Strong RFI impact mitigation in the synthetic aperture interferometric radiometer

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Radio Frequency Interference (RFI) is one of the problems causing the performance degradation in passive microwave radiometry. Especially, Synthetic Aperture Interferometric Radiometer (SAIR) is quite vulnerable to strong RFI. The Soil Moisture Ocean Salinity (SMOS) brightness temperature images show serious contamination by the RFI. The RFI affection in SAIR images should be mitigated or filtered out to retrieve the geophysical parameters. This work presents a method to RFI mitigation/filtering for SAIRs. Different from the existing method processing the brightness temperature image directly, RFI filtering of the subspace of covariance matrix is introduced, and the results are shown. The proposed method shows decent results for strong RFI with efficiency compared to the existing methods. © 2018 IEEE.Peer ReviewedPostprint (published version

Deriving VTEC Maps from SMOS Radiometric Data

Special Issue Ten Years of Remote Sensing at Barcelona Expert Center.-- 18 pages,14 figures, 2 tablesIn this work, a new methodology is proposed in order to derive vertical total electron content (VTEC) maps from the radiometric measurements of the Soil Moisture and Ocean Salinity (SMOS) mission as an alternative approach to those based on external databases and models. This approach uses spatiotemporal filtering techniques with optimized filters to be robust against the thermal noise and image reconstruction artifacts present in SMOS images. It is also possible to retrieve the Faraday rotation angle from the recovered VTEC maps in order to correct the effect that it causes in the SMOS brightness temperaturesThis research was supported by the European Space Agency and Deimos Engenharia (Portugal), SMOS P7 Subcontract DME CP12 no. 2015-005; ERDF (European Regional Development Fund); by the Spanish public funds, projects TEC2017-88850-R and ESP2015-67549-C3-1-R; and through the award “Unidad de Excelencia María de Maeztu” MDM-2016-0600, financed by the “Agencia Estatal de Investigación” (Spain) and by the European Regional Development Fund (ERDF)With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)Peer reviewe

Correcting the FRA systematic error in VTEC maps from SMOS radiometric data

The Faraday rotation (FR) is a nonnegligible effect at the L-band, which is the operation frequency of the Soil Moisture and Ocean Salinity (SMOS) mission. This effect introduces a rotation in the electromagnetic field polarization when propagating through the ionosphere that must be compensated. Recently, a methodology was developed in order to retrieve the vertical total electron content (VTEC) from SMOS radiometric data with the aim to better correct the FR effect [1] . In that work, systematic patterns in the retrieved FR angle (FRA) were detected. In this article, these systematic patterns are characterized and corrected to improve the quality of the retrieved VTEC maps. These maps can be then reused in the SMOS level 2 processor for the correction of the FRA in the mission. The impact of using the SMOS-derived VTEC maps instead of the VTEC data from global positioning system (GPS) measurements on the ocean brightness temperatures (TB) measurement has also been analyzed. Results of this analysis show that the usage of those maps allows a significant enhancement in the quality of the TB, which will lead to an improvement on salinity retrievals.This work was supported in part by the European Space Agency, Soil Moisture and Ocean Salinity (SMOS) Expert Support Laboratories (ESL) for SMOS Level 1 and Level 2 over Land, Ocean and Ice Project under Grant RFQ/3-16138/19/I-BG; in part by the SMOS P7 under Contract DME CP12 no. 2015-005 (in joint with Deimos Engenharia, Portugal); in part by the Spanish Public Funds under Project TEC2017-88850-R and Project ESP2015-67549-C3-1-R through the Award “Unidad de Excelencia María de Maeztu” MDM-2016-0600, financed by the “Agencia Estatal de Investigación” (Spain); in part by the European Regional Development (ERDF); in part by the SMOS ESL for SMOS Level 1 and Level 2 over Land, Ocean and Ice Project under Grant ARG/003-032/0315/ICMCSIC; in part by the Spanish Research and Development Project INTERACT under Grant PID2020-114623RB-C31; and in part by the Spanish Government through the “Severo Ochoa Centre of Excellence” accreditation under Grant CEX2019-000928-S.Peer ReviewedPostprint (author's final draft

Calibration of the MIRAS Radiometers

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The microwave imaging radiometer with aperture synthesis (MIRAS) is formed by 69 total power radiometers, of which three are the noise-injection type. Their calibration is reviewed on the basis of the data gathered during more than eight years of operation. Internally calibrated gain and offset corrections with improved temporal stability are presented. New front-end loss characterization with lower seasonal dependence originated from external temperature swings is also proposed. Finally, a methodology to validate the external calibrations, with the instrument pointing to the cold sky, is developed. It seems to indicate that the change of orientation of the instrument, with associated thermal variations, may induce small changes in the radiometer front-end losses, thus introducing calibration errors.Peer ReviewedPostprint (author's final draft

Kostspielige Verantwortungsrhetorik : der Bundeswehr-Umbau führt zu einer Erhöhung des Rüstungshaushaltes

