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Grieco G., Stoffelen A., Verhoef A., Vogelzang J., Portabella M. (2023)
Proc. of the International workshop on metrology for the sea (Metrosea) Valetta, Malta, 4-6 October. (BibTeX: grieco.etal.2023)
Abstract: See
This paper presents a new methodology to improve the sampling of coastal winds derived from the SeaWinds scatterometer, which flew onboard the polar orbiting satellite platform Quick Scatterometer (QuikSCAT) from 1999 until 2009. The coastal SeaWinds Normalized Radar Cross Sections (σ0s) are corrected for land contamination using the so-called “noise-regularization” procedure. The results show that this methodology is effective in filling the typical coastal scatterometer gap of ≈30 km. From a visual check on a coastal test area, the distribution of the newly derived winds seems to be consistent with that of the offshore winds. However, proper validation is needed. This is left for the future.
Keywords: SeaWinds, ocean vector winds, coastal areas
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Llorach-Tó G., Martínez E., Del Río J., García-Ladona E. (2023)
In OCEANS 2023, June 2023, Limerick, Ireland. (BibTeX: llorach-to.etal.2023)
Abstract: See
Oceanographic data such as wave conditions (height, period, direction), wind, and sea currents are often difficult to interpret. What is the sea state given a certain wave height, wave directional spreading, and wind speed (e.g., 2 m, 29º, 18 m/s)? An expert user might be able to imagine the sea conditions with such information, but this will be almost impossible for a non-expert user. The common approach for visualizing oceanographic data and its variability is usually through tables and 2D graphs, for example plots, bar diagrams, and latitude-longitude maps. These visualizations are often limited to displaying raw data values, which still require user interpretation. With the purpose of providing a more intuitive view of the marine environment and sea conditions to a widespread audience, this work presents an experimental web application. The open-source application represents in a realistic and intuitive way the observations from a meteo-oceanographic and seafloor observatory located in the Western Mediterranean; the OBSEA observatory. The user can visualize the marine observatory facilities within a 3D virtual environment that changes and evolves according to the data acquired. This work aims at a digital twin of the seafloor observatory using near-real- time and historical data
Keywords: data visualization, 3D virtual environment, webGL, ocean simulation, digital twin
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Nunziata F., Migliaccio M., Buono A., Ferrentino E., Alparone M., Zecchetto S., Zanchetta A., Portabella M., Grieco G. (2023)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Pasadena (CA), USA, 16-21 July, 2023. (BibTeX: nunziata.etal.2023)
Abstract: See
This study is to present the lesson learned during the activities related to the Italian Space Agency (ASI) funded APPLICAVEMARS project which aims at estimating sea surface wind field from L-, C- and X-band Synthetic Aperture Radar (SAR) imagery. The paper focuses on the X-band results and it describes a new approach to estimate ancillary wind direction info from the SAR image itself using neural networks.
Keywords: Ocean, Wind field, SAR, NN
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Pablos M., Portal G., Camps A., Vall-llossera M., González-Haro C., Portabella M. (2023)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Pasadena (CA), USA, 16-21 July, 2023. (BibTeX: pablos.etal.2023)
Abstract: See
A modification of the Barcelona Expert Center (BEC) algorithm to downscale the Soil Moisture and Ocean Salinity (SMOS) soil moisture (SM) to 300 m spatial resolution is presented. It maintains the same functional relationship as the currently implemented version but employs the following inputs: SMOS brightness temperature (TB) and SM (25 km), European Center for Medium Weather Forecast (ECMWF) skin temperature (9 km), and Sentinel 3 Normalized Difference Vegetation Index (NDVI, 300 m). The performance of the downscaled SMOS SM at 300 m is analyzed by means of a temporal validation with in-situ observations from the Soil Moisture Measurements Stations Network of the University of Salamanca (REMEDHUS) and the Continuous Soil Moisture and Temperature Ground- based Observation Network (RSMN) during the year 2021. No significant differences in correlation, unbiased root mean square difference (ubRMSD) and bias are obtained over both networks compared to the 25 km and 1 km SM products, suggesting the BEC downscaling algorithm could work at hundreds of meters and result in a similar SM accuracy
Keywords: Soil moisture, disaggregation, downscaling, SMOS, Sentinel 3
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Xu X., Stoffelen A., Ni W., Portabella M., Rabaneda A.S. (2023)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Pasadena (CA), USA, 16-21 July, 2023. (BibTeX: xu.etal.2023)
Abstract: See
C-band scatterometer winds have been adjusted for extreme conditions and in this research extension to Ku-band scatterometers is investigated. With rain rates from the Global Precipitation Measurement mission collocated to the Ku-band scatterometer observations to identify and exclude rain contamination of winds, calibration of the Ku-band observations can be done. Using high-wind cases extracted from collocated C- and Ku-band observations, we develop a calibration model and extend the Ku-band winds to 35 m/s. Validation is obtained from the set not included in the model derivation, indicating a speed error less than 10% for wind speed larger than 30m/s. The modified speed is consistent with the Step Frequency Microwave Radiometer measurements, when collocated with another Ku-band scatterometer. A comparison for the Tropical Cyclone Manyi in 2018 shows the adjustedd wind fits better with the besttrack information provided by the Chinese Meteorological Administration, while more details are revealed. Results can be improved after obtaining more collocations with the dualfrequency scatterometer “WindRad” onboard the FY-3E satellite. A method for wind direction enhancement in extreme conditions is also discussed.
