0.6 and 0.8 were observed at different sites. The temporal evolution of the backscatter-related A° ngstro¨m exponents points out a possible decrease of the volcanic particle size as the plume moves from west to east. Particle depolarization ratios on the order of 0.06–0.08 confirmed the coexistence of both ash and non-ash particles. Additionally profiles of mass concentration were obtained with a method using the opposite depolarizing effects of ash particles (strongly depolarizing) and non-ash particles (very weakly depolarizing), and sun-photometer observations. In Granada the ash mass concentration was found approximately 1.5 higher than that of non-ash particles, and probably did not exceed the value of 200 μgm−3 during the whole event. http://hdl.handle.net/2117/14140 Title: Downscaling SMOS-derived soil moisture using MODIS visible/infrared data<br/><br/>Authors: Piles, Maria; Camps Carmona, Adriano José; Vall-Llossera Ferran, Mercedes Magdalena; Corbella Sanahuja, Ignasi; Panciera, Rocco; Ruediger, Christoph; Kerr, Yann H.; Walker, Jeffrey<br/><br/>Abstract: A downscaling approach to improve the spatial resolution of Soil Moisture and Ocean Salinity (SMOS) soil moisture estimates with the use of higher resolution visible/infrared (VIS/IR) satellite data is presented. The algorithm is based on the so-called “universal triangle” concept that relates VIS/IR parameters, such as the Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (Ts), to the soil moisture status. It combines the accuracy of SMOS observations with the high spatial resolution of VIS/IR satellite data into accurate soil moisture estimates at high spatial resolution. In preparation for the SMOS launch, the algorithm was tested using observations of the UPC Airborne RadIomEter at L-band (ARIEL) over the Soil Moisture Measurement Network of the University of Salamanca (REMEDHUS) in Zamora (Spain), and LANDSAT imagery. Results showed fairly good agreement with ground-based soil moisture measurements and illustrated the strength of the link between VIS/IR satellite data and soil moisture status. Following the SMOS launch, a downscaling strategy for the estimation of soil moisture at high resolution from SMOS using MODIS VIS/IR data has been developed. The method has been applied to some of the first SMOS images acquired during the commissioning phase and is validated against in situ soil moisture data from the OZnet soil moisture monitoring network, in South-Eastern Australia. Results show that the soil moisture variability is effectively captured at 10 and 1 km spatial scales without a significant degradation of the root mean square error. Thu, 01 Dec 2011 16:09:11 GMT Piles, Maria; Camps Carmona, Adriano José; Vall-Llossera Ferran, Mercedes Magdalena; Corbella Sanahuja, Ignasi; Panciera, Rocco; Ruediger, Christoph; Kerr, Yann H.; Walker, Jeffrey no A downscaling approach to improve the spatial resolution of Soil Moisture and Ocean Salinity (SMOS) soil moisture estimates with the use of higher resolution visible/infrared (VIS/IR) satellite data is presented. The algorithm is based on the so-called “universal triangle” concept that relates VIS/IR parameters, such as the Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (Ts), to the soil moisture status. It combines the accuracy of SMOS observations with the high spatial resolution of VIS/IR satellite data into accurate soil moisture estimates at high spatial resolution. In preparation for the SMOS launch, the algorithm was tested using observations of the UPC Airborne RadIomEter at L-band (ARIEL) over the Soil Moisture Measurement Network of the University of Salamanca (REMEDHUS) in Zamora (Spain), and LANDSAT imagery. Results showed fairly good agreement with ground-based soil moisture measurements and illustrated the strength of the link between VIS/IR satellite data and soil moisture status. Following the SMOS launch, a downscaling strategy for the estimation of soil moisture at high resolution from SMOS using MODIS VIS/IR data has been developed. The method has been applied to some of the first SMOS images acquired during the commissioning phase and is validated against in situ soil moisture data from the OZnet soil moisture monitoring network, in South-Eastern Australia. Results show that the soil moisture variability is effectively captured at 10 and 1 