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An application of the Soil Moisture Agricultural Drought Index (SMADI) for global agricultural drought monitoring is presented. The index integrates surface soil moisture from the Soil Moisture and Ocean Salinity (SMOS) mission with the Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) and Normalized Difference Vegetation Index (NDVI) and allows for global drought...
The European Space Agency's Climate Change Initiative (CCI) soil moisture (or Essential Climate Variable soil moisture) long-term database was used to assess the agricultural drought evolution. With this aim, the Soil Water Deficit Index (SWDI) was calculated with the CCI soil moisture product over the agricultural area of the Zamora province (Spain) from 1978 to 2014. The SWDI was compared with other...
New ocean products from the Soil Moisture and Ocean Salinity (SMOS) mission are being developed at the Barcelona Expert Centre. Besides the already operational 9-day and monthly sea surface salinity (SSS) products, two additional daily SSS products have been recently become operational: a simple user-friendly product containing all swath-based Level 2 data for each day, and a more elaborated product...
Drought is a major cause of limited agricultural productivity and of crop yield uncertainty throughout the world. For that reason, agricultural drought research and monitoring are of increasing interest. Although soil moisture is the main variable to define and identify agricultural drought, the actual soil water content is rarely taken into account because this type of drought is commonly studied...
This work is focused on the quality improvement of ESA's SMOS (Soil Moisture and Ocean Salinity) salinity retrievals, paying special attention to coastal regions. Two correction techniques have been applied to enhance the quality of brightness temperatures: the nodal sampling for the reduction of Gibbs-like contamination and the correction of residual amplitude calibration errors for the mitigation...
The European Space Agency mission Soil Moisture and Ocean Salinity (SMOS) is devoted, since its launch in 2009, to provide global soil moisture and sea surface salinity values. SMOS uses an L band 2-D interferometric radiometer by aperture synthesis to obtain polarimetric brightness temperature images. This work is devoted to compute the spatial correlations in the measured antenna brightness temperature...
A comparison analysis was made between the SWDI (Soil Water Deficit Index) calculated with in situ and SMOS (Soil Moisture and Ocean Salinity satellite) soil moisture series (June-2010 to December-2014), over an agricultural area in Spain. Additionally, both SWDI have been compared with two well-known agricultural drought indices, the CMI (Crop Moisture Index) and the AWD (Atmospheric Water Deficit...
A comprehensive spatial and temporal validation of long-term dataset of SMOS (Soil Moisture and Ocean Salinity) and Aquarius-derived soil moisture estimates was made using two in situ networks (REMEDHUS and Inforiego) within the Duero River Basin (Spain). Results from comparison with in situ show that the SMOS L2 product has better accuracy (with values of R>0.8 and cRMSD<0.04 m3m−3) than Aquarius...
RFI (Radio Frequency Interference) sources, Sun signal and even land-sea transitions may generate large sidelobes that corrupt SMOS brightness temperature products and therefore, the quality of the soil moisture and sea surface salinity retrievals. This work focuses on the reduction of this Gibbs-like contamination in brightness temperature scenes using an alternative image reconstruction approach...
The Local Oscillators (LO) of the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) onboard the Soil Moisture and Ocean Salinity (SMOS) satellite are used to maintain the operating frequency of the 69 receivers. The phase of the LO drifts over time, in turn blurring the MIRAS brightness temperature (TB) measurements. After a pre-launch assessment, it was decided to calibrate the LO every...
The vegetation optical thickness (τ) from the Soil Moisture and Ocean Salinity (SMOS) L2 products is compared to some vegetation parameters estimated both at field scale and by means of an upscaling procedure through the MODIS Normalized Difference Vegetation Index (NDVI). Vegetation measurements over rainfed cereals indicated that NDVI, Leaf Area Index (LAI) and Vegetation Water Content (VWC) were...
This paper describes the relationships found between remotely sensed soil moisture, in situ observed soil moisture, and spatial distribution of soil and climatic factors. For the comparison between remote and in situ soil moisture, soil moisture map series at high resolution, obtained by applying a downscaling approach that combines Soil Moisture and Ocean Salinity (SMOS) and MODIS imagery is extracted...
A prospective sounding of the capabilities of a novel salinity retrieval by means of Support Vector Regression has been performed. Co-located SMOS measurements and additional auxiliary parameters have been considered, whilst salinity data collected by ARGO buoys represented the ground-truth to be matched by the algorithm. Salinity fields estimated by the SVR are in good agreement with the ground-truth,...
SMOS salinity inversion consists of minimizing the residual between measured and modeled brightness temperatures. The minimization procedure is a great challenge and crucial step, but its success depends on the quality of the forward model. Consequently, we present an empirical update of pre-launch L-band emissivity forward models, where the essential improvement is related to the emissivity by a...
The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) mission will provide accurate global surface soil moisture estimates. However, due to technological limitations, the spatial resolution of SMOS observations is limited to 40-km. This resolution is adequate for many global applications, but restricts the use of the data in regional studies over land, where a resolution of 1-10...
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