Keywords: wind scatterometers, Ku-band and C-band collocations, extreme wind speed adjustment
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Cossu F., Portabella M., Lin W., Stoffelen A., Vogelzang J., Marseille G.J., de Haan S. (2022)
IEEE International Geoscience and Remote Sensing Symposium (IGARSS). 6494-6497. DOI: 10.1109/IGARSS46834.2022.9883249. (BibTeX: cossu.etal.2022)
Abstract: See
The resolution of regional numerical weather prediction (NWP) models has continuously been increased over the past decades, in part, thanks to the improved computational capabilities. At such small scales, the fast weather evolution is driven by wind rather than by temperature and pressure. Over the ocean, where global NWP models are not able to resolve wind scales below 150 km, regional models provide wind dynamics and variance equivalent to 25 km or lower. However, although this variance is realistic, it often results in spurious circulation (e.g., moist convection systems), thus misleading weather forecasts and interpretation. An accurate and consistent initialization of the evolution of the 3- dimensional (3-D) wind structure is therefore essential in regional weather analysis. The research will focus on a comprehensive characterization of the spatial scales and measurement errors for the different operational space-borne wind products currently used and/or planned to be used in regional models. Regarding the characterization of the spatial scales and measurement errors, the widely used triple collocation analysis in scatterometry is further analyzed and adapted for the purpose of this project. An algorithm for collocating 4D wind observations from Aeolus, Mode-S data, and ECMWF model output over a region of Western Europe is will be presented, along with measurement errors from triple collocation
Keywords: Aeolus, Mode-S, wind, triple collocation
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Grieco G., Portabella M., Stoffelen A., Vogeltang J., Verhoef A. (2022)
IEEE International Geoscience and Remote Sensing Symposium (IGARSS). 6919-6922. DOI: 10.1109/IGARSS46834.2022.9884598. (BibTeX: grieco.etal.2022a)
Abstract: See
This paper describes some preliminary steps to improve the coastal winds retrieved from the Seawinds scatterometer onboard the QuikSCAT satellite platform. In particular, it describes a method for estimating the slice Normalized Radar Cross Section (σ0) noise. Moreover, it shows a simple method for selecting the best-suited σ0 domain for implementing a Land Contribution Ratio (LCR) based σ0 correction scheme aiming to reduce the land contamination from coastal measurements. The results are discussed with a particular focus on the differences between the noise characteristics of the open ocean measurements compared to those acquired on every type of surface, including land and ice, and their consistency with the information reported in the QuikSCAT files. In addition, the effects of the biases induced by the intra-footprint (egg) incidence angle variation on the noise estimation are shown. Finally, the differences between the σ0 dependency on LCR in the linear and logarithmic spaces are analyzed. The preliminary results suggest that there are some non-negligible differences between the open sea and the ”every kind of surface” noise characteristics, even if such differences are not reported in the QuikSCAT files. The intra-egg σ0 biases may amount to approximately ±0.6 dB for H-Pol acquisitions and half of that for V-Pol, but the impact on the noise estimation amounts to less than 2%. Finally, the σ0 dependency on LCR is more pronounced in the linear space, suggesting that this is the best-suited domain to implement the LCR based σ0 correction scheme, which is now being tested and developed
Keywords: Coastal winds, Normalized Radar Cross Section noise, QuikSCAT, Land Contribution Ratio
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Grieco G., Stoffelen A., Verhoef A., Vogelzang J., Portabella M. (2022)
IEEE International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea). 383-387. DOI: 10.1109/MetroSea55331.2022.9950798. (BibTeX: grieco.etal.2022b)
Abstract: See
This paper presents a new methodology to cor- rect the land-contaminated normalized radar cross-section (σ0) measurements acquired by the SeaWinds scatterometer, which flew onboard the QuikSCAT satellite platform from 1999 to 2009, operated by the National Aeronautics and Space Ad- ministration (NASA). This method is based on the hypothesis that contaminated σ0s are linearly dependent on the Land Contribution Ratio (LCR) index, which is defined as the ratio of the footprint area contaminated by the presence of land to the total footprint area. Furthermore, the σ0 deviations from the expected contaminated σ0 values are “regularized” by means of an adimensional constant, which is defined as the ratio of the noise level evaluated at the σ0 level of the sea to the noise level of the expected contaminated σ0 level. The preliminary results show that this methodology is effective up to few kilometers to the coast. In addition, it prevents the excessive presence of negative corrected
Keywords: Ocean vector wind, scatterometer, SeaWinds
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Grieco G., Portabella M., Vogelzang J., Verhoef A., Stoffelen A. (2022)
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Grieco G., Stoffelen A., Vogelzang J., Verhoef A., Portabella M. (2022)
Proc. of the Oceans from Space 2022. Ed. Eds. V. Barale, J.F.R. Gower, L. Alberotanza, NSA Group, pp. 120-121. 120-121. (BibTeX: grieco.etal.2022d)
Abstract: See
This paper presents a new methodology to correct the land-contaminated normalized radar crosssection (σ0) measurements acquired by the scatterometer SeaWinds, which flew aboard the QuikSCAT satellite platform from 1999 to 2009, operated by the National Aeronautics and Space Administration (NASA). This method is based on the hypothesis that contaminated σ0s are linearly dependent on the Land Contribution Ratio (LCR) index, which is defined as the ratio of the footprint area contaminated by the presence of land to the total footprint area. Furthermore, the σ0 deviations from the expected contaminated σ0 values are “regularized” by homogenizing their distribution, making them independent of land contamination. The preliminary results show that this methodology is effective up to few kilometers to the coast. In addition, it prevents the presence of negative corrected
Keywords: Ocean vector wind, scatterometer, SeaWinds.
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Makarova E., Portabella M., Stoffelen A. (2022)
Associated Scientist report for the EUMETSAT OSI SAF, OSI_VSA22_01. (BibTeX: makarova.etal.2022)
Abstract: See
This work aims at creating a preliminary machine learning (ML) model for correcting the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis stress-equivalent local wind biases, based on atmospheric and oceanic parameters. Several errors in the ECMWF global output for near surface ocean winds have been reported when validated against scatterometer observations. An existing approach for correcting these biases (the so-called ERA* method) consists of scatterometer-based corrections accumulated over a certain time window at each grid point, which allows to reduce local persistent biases. This approach is sensitive to scatterometer sampling and, to collect a statistically significant number of samples, assumes that such biases are static. This is not the case for errors due to moist convection or the diurnal cycle. For operational purposes, the temporal window is lagged with respect to the reanalysis forecast time and the time difference betweeen scatterometer-based correction (SC) and sample data collections can be ten days. We propose a preliminary ML setup that looks for the functional relationship between several oceanic and atmospheric variables that describe the persistent NWP errors as observed in the NWP-scatterometer differences. This would allow to predict the biases of the stress- equivalent wind forecasts and using the bias corrections in coupled weather or seasonal forecasts, or to account for these in climate runs. Such variables are first identified as ECMWF model parameters, such as stress-equivalent winds, their derivatives (curl and divergence), atmospheric stability related parameters, i.e., sea-surface temperature (SST), air temperature (Ta), relative humidity (rh), surface pressure (sp), as well as SST gradients and ocean currents. This work evaluates the feasibility of such approach and provides an overview of possible implementations of this regression
Keywords: scatterometer-based corrections, ERA5 biases, Machine Learning, Ocean forcing
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Martin A., McCann D., Macedo K., Meta A., Gommenginger C., Portabella M., Marié L., Horstmann J., Filipot J.F., Marquez J., Martín-Iglesias P., Casal T. (2022)
Proc. of the Oceans from Space 2022. Ed. Eds. V. Barale, J.F.R. Gower, L. Alberotanza, NSA Group, pp. 128-129. 128-129. (BibTeX: martin.etal.2022)
Abstract: See
The ocean interacts with the atmosphere, land and ice on multiple spatial scales including fine submesoscales that are often observed in high resolution optical images. Little is known about their dynamics however. SeaSTAR is an innovative satellite mission concept that proposes to address this gap by mapping ocean current and wind vectors at 1 km resolution. In this paper, we present the OSCAR instrument - an airborne demonstrator of the SeaSTAR concept - and the first results from a scientific campaign over the Iroise Sea in May 2022. The capabilities of OSCAR are demonstrated against ground truth data with very promising first results. These results open the door to using OSCAR as a scientific tool to provide unique 2D synoptic views of ocean and atmosphere dynamics at km-scales.
