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1. Three-dimensional mapping of the local interstellar medium with composite data

Author

Capitanio, Letizia, Lallement, Rosine, Vergely, Jean Luc, Elyajouri, Meriem, and Monreal-Ibero, Ana

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Three-dimensional maps of the Galactic interstellar medium are general astrophysical tools. Reddening maps may be based on the inversion of color excess measurements for individual target stars or on statistical methods using stellar surveys. Three-dimensional maps based on diffuse interstellar bands (DIBs) have also been produced. All methods benefit from the advent of massive surveys and from Gaia data. We first updated our previous local dust maps based on a regularized Bayesian inversion of individual color excess data by replacing Hipparcos or photometric distances with Gaia Data Release 1 values when available. Secondly, we complemented this database with a series of ~5,000 color excess values estimated from the strength of the lambda 15273 DIB toward stars from SDSS/APOGEE, possessing a Gaia parallax. Third, we computed a low-resolution map based on a grid of Pan-STARRS reddening measurements by means of a new hierarchical technique and used this map as the prior distribution during the inversion of the two other datasets. Here we present a first attempt to combine different datasets and methods to improve the local maps. The use of Gaia parallaxes introduces significant changes in some areas and globally increases the compactness of the structures. Additional DIB-based data make it possible to assign distances to clouds located behind closer opaque structures and do not introduce contradictory information for the close structures. A more realistic prior distribution instead of a plane-parallel homogeneous distribution helps better define the structures. We validated the results through comparisons with other maps and with soft X-ray data. Our study demonstrates that the combination of various tracers is a potential tool for more accurate maps. An online tool makes it possible to retrieve maps and reddening estimations (http://stilism.obspm.fr).

Published
2017
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4. Variability of Satellite Sea Surface Salinity Under Rainfall

Author

Supply, Alexandre, Boutin, Jacqueline, Reverdin, Gilles, Vergely, Jean-Luc, Bellenger, Hugo, Stoffel, Markus, Series Editor, Cramer, Wolfgang, Advisory Editor, Luterbacher, Urs, Advisory Editor, Toth, F., Advisory Editor, Levizzani, Vincenzo, editor, Kidd, Christopher, editor, Kirschbaum, Dalia B., editor, Kummerow, Christian D., editor, Nakamura, Kenji, editor, and Turk, F. Joseph, editor

Published
2020
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6. 3D maps of the local ISM from inversion of individual color excess measurements

Author

Lallement, Rosine, Vergely, Jean-Luc, Valette, Bernard, Puspitarini, Lucky, Eyer, Laurent, and Casagrande, Luca

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Three-dimensional (3D) maps of the Galactic interstellar matter (ISM) are a potential tool of wide use, however accurate and detailed maps are still lacking. One of the ways to construct the maps is to invert individual distance-limited ISM measurements, a method we have here applied to measurements of stellar color excess in the optical. We have assembled color excess data together with the associated parallax or photometric distances to constitute a catalog of ~ 23,000 sightlines for stars within 2.5 kpc. The photometric data are taken from Stromgren catalogs, the Geneva photometric database, and the Geneva-Copenhagen survey. We also included extinctions derived towards open clusters. We applied, to this color excess dataset, an inversion method based on a regularized Bayesian approach, previously used for mapping at closer distances. We show the dust spatial distribution resulting from the inversion by means of planar cuts through the differential opacity 3D distribution, and by means of 2D maps of the integrated opacity from the Sun up to various distances. The mapping assigns locations to the nearby dense clouds and represents their distribution at the spatial resolution that is allowed by the dataset properties, i.e. of the order of ~10 pc close to the Sun and increasing to ~100 pc beyond 1 kpc. Biases towards nearby and/or weakly extincted stars make this dataset particularly appropriate to map the local and neighboring cavities, and to locate faint, extended nearby clouds, both goals that are difficult or impossible with other mapping methods. The new maps reveal a ~1 kpc wide empty region in the third quadrant in the continuation of the so-called CMa tunnel of the Local Cavity, a cavity that we identify as the Superbubble GSH238+00+09 detected in radio emission maps and that is found to be bounded by the Orion and Vela clouds., Comment: accepted in A&A

Published
2013
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7. A southern hemisphere survey of the 5780 and 6284 {\AA} diffuse interstellar bands: correlation with the extinction

Author

Raimond, Séverine, Lallement, Rosine, Vergely, Jean-Luc, Babusiaux, Carine, and Eyer, Laurent

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present a new database of 5780.5 and 6283.8 {\AA} DIB measurements and also study their correlation with the reddening. The database is based on high-resolution, high-quality spectra of early-type nearby stars located in the southern hemisphere at an average distance of 300 pc. Equivalent widths of the two DIBs were determined by means of a realistic continuum fitting and synthetic atmospheric transmissions. For all stars that possess a precise measurement of their color excess, we compare the DIBs and the extinction. We find average linear relationships of the DIBS and the color excess that agree well with those of a previous survey of northern hemisphere stars closer than 550 pc. This similarity shows that there is no significant spatial dependence of the average relationship in the solar neighborhood within $\simeq$ 600 pc. A noticeably different result is our higher degree of correlation of the two DIBs with the extinction. We demonstrate that it is simply due to the lower temperature and intrinsic luminosity of our targets. Using cooler target stars reduces the number of outliers, especially for nearby stars, confirming that the radiation field of UV bright stars has a significant influence on the DIB strength. We have used the cleanest data to compute updated DIB shapes., Comment: Astronomy & Astrophysics (in press)

Published
2012
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8. Spatial distribution of interstellar dust in the Sun vicinity, comparison with neutral sodium-bearing gas

