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A Review on European Remote Sensing Activities in Wildland Fires Prevention
Published in George P. Petropoulos, Tanvir Islam, Remote Sensing of Hydrometeorological Hazards, 2017
David Chaparro, Mercè Vall-llossera, Maria Piles
The ESA SMOS satellite was the first mission specifically dedicated to SM measurements. Its unique payload is an L-band interferometric radiometer, the Microwave Imaging Radiometer with Aperture Synthesis (MIRAS). After more than 6 years in orbit, SMOS continues providing global SM maps every 3 days, with a target accuracy of 0.04 m3 · m−3 (Kerr et al. 2012). The spatial resolution of the SMOS data is ~40 km (L2 product). This meets the needs for global applications, but it is still too coarse to serve regional and local uses. Downscaling techniques allow improving the spatial resolution to 1 km (Merlin et al. 2005, 2008, Piles et al. 2011a, 2014). The NASA SMAP satellite has a real aperture L-band radiometer and an L-band radar. The specific advantages of both instruments allow for a high temporal resolution and enhance the spatial resolution from 36 km to 9 km (Entekhabi et al. 2010). However, the SMAP active–passive operations were ceased abruptly with the failure of the SMAP radar on July 2016. Nonetheless, the SMAP radiometer is continuing to make measurements, and the use of Sentinel-1 data as a replacement of its radar is under evaluation. The Aquarius satellite was an L-band mission shared between NASA and the Comisión Nacional de Actividades Espaciales (CONAE; Argentina). This mission, which was designed for measuring ocean salinity, was proved to be valid for SM retrievals (Bindlish et al. 2015). Nevertheless, the Aquarius mission ended in June 2015.
Integrating satellite soil-moisture estimates and hydrological model products over Australia
Published in Australian Journal of Earth Sciences, 2020
M. Khaki, A. Zerihun, J. L. Awange, A. Dewan
Satellite-based soil-moisture products are sourced from the AMSR-E for the period 2003–2011 and from European Space Agency SMOS Earth Explorer mission for the period 2011–2017. The AMSR-E measures the surface brightness temperature, which is correlated to the surface 0–2 cm soil-moisture content (Njoku et al., 2003). SMOS Microwave Imaging Radiometer using Aperture Synthesis radiometer measures the Earth’s surface emitted microwave to map land soil-moisture for the 0–5 cm depth. Level 3 CATDS (Centre Aval de Traitement des Donnees SMOS) products (Jacquette et al., 2010) with the same spatial resolution (0.25° × 0.25°) of AMSR-E are used. SMOS and AMSR-E are selected from ascending and descending passes subject to their higher agreement to insitu measurements (see, e.g. De Jeu & Owe, 2003; Draper et al., 2009; Jackson et al., 2012; Su et al., 2013).