SMOS and Aquarius/SAC-D Missions: The Era of Spaceborne Salinity Measurements is About to Begin

Chapter

Abstract

The SMOS and Aquarius/SAC-D are explorer missions that aim to measure ocean salinity for the first time from space, and usher in the new era of ocean remote sensing. Here we provide a brief description of the evolution and development of the missions since the last Oceans from Space a decade ago. Salinity remote sensing is done in the microwave frequency band centered at 1.413 GHz (L-band). The two missions apply very different technical approaches. SMOS sensor is phased array synthetic aperture radiometer, whereas the Aquarius sensor is a real aperture 3-beam push broom design with both radiometer and radar measurements to better correct for the surface roughness effects. Both will require data averaging to map surface salinity at 150–200 km resolution and monthly time scales needed to understand the links between ocean circulation, changes in the water cycle, and climate. These pathfinder missions will likely provide a decade of salinity data to evaluate at the 2020 Oceans from Space meeting, and will guide the future technology development to improve resolution and accuracy.

References

  1. Blanch S, Aguasca A (2004) Seawater dielectric permittivity model from measurements at L-band. Paper presented at International Geoscience and Remote Sensing Symposium IGARSS, 20–24 September 2004Google Scholar
  2. Boutin J, Waldteufel P, Martin N, Caudal G, Dinnat EP (2003) Surface salinity retrieved from SMOS measurements over the global ocean: imprecisions due to sea surface roughness and temperature uncertainties. J Atmos Ocean Technol 21:1432–1447CrossRefGoogle Scholar
  3. Broecker WS (1991) The great ocean conveyor. Oceanography 4:79–89Google Scholar
  4. Camps A (1996) Application of interferometric radiometry to Earth observation. PhD Thesis, Univ Politècnica de Catalunya, http://www.tdx.cesca.es/TDX-1020104-091741/
  5. Camps A, Font J, Vall-llossera M, Gabarró C, Corbella I, Duffo N, Torres F, Blanch S, Aguasca A, Villarino R, Enrique L, Miranda J, Arenas J, Julià A, Etcheto J, Caselles V, Weill A, Boutin J, Contardo S, Niclós R, Rivas R, Reising SC, Wursteisen P, Berger M, Martín-Neira M (2004) The WISE 2000 and 2001 field experiments in support of the SMOS mission: sea surface L-band brightness temperature observations and their application to multi-angular salinity retrieval. IEEE Trans Geosci Rem Sens 42:804–823CrossRefGoogle Scholar
  6. Corbella I, Duffo N, Vall-llossera M, Camps A, Torres F (2004) The visibility function in interferometric aperture synthesis radiometry. IEEE Trans Geosci Rem Sens 42:1677–1682CrossRefGoogle Scholar
  7. Dinnat EP, Boutin J, Caudal G, Etcheto J, Waldteufel P (2002) Influence of sea surface emissivity model parameters at L-band for the estimation of salinity. Int J Remote Sens 23:5117–5122CrossRefGoogle Scholar
  8. Drinkwater M, Kerr YH, Font J, Berger M (2009) Exploring the water cycle of the blue planet: the soil moisture and ocean salinity (SMOS) mission. ESA Bull 137:6–15Google Scholar
  9. Ellison W, Balana A, Delbos G, Lamkaouchi K, Eymard L, Guillou C, Prigent C (1998) New permittivity measurements of sea water. Radio Sci 33(3):639–648CrossRefGoogle Scholar
  10. Font J, Lagerloef GSE, Le Vine DM, Camps A, Zanifé OZ (2004) The determination of surface salinity with the European SMOS space mission. IEEE Trans Geosci Rem Sens 42:2196–2205CrossRefGoogle Scholar
  11. Font J, Boutin J, Reul N, Waldteufel P, Gabarró C, Zine S, Tenerelli J, Petitcolin F, Vergely JL (2006) An iterative convergence algorithm to retrieve sea surface salinity from SMOS L-band radiometric measurements. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium 2006 (IGARSS 2006), Denver, pp. 1697–1701Google Scholar
  12. Font J, Camps A, Borges A, Martín-Neira M, Boutin J, Reul N, Kerr YH, Hahne A, Mecklenburg S (2010) SMOS: the challenging sea surface salinity measurement from space. Proc IEEE (in press)Google Scholar
  13. Gabarró C, Font J, Camps A, Vall-llossera M, Julià A (2004) A new empirical model of sea surface microwave emissivity for salinity remote sensing. Geophys Res Lett 31(L0):1309, doi:10.1029/2003GL018964CrossRefGoogle Scholar