Keywords: Doppler Oceanography, Total Surface Current, Wind
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Nunziata F., Migliaccio M., Buono A., Ferrentino E., Alparone M., Zecchetto S., Zanchetta A., Portabella M., Grieco G. (2022)
IEEE International Workshop on Metrology for the Sea (Metrosea), Milazzo, Italy, 3-5 October, 2022. (BibTeX: nunziata.etal.2022)
Abstract: See
In this study, wind speed is estimated from COSMO- SkyMed (CSK) Synthetic Aperture Radar (SAR) imagery using two approaches, which both exploit the X-band Geophysical Model Function (GMF) XMOD2 developed for the German TerraSAR-X SAR mission. The first approach uses external wind direction information provided by collocated ASCAT scat- terometer measurements; the second one incorporates wind direction derived from the SAR scene using the Continuous Wavelet Transform (CWT). Experimental results, obtained using a relatively small collocated CSK data set, show the robustness of the wind estimation from the CSK imagery that result in accurate enough estimates under a range of incidence angles that span between 30° and 50°. The CWT approach allows reliable wind estimates on a 1km spatial grid.
Keywords: Sea wind, SAR, GMF, CWT
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Nunziata F., Migliaccio M., Buono A., Ferrentino E., Alparone M., Zecchetto S., Zanchetta A., Portabella M., Grieco G. (2022)
IEEE International Geoscience and Remote Sensing Symposium (IGARSS). 5184-5187. (BibTeX: nunziata.etal.2022a)
Abstract: See
This abstract is to present preliminary results related to the Italian Space Agency (ASI) funded APPLICAVEMARS project which aims at estimating sea surface wind field from L-, C- and X-band Synthetic Aperture Radar (SAR) imagery. First experimental results related to C-band Sentinel-1 SAR imagery are presented
Keywords: One, two, three, four, five
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Portabella M., Trindade A., Grieco G., Makarova and F. Cossu E. (2022)
IEEE International Geoscience and Remote Sensing Symposium (IGARSS). 6783-6786. DOI: 10.1109/IGARSS46834.2022.9883300. (BibTeX: portabella.etal.2022)
Abstract: See
The ERA* stress-equivalent wind (U10S) is a correction of the ECMWF Fifth Reanalysis (ERA5) output by means of geo-located scatterometer-ERA5 differences over a 3-day temporal window, in which the combined sampling of the Advanced Scatterometers on board the Metop satellite series (ASCAT-A, -B, and -C) and the SCATSat-1 scatterometer (OSCAT2) have been used, for the year 2019. ERA* can correct for local, persistent NWP model output errors associated with physical processes that are absent or misrepresented by the model, e.g., strong current effects (such as western boundary current systems, highly stationary), wind effects associated with the ocean mesoscales (sea surface temperature), coastal effects (land see breezes, katabatic winds), Planetary Boundary Layer parameterization errors, and large-scale circulation effects, e.g., at the inter- tropical convergence zone
Keywords: ERA*, numerical weather prediction, ocean wind forcing, oceanic mesoscale, scatterometer wind
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Portabella M., Rabaneda A.S., Grieco G. (2022)
ESA report MAXSS-ATBD-satellite-wind-recalibration_v2 (Contract No. 4000132954/20/I-NB). (BibTeX: portabella.etal.2022a)
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Portabella M., Trindade A., Grieco G., Makarova E. (2022)
ESA report WOC-ESA-ODL-NR-009_T1_ERAstar_V2.0 (Contract No. 4000130730/20/I-NB). (BibTeX: portabella.etal.2022b)
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Portabella M., Trindade A., Grieco G., Makarova E. (2022)
ESA report WOC-ESA-ODL-NR-010_T1_ERAstar_V2.0 (Contract No. 4000130730/20/I-NB). (BibTeX: portabella.etal.2022c)
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Portabella M., Rabaneda A.S., Grieco G., Polverari F., Stoffelen A., Sapp J., Jelenak Z., Chang P., Cossu F. (2022)
Proc. of the Oceans from Space 2022. Ed. Eds. V. Barale, J.F.R. Gower, L. Alberotanza, NSA Group, pp. 122-123. 121-123. (BibTeX: portabella.etal.2022d)
Abstract: See
Accurate high and extreme sea surface wind observations are essential for meteorological, ocean, and climate applications. A method to inter-calibrate spaceborne scatterometer and radiometer derived high and extreme winds using NOAA hurricane “hunter” data is presented. The proposed method is effective, providing highly consistent satellite-derived extreme wind datasets in the period 2009-2020. Further work is needed though to consolidate an in-situ reference for extreme wind calibration purposes.
Keywords: Ocean extreme winds, scatterometers, radiometers, inter-calibration.
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Alfredsson I., Anaya-Carlsson K., Barker M., Blanquer-Espert I., Carrillo R., Carrosán-Amilburu C., Cesevičiūtė I., Clare H., Diochnou V., Dobrucky M., Dumouchel S., Fazekas-Parragh J., Filiposka S., Fillery-Travis A., Flynn K., Gaillard V., Kalaitzi V., Konijn J., Kuchma I., La Rocca G., Lazzeri E., Legat D., Maarit-Sunikka A., Manola N., Matser V., Mayor L., Petra E., Petrillo C., Piera J., Portugal-Melo A., Proficz J., Psomopoulos F., T.D. Reimer R., Smith C., Stangeland E., Stoy L., Svendsen M., Toth-Czifra E. (2021)
Ed. Michelle Barker, Natalia Manola, Vinciane Gaillard, Iryna Kuchma, Emma Lazzeri and Lennart Stoy. The EOSC Executive Board. DOI: 10.2777/59065. ISBN. 978-92-76-28948-7. (BibTeX: alfredsson.etal.2021)
Abstract: See
Digital skills for FAIR1 and open science are a cornerstone of the European Open Science Cloud (EOSC)’s operations and future. An EOSC network of skilled professionals is essential to bring a culture change for sharing research outcomes, and to empower individuals and institutions to develop and maintain EOSC competences, skills and capabilities. The EOSC Skills and Training Working Group (WG) was formed in 2020 to identify a framework for building competence and capabilities for EOSC.
Álvarez-Solas J., Blasco J., Gabarró C., Montoya M., Robinson A., Tabone I. (2021)
Criosfera: el hielo polar y su papel en el clima terrestre
Observando los polos. In: EAN 9788413522999 colección Divulgación. Ed. V. Balagué, M. Vila, C. Cardelús. CSIC y Catarata. ol. 34, Chap. 9. ISBN. 978-84-1352-299-9. (BibTeX: alvarezsolas.etal.2021)
Abstract: See
Las zonas polares, principales responsables del clima de nuestro planeta, están sufriendo cambios drásticos en su naturaleza debido a su alta sensibilidad al cambio global, que afectan directamente a la dinámica climática, oceanográfica y ambiental de latitudes extrapolares. El presente libro pretende dar una visión integral y multidisciplinar del estado del conocimiento de las zonas árticas y antárticas: su evolución geológica, los acuciantes problemas de contaminación de estos territorios, la caracterización de los diversos ecosistemas terrestres y marinos, así como la evolución pasada y futura del clima polar. El objetivo final es explicar, de forma clara y amena, las similitudes y diferencias entre ambos polos y concienciar sobre las alteraciones que están sufriendo debido al cambio global. Asimismo, se dan a conocer las investigaciones, de gran relevancia científica y social, realizadas por el personal científico y técnico del Consejo Superior de Investigaciones Científicas (CSIC), acercándonos a la historia y situación actual de la investigación polar en España
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Dong X., Chang P.S., Stoffellen A., Portabella M., Kuma R., Linow S., Zou J., Lin W., Xu X. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: dong.etal.2021)
Abstract: See
Decades of ocean surface vector wind (OSVW) data acquired from space-based radar scatterometry have been providing short and long-term researches and applications information about ocean surfaces. The main objective of the project, stands and metrics of ocean surface vector wind by space-borne microwave remote sensing, of Working Group on Calibration and Validation of the Committee on Earth Observation Satellites (CEOS WGCV) , is to develop the standard and guideline for the requirement, procedure, processing and assessment for the spaceborne radar scatterometer measurement calibration, wind retrieval approaches, wind data validation and assessment for OSVW, which will be used to assure the consistency of the data quality of these satellites and instruments are the prerequisite for related scientific researches and applications. This synthesizes calibration, standardized practices of retrieval approaches for ocean surface winds, development of guidelines/standards of validation of ocean surface winds, and identifying and organizing collocation related data. This presentation will provide an overview of the project and the recent progresses
Keywords: Scatterometry, Calibration, Metrics, Data quality.