Author

Vergely, Jean-Luc, Valette, Bernard, Lallement, Rosine, and Raimond, Severine

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

3D tomography of the interstellar dust and gas may be useful in many respects, from the physical and chemical evolution of the ISM itself to foreground decontamination of the CMB, or various studies of the environments of specific objects. Our goal here is to bring more precise information on the distance to nearby interstellar dust and gas clouds within 250 pc. We apply the best available calibration methods to a carefully screened set of stellar Stromgren photometry data for targets possessing a Hipparcos parallax and spectral type classification. We combine the derived interstellar extinctions and the parallax distances for about 6,000 stars to build a 3D tomography of the local dust. We use an inversion method based on a regularized Bayesian approach and a least squares criterion. We obtain 3D maps of the opacity and the distance to the main dust-bearing clouds with 250 pc. We calculate the integrated extinction between the Sun and the cube boundary and compare with the total galactic extinction derived from infrared 2D maps. We also compare the opacity distribution with the 3D distribution of interstellar neutral sodium resulting from the inversion of sodium columns towards about 1,700 target stars. Our maps show a larger high latitude dust opacity in the North compared to the South, while gas maps do not show the same asymmetry, suggesting a polar asymmetry of the dust to gas ratio at small distances., Comment: 13 pages, 12 figures

Published
2010
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9. New 3-D gas density maps of NaI and CaII interstellar absorption within 300pc

Author

Welsh, Barry Y., Lallement, Rosine, Vergely, Jean-Luc, and Raimond, Severine

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present new high resolution (R>50,000) absorption measurements of the NaI doublet (5889 - 5895A) along 482 nearby sight-lines, in addition to 807 new measurements of the CaII K (3933A) absorption line. We have combined these new data with previously reported measurements to produce a catalog of absorptions towards a total of 1857 early-type stars located within 800pc of the Sun. Using these data we have determined the approximate 3-dimensional spatial distribution of neutral and partly ionized interstellar gasdensity within a distance-cube of 300pc from the Sun. All newly recorded spectra were analyzed by means of a multi-component line profile-fitting program, in most cases using simultaneous fits to the line doublets. Normalized absorption profiles were fitted by varying the velocity, doppler width and column density for all intervening interstellar clouds. The resulting total column densities were then used in conjunction with the Hipparcos distances of the target stars to construct inversion maps of the 3-D spatial density distribution of the NaI and CaII bearing gas. A plot of the equivalent width of NaI versus distance reveals a wall of neutral gas at ~80pc that can be associated with the boundary wall to the central rarefied Local Cavity region. In contrast, a similar plot for the equivalent width of CaII shows no sharply increasing absorption at 80pc, but instead we observe a slowly increasing value of CaII equivalent width with increasing sight-line distance sampled., Comment: A&A accepted

Published
2009
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10. Interannual variability of Sea Surface Salinity in North-Eastern Tropical Atlantic: influence of freshwater fluxes.

Author

Thouvenin-Masson, Clovis, Boutin, Jacqueline, Échevin, Vincent, Lazar, Alban, and Vergely, Jean-Luc

Subjects
STREAMFLOW, SALINITY, MOORING of ships, MIXING height (Atmospheric chemistry), OCEAN dynamics
Abstract

In tropical regions, the fresh water flux entering the ocean originates primarily from precipitation and, to a lesser extent when considering basin scale averages, from continental rivers. Nevertheless, at regional scale, river flows can have a significant impact on the surface ocean dynamics. Riverine fresh water modifies salinity, and therefore density, stratification and circulation. With its particular coastline, relatively high cumulative river discharge, and the vicinity of Inter Tropical Convergence Zone (ITCZ), the eastern Southern North Tropical Atlantic (e-SNTA) region off Northwest Africa is a particularly interesting location to study the linkage between precipitations, river outflows and Sea Surface Salinity (SSS). Here we focus on the regional e-SNTA SSS seasonal cycle and interannual variability. We quantify the impact of river runoff and precipitation on SSS by means of regional simulations forced by different interannual and climatological river runoffs and precipitation products. The simulated SSS are compared with the Climate Change Initiative (CCI) SSS, in situ SSS from Argo, ships and a coastal mooring, and the GLORYS reanalysis SSS. The analysis of the salinity balance in the mixed layer is conducted to explore the dynamics influencing the SSS variability. Overall, the simulations reproduce well the seasonal cycle and interannual variability despite a positive mean model bias north of 15N. The seasonal cycle is impacted by the phasing of the different runoff products. The mixed layer SSS decrease during the rainy season is mainly driven by precipitation followed by runoff by means of horizontal advection and partly compensated by vertical mixing. In terms of interannual anomalies, river runoffs have a more direct impact on SSS than precipitation. This study highlights the importance of properly constraining river runoff and precipitation to simulate realistic SSS, and the importance of observing SSS in coastal regions to validate such constraints. [ABSTRACT FROM AUTHOR]

Published
2024
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11. An inverse method to interpret colour-magnitude diagrams

Author

Vergely, Jean-Luc, Koeppen, Joachim, Egret, Daniel, and Bienayme, Olivier

Subjects
Astrophysics
Abstract

An inverse method is developed to determine the star formation history, the age-metallicity relation, and the IMF slope from a colour-magnitude diagram. The method is applied to the Hipparcos HR diagram. We found that the thin disk of our Galaxy shows a peak of stellar formation 1.6 Gyr ago. The stars close to the Sun have a solar metallicity and a mean IMF index equal to 3.2. However, the model and the evolutionary tracks do not correctly reproduce the horizontal giant branch., Comment: 14 pages, 11 figures. To be published in Astronomy & Astrophysics

Published
2002
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12. Recovery of SMOS Salinity Variability in RFI-Contaminated Regions

Author

Bonjean, Fabrice, Boutin, Jacqueline, Vergely, Jean-Luc, Richaume, Philippe, and Sabia, Roberto

Abstract

The Soil Moisture and Ocean Salinity (SMOS) satellite mission, operational since 2010, relies on an L-band microwave interferometric radiometer to generate brightness temperature (BT) images along the swath, with global coverage every three days. These images are then used to derive sea surface salinity (SSS) with an effective resolution of less than 50 km. However, signal acquisition in some ocean regions is intermittently and significantly disrupted by radio frequency interferences (RFIs) from various terrestrial military or civilian sources worldwide. We develop a new methodology based on principal component and regression analyses to extract the RFI signatures in time and space, thereby enabling the construction of a corrected SSS estimate along the swath. This method successfully filters out many disruptive features characterized by long and wide branches occurring around the RFI sources, hence recovering SSS variability as demonstrated in comparison to in situ reference data. This correction methodology is an alternative to separate filtering procedures that were applied on BT at Level 1. Independent information indicating the probability of RFI occurrence on land areas or nearby is used to verify the timing of oceanic RFI contamination inferred by the correction process. The methodology performs particularly well in areas where the probability is close to 1 for a significant and contiguous portion of the entire period. Already applied with significant improvement in three selected regions, this exemplary study is a starting point for expanding and systematizing the methodology to treat as many RFI-polluted regions as possible and to recover SMOS SSS variability.