km spatial scales without a significant degradation of the root mean square error. http://hdl.handle.net/2117/14137 Title: MIRAS calibration and performance: results from the SMOS in-orbit commissioning phase<br/><br/>Authors: Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Duffo Ubeda, Núria; González Gambau, Veronica; Pablos Hernández, Míriam; Duran Martínez, Israel; Martín Neira, Manuel<br/><br/>Abstract: After the successful launching of the Soil Moisture and Ocean Salinity satellite in November 2009, continuous streams of data started to be regularly downloaded and made available to be processed. The first six months of operation were fully dedicated to the In-Orbit Commissioning Phase, with an intense activity aimed at bringing the satellite and instrument into a fully operational condition. Concerning the payload Microwave Imaging Radiometer with Aperture Synthesis, it was fully characterized using specific orbits dedicated to check all instrument modes. The procedures, already defined during the on-ground characterization, were repeated so as to obtain realistic temperature characterization and updated internal calibration parameters. External calibration maneuvers were tested for the first time and provided absolute instrument calibration, as well as corrections to internal calibration data. Overall, performance parameters, such as stability, radiometric sensitivity and radiometric accuracy were evaluated. The main results of this activity are presented in this paper, showing that the instrument delivers stable and well-calibrated data thanks to the combination of external and internal calibration and to an accurate thermal characterization. Finally, the quality of the visibility calibration is demonstrated by producing brightness temperature images in the alias-free field of view using standard inversion techniques. Images of ocean, ice, and land are given as examples. Thu, 01 Dec 2011 15:29:05 GMT Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Duffo Ubeda, Núria; González Gambau, Veronica; Pablos Hernández, Míriam; Duran Martínez, Israel; Martín Neira, Manuel no After the successful launching of the Soil Moisture and Ocean Salinity satellite in November 2009, continuous streams of data started to be regularly downloaded and made available to be processed. The first six months of operation were fully dedicated to the In-Orbit Commissioning Phase, with an intense activity aimed at bringing the satellite and instrument into a fully operational condition. Concerning the payload Microwave Imaging Radiometer with Aperture Synthesis, it was fully characterized using specific orbits dedicated to check all instrument modes. The procedures, already defined during the on-ground characterization, were repeated so as to obtain realistic temperature characterization and updated internal calibration parameters. External calibration maneuvers were tested for the first time and provided absolute instrument calibration, as well as corrections to internal calibration data. Overall, performance parameters, such as stability, radiometric sensitivity and radiometric accuracy were evaluated. The main results of this activity are presented in this paper, showing that the instrument delivers stable and well-calibrated data thanks to the combination of external and internal calibration and to an accurate thermal characterization. Finally, the quality of the visibility calibration is demonstrated by producing brightness temperature images in the alias-free field of view using standard inversion techniques. Images of ocean, ice, and land are given as examples. http://hdl.handle.net/2117/13680 Title: Improving the wishart synthetic aperture radar image classifications through deterministic simulated annealing<br/><br/>Authors: Sánchez Lladó, Francisco Javier; Pajares Martinsanz, Gonzalo; López Martínez, Carlos<br/><br/>Abstract: This paper proposes the use of Deterministic Simulated Annealing (DSA) for Synthetic Aperture Radar (SAR) image classification for cluster refinement. We use the initial classification provided by the maximum-likelihood classifier based on the complex Wishart distribution that is then supplied to the DSA optimization approach. The goal is to improve the classification results obtained by the Wishart approach. The improvement is verified by computing a cluster