2000 days of SMOS at the Barcelona Expert Centre: a tribute to the work of Jordi Font

Soil Moisture and Ocean Salinity (SMOS) is the first satellite mission capable of measuring sea surface salinity and soil moisture from space. Its novel instrument (the L-band radiometer MIRAS) has required the development of new algorithms to process SMOS data, a challenging task due to many processing issues and the difficulties inherent in a new technology. In the wake of SMOS, a new community of users has grown, requesting new products and applications, and extending the interest in this novel brand of satellite services. This paper reviews the role played by the Barcelona Expert Centre under the direction of Jordi Font, SMOS co-principal investigator. The main scientific activities and achievements and the future directions are discussed, highlighting the importance of the oceanographic applications of the mission.Peer ReviewedPostprint (published version

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

SMOS Measurements Preliminary Validation: Objectives and Approach

European Geosciences Union General Assembly, 2-7 May 2010, Vienna, Austria.-- 2 pagesThe Earth Explorer Soil Moisture and Ocean Salinity (SMOS) mission was successfully launched on November 2nd, 2009, in the framework of the European Space Agency Living Planet programme. It will provide long-awaited remotely-sensed Sea Surface Salinity (SSS) maps over the oceans with a 3-day revisiting time [1]. The SMOS Barcelona Expert Centre (SMOS-BEC) in Barcelona, Spain, will be involved in several activities at different levels of the salinity retrieval processing chain, which are classified according to the objectives/issues being addressed. In particular, those described hereafter refer to the validation of the products and the consolidation/improvement of the salinity retrieval procedure itself [2]. This will be carried out by performing specific comparisons against modelled brightness temperatures (TB) or external salinity data sources. Due to start at the beginning of the Commissioning Phase, the post-launch 6-month checkout and calibration period, these studies will continue through the nominal satellite operation phase. They will support the choice of an optimal data selection strategy in regard to the existing trade-off, for instance the Ascending/Descending tracks selection, the AF-FOV/EAF-FOV (Alias-Free Field Of View/Extended Alias-Free Field Of View) selection, and some possible across-track data filtering. Moreover, they will help in the definition of an optimal processing configuration (separated polarization retrieval versus first Stokes parameter retrieval). Concerning the TB, the approach is to perform inter-comparisons of the TB departures (SMOS TB minus modelled TB, assuming knowledge of auxiliary information and proper TB direct modelling). [...]Peer reviewe

Mare salis intellegere. Comprendre la sal dels oceans

3 pages, 2 figures[EN] In 1987, Konstantin Fedorov, a prominent Soviet oceanographer of the time, dedicated one of his popular science talks to the salinity of the ocean and called it “The Cinderella of Dynamic Oceanology”. Fedorov said that “The fate of salinity as a physical parameter is closely related to the dynamics of ocean waters and is very similar to the fate of poor Cinderella in Charles Perrault’s fairy tale. And, like the fate of poor Cinderella, salinity has long cried out for justice”. […][ES] En 1987, el Prof. Fedorov, destacado oceanógrafo soviético de la época, dedicó una de sus charlas divulgativas a la salinidad del océano y la llamó “La Cenicienta de la oceanología dinámica”. Fedorov decía que “El destino de la salinidad como parámetro físico está estrechamente relacionado con la dinámica de las aguas del océano y es muy similar al destino de la pobre Cenicienta del cuento de hadas de Charles Perrault. Y, como el destino de la pobre Cenicienta, hace tiempo que la salinidad clama justicia”. […][CAT] El 1987, el Prof. Fedorov, destacat oceanògraf soviètic de l’època, va dedicar una de les seves xerrades divulgatives a la salinitat de l’oceà i la va anomenar “La Ventafocs de l’oceanologia dinàmica”. Fedorov deia que “El destí de la salinitat com a paràmetre físic està estretament relacionat amb la dinàmica de les aigües de l’oceà i és molt similar al destí de la pobra Ventafocs del conte de fades de Charles Perrault. I, com la pobra Ventafocs, fa temps que la salinitat clama justícia”. […]Peer reviewe