Published
2024
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13. Comparison of two different extinction laws with Hipparcos observations

Author

Chen, Bing, Vergely, Jean Luc, Valette, Bernard, and Carraro, Giovanni

Subjects
Astrophysics
Abstract

Interstellar absorption in the galactic plane is highly variable from one direction to another. In this paper colour excesses and distances from a new open cluster sample are used to investigate the spatial distribution of the interstellar extinction. An inverse method (Tarantola & Valette, 1982) is used to construct the extinction map in the galactic plane below $|b| < 10^{o}$. The $A_{v} (r,l) $ diagrams are compared with those derived from individual stars (Arenou et al. 1992, Neckel & Klare 1980). An analytic expression for the interstellar extinction as a function of galactic longitude and distance in the solar neighborhood is given. The comparison of the model predictions with Hipparcos observations in the 4-dimensional space of ($V$, $B-V$, $H_v$, $r$) shows that our extinction model provides a better fit to the data. However, a new and more detailed extinction model is still lacking., Comment: 16 pages, 16 figures, latex, accepted for pubblication in Astronomy and Astrophysics Main Journal

Published
1998

17. CarbonCGI road map to observe faint GHG source’s emissions with high resolution observing system

Author

Siméoni, Denis, primary, Graziosi, Francesco, additional, Broquet, Grégoire, additional, Kumar, Pramod, additional, Ciais, Philippe, additional, Vergely, Jean Luc, additional, Ferron, Stéphane, additional, Khodnevych, Vitalii, additional, Carlavan, Mikael, additional, Chétrite, Bruno, additional, Tetaz, Nicolas, additional, Delzenne, Christian, additional, Guercio, Nicolas, additional, Boesch, Hartmut, additional, Vogel, Leif, additional, Mariani, Flavio, additional, Windpassinger, Roman, additional, and Sierk, Bernd, additional

Published
2022
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19. Compact static interferometer instrument studies for greenhouse gas detection

Author

Minoglou, Kyriaki, Karafolas, Nikos, Cugny, Bruno, Mariani, Flavio, Simeoni, Denis, Alpay Koc, Nurcan, Khodnevych, Vitalii, Tetaz, Nicolas, Chetrite, Bruno, Carlavan, Mikael, Ferron, Stephane, Vergely, Jean-Luc, van der Valk, Nick, van Brug, Hedser, Brenny, Benjamin, Visser, Huib, Landgraf, Jochen, Rusli, Stephanie, Windpassinger, Roman, and Sierk, Bernd

Published
2023
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20. Satellite and In Situ Sampling Mismatches: Consequences for the Estimation of Satellite Sea Surface Salinity Uncertainties

Author

Thouvenin-Masson, Clovis, primary, Boutin, Jacqueline, additional, Vergely, Jean-Luc, additional, Reverdin, Gilles, additional, Martin, Adrien C. H., additional, Guimbard, Sébastien, additional, Reul, Nicolas, additional, Sabia, Roberto, additional, Catany, Rafael, additional, and Hembise Fanton-d’Andon, Odile, additional

Published
2022
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21. SMOS OS Level 3 and Level 4. Algorithm Theoretical Basis Document

Author

Vergely, Jean-Luc, Boutin, Jacqueline, and Kolodziejczyk, Nicolas

Abstract

The purpose of this Algorithm Theoretical Basis Document is to describe the procedure that is used in the SMOS CATDS Production Data Center (CPDC) to generate operational sea surface salinity (SSS) maps (also called L3OS/L4OS product, Level 3/4 Ocean Salinity product). Moreover, this document gives an overview of the different steps of the global processing, from Level 1b to Level 3 and Level 4 products knowing that only L3OS/L4OS products are provided to users by the CATDS (intermediate products are not officially distributed).

Published
2022
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22. Satellite-based Sea Surface Salinity designed for Ocean and Climate Studies

Author

Boutin, Jacqueline, primary, Reul, Nicolas, additional, Köhler, Julia, additional, Martin, Adrien C.H., additional, Catany, Rafael, additional, Guimbard, Sebastien, additional, Rouffi, Frederic, additional, Vergely, Jean-Luc, additional, Arias, Manuel, additional, Chakroun, Meriem, additional, Corato, Giovanni, additional, Esttella-Perez, Victor, additional, Hasson, Audrey Emilie Alice, additional, Josey, Simon A., additional, Khvorostyanov, Dimitry, additional, Kolodziejczyk, Nicolas, additional, Mignot, Juliette, additional, Olivier, Léa, additional, Reverdin, Gilles, additional, Stammer, Detlef, additional, Supply, Alexandre, additional, Thouvenin-Masson, Clovis, additional, Turiel, Antonio, additional, Vialard, Jerome, additional, Cipollini, Paolo, additional, Donlon, Craig, additional, Sabia, Roberto, additional, and Mecklenburg, Susanne, additional

Published
2021
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24. Results of the Dragon 4 Project on New Ocean Remote Sensing Data for Operational Applications