separability coefficient. During the DSA optimization process, for each iteration and for each pixel, two consistency coefficients are computed taking into account two kinds of relations between the pixel under consideration and its neighbors. Based on these coefficients and on the information coming from the pixel itself, it is re-classified. Several experiments are carried out to verify that the proposed approach outperforms the Wishart strategy. We try to improve the classification results by considering the spatial influences received by a pixel through its neighbors. Finally, a link about the contribution of DSA to thematic mapping is also established. Thu, 27 Oct 2011 11:24:20 GMT Sánchez Lladó, Francisco Javier; Pajares Martinsanz, Gonzalo; López Martínez, Carlos no This paper proposes the use of Deterministic Simulated Annealing (DSA) for Synthetic Aperture Radar (SAR) image classification for cluster refinement. We use the initial classification provided by the maximum- likelihood classifier based on the complex Wishart distribution that is then supplied to the DSA optimization approach. The goal is to improve the classification results obtained by the Wishart approach. The improvement is verified by computing a cluster separability coefficient. During the DSA optimization process, for each iteration and for each pixel, two consistency coefficients are computed taking into account two kinds of relations between the pixel under consideration and its neighbors. Based on these coefficients and on the information coming from the pixel itself, it is re-classified. Several experiments are carried out to verify that the proposed approach outperforms the Wishart strategy. We try to improve the classification results by considering the spatial influences received by a pixel through its neighbors. Finally, a link about the contribution of DSA to thematic mapping is also established. http://hdl.handle.net/2117/13544 Title: On the use of GNSS-R data to correct L-band brightness temperatures for sea-state effects: results of the ALBATROSS field experiments<br/><br/>Authors: Valencia Domènech, Enric; Camps Carmona, Adriano José; Bosch Lluís, Xavier; Rodríguez Álvarez, Nereida; Ramos Pérez, Isaac; Eugenio, Francisco Javier; Marcello, Javier<br/><br/>Abstract: Sea surface salinity is a key oceanographic parameter that can be measured by means of L-band microwave radiometry. The measured brightness temperatures over the ocean areinfluenced by the sea state, which can entirely mask the salinity signature. Sea-state corrections parameterized in terms of wind speed and/or significant wave height have proven not to be fully satisfactory. In 2003, it was proposed to use reflectometry using navigation opportunity signals [Global Navigation Satellite System Reflectometer (GNSS-R)] for sea-state determination and correction of the measured L-band brightness temperature changes associated to the sea state. The novelty of the approach relies in the measurement of the whole Delay-Doppler Map that captures the scattering of the GNSS signals in the whole glistening zone. In thisframework, the “Advanced L-BAnd emissiviTy and Reflectivity Observations of the Sea Surface” (ALBATROSS) field experimentswere undertaken in 2008 and 2009, collecting an extensive data set of collocated radiometric and reflectometric measurements over the Atlantic Ocean, as well as oceanographic and meteorological data. In this paper, the experimental results and conclusions of the ALBATROSS 2009 field experiment are compiled and presented,showing the great potential of this technique to perform the necessarycorrections in future salinity missions. Empirical relationships are derived among measured brightness temperature variationsdue to the sea-state effect and direct GNSS-R observables, and the sea surface correlation time at L1 band, a key parameterfor GNSS-R data processing since it determines the maximum coherent integration time, was experimentally determined. Mon, 17 Oct 2011 13:49:42 GMT Valencia Domènech, Enric; Camps Carmona, Adriano José; Bosch Lluís, Xavier; Rodríguez Álvarez, Nereida; Ramos Pérez, Isaac; Eugenio, Francisco Javier; Marcello, Javier no Sea surface salinity is a key oceanographic parameter that can be measured by means of L-band microwave radiometry. The measured brightness temperatures over the ocean