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Soil moisture is a key component in the hydrologic cycle and climate system. It is an important input parameter for many
hydrologic and meteorological models. NASA’S upcoming Soil Moisture Active Passive (SMAP) mission, to be
launched in October 2014, will address this need by utilizing passive and active microwave measurements at L-band,
which will penetrate moderately dense canopies. In preparation for the SMAP mission, the Soil Moisture Validation
Experiment 2012 (SMAPVEX12) was conducted from 6 June to 17 July 2012 in the Carment-Elm Creek area in
Manitoba, Canada. Over a period of six weeks diverse land cover types ranging from agriculture over pasture and
grassland to forested sites were re-visited several times a week. The Passive/Active L-band Sensor (PALS) provides
radiometer products, vertically and horizontally polarized brightness temperatures, and radar products. Over the past two
decades, successful estimation of soil moisture has been accomplished using passive and active L-band data. However,
remaining uncertainties related to surface roughness and the absorption, scattering, and emission by vegetation must be
resolved before soil moisture retrieval algorithms can be applied with known and acceptable accuracy using satellite
observations. This work focuses on analyzing the Passive/Active L-band Sensor observations of sites covered during
SMAPVEX12, investigating the observed data, parameterizing vegetation covered surface model, modeling inversion
algorithm and analyzing observed soil moisture changes over the time period of six weeks. The data and analysis results
from this study are aimed at increasing the accuracy and range of validity of SMAP soil moisture retrievals via
enhancing the accuracy for soil moisture retrieval.
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