Author

Gibert, Ferran, primary, Boutin, Jacqueline, additional, Dierking, Wolfgang, additional, Granados, Alba, additional, Li, Yan, additional, Makhoul, Eduard, additional, Meng, Junmin, additional, Supply, Alexandre, additional, Vendrell, Ester, additional, Vergely, Jean-Luc, additional, Wang, Jin, additional, Yang, Jungang, additional, Xiang, Kunsheng, additional, Yin, Xiaobin, additional, and Zhang, Xi, additional

Published
2021
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25. Satellite-based Time-Series of Sea Surface Salinity designed for Ocean and Climate Studies

Author

Boutin, Jacqueline, primary, Reul, Nicolas, additional, Köhler, Julia, additional, Martin, Adrien C.H., additional, Catany, Rafael, additional, Guimbard, Sebastien, additional, Rouffi, Frederic, additional, Vergely, Jean-Luc, additional, Arias, Manuel, additional, Chakroun, Meriem, additional, Corato, Giovanni, additional, Esttella-Perez, Victor, additional, Hasson, Audrey Emilie Alice, additional, Josey, Simon A., additional, Khvorostyanov, Dimitry, additional, Kolodziejczyk, Nicolas, additional, Mignot, Juliette, additional, Olivier, Léa, additional, Reverdin, Gilles, additional, Stammer, Detlef, additional, Supply, Alexandre, additional, Thouvenin-Masson, Clovis, additional, Turiel, Antonio, additional, Cipollini, Paolo, additional, Donlon, Craig, additional, Sabia, Roberto, additional, and Mecklenburg, Susanne, additional

Published
2021
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26. Towards an improved temporal stability of CCI+SSS time series

Author

Perrot, Xavier, primary, Boutin, Jacqueline, additional, Vergely, Jean Luc, additional, Rouffi, Frédéric, additional, Martin, Adrien, additional, Guimbard, Sébastien, additional, Koehler, Julia, additional, Reul, Nicolas, additional, Catany, Rafael, additional, and Cipollini, Paolo, additional

Published
2021
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29. Overview of the SMOS sea surface salinity prototype processor

Author

Zine, Sonia, Boutin, Jacqueline, Font, Jordi, Reul, Nicolas, Waldteufel, Philippe, Gabarro, Carolina, Tenerelli, Joseph, Petitcolin, Francois, Vergely, Jean-Luc, Talone, Marco, and Delwart, Steven

Subjects
Soil moisture -- Analysis, Earth temperature -- Observations, Oceanography -- Research, Salinity -- Observations, Business, Earth sciences, Electronics and electrical industries
Abstract

The L-band interferometric radiometer onboard the Soil Moisture and Ocean Salinity mission will measure polarized brightness temperatures (Tb). The measurements are affected by strong radiometric noise. However, during a satellite overpass, numerous measurements are acquired at various incidence angles at the same location on the Earth's surface. The sea surface salinity (SSS) retrieval algorithm implemented in the Level 2 Salinity Prototype Processor (L2SPP) is based on an iterative inversion method that minimizes the differences between Tb measured at different incidence angles and Tb simulated by a full forward model. The iterative method is initialized with a first-guess surface salinity that is iteratively modified until an optimal fit between the forward model and the measurements is obtained. The forward model takes into account atmospheric emission and absorption, ionospheric effects (Faraday rotation), scattering of celestial radiation by the rough ocean surface, and rough sea surface emission as approximated by one of three models. Potential degradation of the retrieval results is indicated through a flagging strategy. We present results of tests of the L2SPP involving horizontally uniform scenes with no disturbing factors (such as sun glint or land proximity) other than wind-induced surface roughness. Regardless of the roughness model used, the error on the retrieved SSS depends on the location within the swath and ranges from 0.5 psu at the center of the swath to 1.7 psu at the edge, at 35 psu and 15 [degrees]C. Dual-polarization (DP) mode provides a better correction for wind-speed (WS) biases than pseudofirst Stokes mode (ST1). For a WS bias of -1 m. [s.sup.-1], the corresponding SSS bias at the center of the swath is equal to -0.3 psu in DP mode and to -0.5 psu in ST1 mode. The inversion methodology implicitly assumes that WS errors follow a Gaussian distribution, even though these errors should follow more closely a Rayleigh distribution. For this reason, the use of wind components, which typically exhibit Gaussian error distributions, may be preferred in the retrieval. However, the use of noisy wind components creates WS and SSS biases at low WSs (0.1 psu at 3 m [s.sup.-l]). At a sea surface temperature (SST) of 15 [degrees]C, the retrieved SSS is weakly sensitive to the SST biases, with the SSS bias always lower than 0.3 psu for SST biases ranging from --0.5 [degrees]C to --2 [degrees]C. In DP mode, biases in the vertical total electron content (TEC) of the atmosphere result in SSS biases smaller than 0.2 psu. The pseudofirst Stokes mode is insensitive to TEC. Failure to fully account for sea surface roughness scattering effects in the computation of sky radiation contribution leads to a maximum SSS bias of 0.2 psu in the selected configuration, i.e., a descending orbit over the Northern Pacific in February. To achieve SSS biases that are smaller than 0.2 psu, special care must be taken to correct for biases at low WS and to ensure that the bias on the mean WS (averaged over 200 km x 200 km and ten days) remains smaller than 0.5 m [s.sup.-1]. Index Terms--Microwave radiometry, oceanography, salinity.