Escayo J., Fernández J., Gabarró C., Marsal S., Navarro G., Ugalde A. (2021)
Observaciones al límite. Instrumentación para la observación en zonas polares
Observando los polos. In: EAN 9788413522999 colección Divulgación. Ed. V. Balagué, M. Vila, C. Cardelús. CSIC y Catarata. ol. 34, Chap. 11. ISBN. 978-84-1352-299-9. (BibTeX: escayo.etal.2021)
Abstract: See
Las zonas polares, principales responsables del clima de nuestro planeta, están sufriendo cambios drásticos en su naturaleza debido a su alta sensibilidad al cambio global, que afectan directamente a la dinámica climática, oceanográfica y ambiental de latitudes extrapolares. El presente libro pretende dar una visión integral y multidisciplinar del estado del conocimiento de las zonas árticas y antárticas: su evolución geológica, los acuciantes problemas de contaminación de estos territorios, la caracterización de los diversos ecosistemas terrestres y marinos, así como la evolución pasada y futura del clima polar. El objetivo final es explicar, de forma clara y amena, las similitudes y diferencias entre ambos polos y concienciar sobre las alteraciones que están sufriendo debido al cambio global. Asimismo, se dan a conocer las investigaciones, de gran relevancia científica y social, realizadas por el personal científico y técnico del Consejo Superior de Investigaciones Científicas (CSIC), acercándonos a la historia y situación actual de la investigación polar en España.
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García-Ladona E., Allegue J.M., Ballabrera J., Pérez F. (2021)
DOI: 10.13140/RG.2.2.30493.23525. (BibTeX: garcialadona.etal.2021)
Abstract: See
Este documento recoge los aspectos técnicos relativos a los formatos y sistemas de intercambio de información entre las diferentes instituciones del proyecto Corrientes Oceánicas y Seguridad en el MedioMarinO(COSMO)
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Geyer A., Giralt S., Madurell T. (2021)
Madrid: Consejo Superior de Investigaciones Científicas. 83. ISBN. 978-84-00-10859-5. (BibTeX: geyer.etal.2021)
Abstract: See
Pocas áreas geográficas de nuestro planeta son tan fascinantes y, a su vez, tan desconocidas como las regiones polares. Su gran interés científico reside en el importante y decisivo papel que juegan en la dinámica y el futuro de nuestro planeta, especialmente en el actual contexto de cambio global, ya que las regiones polares son los grandes y principales motores reguladores del clima de la Tierra. Los drásticos cambios que están sufriendo en respuesta al aumento de temperatura, ocasionado por el incremento en la emisión de gases de efecto invernadero como consecuencia de las actividades humanas, están afectando directamente a la dinámica climática, oceanográfica y ambiental, tanto de los propios polos como de latitudes extrapolares. Este libro de fotografías persigue mostrar la belleza de estas regiones tan remotas a la par que proporcionar una visión integral y multidisciplinar del estado del conocimiento de las zonas polares, remarcando las semejanzas y diferencias entre el Ártico y la Antártida. Especialmente, busca concienciar a las nuevas generaciones sobre la importancia y vulnerabilidad de las regiones polares. Además, pretende resaltar la necesidad de una investigación enfocada a comprender y evaluar su papel en el futuro incierto de nuestro planeta en un contexto de transformación derivada del cambio global actual.
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Grieco G., Portabella M., Stoffelen A., Vogelzang J., Verhoef A. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: grieco.etal.2021)
Abstract: See
This paper presents the implementation of the Land Contri- bution Ratio (LCR) methodology for the pencil-beam scat- terometer QuikSCAT, with the aim of improving the coastal sampling of the retrieved winds. This methodology is pre- sented with two different models of the Spatial Response Function (SRF): the analytical model and the parameterized one, which is based on a pre-computed Look-up-Table (LUT) of SRFs provided by the Brigham Young University (BYU). Furthermore, a method to characterize the slice σ0 noise (Kp) is presented and compared to the noise information provided in the full resolution QuikSCAT files. The preliminary results show that despite the overall consistency between the two SRF models, their discrepancies may induce LCR differences up to few percent. Furthermore, the Kp estimated by means of the slice Normalized Radar Cross Section (σ0) is different from the Kp provided in the files, while such differencies are larger for certain slices and wind conditions. Such discrepan- cies can impact the wind field retrievals and, as such, should be further investigated.
Keywords: Coastal winds, pencil-beam scatterome- ters, QuikSCAT, Land Contribution Ratio
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Grieco G., Portabella M., Vogelzang J., Verhoef A., Stoffelen A. (2021)
Associated Scientist report for the EUMETSAT OSI SAF, OSI_VS20_03. (BibTeX: grieco.etal.2021a)
Abstract: See
An assessment of the noise affecting the QuikSCAT Normalized Radar Cross Sections is carried out in this study. The estimation of Kp ( ^Kp) is compared to the median of the Kp values ( ~Kp) provided in the Level 1B Full Resolution (L1B) file with orbit number 40651, dated 10th of April 2007, and the main differences are discussed. A sensitivity analysis aiming at assessing the presence of any dependencies with respect to (w.r.t.) different wind regimes, the kind of scattering surface, the scatterometer view and the polarization of the signal is carried out. In addition, the presence of any biases is assessed and discussed. Finally, a theoretical distribution model is proposed and validated against the true measurements. The main outcomes of this study demonstrate that H-Pol measurements are noisier than those V-Pol and that the noise lowers with increasing levels, in line with the expectations. Furthermore, ^Kp may largely differ from ~Kp, especially for the peripheral slices w.r.t. to the footprint (egg) centroid. In particular, the Kp values provided for the slices with indices 0 and 1 seem to be overestimated, while the opposite happens for those with indices 6 and 7. In addition, the ^Kp values estimated over the sea surface are lower than those estimated without making any distinctions among the scattering surfaces. This trend is not seen for ~Kp, for which the differences are almost absent. In addition, ^Kps relating to aft acquisitions do not differ from those relating to fore ones. Furthermore, some inter slice biases up to 0.8 dB are present for H-Pol acquisitions while they are up to 0.3 dB for V-Pol ones, in both cases increasing with the relative distance between the slices, in line with the general Geophysical Model Function (GMF) sensitivity as a function of incidence angle. These biases have a non at trend w.r.t. the acquisition azimuth angle for both polarizations. These small variations may be due to the changes in wind speed and direction sample for each bin. The theoretical model proves to be effective. It can be used both for simulation studies and for checking the accuracy of the noise.
