The SMOS Soil Moisture Retrieval Algorithm
Yann Kerr,Philippe Waldteufel,P. Richaume,Jean-Pierre Wigneron,Paolo Ferrazzoli,A. Mahmoodi,Ahmad Al Bitar,Francois Cabot,C. Gruhier,S. Juglea,Delphine Leroux,Arnaud Mialon,Steven Delwart +12 more
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TLDR
A retrieval algorithm to deliver global soil moisture (SM) maps with a desired accuracy of 0.04 m3/m3 is given, discusses the caveats, and provides a glimpse of the Cal Val exercises.Abstract:
The Soil Moisture and Ocean Salinity (SMOS) mission is European Space Agency (ESA's) second Earth Explorer Opportunity mission, launched in November 2009. It is a joint program between ESA Centre National d'Etudes Spatiales (CNES) and Centro para el Desarrollo Tecnologico Industrial. SMOS carries a single payload, an L-Band 2-D interferometric radiometer in the 1400-1427 MHz protected band. This wavelength penetrates well through the atmosphere, and hence the instrument probes the earth surface emissivity. Surface emissivity can then be related to the moisture content in the first few centimeters of soil, and, after some surface roughness and temperature corrections, to the sea surface salinity over ocean. The goal of the level 2 algorithm is thus to deliver global soil moisture (SM) maps with a desired accuracy of 0.04 m3/m3. To reach this goal, a retrieval algorithm was developed and implemented in the ground segment which processes level 1 to level 2 data. Level 1 consists mainly of angular brightness temperatures (TB), while level 2 consists of geophysical products in swath mode, i.e., as acquired by the sensor during a half orbit from pole to pole. In this context, a group of institutes prepared the SMOS algorithm theoretical basis documents to be used to produce the operational algorithm. The principle of the SM retrieval algorithm is based on an iterative approach which aims at minimizing a cost function. The main component of the cost function is given by the sum of the squared weighted differences between measured and modeled TB data, for a variety of incidence angles. The algorithm finds the best set of the parameters, e.g., SM and vegetation characteristics, which drive the direct TB model and minimizes the cost function. The end user Level 2 SM product contains SM, vegetation opacity, and estimated dielectric constant of any surface, TB computed at 42.5°, flags and quality indices, and other parameters of interest. This paper gives an overview of the algorithm, discusses the caveats, and provides a glimpse of the Cal Val exercises.read more
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Proceedings ArticleDOI
Global Weekly Inland Surface Water Dynamics from L-Band Microwave
TL;DR: In this paper, the authors presented a new methodology to retrieve water fraction at coarse scale and high temporal resolution (one week) using L-band multi-angular and dual polarisation remote sensing data from SMOS mission.
Journal ArticleDOI
Fourier-Correlation Imaging
TL;DR: In this paper, the authors investigated whether correlations between the Fourier components at slightly shifted frequencies of the fluctuations of the electric field measured with a one-dimensional antenna array on board a satellite flying over a plane allow one to measure the two-dimensional brightness temperature as a function of position in the plane.
Potential Satellite Monitoring of Surface Organic Soil Properties in Arctic Tundra From SMAP
Yonghong Yi,Richard H. Chen,John S. Kimball,M. Lotfi Moghaddam,Xiaolan Xu,Eugénie S. Euskirchen,Narendra N. Das,Charles E. Miller +7 more
TL;DR: In this paper , the authors explored the links between surface organic soil properties and soil moisture dynamics in the Alaska North Slope through data analysis and process-based modeling, and found that more rapid drydown was generally observed in areas with high organic carbon concentration (SOCC) or low bulk density.
Journal ArticleDOI
Performance Simulation of the Payload IMR and MICAP Onboard the Chinese Ocean Salinity Satellite
TL;DR: In this paper , a series of simulations is applied to analyze the payloads performance, including the brightness temperature (TB) characteristic, the SSS accuracy, and the effects of Sun and land contamination.
Proceedings ArticleDOI
Compared performances of microwave passive soil moisture retrievals (SMOS) and active soil moisture retrievals (ASCAT) using land surface model estimates (MERRA-LAND)
Amen Al-Yaari,Jean-Pierre Wigneron,Agnès Ducharne,Yann Kerr,Wolfgang Wagner,Rolf H. Reichle,G. De Lannoy,Ahmad Al Bitar,Wouter Dorigo,Marie Parrens,R. Fernandez,Philippe Richaume,Arnaud Mialon +12 more
TL;DR: This study showed that both SMOSL3 and ASCAT provide complementary information on SSM, which implies a potential for data fusion which would be pertinent for the ESA climate change initiative (CCI).
References
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Book
Microwave Remote Sensing, Active and Passive
TL;DR: In this article, the authors present a model of a MICROWAVE REMOTE SENSING FUNDAMENTALS and RADIOMETRY, which is based on the idea of surface scattering.
Journal ArticleDOI
The Soil Moisture Active Passive (SMAP) Mission
Dara Entekhabi,Eni G. Njoku,Peggy O'Neill,Kent Kellogg,Wade T. Crow,W. Edelstein,Jared Entin,Shawn D Goodman,Thomas J. Jackson,Joel T. Johnson,John S. Kimball,Jeffrey R. Piepmeier,Randal D. Koster,Neil R.W. Martin,Kyle C. McDonald,Mahta Moghaddam,Susan Moran,Rolf H. Reichle,Jiancheng Shi,Michael W. Spencer,Samuel W Thurman,Leung Tsang,Jakob van Zyl +22 more
TL;DR: The Soil Moisture Active Passive mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council's Decadal Survey to make global measurements of the soil moisture present at the Earth's land surface.
Journal ArticleDOI
Microwave Dielectric Behavior of Wet Soil-Part II: Dielectric Mixing Models
TL;DR: In this paper, the authors evaluated the microwave dielectric behavior of soil-water mixtures as a function of water content and soil textural composition for the 1.4-to 18-GHz region.
Journal ArticleDOI
The SMOS Mission: New Tool for Monitoring Key Elements ofthe Global Water Cycle
Yann Kerr,Philippe Waldteufel,Jean-Pierre Wigneron,Steven Delwart,Francois Cabot,Jacqueline Boutin,Maria-José Escorihuela,Jordi Font,Nicolas Reul,C. Gruhier,S. Juglea,Mark R. Drinkwater,Achim Hahne,Manuel Martin-Neira,Susanne Mecklenburg +14 more
TL;DR: The SMOS satellite was launched successfully on November 2, 2009, and will achieve an unprecedented maximum spatial resolution of 50 km at L-band over land (43 km on average over the field of view), providing multiangular dual polarized (or fully polarized) brightness temperatures over the globe.
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