Published
2008

30. Sea surface salinity estimates from spaceborne L-band radiometers: An overview of the first decade of observation (2010–2019)

Author

Reul, Nicolás, Grodsky, S.A., Arias, Manuel, Boutin, Jacqueline, Catany, Rafael, Chapron, Bertrand, D'Amico, Francesco, Dinnat, Emmanuel, Donlon, C.J., Fore, Alexander, Fournier, Séverine, Guimbard, Sébastien, Hasson, Audrey, Kolodziejczyk, Nicolas, Lagerloef, Gary, Lee, Tong, Le Vine, D.M., Lindstrom, E., Maes, C., Mecklenburg, S., Meissner, Thomas, Olmedo, Estrella, Sabia, Roberto, Tenerelli, Joseph, Thouvenin-Masson, C., Turiel, Antonio, Vergely, Jean-Luc, Vinogradova, N., Wentz, Frank, Yueh, Simon, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric and Oceanic Science [College Park] (AOSC), University of Maryland [College Park], University of Maryland System-University of Maryland System, ARGANS Limited, Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), GSFC Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center (GSFC), Agence Spatiale Européenne (ESA), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), OceanDataLab, Earth and Space Research Institute [Seattle] (ESR), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), NASA Headquarters, European Space Research Institute (ESRIN), Remote Sensing Systems [Santa Rosa] (RSS), Mediterranean Center for Marine and Environmental Research (CMIMA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), CNES-TOSCA SMOS-Ocean, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Agence Spatiale Européenne = European Space Agency (ESA), European Space Agency, Centre National D'Etudes Spatiales (France), National Aeronautics and Space Administration (US), and Agencia Estatal de Investigación (España)

Subjects
Sea surface salinity, L-band, Aquarius/SAC-D, Ocean microwave remote sensing, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], SMAP, Radiometer, SMOS
Abstract

37 pages, 27 figures, 2 tables, 2 appendixes, Operated since the end of 2009, the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite mission is the first orbiting radiometer that collects regular and global observations from space of two Essential Climate Variables of the Global Climate Observing System: Sea Surface Salinity (SSS) and Soil Moisture. The National Aeronautics and Space Administration (NASA) Aquarius mission, with the primary objective to provide global SSS measurements from space operated from mid-2011 to mid-2015. NASA's Soil Moisture Active-Passive (SMAP) mission, primarily dedicated to soil moisture measurements, but also monitoring SSS, has been operating since early 2015. The primary sensors onboard these three missions are passive microwave radiometers operating at 1.4 GHz (L-band). SSS is retrieved from radiometer measurements of the sea surface brightness temperature (TB). In this paper, we first provide a historical review of SSS remote sensing with passive L-band radiometry beginning with the discussions of measurement principles, technology, sensing characteristics and complementarities of the three aforementioned missions. The assessment of satellite SSS products is then presented in terms of individual mission characteristics, common algorithms, and measurement uncertainties, including the validation versus in situ data, and, the consideration of sampling differences between satellite SSS and in situ salinity measurements. We next review the major scientific achievements of the combined first 10 years of satellite SSS data, including the insights enabled by these measurements regarding the linkages of SSS with the global water cycle, climate variability, and ocean biochemistry. We also highlight the new ability provided by satellites to monitor mesoscale and synoptic-scale SSS features and to advance our understanding of SSS' role in air-sea interactions, constraining ocean models, and improving seasonal predictions. An overview of satellite SSS observation highlights during this first decade and upcoming challenges are then presented, The EU authors acknowledge support of ESA in the frame of the SMOS ESL Level 2 phase 3 contract (https://smos.argans.co.uk/), the SMOS Pilot-Mission Exploitation Platform (Pi-MEP) project (https://www.salinity-pimep.org/), and the Climate Change Initiative (CCI) project (http://cci.esa.int/salinity). French authors thank the support of the Centre National d'Etudes Spatiales (CNES) in the frame of the Centre Aval de Traitement des Données SMOS (CATDS, http://www.catds.fr) and of CNES-TOSCA SMOS-Ocean projects. US authors thank the support of the NASA Ocean Surface Salinity Team (OSST). SMAP CAP SSS is produced at Jet Propulsion Laboratory. Thomas Meissner and Frank Wentz acknowledge funding from NASA (contracts no. NNG04HZ29C, NNH15CM44C, 80HQTR18C0015, and JPL sub-contract 1602331), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Published
2020

33. Issues about retrieving sea surface salinity in coastal areas from SMOS data

Author

Zine, Sonia, Boutin, Jacqueline, Waldteufel, Philippe, Vergely, Jean-Luc, Pellarin, Thierry, and Lazure, Pascal

Subjects
Coasts -- Analysis, Artificial satellites in geographical research -- Usage, Salinity -- Analysis, Business, Earth sciences, Electronics and electrical industries
Abstract

This paper aims at studying the quality of the sea surface salinity (SSS) retrieved from Soil Moisture and Ocean Salinity (SMOS) data in coastal areas. These areas are characterized by strong and variable SSS gradients [several practical salinity units (psu)] on relatively small scales: the extent of river plumes is highly variable, typically at kilometric and daily scales. Monitoring this variability from SMOS measurements is particularly challenging because of their resolution (typically 30-100 km) and because of the contamination by the nearby land. A set of academic tests was conducted with a linear coastline and constant geophysical parameters, and more realistic tests were conducted over the Bay of Biscay. The bias of the retrieved SSS has been analyzed, as well as the root mean square (rms) of the bias, and the retrieved SSS compared to a numerical hydrodynamic model in the semirealistic case. The academic study showed that the Blackman apodization window provides the best compromise in terms of magnitude and fluctuations of the bias of the retrieved SSS. Whatever the type of vegetation cover, a strong negative bias, greater than 1 psu, was found when nearer than 36 km from the coast. Between 44 and 80 km, the type of vegetation cover has an impact of less than a factor 2 on the bias, and no influence further than 80 km from the coast. The semirealistic study conducted in the Bay of Biscay showed a bias over ten days lower than 0.2 psu for distances greater than 47 km, due to an averaging over various geometries (coastline orientation, swath orientation, etc.). The bias showed a weak dependence on the location of the grid point within the swath. Despite the noise on the retrieved SSS, contrasts due to the plume of the Loire River and the Gironde estuary remained detectable on ten-day averaged maps with an rms of 0.57 psu. Finally, imposing thresholds on the major axis of the measurements brought little improvement to the bias, whereas it increased the rms and could lead to strong swath restriction: a 49-km threshold on the major axis resulted in an effective swath of 800-900 km instead of 1200 km. Index Terms--Coastal areas, L-band radiometry, sea surface salinity (SSS) retrieval, Soil Moisture and Ocean Salinity (SMOS) mission.