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Lin W., Portabella M., Lv S., Stoffelen A., Wang Z. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: lin.etal.2021)
Abstract: See
In the context of the ocean surface vector wind virtual constellation, the combined wind products from the ongoing operational scatterometers will unprecedentedly increase the spatial and temporal coverage of remote sensing winds, and ease the development of gap-free sea surface wind data of high quality and high spatial/temporal resolution for a variety of applications, including a better marine forecasting and monitoring. However, systematic differences do exist in the wind products derived from different scatterometers, which may result in detrimental impacts in these applications. Therefore, the difference between the retrieved winds from C- and Ku-band scatterometers is further explored in this paper. In particular, sea surface temperature (SST) effects, quality control and high wind sensitivity of both C- and Ku-band scatterometers are analyzed, with the objective to better understand the sources of the inconsistencies, and to provide the wind users with support and recommendations in terms of wind applications.
Keywords: Scatterometer, high wind, quality control, rain, wind variability.
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Logares R., Alós J., Catalán I., Crespo-Solana A., Del Campo J., Ercilla G., Fablet R., Fernández-Guerra A., Galí-Tapias M., Gasol J.M., González A.F., Hernández-García E., López C., Massana R., Montiel L., Palmer M., Pascual S., Pascual A., Pérez F., Portabella M., Ramasco J.J., Richter D., Sallarés V., Sánchez P., Sanllehi J., Turiel A., Villaseñor A. (2021)
White Paper 13: Ocean Science Challenges for 2030. Editorial CSIC. 163-179. ISBN. 978-84-00-10762-8. (BibTeX: logares.etal.2021)
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Pablos M., Turiel A., Vall-llossera M., Camps A., Portabella M. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: pablos.etal.2021a)
Abstract: See
The novel Correlated Triple Collocation (CTC) analysis allows to assess three different data sources of similar spatial resolutions, but with two of them being correlated. In this study, the CTC was applied to estimate the unbiased random errors of the global soil moisture (SM) data provided by two L-band satellite missions —the Soil Moisture and Ocean Salinity (SMOS) and the Soil Moisture Active Passive (SMAP)— and one numerical model —the ERA5-Land. The three existing SMOS SM products distributed by different research institutions were also analyzed. Preliminary results revealed that errors of SMOS and SMAP SM are correlated, with correlations of ∼0.5–0.6. Thus, only ERA5-Land can be considered as independent. The lowest error was obtained for SMAP (0.025 m3m−3), followed by ERA5-Land (0.036 m3m−3). Among the SMOS SM, SMOS-IC had the lowest error (0.046 m3m−3), SMOS- BEC showed an intermediate value (0.048 m3m−3), and SMOS-CATDS had the highest error (0.055 m3m−3).
Keywords: Soil moisture, triple collocation, SMOS, SMAP, ERA5-Land
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Portabella M., Trindade A., Grieco G., Makarova E. (2021)
ESA report WOC-ESA-ODL-NR-009_T1_ERAstar_V1.0 (Contract No. 4000130730/20/I-NB). (BibTeX: portabella.etal.2021)
Abstract: See
The ERA* stress-equivalent wind (U10S) and stress vector product version 1.0 is a correction of the ECMWF Fifth Reanalysis (ERA5) output by means of geo-located scatterometer-ERA5 differences over a 3-day temporal window, in which the combined sampling of the Advanced Scatterometers on board the Metop satellite series (ASCAT-A, -B, and -C) and the SCATSat-1 scatterometer (OSCAT2) have been used, for the year 2019. ERA* can correct for local, persistent NWP model output errors associated with physical processes that are absent or misrepresented by the model, e.g., strong current effects (such as WBCS, highly stationary), wind effects associated with the ocean mesoscales (SST), coastal effects (land see breezes, katabatic winds), PBL parameterization errors, and large-scale circulation effects, e.g., at the ITCZ.
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Portabella M., Trindade A., Grieco G., Makarova E. (2021)
ESA report WOC-ESA-ODL-NR-010_T1_ERAstar_V1.0 (Contract No. 4000130730/20/I-NB). (BibTeX: portabella.etal.2021a)
Abstract: See
The present document is the Product User Manual dedicated to the content and format description of the ERA star stress-equivalent wind vector (U10S) and wind stress product. This is the primary document that users should read before handling the product. It provides an overview of processing algorithm, technical product content and format and main validation results.
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Portabella M., Lin W., Stoffelen A., Xu X., Dong X. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: portabella.etal.2021b)
Abstract: See
With the advent of the golden era of scatterometry, with seven scatterometers currently operating in orbit and a few others to be launched in the near future, a wide variety of scientific and operational applications will certainly benefit from consolidated wind retrieval procedures. In particular, an important component of the scatterometer wind processing is the quality control (QC) procedure. Over the last two decades, several QC indicators have been developed for C-band and Ku-band scatterometers, and used in the operational generation of sea surface wind products. Such indicators mostly aim at identifying and filtering retrieved wind quality degradation due to high wind variability and/or rain contamination effects. As such, the different QC indicators may be applied for different oceanographic and meteorological applications. The methods will be presented at the conference to motivate a discussion on their application-dependent use and come up with a consolidated view from the different user communities
Keywords: Scatterometer, wind, quality control, rain, wind variability.
