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| Titel |
Validation of the SMOS-MIRAS Soil Moisture Product (SML2UDP) in the Pampean Region of Argentina |
| VerfasserIn |
Raquel Niclòs, Raúl Rivas, Juan Manuel Sánchez, Vicente García-Santos, Carolina Doña, Enric Valor, Mauro Holzman, Martín Ignacio Bayala, Facundo Carmona, Dora Ocampo, Alvaro Soldano, Marc Thibeault |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093038
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| Publikation (Nr.) |
 EGU/EGU2014-7408.pdf |
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| Zusammenfassung |
| A validation campaign was carried out to evaluate the SMOS-MIRAS Soil Moisture (SM)
SML2UDP product (v5.51) in the Pampean Region of Argentina on February 2013. The
study area was selected because it is a vast area of flatlands containing quite homogeneous
rainfed croplands, with prevalence of soybean crops, considered SMOS nominal land
uses (i.e., crops with vegetation heights not exceeding 1 to 2 m by opposition to
trees).
Transects of ground SM measurements were collected by Delta-T ThetaProbe
ML2x SM probes within four ISEA-4H9 DGG SMOS nodes. The SM data obtained
by each probe transect in each parcel were checked by collecting soil samples in
the same parcels at the same time and measuring their masses. The gravimetric
method was used to obtain reference values. An uncertainty of ± 0.03 m3m-3 was
obtained for the ML2x probes. Additionally, they were calibrated in the laboratory
for different SMs by saturating and drying a specific and representative variety
of soil samples collected from the experimental parcels (loam, clay loam and silt
loam samples). This calibration showed again accurate operations for the ML2x
probes, which even attain uncertainties of ±0.01 m3m-3, in agreement with the
manufacturer.
The comparison of the SM transect data collected during the campaign with the
SMOS-MIRAS SML2UDP product values showed a negative bias between concurrent
SMOS data and ground SM measurements, which means a slight SMOS-MIRAS
underestimation, and a standard deviation of ± 0.06 m3m-3.
The validation sites were selected taking as reference the locations of permanent SM
stations property of the Argentinean Comisión Nacional de Actividades Espaciales (CONAE,
National Commission of Space Activities), Instituto Nacional de Tecnología Agropecuaria
(INTA, National Institute of Farming Technology) and Instituto de Hidrología de Llanuras
(IHLLA, Plain Hydrology Institute). During the campaign several transects were carried out
in the parcels where permanent SM stations were located, mainly in those within one of the
nodes (with 5 stations inside). The objective was to evaluate the station SM data reliability at
the SMOS spatial resolution with the aim of using station data series as reference for
SMOS-MIRAS SM product validations. A linear correlation was obtained between the
ground SM values and the SM station data within the node, with a coefficient of
determination of 0.98 and a fitting error of ± 0.010 m3m-3. Therefore, the station
data adjusted to obtain node representative values are being evaluated as reference
data to extend the validation of SMOS-retrieved data beyond the campaign results. |
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