Published
2007

35. A modified cardioid model for processing multiangular radiometric observations

Author

Waldteufel, Philippe, Vergely, Jean-Luc, and Cot, Charles

Subjects
Microwave devices -- Usage, Soil moisture -- Observations, Radiation -- Measurement, Radiation -- Observations, Business, Earth sciences, Electronics and electrical industries
Abstract

L-band spaceborne microwave radiometers are becoming able to provide estimates of surface soil moisture, on both spatial and temporal scales compatible with applications to meteorology and hydrology. The basic rationale for retrieving soil moisture from radiometric measurements is the assumption that the surface layer can be modeled as a dielectric medium. Its dielectric constant then depends on several physical parameters, including soil moisture; emissivities for various incidence angles are computed using Fresnel's formulas. Many controlled field experiments have demonstrated the validity of this approach. Scenes exist still (e.g., ice-covered or frozen surfaces, barren areas) where surface soil moisture is not a relevant concept. For such scenes, information should, however, be available on the complex dielectric constant itself. This paper shows that the dielectric constant cannot be fully retrieved from single-frequency multiangular data; it describes, however, a methodology that aims at retrieving in an optimized way the available information. Index Terms--Dielectric constant, radiometry, regularization, retrieval.

Published
2004

40. Supply egu 2019

Author

Supply, Alexandre, Boutin Jacqueline, Reverfdin, Gilles, Vergely, Jean-Luc, Bellenger, Hugo, and Katsumata, Masaki

Published
2019
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41. New SMOS surface salinity retrieval overcomes previous issues in the Bay of Bengal: assessment of its seasonal and interannual variability

Author

Parambil Akhil, Valiya, Vialard, Jérôme, Lengaigne, Matthieu, Keerthi, Madhavan Girijakumari, Boutin, Jacqueline, Vergely, Jean-Luc, Marchand, Stéphane, CSIR National Institute of Oceanography [India] (NIO), Océan et variabilité du climat (VARCLIM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Processus et interactions de fine échelle océanique (PROTEO), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), EGU, Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Pinsard, Françoise

Subjects
[PHYS.PHYS.PHYS-GEO-PH] Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]
Abstract

International audience; The Bay of Bengal (BoB) exhibits a contrasted sea surface salinity (SSS), with very fresh water induced by heavy monsoonal precipitation and river discharge to the north, and saltier water to the south. The strong northern BoB haline stratification is believed to limit vertical mixing of heat and nutrients, with strong impacts on tropical cyclones intensity and primary production. While in situ data coverage is denser since the advent of the Argo program, it is still far from sufficient to provide complete maps of seasonal SSS. Salinity remote sensing (e.g. satellites such as SMOS, AQUARIUS, or SMAP) offers a unique opportunity to provide synoptic maps of the BoB SSS every 8 days. While recent studies have shown a good performance of the so far 2 years SMAP record in the BoB, the Aquarius mission is now over, and previous retrievals from the longer (2010 to now) SMOS mission did not perform well in this region. In this work, we provide an in-depth assessment of the new CATDS level-3 2010-2017 SSS retrieval from the SMOS instrument. This new retrieval includes an improved bias correction and a less stringent flagging of "outliers" based on both SMOS radiometric noise and natural SSS variability. Our results indicate that this new SMOS SSS performs considerably better than earlier versions, with a 0.8 correlation and -0.07 pss bias with respect to available in situ observations in the BoB. Comparisons with RAMA data also show that this new retrieval captures the interannual variability of SSS remarkably well in the Northern BoB ( 0.8 correlation). We further take advantage of the 7 years of SMOS data to describe interannual SSS variability in the BoB, that is strongest in boreal fall, in relation with the occurrence of the Indian Ocean Dipole. This new SMOS retrieval can now be confidently used to monitor the year-to-year SSS variations in the BoB.

Published
2018

42. SMOS_RAINFALL_POSTER

Author

Supply, Alexandre, Boutin, Jacqueline, Hasson, Audrey, Vergely, Jean-Luc, Viltard, Nicolas, Marchand, Stéphane, Martin, Nicolas, and Bellenger, Hugo

Published
2017
Full Text
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43. What can we learn on rainfall from SMOS Sea Surface Salinity?

Author

Supply, Alexandre, Boutin, Jacqueline, Vergely, Jean-Luc, Hasson, Audrey, Mallet, Cécile, Reverdin, Gilles, Viltard, Nicolas, Interactions et Processus au sein de la couche de Surface Océanique (IPSO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; The Soil Moisture and Ocean Salinity (SMOS) satellite mission has been measuring sea surface salinity (SSS) for over 6 years with about 5-day global ocean coverage and a spatial resolution of about 50 km. In rainy regions, at local and short time scales, the spatio-temporal variability of SSS is dominated by rainfall. The relationship between surface freshening and rain rate (RR) has been highlighted in the Pacific intertropical convergence zone (Boutin et al., 2014). In this context, this study investigates the rainfall characteristics that may be inferred from SMOS SSS based on statistical approach.Salinity anomalies associated with rainfall events are first estimated. In order to do so, a reference salinity (i.e. with no rain-induced signal) is computed for each pixel of the SMOS observation using the statistical distribution within 3°x3° region of SMOS SSS. In case the distribution is asymmetrical toward low values, suggesting a rain influence, a mean ‘non-rainy’ SSS corresponding to a Gaussian distribution fitted onto the highest part of the distribution (quantile>0.8) is computed. Rain rate probability associated with SSS anomalies are then inferred from a probabilistic approach. It also enables us to separate the rain intensity depending on the SSS anomaly. Finally, a RR retrieval algorithm based on SSS is developed combining this dependence with the SSS-RR relationship described in Boutin et al. (2014) and a spatial association index (spatial correlations of SSS anomalies within 100 km). SMOS-derived RRs are then collocated with various radiometers and CMORPH RR datasets. Their consistency is assessed.A particular focus will be put on RRs estimates derived during the Salinity Processes in the Upper Ocean Regional Study (SPURS-2, http://spurs2.jpl.nasa.gov) from a near real time implementation of rain retrieval from SMOS SSS.Boutin et al. (2014), Sea surface salinity under rain cells: SMOS satellite and in situ drifters observations, JGR: Oceans, doi:10.1002/2014JC010070