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Stoffelen A., Marseille G.J., Ni W., Mouche A., Polverari F., Portabella M., Lin W., Sapp J., Chang P., Zelenak J. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: stoffelen.etal.2021)
Abstract: See
How strong does the wind blow in a hurricane? This proves a question that is difficult to answer, but has farreaching consequences for satellite meteorology, weather forecasting and hurricane advisories. In the EUMETSAT CHEFS project, KNMI, ICM and IFREMER worked with international colleagues to address this question to prepare for the EPS-SG SCA scatterometer, which introduces C-band cross-polarization measurements to improve the detection of hurricane-force winds. To calibrate the diverse available satellite, airplane and model winds, in-situ wind speed references are needed. Unfortunately, these prove rather inconsistent in the wind speed range of 15 to 25 m/s, casting doubt on the higher winds too. Should we trust dropsondes at high and extreme winds or perhaps put more confidence in the moored buoy references? This dilemma will be presented to initiate a discussion with the international community gathered at IGARSS ‘21
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Tintoré J., Turiel A., Bartolomé R., Ballabrera J., Casas B., Dañobeitia J., Fernández F.F., García-Ladona E., Isern-Fontanet J., López C., Mourre B., Navarro G., Orfila A., Pascual A., Pelegrí J.L., Peters F., Piera J., Portabella M., Ruiz S., Simarro G., Sorribas J., Talone M. (2021)
White Paper 13: Ocean Science Challenges for 2030. Editorial CSIC. 17-32. ISBN. 978-84-00-10762-8. (BibTeX: tintore.etal.2021)
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Xu X., Stoffelen A., Portabella M., Lin W., Dong X. (2021)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Brussels, Belgium (online), 12-17 July, 2021. (BibTeX: xu.etal.2021b)
Abstract: See
Uncertainties in wind inversion from scatterometer observations are contributed by system and geophysical noise. In practice, both can be quantified by the indicators applied in the quality control (QC) procedures during wind processing. In this research, the underlying principles of three reported indicators, MLE, SE and Joss, are discussed for CSCAT. In the observation scenes of this Ku-band scatterometer, one of the major reasons for geophysical noise are rain clouds, which are analyzed specifically with respect to those indicators. Finally, examples for super typhoon Lekima, followed by Krosa in 2019, are discussed. We confirm that the MLE and Joss indicators are relatively independent from each other, and show different features in rain screening. The combined application of them would result in a better result of rain labelling. Another conclusion derived from this research is that SE and Joss are similar indicators of spatial heterogeneity in scatterometer wind fields, but that the wind speed depression measured by Joss is a more unique indicator of rain than SE. This research contributes to improving the quality of wind retrieval from scatterometers.
Keywords: Uncertainties, Quality indicators, Rain clouds, MLE, SE, Joss, Ku-band Scatterometer, CSCAT.
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Berdalet E., Marrasé C., Pelegrí J.Ll. (2020)
Resumen sobre la Formación y Consecuencias de la Borrasca Gloria (19-24 enero 2020). Ed. E. Berdalet, C. Marrasé, J.Ll. Pelegrí. CSIC - Instituto de Ciencias del Mar (ICM). 1-37. DOI: 10.20350/digitalCSIC/12496. (BibTeX: berdalet.etal.2020b)
Abstract: See
[ES] La borrasca o tormenta Gloria, que nació el 17 de enero de 2020 en el Atlántico Norte como una pequeña perturbación, tuvo un importante impacto sobre las Islas Balears y todo el litoral levantino de la Península Ibérica, entre Cap de Creus y Cap de la Nau. Entre el 19 y 24 de enero, toda la parte oriental de la Península Ibérica experimentó fuertes precipitaciones (valores máximos de más de 400 litros/m2), y a lo largo de toda la costa levantina se sucedieron fuertes vientos (valores medios de 15 m/s y rachas de hasta 36 m/s), una notable subida en el nivel del mar (hasta más de 0.6 m), fuertes corrientes (valores máximos por encima de 0.8 m/s) y oleaje extremo (altura significante máxima alrededor de 8 m). Todo ello impactó severamente en la costa, con un retroceso significativo de las playas, particularmente aquellas abiertas hacia el este y noreste. También se produjeron notables fenómenos de inundación que afectaron a estructuras costeras y formaciones naturales, muy especialmente, al Delta del Ebre. [...] [CAT] Resum sobre la Formació i Conseqüències de la Borrasca Glòria (19-24 gener 2020). La borrasca o tempesta Glòria, que va néixer el 17 de gener de 2020 a l\'Atlàntic Nord com una petita pertorbació, va tenir un important impacte sobre les Illes Balears i tot el litoral llevantí de la Península Ibèrica, entre el Cap de Creus i el Cap de la Nao. Del 19 al 24 de gener, tota la part oriental de la Península Ibèrica va experimentar fortes precipitacions (valors màxims de més de 400 litres/m²), i al llarg de tota la costa llevantina van bufar forts vents (amb valors mitjans de 15 m/s i ratxes de fins a 36 m/s), es va produir un notable increment en el nivell de la mar (fins a més de 0,6 m), forts corrents (amb valors màxims per sobre de 0,8 m/s) i onatge extrem (altura significant màxima al voltant dels 8 m). Tot això va impactar severament la costa, on les platges van experimentar una reculada significativa, particularment les obertes amb orientació est i nord-est. També va causar notables inundacions que van afectar tant estructures costaneres com formacions naturals, molt especialment, el Delta del Ebre. [...]
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Gabarró C., Bertino L., Bracher A., Diehl T.L., Dierking W., González-Gambau V., Hugues N., Lavergne T., Malnes E., Scholze M., Isern-Fontanet J., Portabella M., Pablos M., Madurell T. (2020)
Wordpress, 185 pp. (BibTeX: gabarro.etal.2020)
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Grieco G., Portabella M., Vogelzang J., Verhoef A., (2020)
Associated Scientist report for the EUMETSAT OSI SAF, OSI_VS20_01. (BibTeX: grieco.etal.2020a)
Abstract: See
Accurate high-resolution QuikSCAT-derived winds with dense coastal sam-pling are strategic for both scientific and civil applications. The implementa-tion of the QuikSCAT Spatial Response Function (SRF) analytical model andits parameterized version by means of a pre-computed look-up-table (LUT)provided by the Brigham Young University are described. The procedure forthe computation of the Land Contribution Ratio (LCR) index has been alsoimplemented. An optimized use of a high-spatial-resolution Land-Sea Mask(LSM) is described. Finally, an LCR-based procedure for the correction ofthe backscattered normalized radar cross section (σ0) has been implemented.Both analytical and LUT-derived SRF versions have been visually validated,together with the derived LCR indexes. The distribution of the coastalσ0scorresponding to a coastal test area of the Gulf of Taranto, in the southof Italy has been discussed. The main outcomes of this study show thatthe thorough characterization and exploitation of the full resolutionσ0noiseproperties is fundamental for the success of the wind field retrieval close tothe coast. Finally, future developments of the coastal processor are proposed.Most of these developments will be carried-out in the context of a recentlyapproved EUMETSAT Visiting Science Activity (VSA).
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Lin W., Portabella M., Zhao X. (2020)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS) online 26/9-2/10 2020. (BibTeX: lin.etal.2020)
Abstract: See
Rain is known to be the most significant phenomenon in degrading the Ku-band scatterometer wind quality. After the decommission of the National Aeronautics and Space Administration scatterometer (NSCAT), little work has been done in characterizing the impact of rain on Ku-band fan beam scatterometer. In this paper, the rain impact on the backscatter measurements as well as the retrieved wind quality of the China-France Oceanography Satellite (CFOSAT) scatterometer (CSCAT) is investigated using the European Centre for Medium-range Weather Forecasts (ECMWF) winds and the Global Precipitation Measurement (GPM) mission’s Microwave Imager (GMI) rain data as reference. The dependence of rain effects on the observing incidence angle is studied with the objective to optimize the configurations of wind inversion and quality control (QC). It is shown that the backscatter measurements at low incidence angles (~30º) are much less affected by rain than those at higher incidence angles. The operational CSCAT processing proves to be effective in screening rain-contaminated wind vectors but at the expense of many valuable winds. An adapted wind inversion scheme is proposed to further improve the CSCAT wind quality under rainy conditions.