are influenced by the sea state, which can entirely mask the salinity signature. Sea-state corrections parameterized in terms of wind speed and/or significant wave height have proven not to be fully satisfactory. In 2003, it was proposed to use reflectometry using navigation opportunity signals [Global Navigation Satellite System Reflectometer (GNSS-R)] for sea-state determination and correction of the measured L-band brightness temperature changes associated to the sea state. The novelty of the approach relies in the measurement of the whole Delay-Doppler Map that captures the scattering of the GNSS signals in the whole glistening zone. In this framework, the “Advanced L-BAnd emissiviTy and Reflectivity Observations of the Sea Surface” (ALBATROSS) field experiments were undertaken in 2008 and 2009, collecting an extensive data set of collocated radiometric and reflectometric measurements over the Atlantic Ocean, as well as oceanographic and meteorological data. In this paper, the experimental results and conclusions of the ALBATROSS 2009 field experiment are compiled and presented, showing the great potential of this technique to perform the necessary corrections in future salinity missions. Empirical relationships are derived among measured brightness temperature variations due to the sea-state effect and direct GNSS-R observables, and the sea surface correlation time at L1 band, a key parameter for GNSS-R data processing since it determines the maximum coherent integration time, was experimentally determined. http://hdl.handle.net/2117/13477 Title: Interpolation-free Coregistration and Phase-Correction of Airborne SAR Interferograms<br/><br/>Authors: Prats Iraola, Pau; Reigber, Andreas; Mallorquí Franquet, Jordi Joan<br/><br/>Abstract: This letter discusses the detection and correction ofresidual motion errors that appear in airborne synthetic apertureradar (SAR) interferograms due to the lack of precision in the navigationsystem. As it is shown, the effect of this lack of precision istwofold: azimuth registration errors and phase azimuth undulations.Up to now, the correction of the former was carried out byestimating the registration error and interpolating, while the latterwas based on the estimation of the phase azimuth undulations tocompensate the phase of the computed interferogram. In this letter,a new correction method is proposed, which avoids the interpolationstep and corrects at the same time the azimuth phase undulations.Additionally, the spectral diversity technique, used to estimateregistration errors, is critically analyzed. Airborne L-bandrepeat-pass interferometric data of the German Aerospace Center(DLR) experimental airborne SAR is used to validate the method Tue, 11 Oct 2011 09:56:57 GMT Prats Iraola, Pau; Reigber, Andreas; Mallorquí Franquet, Jordi Joan no This letter discusses the detection and correction of residual motion errors that appear in airborne synthetic aperture radar (SAR) interferograms due to the lack of precision in the navigation system. As it is shown, the effect of this lack of precision is twofold: azimuth registration errors and phase azimuth undulations. Up to now, the correction of the former was carried out by estimating the registration error and interpolating, while the latter was based on the estimation of the phase azimuth undulations to compensate the phase of the computed interferogram. In this letter, a new correction method is proposed, which avoids the interpolation step and corrects at the same time the azimuth phase undulations. Additionally, the spectral diversity technique, used to estimate registration errors, is critically analyzed. Airborne L-band repeat-pass interferometric data of the German Aerospace Center (DLR) experimental airborne SAR is used to validate the method http://hdl.handle.net/2117/13476 Title: Impact of antenna errors on the radiometric accuracy of large aperture synthesis radiometers. study applied to miras.