Published
2016

44. Partitioning ocean wave spectra obtained from SAR observations or from the future real aperture wave scatterometer SWIM on CFOSAT

Author

Delaye, Lauriane, Vergely, Jean-Luc, Hauser, Danièle, Guitton, Gilles, Mouche, Alexis, Tison, Céline, Cardon, Catherine, L. Ouwehand (ed.), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), OceanDataLab, Laboratoire d’Oéanographie Spatiale [Plouzané] (LOS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.STU.OC] Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

ISBN: 978-92-9221-305-3; International audience; In oceanography, one of the important products that can be provided from satellites is the directional spectrum of ocean waves (also called 2D spectrum), which describes the energy of the surface ocean waves as a function of wave number and direction of propagation. This information is essential for wave forecast systems, improvement of wave models, wave climate studies and scientific studies related to the ocean/atmosphere interface, coastal and marginal ice zone processes. This has motivated the specification of SAR instruments to deliver 2D wave spectra (ERS, ENVISAT, SENTINEL-1, RADARSAT, etc.), and the future CFOSAT mission [1] which will embark the wave scatterometer SWIM (low incidence real aperture scanning scatterometer) to provide directional wave spectra with wavelengths from 70 to 600 m.Because directional spectra contain a large amount of information, a way to use this information is usually to decompose the two-dimensional spectra into several partitions, each of them characterizing a “wave component”. For example partitioning wave spectra is a way to distinguish swell components from wind sea components that have different spectral characteristics and correspond to different wave evolutions (swell waves, in opposite to wind sea waves, re defined as ocean waves which are no longer under the influence of the local wind). Partitioning is a key issue for a good retrieval of wave parameters such as significant wave height, peak direction and wavelength, of the different wave components in a 2D wave spectrum.Partitioning methods of wave spectra have originally been developed for analysing outputs of wave forecasting numerical models. The most famous method is the watershed method proposed by Hanson and Phillips [2]. Extending the application of this method to satellite data raises several difficulties because of the presence of noise in the data, which makes the result of the partitioning rather sensitive to the noise.Our presentation will address this issue in the context of 2D wave spectra observed from i) SAR (Sentinel-1), ii) simulated wave spectra expected from SWIM observations (including noise effects) and iii) observed wave spectra from the airborne wave scatterometer KuROS [3]. We will compare different adaptations of the watershed principle to account for noise effects. Furthermore, we will present results obtained from an alternative method, namely a method based on a Bayesian approach. In opposite to the watershed method, the bayesian method presents the advantage of taking explicitly into account noise into the partitioning process and can even be used to estimate the noise floor. After explaining both methods and showing comparative results, we will discuss the pros, cons and limits of both partitioning techniques.

Published
2016

45. TEC obtained from 3rd Stokes parameter for improved quality of SMOS salinity retrieval

Author

Vergely, Jean-Luc, Waldteufel, Philippe, Boutin, Jacqueline, Yin, Xiaobin, Spurgeon, Paul, Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Interactions et Processus au sein de la couche de Surface Océanique (IPSO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ARGANS Limited, Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Physics::Space Physics, Physics::Geophysics
Abstract

International audience; While SMOS was designed with full polarimetric capability, the 3rd Stokes parameter information has not been introduced so far in the data processing. The analysis reported in the present contribution proposes to estimate from this information the total ionospheric electron content (TEC). Indeed the Faraday effect generated by the ionospheric electrons on the path from Earth to satellite is believed to be responsible for large uncertainties in the evening half-orbits (circa 06 PM local time) when the ionospheric content is close to its diurnal maximum. It is shown that the 3rd Stokes parameter exhibits a maximal sensitivity to TEC in a restricted area located at the front of the SMOS 2D field of view. However, since the Faraday angle depends on the scalar product between line-of-sight and magnetic field vectors, a latitudinal zone is found where this sensitivity vanishes. This zone occurs around 15° N a latitude nearly invariant with longitude around the Earth. Accordingly it is possible, when carrying out the TEC estimation over a descending half-orbit, to isolate over this "blind zone" the so-called "Ocean Target Transformation" parameter, which aims at correcting for pixel dependent biases. TEC maps obtained in this way compare favorably with maps built from GPS measurements, which have been introduced so far in the SMOS processing chain as auxiliary data. The space resolution is somewhat improved, allowing a better selection of the relevant electron content in zones exhibiting large horizontal TEC gradients. In a latter step, based on the TEC maps, it becomes possible to recompute the OTT correction for those brightness temperature components to be used as input in the salinity retrieval. Then the additional information impacts the salinity retrieval both directly (as the quality of the TEC auxiliary data is improved) and indirectly (as the empirical OTT correction is no longer contaminated by spurious Faraday rotation effects). The respective contributions of both effects will be assessed and discussed. They result on the whole in a significant improvement of the SMOS retrieved salinity; this is evidenced by a large reduction of a spurious latitudinal variation which was so far considered as a bias originating in instrumental effects.