  14. Gabarró C, Portabella M, Talone M, Font J (2009) Towards an optimal SMOS ocean salinity inversion algorithm. IEEE Trans Geosci Rem Sens 6:509–513CrossRefGoogle Scholar
  15. Gordon AL, Giulivi CF (2008) Sea surface salinity trends over 50 years within the Subtropical North Atlantic. Oceanography 21:20–29Google Scholar
  16. Hakkinen S, Rhines PB (2009) Shifting surface currents in the northern North Atlantic Ocean. J Geophys Res 114(C04005), doi:10.1029/2008JC004883Google Scholar
  17. Hollinger JP (1971) Passive microwave measurements of sea surface roughness. IEEE Trans Geosci Electron GE-9(3):165–169CrossRefGoogle Scholar
  18. Holliday NP, Hughes SL, Bacon S, Beszczynska-Modieller A, Hansen B, Lavín A, Loeng H, Mork KA, Østerhus S, Sherwin T, Walczowski W (2008) Reversal of the 1960s to 1990s freshening trend in the northeast North Atlantic and Nordic Seas. Geophys Res Lett 35(L03614), doi:10.1029/2007GL032675Google Scholar
  19. 1.
    IPCC (2007) Climate change 2007: the physical science basis. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Avery KB, Tignor M, Miller HL (eds.) Fourth assessment report, Cambridge University Press, Cambridge, UK, pp. 996Google Scholar
  20. Johnson JT, Zhang M (1999) Theoretical study of the small slope approximation for ocean polarimetric thermal emission. Wave Random Complex 37:2305–2316Google Scholar
  21. Kerr YH, Fukami K, Skou N, Srokosz MA, Lagerloef GSE, Goutoule JM, Le Vine DM, Martín-Neira M, Marczewski W, Laursen B, Gazdewich J, Barà J, Camps A (1995) Proceedings of the Consultative Meeting on Soil Moisture and Ocean Salinity Measurement Requirements and Radiometer Techniques (SMOS), ESA WPP-87, ESTEC, Noordwijk, The NetherlandsGoogle Scholar
  22. Kerr YH, Waldteufel P, Wigneron JP, Martinuzzi JM, Font J, Berger M (2001) Soil moisture from space: the soil moisture and ocean salinity (SMOS) mission. IEEE Trans Geosci Rem Sens 39:1729–1735CrossRefGoogle Scholar
  23. Kim SB, Wentz F, LeVine D, Lagerloef GSE (2010) Simulation of sea surface salinity retrieval with the Aquarius L-band radiometer. IEEE Trans Geosci Rem Sens (in press)Google Scholar
  24. Klein LA, Swift CT (1977) An improved model for the dielectric constant of sea water at microwave frequencies. IEEE J Ocean Eng 2:104–111.CrossRefGoogle Scholar
  25. Lagerloef GSE, Swift C, Le Vine D (1995) Sea surface salinity: the next remote sensing challenge. Oceanography 8:44–50Google Scholar
  26. Lagerloef GSE (2001) Satellite measurements of salinity. In: Steele J, Thorpe S, Turekian K (eds.) Encyclopedia of Ocean Sciences, Academic Press, London, pp. 2511–2516Google Scholar
  27. Lagerloef GSE (2002) Introduction to the special section: the role of surface salinity on upper ocean dynamics, air sea interaction and climate. J Geophys Res 107(C12):8000, doi:10.1029/2002JC001669CrossRefGoogle Scholar
  28. Lagerloef GSE, Colomb F, Le Vine D, Wentz F, Yueh S, Ruf C, Lilly J, Gunn J, Chao Y, deCharon A, Feldman G, Swift C (2008) The Aquarius/SAC-D mission: designed to meet the salinity remote-sensing challenge. Oceanography 20:68–81Google Scholar
  29. Lagerloef G, Boutin J, Chao Y, Delcroix T, Font J, Niiler P, Reul N, Riser S, Schmitt R, Stammer D, Wentz F (2010) Resolving the global surface salinity field and variations by blending satellite and in situ observations. In: Hall J, Harrison DE, Stammer D (eds.) Proceedings of OceanObs’09: Sustained Ocean Observations and Information for Society (Vol. 2), Venice, Italy, 21–25 September 2009, ESA Publication WPP-306Google Scholar
  30. 2.
    Lang RH, Tarkocin Y, Utku C, Le Vine DM (2008) Recent results on the accurate measurements of the dielectric constant of seawater at 1.413 GHz. Geoscience and Remote Sensing Symposium. IGARSS 2008. IEEE International, Vol. IV, Boston, MA, pp. 950–953Google Scholar
  31. Le Vine DM, Zaitzeff JB, D’Sa EJ, Miller JL, Swift C, Goodberlet M (2000) Sea surface salinity: toward an operational remote-sensing system. In: Halpern D (ed.) Satellites, Oceanography and Society, Elsevier Oceanography Series 63, Amsterdam, pp. 321–335CrossRefGoogle Scholar