2014 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2014) & 35th Canadian Symposium on Remote Sensing, 13-18 july 2014, Québec City, Québec, Canada.-- 4 pages, 4 figuresThe current ASCAT Wind Data Processor (AWDP) uses the 2D variational ambiguity removal (2DVAR) scheme to select a unique wind field from a set of retrieved ambiguities. This has led to spatially consistent and accurate ASCAT Level 2 wind products. Nevertheless, recent research shows that 2DVAR picks up the wrong wind direction ambiguities in regions where the background field shows mislocation of fronts (convergence) or misses convective systems. In this paper, the exploitation of complementary information derived from the inversion and from an image processing technique is proposed to improve the current 2DVAR for ASCAT in mesoscale conditionsPeer reviewe

Correlation between Arctic river discharge and sea ice formation in Laptev Sea using sea surface salinity from SMOS satellite

European Geosciences Union (EGU) General Assembly 2020, 4-8 May 2020During the last 3 decades, the Arctic rivers have increased their discharge around 10%, mainly due to the increase of the global atmospheric temperature. The increase of the river discharge carries higher loads of dissolved organic matter (DOM) and suspended matter (SM) entering to the Arctic Ocean. This results in increased absorption of solar energy in the mixed layer, which can potentially contribute to the general sea ice retreat. Observation based studies (e.g. Bauch et al., 2013) showed correlation between river water discharge and local sea ice melting on the Laptev sea shelf due to the change on the ocean heat. Previous studies are based with a limited number of observations, both in space and in time. Thanks to the ESA SMOS (Soil Moisture and Ocean Salinity) and NASA SMAP (Soil Moisture Active Passive) missions we have daily the sea surface salinity (SSS) maps from the Arctic, which permit to observe the salinity variations due to the river discharges. The Arctic sea surface salinity products obtained from SMOS measurements have been improved considerable by the Barcelona Expert Center (BEC) team thanks to the project Arctic+Salinity, funded by ESA. The new version of the product (v3) covers the years from 2011 up to 2018, have a spatial resolution of 25km and are daily maps with 9 day averages. The Arctic+ SSS maps provide a better description of the salinity gradients and a better effective spatial resolution than the previous versions of the Arctic product, so the salinity fronts are better resolved. The quality assessment of the Arctic+SSS product is challenging because, in this region, there are scarce number of in-situ measurements. The high effective spatial resolution of the Arctic+ SSS maps will permit to study for the first time scientific physical processes that occurs in the Arctic. We will explore if a correlation between the Lena and Ob rivers discharge with the sea ice melting and freeze up is observed with satellite data, as already stated with in-situ measurements by Bauch et al. 2013. Salinity and sea ice thickness maps from SMOS and sea ice concentration from OSISAF will be used in this study. Bauch, D.,Hölemann, J. , Nikulina, A. , Wegner, C., Janout, M., Timokhov, L. and Kassens, H. (2013): Correlation of river water and local sea-ice melting on the Laptev Sea shelf (Siberian Arctic) , Journal of Geophysical Research C: Oceans, 118 (1), pp. 550-561 . doi: 10.1002/jgrc.2007

First SMOS Sea Surface Salinity dedicated products over the Baltic Sea

1st ESA Ocean Science Cluster Collocation Meeting, 29 November - 2 December 202

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

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

Oceanographic added-value of the first regional SMOS sea surface salinity products over the Baltic Sea

Ocean Salinity Conference, 6-9 June 2022, New York, USAThis work has been carried out as part of the Baltic+ Salinity Dynamics project (4000126102/18/I-BG), funded by the European Space Agency. It has been also supported in part by the Spanish R&D project INTERACT (PID2020-114623RB-C31), which is funded by MCIN/AEI/10.13039/501100011033. We also received funding from the Spanish government through the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S)Peer reviewe

Review of the CALIMAS Team Contributions to European Space Agency's Soil Moisture and Ocean Salinity Mission Calibration and Validation

Camps, Adriano ... et al.-- 38 pages, 22 figuresThis work summarizes the activities carried out by the SMOS (Soil Moisture and Ocean Salinity) Barcelona Expert Center (SMOS-BEC) team in conjunction with the CIALE/Universidad de Salamanca team, within the framework of the European Space Agency (ESA) CALIMAS project in preparation for the SMOS mission and during its first year of operation. Under these activities several studies were performed, ranging from Level 1 (calibration and image reconstruction) to Level 4 (land pixel disaggregation techniques, by means of data fusion with higher resolution data from optical/infrared sensors). Validation of SMOS salinity products by means of surface drifters developed ad-hoc, and soil moisture products over the REMEDHUS site (Zamora, Spain) are also presented. Results of other preparatory activities carried out to improve the performance of eventual SMOS follow-on missions are presented, including GNSS-R to infer the sea state correction needed for improved ocean salinity retrievals and land surface parameters. Results from CALIMAS show a satisfactory performance of the MIRAS instrument, the accuracy and efficiency of the algorithms implemented in the ground data processors, and explore the limits of spatial resolution of soil moisture products using data fusion, as well as the feasibility of GNSS-R techniques for sea state determination and soil moisture monitoringThis work has been performed under research grants TEC2005-06863-C02-01/TCM, ESP2005-06823-C05, ESP2007-65667-C04, AYA2008-05906-C02-01/ESP and AYA2010-22062-C05 from the Spanish Ministry of Science and Innovation, and a EURYI 2004 award from the European Science FoundationPeer Reviewe