Published
2014

46. A southern hemisphere survey of the 5780 and 6284 �� diffuse interstellar bands: correlation with the extinction

Author

Raimond, S��verine, Lallement, Rosine, Vergely, Jean-Luc, Babusiaux, Carine, and Eyer, Laurent

Subjects
Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present a new database of 5780.5 and 6283.8 �� DIB measurements and also study their correlation with the reddening. The database is based on high-resolution, high-quality spectra of early-type nearby stars located in the southern hemisphere at an average distance of 300 pc. Equivalent widths of the two DIBs were determined by means of a realistic continuum fitting and synthetic atmospheric transmissions. For all stars that possess a precise measurement of their color excess, we compare the DIBs and the extinction. We find average linear relationships of the DIBS and the color excess that agree well with those of a previous survey of northern hemisphere stars closer than 550 pc. This similarity shows that there is no significant spatial dependence of the average relationship in the solar neighborhood within $\simeq$ 600 pc. A noticeably different result is our higher degree of correlation of the two DIBs with the extinction. We demonstrate that it is simply due to the lower temperature and intrinsic luminosity of our targets. Using cooler target stars reduces the number of outliers, especially for nearby stars, confirming that the radiation field of UV bright stars has a significant influence on the DIB strength. We have used the cleanest data to compute updated DIB shapes., Astronomy & Astrophysics (in press)

Published
2012
Full Text
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47. SMOS: Objectives and Approach for Ocean Salinity Observations

Author

Font, Jordi, Boutin, Jacqueline, Reul, Nicolas, Spurgeon, Paul, Ballaberea, Joaquim, Chuprin, Andrei, Gabarro, Carolina, Gourrion, Jerome, Hénocq, Claire, Lavender, Samantha, Martin, Nicolas, Martinez, Justino, Mcculloch, Michael, Meirold-Mautner, Ingo, Petitcolin, Francois, Portabella, Marcos, Sabia, Roberto, Talone, Marco, Tenerelli, Joe, Turiel, Antonio, Vergely, Jean-Luc, Waldteufel, Philippe, Yin, Xiaobin, Zine, Sonia, Delwart, Steven, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), Collecte Localisation Satellites (CLS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), and Université Grenoble Alpes (UGA)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

International audience; SMOS (Soil Moisture and Ocean Salinity), launched in November 2, 2009 is the first satellite mission addressing the salinity measurement from space through the use of MIRAS (Microwave Imaging Radiometer with Aperture Synthesis), a new two-dimensional interferometer designed by the European Space Agency (ESA) and operating at L-band. This paper presents a summary of the sea surface salinity retrieval approach implemented in SMOS, as well as first results obtained after completing the mission commissioning phase in May 2010. A large number of papers have been published about salinity remote sensing and its implementation in the SMOS mission. An extensive list of references is provided here, many authored by the SMOS ocean salinity team, with emphasis on the different physical processes that have been considered in the SMOS salinity retrieval algorithm.

Published
2010

48. 3D tomography of local interstellar gas and dust

Author

Raimond, Séverine, Lallement, Rosine, Vergely, Jean-Luc, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), S. Boissier, M. Heydari-Malayeri, R. Samadi and D. Valls-Gabaud, Cardon, Catherine, and S. Boissier, M. Heydari-Malayeri, R. Samadi and D. Valls-Gabaud

Subjects
[PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
Abstract

http://sf2a.cesr.fr/2010/2010sf2a.conf..0045R.pdf; International audience; Interstellar absorption data and Strömgren photometric data for target stars possessing a Hipparcos parallax have been combined to build a 3D tomography of local gas and dust. We show the latest inverted 3D distributions within 250 pc, compare gas and dust maps and discuss the present limitations and work in progress. Gaia extinction data and follow-up ground-based stellar spectra (e.g. with GYES at the CFHT) will provide a far larger database that should allow a 3D tomography of much higher quality and extended to much larger distances.

Published
2010

49. Preliminary results of SMOS data analysis over the ocean during commissioning phase

Author

Yin, Xiaobin, Boutin, Jacqueline, Meirold-Mautner, Ingo, Vergely, Jean-Luc, Waldteufel, Philippe, Spurgeon, Paul, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and ARGANS Limited

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

International audience; The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched on 2nd November 2009. The first 6 months after launch is dedicated to the commissioning phase during which the ground segment processing chains are validated. SMOS is the first interferometric radiometer in orbit. In the first ground processing (Level 1) an image reconstruction algorithm is applied which yields measured brightness temperatures (TB). Preliminary studies have shown that this processing is critical and likely to introduce biases that affect subsequent processing. Therefore, a comparison of modeled to reconstructed TB is essential. Homogenous ocean surfaces far from land masses are ideal for this task as the TB variation with the satellite geometry (incidence angle) is relatively well known. In this presentation we will focus on the following analysis: 1. Extensive comparisons between SMOS Level 1c TB and forward model simulated TB using ECMWF (European Centre for Medium-Range Weather Forecast) forcings. Comparisons will be performed with one of the forward models implemented in the L2 ocean salinity processor (2-scale model, Dinnat et al. 2003). Statistics of the TB differences will be presented. They may be related to flaws in the level 1c Tb related to image reconstruction or to instrumental imperfections, in the ECMWF forcings, or in the forward model. In order to discriminate between these various sources of uncertainties, the statistics of the Tb differences will be analysed in various reference frame: - the antenna reference frame (director cosines) - the earth reference frame and the correlation of the differences with the geometry of the measurement (incidence angle, distance to the center of the swath, ascending or descending orbit…) and with respect to the auxiliary geophysical parameters (wind speed, sea surface temperature…) will be looked at. 2. The pseudo-dielectric parameter Acard (Waldteufel et al., 2004) is used to synthesize information contained in both the real and the imaginary parts of dielectric constant of medium, such as sea water. The principle for retrieving sea surface salinity (SSS) from radiometric measurements is that the dielectric constant of sea water depends on several physical parameters, including SSS and sea surface temperature (SST). Given the relation between dielectric constant and Acard, retrieving Acard with the whole direct model is in a way equivalent to retrieve dielectric constant, which represents the property of sea water more directly than SSS and SST. The consistency between Acard_retrieved and Acard_modeled will be another tool for testing and assessing the validity of SMOS measurements and retrieved parameters. The consistency between retrieved Acard (Acard_retrieved) and Acard from known values of dielectric constants (Acard_modeled) will be investigated using similar methods as the ones described in 1. Perspectives about the accuracy on sea surface salinity retrieved from SMOS measurements will be given based on the above comparisons and analysis.

Published
2010

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