Keywords: CFOSAT, scatterometer, wind, quality control, rain
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Stoffelen A., Mouche A., Polverari F., Van Zadelhoff G.J., Saap J., Portabella M., Chang P., Lin W., Jelenak Z. (2020)
EUMETSAT ITT 16/166. (BibTeX: stoffelen.etal.2020g)
Abstract: See
Global information on the motion near the ocean surface is generally lacking, limiting the physical modelling capabilities of the forcing of the world´s water surfaces by the atmosphere (Belmonte and Stoffelen, 2019). This also limits our knowledge of the exchange of momentum across the ocean‐atmosphere interface, affecting meteorological and ocean applications (Trindade et al., 2019). A particularly pressing requirement in the Ocean Surface Vector Wind (OSVW) community is to obtain reliable extreme winds in hurricanes (> 30 m s‐1) from wind scatterometers, since extreme wind, storm surge and wave forecasts for societal warning are a high priority in nowcasting as well as in Numerical Weather Prediction (NWP)
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Zhan Q., Vall-llossera M., Pablos M., , , Portal G., Chaparro D. (2020)
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium, Virtual Event, 2020. (BibTeX: zhan.etal.2020)
Abstract: See
Unaffected by the atmospheric conditions and solar illumination, L-band emission and scattering are sensitive to vegetation water content and can be used to estimate crop yield. However, for rice which has an inundated period during its growing cycle, the current methods do not work due to the water under the crops. In this paper, we propose to use Global Navigation Satellite System Reflectometry (GNSS-R) signals to find how the water in rice field influence vegetation optical depth (VOD) which had been recently used to estimate the crop yield. SM and VOD in Thailand rice fields are compared to signal to noise ratio (SNR) from CYGNSS. Good correlation among them has been found. Results indicate that GNSS-R signals can be used to flag the presence of water and develop an adapted VOD algorithm that can be used to improve the estimation of rice yields.
Keywords: yield estimation, rice, SMOS, GNSS-R, VOD
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García-Olivares A., Solé J., Osychenko O. (2019)
Energy Conversion and Management. ol. 185, 891. DOI: 10.1016/j.enconman.2018.12.036. (BibTeX: garciaolivares.etal.2019b)
Abstract: See
The authors regret that in page 274 of the pdf file (Section 3.5) it appears the following text. The equation should be modified adding the red expression in it; the numbers in red in the text should replace the numbers that appear in the current pdf. [...]
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Grieco G., Stoffelen A., Portabella M. (2019)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Yokohama, Japan, 28 July - 2 August. (BibTeX: grieco.etal.2019b)
Abstract: See
This paper presents an assessment of the effects of specular point (SP) estimation inaccuracies on the Signal to Noise Ratio peak (SNRPEAK) used for ocean wind speed retrievals from TechDemoSat-1 (TDS-1) Delay Doppler Maps (DDMs). Results show that the more inaccurate the estimated Doppler frequency at the SP, the lower the intensity of the SNRPEAK. Differences may be up to 2 dB.
Keywords: GNSS-R, SNR peak, Doppler frequency, specular point.
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Hilliard L.M., Petrov L., LeMoine F., Rajagopalan G., Elosegui P., Ruszczyk C., Gipson J., Horsley D., Brown G. (2019)
In IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium, 8956–59. Yokohama, Japan: IEEE. DOI: 10.1109/IGARSS.2019.8897849. (BibTeX: hilliard.etal.2019)
Abstract: See
A Technology Development, Infusion, and an interleaved joint cal/val opportunity plan is described for the VLBI GLOBAL OBSERVING SYSTEM (VGOS), and Earth Science satellite missions that measure water vapor such as Global Precipitation Measurement (GPM) Core Observatory that covers the Earth from 65°S to 65°N. The Jason Continuity of Service (Jason-CS) mission that will extend global sea-level records to 2030 and beyond is also a beneficiary and potential partner. The Space Geodesy Project (SGP) technique known as Very Long Baseline Interferometry (VLBI) is already deployed worldwide, and there are technology returns on investment to be gained by looking at the water vapor (wet) delay calibration in a 5year plan that serves to improve atmospheric models for Global Precipitation Measurement (GPM), Jason-CS, and the higher spatial resolution International Terrestrial Reference Frame (ITRF), a primary mission of SGP.
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Lin W., Portabella M., Lang S., Dong X., Xu X., Wang Z., He Y. (2019)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Yokohama, Japan, 28 July - 2 August. (BibTeX: lin.etal.2019d)
Abstract: See
The sea surface winds from the CFOSAT scatterometer (CFOSCAT) are retrieved using the maximum likelihood estimator, and the inversion residual is used to sort the good-quality winds from the poor-quality ones. A twodimensional variational analysis ambiguity removal (2DVAR) scheme is then applied over the CFOSCAT swath such that a unique wind field is selected from the available local scatterometer wind vector ambiguities. The preliminary results of CFOSCAT Level 2 (L2) processing show that the retrieved wind speed is overestimated under low-wind conditions (w < 4 m/s), and is underestimated at high wind conditions (w > 15 m/s). Moreover, the inversion residual for the sweet swath (where there are more than 10 views) is generally higher than that for the nadir/outer swath. These imply that observations with different geometries (views) at the same WVC are inconsistent with respect to the geophysical model function, and thus a comprehensive calibration is highly demanded. A more detailed assessment of the CFOSCAT wind quality will be carried out after calibration and validation campaign.
Keywords: CFOSAT, scatterometer, wind, quality control, calibration
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Olmedo E., González-Gambau V., Martínez J., González-Haro C., Turiel A., Portabella M., Arias M., Sabia R., Oliva R., Corbella I. (2019)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Yokohama, Japan, 28 July - 2 August. DOI: 10.1109/IGARSS.2019.8900562. ISBN. 978-1-5386-9154-0. (BibTeX: olmedo.etal.2019b)
Abstract: See
The quality of the Soil Moisture and Ocean Salinity (SMOS) Sea Surface Salinity (SSS) maps has been noticeably improved in the last two years, in particular those produced at the Barcelona Expert Center (BEC). However, the BEC SSS maps are still affected by a latitudinal and seasonal bias. In this work, we comprehensively characterize the residual latitudinal and seasonal biases, which are used to correct de retrieved SSS, leading to a new generation of higher-quality SSS maps. The shape and regularity of this bias suggests that the effect, which produces this error, is not a poor characterization of the galaxy, some residual Total Electron Content (TEC) effect, or a poor characterization of the systematic Sea Surface Temperature (SST) effects on the SSS retrieval. It appears to be related to a geometrical effect associated to the relative position between the SMOS antenna, the Sun and the Earth.
Keywords: SMOS; Sea Surface Salinity; Latitudinal bias; Seasonal bias.
