Passive Microwave Measurements of Temperature And Salinity in Coastal Zones

Blume, Hans-Juergen C.; Kendall, B. M.

doi:10.1109/tgrs.1982.350461

Cited by 27 publications

(13 citation statements)

References 10 publications

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“…At these frequencies, the amount of microwave thermal radiation naturally emitted by the Earth's surface decreases with increasing soil moisture over land [2], and increasing surface salinity in the oceans [3]. Also, this band is significantly less affected by rain and atmospheric effects than higher microwave frequencies.…”

Section: Introductionmentioning

confidence: 98%

SMOS and Aquarius Radiometers: Inter-Comparison Over Selected Targets

Pablos

Piles

González-Gambau

et al. 2014

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Passive microwave remote sensing at L-band is considered to be the most suitable technique to measure soil moisture and ocean salinity. These two variables are needed as inputs of predictive models, to improve climate and weather forecast, and to increase our knowledge of the water cycle. Nowadays, there are two space missions providing frequent and global observations of moisture and salinity of the Earth's surface with L-band radiometers on-board. The first one is the ESA's SMOS satellite, launched on November 2, 2009, which carries a two-dimensional, multi-angular, and full-polarimetric synthetic aperture radiometer. The second one is the NASA/CONAE's Aquarius/SAC-D mission, launched on June 10, 2011, which includes three beam push-broom real aperture radiometers. The objective of this work is to compare SMOS and Aquarius brightness temperatures and verify the continuity and consistency of the data over the entire dynamic range of observations. This is paramount if data from both radiometers are used for any long term enviromental, meteorological, hydrological, or climatological studies. The intercomparison approach proposed is based on the study of 1 year of measurements over key target regions selected as representative of land, ice, and sea surfaces. The level of linearity, the correlation, and the differences between the observations of the two radiometers are analyzed. Results show a higher linear correlation between SMOS and Aquarius brightness temperatures over land than over sea. A seasonal effect and spatial inhomogeneities are observed over ice, at the Dome-C region. In all targets, better agreement is found in horizontal than in vertical polarization. Also, the correlation is higher at higher incidence angles. These differences indicate that there is a non-linear effect between the two instruments, not only a bias.Index Terms-Aquarius/Satélite de Aplicaciones Científicas (SAC)-D mission, brightness temperature, inter-comparison, L-band radiometer, passive microwave remote sensing, Soil Moisture and Ocean Salinity (SMOS) mission.

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Section: Introductionmentioning

confidence: 98%

SMOS and Aquarius Radiometers: Inter-Comparison Over Selected Targets

Pablos

Piles

González-Gambau

et al. 2014

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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“…The approach adopted for Aquarius is to use conventional radiative transport theory to model attenuation and emission from the atmosphere [e.g. Blume and Kendall, 1982] and to obtain the parameters such as temperature and pressure profiles needed in the model from measurements and meteorlogical models such as provided by the National Center for Environmental Prediction (NCEP). The emission at L-band is weakly dependent on atmospheric conditions [Yeuh et al, 2001] and modern models exist to predict its value [Liebe, Rosenkranz and Hufford, 1992;Thompson, Moran and Swenson, 1986]; however direct measurements of the emission from the atmosphere at the accuracy needed for remote sensing of salinity haven't been made at L-band.…”

Section: Remote Sensing Salinity From Spacementioning

confidence: 99%

Aquarius and Remote Sensing of Sea Surface Salinity from Space

2010

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“…There are two components of this emission, a signal emitted upward toward the radiometer from the column of ionosphere between the sensor and surface and signal emitted downward that is reflected at the surface into the sensor's field-of-view. Using a conventional radiative transfer model for a uniform layer, one can write these terms as follows [7], [22]: In these expressions, (13a) is the nominal emission from the surface, is the altitude of the sensor (675 km in the numerical examples), is the attenuation coefficient for power at altitude as given by (7), is the emissivity of the surface and is the Fresnel reflection coefficient of the surface as defined by (6), and is the temperature of the ionosphere and is the temperature of the surface. is the signal emitted by the ionosphere along the line-of-sight between the surface and sensor.…”

Section: Ionosphere Emissionmentioning

confidence: 99%