  32. Le Vine DM, Lagerloef GSE, Colomb R, Yueh S, Pellerano F (2007) Aquarius: an instrument to monitor sea surface salinity from space. IEEE Trans Geosci Rem Sens 45:2040–2050CrossRefGoogle Scholar
  33. Le Vine DM, Abraham S (2002) The effect of the ionosphere on remote sensing of sea surface salinity from space: absorption and emission at L-band. IEEE Trans Geosci Rem Sens 40:771–782CrossRefGoogle Scholar
  34. Le Vine DM, Abraham S (2004) Galactic noise and passive microwave remote sensing from space at L-band. IEEE Trans Geosci Rem Sens 42:119–129CrossRefGoogle Scholar
  35. Le Vine DM, Abraham S, Wentz F, Lagerloef GSE (2005) Impact of the sun on remote sensing of sea surface salinity from space. Proc Internat Geosci Rem Sens Symp 1:288–291, doi:10.1109/IGARSS.2005.1526164Google Scholar
  36. Martín-Neira M, Goutoule JM (1997) A two-dimensional aperture-synthesis radiometer for soil moisture and ocean salinity observations. ESA Bull 92:95–104Google Scholar
  37. Martín-Neira M, Ribó S, Martín-Polegre AJ (2002) Polarimetric mode of MIRAS. IEEE Trans Geosci Rem Sens 40:1755–1768CrossRefGoogle Scholar
  38. McMullan KD, Brown MA, Martín-Neira M, Ritts W, Ekholm S, Marti J, Lemanczyk J (2008) SMOS: the payload. IEEE Trans Geosci Rem Sens 46:594–605CrossRefGoogle Scholar
  39. 3.
    Meissner T, Wentz FJ (2003) The complex dielectric constant of pure and sea water from microwave satellite observations. IEEE Trans Geosci Remote Sens 42:1836–1849CrossRefGoogle Scholar
  40. Ruf CS, Swift CT, Tanner AB, Le Vine DM (1988) Interferometric synthetic aperture microwave radiometry for the remote sensing of the Earth. IEEE Trans Geosc Rem Sens 26:597–611CrossRefGoogle Scholar
  41. Sabia R, Camps A, Talone M, Vall-llossera M, Font J (2010) Determination of the sea surface salinity error budget in the soil moisture and ocean salinity mission. IEEE Trans Geosci Rem Sens doi: 10.1109/TGRS.2009.2034648Google Scholar
  42. Stott PA, Sutton RT, Smith DM (2008) Detection and attribution of Atlantic salinity changes. Geophys Res Lett 35:L21702, doi:10.1029/2008GL035874CrossRefGoogle Scholar
  43. Stogryn A (1997) Equations for the permittivity of sea water. GenCorp, Aerojet Electron Syst Rep, Azusa, CAGoogle Scholar
  44. Swift CT, McIntosh RE (1983) Considerations for microwave remote sensing of ocean-surface salinity. IEEE Trans Geosci Rem Sens 21:480–491CrossRefGoogle Scholar
  45. 4.
    US CLIVAR Salinity Working Group (2007) Report of the US CLIVAR Salinity Working Group. US CLIVAR Report No. 2007-1, US CLIVAR Office, Washington, DC, available online at: http://www.sclivar.org/Pubs/Salinity_final_report.pdf
  46. Waldteufel P, Boutin J, Kerr YH (2003) Selecting an optimal configuration for the soil moisture and ocean salinity mission. Radio Sci 38:8051CrossRefGoogle Scholar
  47. 5.
    Wilson W, Yueh S, Dinardo SJ, Chazanoff S, Kitiyakara A, Li FK, Rahmat-Samii Y (2001) Passive Active L- and S-band (PALS) microwave sensor for ocean salinity and soil moisture measurements. IEEE Trans Geosci Remote Sens 39:1039–1048Google Scholar
  48. 6.
    Wilson WJ, Yueh S, Dinardo SJ, Li FK (2004) High-stability L-band radiometer measurements of saltwater. IEEE Trans Geosci Remote Sens 42:1829–1835CrossRefGoogle Scholar
  49. Yueh SH (2000) Estimates of faraday rotation with passive microwave polarimetry for microwave remote sensing of earth surfaces. IEEE Trans Geosci Rem Sens 38(5):2434–2438CrossRefGoogle Scholar
  50. Yueh SH, West R, Wilson WJ, Li FK, Njoku EG, Rahmat-Samii Y (2001) Error sources and feasibility for microwave remote sensing of ocean surface salinity. IEEE Trans Geosci Rem Sens 39:1049–1060CrossRefGoogle Scholar
  51. Zine S, Boutin J, Font J, Reul N, Waldteufel P, Gabarró C, Tenerelli J, Petitcolin F, Vergely JL, Talone M, Delwart S (2008) Overview of the SMOS sea surface salinity prototype processor. IEEE Trans Geosci Rem Sens 46:621–645CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Earth and Space ResearchSeattleUSA
  2. 2.Department Physical OceanographyInstitute of Marine SciencesBarcelonaSpain

Personalised recommendations