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Pablos M., Vall-llossera M., Piles M., Camps A., González-Haro C., Turiel A., Herber C.J., Chaparro D., Portal G. (2019)
IEEE International Geoscience and Remote Sensing Symposium, Yokohama, Japan, 2019. 6941-6944. DOI: 10.1109/IGARSS.2019.8900273. ISBN. 978-1-5386-9155-7. (BibTeX: pablos.etal.2019)
Abstract: See
Global Soil Moisture and Ocean Salinity (SMOS) Level 3 (L3) soil moisture (SM) products are being routinely distributed by the Barcelona Expert Centre (BEC). The quality and accuracy of these SM products have been demonstrated not only by direct validation, but also by its adoption in a wide range of applications. Recently, changes in SMOS Level 2 (L2) SM have led to the reprocessing of the BEC SMOS L3 SM. As in previous versions, a filtering and a weighted binning based on the uncertainty of the SM retrievals by means of the Data Quality Index (DQX) was applied for the L3 production. However, the DQX was modified in the latest L2 release (v650), which could possibly have an influence in the performance of the derived products. This study assesses the impact of the current DQXbased BEC L3 SM quality filtering and binning approach and the possibility of using an alternative strategy based on the chi-squared (χ2 ) parameter, which is defined as the cost function of the retrieval. The study is performed over continental USA using in situ SM from the U.S. Climate Reference Network (USCRN) as a benchmark. In both approaches, similar results were obtained in terms of correlation and unbiased root mean square difference (ubRMSD). Nevertheless, the χ2 -based L3 SM is in general slightly wetter and has a lower dry bias than the DQX-based L3 SM. Further assessments will be performed to stablish the optimal filtering/binning of BEC SMOS L3 SM products.
Keywords: SMOS, soil moisture, DQX, chisquared.
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Pelegrí J.L., Marotta H., Navarrete S.A., Pascual A. (2019)
Cambio global. Una mirada desde Iberoamérica. ACCI. Chap. 7. 129-152. ISBN. 978-84-17519-33-9. (BibTeX: pelegri.etal.2019)
Abstract: See
Aproximadamente el 71% de la superficie del planeta está cubierta por océanos y mares que se encuentran interconectados. A pesar de su importancia, aún desconocemos muchos de los procesos físicos y biogeoquímicos de los océanos y su papel regulador sobre los ecosistemas marinos y terrestres. El objetivo de este capítulo es proporcionar una introducción muchos de los procesos físicos y biogeoquímicos de los océanos, con el énfasis puesto en su capacidad reguladora del ecosistema planetario, en lo que acostumbramos a llamar el estado termodinámico, o clima, de nuestro Planeta. En primer lugar describiremos las principales características de las variables físicas y biogeoquímicas que caracterizan al medio marino, con especial atención a la circulación oceánica y nivel medio del mar, así como a su temperatura, salinidad y nutrientes inorgánicos. A continuación nos centraremos en una de estas propiedades, el carbono, de interés muy especial para comprender el estado actual y posible evolución futura del clima de la Tierra. Concluiremos con unas reflexiones generales sobre la relevancia planetaria de los flujos y transformaciones de masa, energía y vida, y cómo estos flujos están siendo afectados por la actividad humana.
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Pelegrí J.Ll., Vallès‐Casanova I., Orúe‐Echevarría D. (2019)
Kuroshio Current: Physical, Biogeochemical, and Ecosystem Dynamics. In: Geophysical Monograph Series. Ed. T. Nagai, H. Saito, K. Suzuki, M. Takahashi. American Geophysical Union. ol. 243, Chap. 3. 23-50. DOI: 10.1002/9781119428428.ch3. ISBN. 9781119428343. (BibTeX: pelegri.etal.2019c)
Abstract: See
We present the historical development of the nutrient stream concept, from the initial ideas on the nutrient‐bearing stratum and the transport of inorganic nutrients by the Gulf Stream to the large‐scale inorganic and organic connections in the entire Atlantic Ocean. We mostly analyze and discuss available literature but also present some novel calculations using cruise data and the velocity fields from numerical re‐analysis data. We first examine and discuss the structure of the Gulf Nutrient Stream, the significance of boundary exchange, and the importance of epipycnal and diapycnal processes. We then move to explore the subtropical and remote pathways into the Gulf Nutrient Stream, including the effect of the returning limb of the global overturning circulation, and end up reviewing the concept of nutrient irrigation of the subpolar gyre and its relevance in the spring–fall maintenance of the spring bloom. We close the chapter with some thoughts on the role of streams in the Earth system, as the key conduit for recycling properties within any ocean subsystem while simultaneously connecting the different subsystems, hence bringing about the complexity of the living planet.
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Portabella M., Lin W., Stoffelen A., Verhoef A., Wang Z. (2019)
Associated Scientist report for the EUMETSAT OSI SAF, SAF/OSI/CDOP3/KNMI/SCI/RP/344. (BibTeX: portabella.etal.2019a)
Abstract: See
Recent developments on the wind geophysical model function (GMF) of Ku-band scatterometers include a sea surface temperature (SST) dependent term. It has been found that the SST effects on the radar backscatter are wind speed dependent and more pronounced in vertical polarization (VV) than in horizontal polarisation (HH) at higher incidence angles, and are mainly relevant at Ku radar wavelengths rather than at C-band. The new Ku-band GMF, NSCAT-5, was initially based on a physical model and RapidScat radar backscatter measurements, which are only available at two incidence angles, i.e., 48.8⁰ and 55.2⁰, for HH and VV beams, respectively. A more recent CDOP-2 AS study (OSI_AVS_17_01) confirms only small differences when verifying the NSCAT-5 GMF at similar incidence angles, using data from the recently-launched Indian SCATSat-1, which operates at 49.1⁰ (HH) and 57.9⁰ (VV) incidence angle. In order to further consolidate the NSCAT-5 GMF, the current study looks for quality control (QC) dependencies. It is found that indeed, the developed GMF is not particularly sensitive to different QC thresholds. Finally, an improved QC method, based on the successful experience with previous Ku-band rotating pencil-beam scatterometers, is developed for SCATSat-1 data.
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Stoffelen A., De Rosnay P., Calvet J.C., Breivik L.A., Aaboe S., Wagner W., Mouche A., Portabella M., De Chiara G., Cotton J. (2019)
ESA/EUMETSAT Scatterometer Science Advisory Group Report, v1.0. (BibTeX: stoffelen.etal.2019c)
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Stoffelen A., Verhoef A., Verpeek J., Vogelzang J., Portabella M., Trindade A., Wang Z., De Chiara G., Payan C., Dhomps A.L., Cress A., Cotton J., Brocca L., Long D., Monteiro I., Bentamy A. (2019)
Contributed International HY-2B Cal/Val results submitted to National Satellite Ocean Application Service (NSOAS). (BibTeX: stoffelen.etal.2019d)
Abstract: See
With great interest we welcome the NSOAS HY-2Bscatterometer, which favorably complements the METOP Advanced Scatterometer (ASCAT), the ISRO OceanSat-3 and ScatSat and Chinese-French Ocean Satellite (CFOSAT) scatterometers. Altogether, the international meteorological and oceanographic communities could expect to benefit of wind coverage from this virtual constellation ataround6:00, 7:00, 8:30, 9:30, 12:00, 18:00, 19:00, 20:30 21:30 and 24:00 Local Solar Time (LST), which is very useful for regional and coastal applications, but also for small-scale weather tracking, such as hurricanes, moist convection, and ocean forcing globally (Stoffelen et al., 2019). [...]