Secondary Payloads Science Assessment

38 pages, 24 figures, 1 tableSMOSops will introduce several technological modifications to provide an improved determination of soil moisture and ocean salinity from space. It is proposed to measure H and V polarisations in parallel, a good approach since it increases radiometric sensitivity with respect to the present SMOS set up. A fully populated hub will provide better measurement of the short baselines, also a very good approach since it allows redundancy to improve error correction and robustness. Longer arms will lead to improved spatial resolution. A reduced spacing between antenna elements will improve the swath and revisit time by enlarging the alias free field of view, while the Flat Target correction can cope with the increase of antenna coupling due to the reduced spacing. [...]Peer reviewe

El nivell del mar sí que ha augmentat tot i que el port de Sídney sembli no haver canviat en 140 anys

Una publicació compartida a Telegram assegura que el canvi climàtic ha fet que “augmenti 0.0m” el nivell de la mar a Sídney “en els últims 140 anys”. El post està acompanyat de dues imatges que mostren una construcció enmig del mar a la ciutat australiana. Es tracta d'una afirmació ENGANYOSA: sí, totes dues imatges són certes i estan separades aproximadament 140 anys en el temps, però això no mostra que el nivell del mar no hagi incrementat. De fet, la construcció que es veu en la imatge, que disposa d'una de les sèries de dades més completes i llargues, ha enregistrat un augment del nivell de la mar de 0,76 mil·límetres anuals (7,6 centímetres cada segle, uns 10 cm en 140 anys), uns canvis imperceptibles sobre la base de dues fotografies. [...]Peer reviewe

Characterization of Ocean Turbulence Regimes from Satellite Observations of Sea Surface Temperatures

European Space Agency (ESA) Living Planet Symposium, 9-13 September 2013, EdinburghPeer Reviewe

Toward an optimal SMOS ocean salinity inversion algorithm

5 pages, 3 figures, 1 tableAs part of the preparation for the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) satellite mission, empirical sea-surface emissivity (forward) models have been used to retrieve sea-surface salinity from L-band brightness-temperature (T B) measurements. However, the salinity inversion is not straightforward, and substantial effort is required to define the most appropriate cost function. Various Bayesian-based configurations of the cost function are examined, depending on whether a priori information is used in the inversion. A sensitivity analysis of T B to several geophysical parameters has been performed and has shown that the instrument has low sensitivity to the parameters that modulate the T B (including salinity). The SMOS end-to-end simulator is used to test the accuracy of different cost-function configurations. Currently, the general opinion in the SMOS community is that a partially constrained cost function, in which the salinity constraint is effectively removed, is the most appropriate for salinity retrieval. The purpose of this letter is to show that we found no evidence that such a configuration performs better than a fully constrained or a nonconstrained one. Moreover, in contrast to previous results, we found that the fully constrained inversion does not converge to the reference or auxiliary salinity value and produces the most accurate salinity retrievals of the tested configurations. Therefore, such a configuration should not be disregarded for future testsPeer Reviewe

Analysis of the SMOS ocean salinity inversion algorithm

2007 IEEE International Geoscience and Remote Sensing Symposium, 23-28 July 2007, Barcelona, Spain.-- 4 pages, 4 figuresAs part of the preparation for the European Space Agency SMOS (soil moisture and ocean salinity) satellite mission, empirical sea surface emissivity (forward) models have been applied to retrieve sea surface salinity from L-band brightness temperature (T B ) measurements. However, the salinity inversion is not straightforward and an important effort is required to define the most appropriate cost function (inversion algorithm). Different Bayesian-based configurations of the cost function are examined, depending on whether prior information is used in the inversion or not. It is important to properly balance all the terms of the cost function, as well as to have a good knowledge of the quality of the prior information. A sensitivity analysis shows that the instrument has low sensitivity to the geophysical parameters that modulate the Tb (including salinity). As such, the inversion needs to be constrained with prior information. Simulations are also performed using the SMOS simulator to assess the retrieval errors produced by the different cost function configurations. In line with the sensitivity analysis, the errors are very large when no prior information is used in the cost function. The lowest errors are obtained when the inversion is constrained with the full prior information, i.e., information from all the auxiliary (geophysical) parameters. As such, it is concluded that the use of prior information is essential for a successful salinity retrieval from SMOS measurementsPeer reviewe