<br/><br/>Authors: Camps Carmona, Adriano José; Bará Temes, Javier; Torres Torres, Francesc; Corbella Sanahuja, Ignasi; Romeu Robert, Jordi<br/><br/>Abstract: A classification of system errors in aperture synthesis radiometry applied to Earth obervation is presented. A general procedure to quantify th eimpact of antenna errors on the radiometric accuracy is developed and is then particularized to an L-band Y-shaped interferometer called MIRAS (microwave imaging radiometer by aperture synthesis) currently under study at the European Space Agency. This work analyze in detail the impact of antenna errors on the radiometric accuracy of the instrument. These antenna errors are grouped into amplitude and phase antenna pattern errors, antenna position errors and antenna cros polarization errors. Special attention is paid to antenna coupling effects because of their importance in the selection of a suitable inversion algorithm for large aperture synthesis interferometers: the G-matrix techniques or the Fourier techniques proposed for MIRAS. Tue, 11 Oct 2011 09:16:33 GMT Camps Carmona, Adriano José; Bará Temes, Javier; Torres Torres, Francesc; Corbella Sanahuja, Ignasi; Romeu Robert, Jordi no A classification of system errors in aperture synthesis radiometry applied to Earth obervation is presented. A general procedure to quantify th eimpact of antenna errors on the radiometric accuracy is developed and is then particularized to an L-band Y-shaped interferometer called MIRAS (microwave imaging radiometer by aperture synthesis) currently under study at the European Space Agency. This work analyze in detail the impact of antenna errors on the radiometric accuracy of the instrument. These antenna errors are grouped into amplitude and phase antenna pattern errors, antenna position errors and antenna cros polarization errors. Special attention is paid to antenna coupling effects because of their importance in the selection of a suitable inversion algorithm for large aperture synthesis interferometers: the G-matrix techniques or the Fourier techniques proposed for MIRAS. http://hdl.handle.net/2117/13475 Title: The visibility function in interferometric aperture synthesis radiometry<br/><br/>Authors: Corbella Sanahuja, Ignasi; Duffo Ubeda, Núria; Vall-llossera Ferran, Mercè; Camps Carmona, Adriano José; Torres Torres, Francesc Tue, 11 Oct 2011 08:23:26 GMT Corbella Sanahuja, Ignasi; Duffo Ubeda, Núria; Vall-llossera Ferran, Mercè; Camps Carmona, Adriano José; Torres Torres, Francesc no http://hdl.handle.net/2117/13461 Title: Forest parameter estimation in the Pol-InSAR context employing the multiplicative–additive speckle noise model<br/><br/>Authors: López Martínez, Carlos; Fabregas Canovas, Francisco Javier; Pipia, Luca<br/><br/>Abstract: This paper addresses the problem of speckle noise on single baseline polarimetric SAR interferometry (Pol-InSAR) on the basis of the multiplicative–additive speckle noise model. Considering this speckle noise model, a novel filtering technique is defined and studied in terms of simulated and experimental Pol-InSAR data. As demonstrated, the use of the multiplicative–additive speckle noise model does not lead to a corruption of the useful information but to an improvement of its estimation. The performance of the algorithm is analyzed in terms of the physical parameters retrieved from the filtered data, that in this work correspond to the forest height and the ground phase. In case of experimental data, the retrieved forest height is compared and validated against Lidar ground truth measurements. Mon, 10 Oct 2011 09:45:16 GMT López Martínez, Carlos; Fabregas Canovas, Francisco Javier; Pipia, Luca no This paper addresses the problem of speckle noise on single baseline polarimetric SAR interferometry (Pol-InSAR) on the basis of the multiplicative–additive speckle noise model. Considering this speckle noise model, a novel filtering technique is defined and studied in terms of simulated and experimental Pol-InSAR data. As demonstrated, the use of the multiplicative–additive speckle noise model does not lead to a corruption of the useful information but to an improvement of its estimation. The performance of the algorithm is analyzed in terms of the physical parameters retrieved from the filtered data, that in this work correspond to the forest height and the ground phase. In case of experimental data, the retrieved forest height is compared and validated against Lidar ground truth measurements. http://hdl.handle.net/2117/13292 Title: Determination of sea surface salinity and wind speed by L-band microwave radiometry from a fixed platform<br/><br/>Authors: Gabarró Prats, Carolina; Vall-llossera Ferran, Mercè; Font, Jordi; Camps Carmona, Adriano