SMOS: The Challenging Sea Surface Salinity Measurement From Space

Abstract

| Soil Moisture and Ocean Salinity, European Space Agency, is the first satellite mission addressing the challenge of measuring sea surface salinity from space. It uses an L-band microwave interferometric radiometer with aperture synthesis (MIRAS) that generates brightness temperature images, from which both geophysical variables are computed. The retrieval of salinity requires very demanding performances of the instrument in terms of calibration and stability. This paper highlights the importance of ocean salinity for the Earth's water cycle and climate; provides a detailed description of the MIRAS instrument, its principles of operation, calibration, and imagereconstruction techniques; and presents the algorithmic approach implemented for the retrieval of salinity from MIRAS observations, as well as the expected accuracy of the obtained results.Andrés Borges graduated in electrical engineering from the Polithecnic Universisty of Valencia, Spain, in 1989. He received a degree in business administration from UNED, Spain, and the M.B.A. degree from the Instituto de Empresa, Spain. He was a Software Engineer with the European Space Agency, specializing in software development for space robotics. In 1992, he joined EADS CASA Espacio, Madrid, Spain, and he worked during six years in several space projects as a Software and System Engineer. In 1998, he became Project Manager of the MIRAS Demonstrator Project, a technology development project for SMOS. Later, he continued as Project Manager throughout the development phases of the SMOS payload, MIRAS. At present, he is Project Manager of INGENIO, the first Spanish optical satellite. Manuel Martín-Neira (Senior Member, IEEE) received the M.S. and Ph.D. degrees in telecommunication engineering from the

Aquarius geophysical model function and combined active passive algorithm for ocean surface salinity and wind retrieval

“…Two L-band microwave remote sensing satellites, the Soil Moisture and Ocean Salinity (SMOS) mission [Font et al, 2009;Boutin et al, 2012;Reul et al, 2012], and the Aquarius/SAC-D mission [Lagerloef et al, 2008] are currently operating to make global observations of SSS.…”

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

“…The main issues related to the sea surface salinity retrievals from SMOS are discussed in depth in [2] and [39]. Font et al [13] provided a first analysis of SMOS data one year after launch in terms of practical problems encountered in salinity retrieval.…”

“…On 2 November 2009 the European Space Agency successfully launched from Plesetsk, (Northern Russia) the first of its Earth Explorer Opportunity Missions: SMOS, which stands for Soil Moisture and Ocean Salinity [1][2][3][4]. These are small format missions aimed at demonstrating new technologies to provide relevant new information for Earth observation from space, which are submitted to ESA by the scientific community through dedicated calls.…”

Remote sensing of environmental indicators of potential fish aggregation: An overview

“…SMOS retrieves salinity with an accuracy of about 0.5 psu and a resolution of about 50 km (Barre, Duismann, Kerr 2008;ESA 2009;Font et al 2010). Other salinity-related satellites are being developed, such as Aquarius, which will provide a global view of salinity variability (NASA 2011).…”