José<br/><br/>Abstract: The European Space Agency Soil Moisture andOcean Salinity (SMOS) mission aims at obtaining global maps ofsoil moisture and sea surface salinity from space for large-scale andclimatic studies. It uses an L-band (1400–1427 MHz) MicrowaveInterferometric Radiometer by Aperture Synthesis to measurebrightness temperature of the earth’s surface at horizontal andvertical polarizations ( h and v). These two parameters will beused together to retrieve the geophysical parameters. The retrievalof salinity is a complex process that requires the knowledge ofother environmental information and an accurate processing ofthe radiometer measurements. Here, we present recent resultsobtained from several studies and field experiments that were partof the SMOS mission, and highlight the issues still to be solved. Thu, 22 Sep 2011 08:25:06 GMT Gabarró Prats, Carolina; Vall-llossera Ferran, Mercè; Font, Jordi; Camps Carmona, Adriano José no The European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission aims at obtaining global maps of soil moisture and sea surface salinity from space for large-scale and climatic studies. It uses an L-band (1400–1427 MHz) Microwave Interferometric Radiometer by Aperture Synthesis to measure brightness temperature of the earth’s surface at horizontal and vertical polarizations ( h and v). These two parameters will be used together to retrieve the geophysical parameters. The retrieval of salinity is a complex process that requires the knowledge of other environmental information and an accurate processing of the radiometer measurements. Here, we present recent results obtained from several studies and field experiments that were part of the SMOS mission, and highlight the issues still to be solved. http://hdl.handle.net/2117/13291 Title: Comparison of topography- and aperture-dependent motion compensation algorithms for airborne SAR<br/><br/>Authors: Prats Iraola, Pau; Câmara de Macedo, Karlus A.; Reigber, Andreas; Scheiber, Rolf; Mallorquí Franquet, Jordi Joan<br/><br/>Abstract: This letter presents a comparison between threeFourier-based motion compensation (MoCo) algorithms forairborne synthetic aperture radar (SAR) systems. These algorithmscircumvent the limitations of conventional MoCo, namelythe assumption of a reference height and the beam-center approximation.All these approaches rely on the inherent time–frequencyrelation in SAR systems but exploit it differently, with the consequentdifferences in accuracy and computational burden. Aftera brief overview of the three approaches, the performance ofeach algorithm is analyzed with respect to azimuthal topographyaccommodation, angle accommodation, and maximum frequencyof track deviations with which the algorithm can cope. Also, ananalysis on the computational complexity is presented. Quantitativeresults are shown using real data acquired by the ExperimentalSAR system of the German Aerospace Center (DLR). Thu, 22 Sep 2011 08:14:53 GMT Prats Iraola, Pau; Câmara de Macedo, Karlus A.; Reigber, Andreas; Scheiber, Rolf; Mallorquí Franquet, Jordi Joan no This letter presents a comparison between three Fourier-based motion compensation (MoCo) algorithms for airborne synthetic aperture radar (SAR) systems. These algorithms circumvent the limitations of conventional MoCo, namely the assumption of a reference height and the beam-center approximation. All these approaches rely on the inherent time–frequency relation in SAR systems but exploit it differently, with the consequent differences in accuracy and computational burden. After a brief overview of the three approaches, the performance of each algorithm is analyzed with respect to azimuthal topography accommodation, angle accommodation, and maximum frequency of track deviations with which the algorithm can cope. Also, an analysis on the computational complexity is presented. Quantitative results are shown using real data acquired by the Experimental SAR system of the German Aerospace Center (DLR). http://hdl.handle.net/2117/13290 Title: A Small Baseline DIFSAR Approach for Investigating Deformations on Full Resolution SAR Interferograms<br/><br/>Authors: Lanari, Ricardo; Mora Sacristán, Óscar; Manunta, Michele; Mallorquí Franquet, Jordi Joan; Berardino, P.; Sansoti, Eugenio<br/><br/>Abstract: This paper presents a differential synthetic apertureradar (SAR) interferometry (DIFSAR) approach for investigatingdeformation phenomena on full-resolution DIFSAR interferograms.In particular, our algorithm extends the capabilityof the small-baseline subset (SBAS) technique that relies onsmall-baseline DIFSAR interferograms only and is mainly focusedon investigating large-scale deformations with spatial resolutionsof about 100 100 m. The proposed technique is implemented byusing two different sets of data generated at low (multilook data)and full (single-look data) spatial resolution, respectively. Theformer is used to identify and estimate, via the conventional SBAStechnique, large spatial scale deformation patterns, topographicerrors in the available digital elevation model, and possibleatmospheric phase artifacts; the latter allows us to detect, onthe full-resolution residual phase components, structures highlycoherent over time (buildings, rocks, lava, structures, etc.), as wellas their height and displacements. In particular, the estimation ofthe temporal evolution of these local deformations is easily implementedby applying the singular value decomposition technique.The proposed algorithm has been tested with data acquired by theEuropean Remote Sensing satellites relative to the Campania area(Italy) and validated by using geodetic measurements. Thu, 22 Sep 2011 07:59:22 GMT Lanari, Ricardo; Mora Sacristán, Óscar; Manunta, Michele; Mallorquí Franquet, Jordi Joan; Berardino, P.; Sansoti, Eugenio no This paper presents a differential synthetic aperture radar (SAR) interferometry (DIFSAR) approach for investigating deformation phenomena on full-resolution DIFSAR interferograms. In particular, our algorithm extends the capability of the small-baseline subset (SBAS) technique that relies on small-baseline DIFSAR interferograms only and is mainly focused on investigating large-scale deformations with spatial resolutions of about 100 100 m. The proposed technique is implemented by using two different sets of data generated at low (multilook data) and full (single-look data) spatial resolution, respectively. The former is used to identify and estimate, via the conventional SBAS technique, large spatial scale deformation patterns, topographic errors in the available digital elevation model, and possible atmospheric phase artifacts; the latter allows us to detect, on the full-resolution residual phase components, structures highly coherent over time (buildings, rocks, lava, structures, etc.), as well as their height and displacements. In particular, the estimation of the temporal evolution of these local deformations is easily implemented by applying the singular value decomposition technique. The proposed algorithm has been tested with data acquired by the European Remote Sensing satellites relative to the Campania area (Italy) and validated by using geodetic measurements. http://hdl.handle.net/2117/13253 Title: Long-range transport of Saharan dust to northern Europe: The 11-16 October 2001 outbreak observed with EARLINET<br/><br/>Authors: Ansmann, Albert; Bösenberg, Jens; Chaikovsky, Anatoli; Comerón Tejero, Adolfo; Eckhardt, Sabine; Eixmann, Ronald; Freudenthaler, Volker; Ginoux, Paul; Komguem, Leonce; Linné, Holger; López Márquez, Miguel Ángel; Matthias, Volker; Mattis, Ina; Mitev, Valentin<br/><br/>Abstract: The spread of mineral particles over southwestern, western, and central Europeresulting from a strong Saharan dust outbreak in October 2001 was observed at10 stations of the European Aerosol Research Lidar Network (EARLINET). For the firsttime, an optically dense desert dust plume over Europe was characterized coherentlywith high vertical resolution on a continental scale. The main layer was located abovethe boundary layer (above 1-km height above sea level (asl)) up to 3–5-km height, andtraces of dust particles reached heights of 7–8 km. The particle optical depth typicallyranged from 0.1 to 0.5 above 1-km height asl at the wavelength of 532 nm, andmaximum values close to 0.8 were found over northern Germany. The lidar observationsare in qualitative agreement with values of optical depth derived from Total OzoneMapping Spectrometer (TOMS) data. Ten-day backward trajectories clearly indicated theSahara as the source region of the particles and revealed that the dust layer observed,e.g., over Belsk, Poland, crossed the EARLINET site Aberystwyth, UK, and southernScandinavia 24–48 hours before. Lidar-derived particle depolarization ratios,backscatter- and extinction-related A ° ngstro¨m exponents, and extinction-to-backscatterratios mainly ranged from 15 to 25%, 0.5 to 0.5, and 40–80 sr, respectively, within thelofted dust plumes. A few atmospheric model calculations are presented showing the dustconcentration over Europe. The simulations were found to be consistent with thenetwork observations. Tue, 20 Sep 2011 07:11:23 GMT Ansmann, Albert; Bösenberg, Jens; Chaikovsky, Anatoli; Comerón Tejero, Adolfo; Eckhardt, Sabine; Eixmann, Ronald; Freudenthaler, Volker; Ginoux, Paul; Komguem, Leonce; Linné, Holger; López Márquez, Miguel Ángel; Matthias, Volker; Mattis, Ina; Mitev, Valentin no The spread of mineral particles over southwestern, western, and central Europe resulting from a strong Saharan dust outbreak in October 2001 was observed at 10 stations of the European Aerosol Research Lidar Network (EARLINET). For the first time, an optically dense desert dust plume over Europe was characterized coherently with high vertical resolution on a continental scale. The main layer was located above the boundary layer (above 1-km height above sea level (asl)) up to 3–5-km height, and traces of dust particles reached heights of 7–8 km. The particle optical depth typically ranged from 0.1 to 0.5 above 1-km height asl at the wavelength of 532 nm, and maximum values close to 0.8 were found over northern Germany. The lidar observations are in qualitative agreement with values of optical depth derived from Total Ozone Mapping Spectrometer (TOMS) data. Ten-day backward trajectories clearly indicated the Sahara as the source region of the particles and revealed that the dust layer observed, e.g., over Belsk, Poland, crossed the EARLINET site Aberystwyth, UK, and southern Scandinavia 24–48 hours before. Lidar-derived particle depolarization ratios, backscatter- and extinction-related A ° ngstro¨m exponents, and extinction-to-backscatter ratios mainly ranged from 15 to 25%, 0.5 to 0.5, and 40–80 sr, respectively, within the lofted dust plumes. A few atmospheric model calculations are presented showing the dust concentration over Europe. The simulations were found to be consistent with the network observations. http://hdl.handle.net/2117/13227 Title: Observacio de la terra amb sensors passius de microones<br/><br/>Authors: Broquetas Ibars, Antoni Mon, 19 Sep 2011 08:36:26 GMT Broquetas Ibars, Antoni no http://hdl.handle.net/2117/13226 Title: The boundary Layer Growth in an Urban Area<br/><br/>Authors: Pino, D.; Vilà-Guerau de Arellano, Jordi; Comerón Tejero, Adolfo; Rocadenbosch Burillo, Francesc<br/><br/>Abstract: The development and maintenance of the atmospheric boundary layer (ABL) plays a key role in the distribution ofatmospheric constituents, especially in a polluted urban area. In particular, the ABL has a direct impact on the concentration andtransformation of pollutants. In this work, in order to analyze the different mechanisms which control the boundary layergrowth, we have simulated by means of the non-hydrostatic model MM5 several boundary layer observed in the city ofBarcelona (Spain). Sensitivity analysis of the modelled ABL is carried out by using various descriptions of the planetaryboundary layer (PBL). Direct and continuous measurements of the boundary layer depth taken by a lidar are used to evaluatethe results obtained by the model. Mon, 19 Sep 2011 08:22:19 GMT Pino, D.; Vilà-Guerau de Arellano, Jordi; Comerón Tejero, Adolfo; Rocadenbosch Burillo, Francesc no The development and maintenance of the atmospheric boundary layer (ABL) plays a key role in the distribution of atmospheric constituents, especially in a polluted urban area. In particular, the ABL has a direct impact on the concentration and transformation of pollutants. In this work, in order to analyze the different mechanisms which control the boundary layer growth, we have simulated by means of the non-hydrostatic model MM5 several boundary layer observed in the city of Barcelona (Spain). Sensitivity analysis of the modelled ABL is carried out by using various descriptions of the planetary boundary layer (PBL). Direct and continuous measurements of the boundary layer depth taken by a lidar are used to evaluate the results obtained by the model.