NEW COMBINED L-BAND ACTIVE/PASSIVE SOIL MOISTURE RETRIEVAL ALGORITHM OPTIMIZED FOR ARGENTINE PLAINS

CINTIA BRUSCANTINI; FRANCISCO MATIAS GRINGS; MERCEDES SALVIA; PAOLO FERRAZZOLI; HAYDEE KARSZENBAUM

San Francisco

Congreso; American Geophysical Union fall meeting 2015; 2015

AGU ( American Geophysical Union)

p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; widows: 2; orphans: 2; }p.western { font-family: "Times New Roman",serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman",serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 12pt; }The ability of L-band passivemicrowave satellite observations to provide soil moisture (mv)measurements is well known. Despite its high sensitivity tonear-surface mv, radiometric technology suffers from having arelatively low spatial resolution. Conversely active microwaveobservations, although their finer resolution, are difficult to beinterpreted for mv content due to the confounding effects ofvegetation and roughness.There have been and there arestrong motivations for the realization of satellite missions thatcarry passive and active microwave instruments on board. This hasalso led to important contributions in algorithm development. In thisline of work, NASA-CONAE SAC-D/Aquarius mission had on board an Lband radiometer and scatterometer. This was followed by the launch ofNASA SMAP mission (Soil Moisture Active Passive), as well as severalairborne campaigns that provide active and passive measurements.Within thisframe, a new combined active/passive mv retrieval algorithm isproposed by deriving an analytical expression of brightnesstemperature and radar backscattering relation using explicitsemi-empirical models. Simple models (i.e. that can be easilyinverted and have relatively low amount of ancillary parameters) wereselected: ω-τmodel (Jackson et al., 1982) and radar-only model (Narvekar et al.,2015). A major challenge involves coupling the active and passivemodels to be consistent with observations. Coupling equations can bederived using theoretical active/passive high-order radiativetransfer models, such as 3D Numerical Method of Maxwell equations(Zhou et al., 2004) and Tor Vergata (Ferrazzoli et al., 1995) models.In this context, different coupling equations can be optimized fordifferent land covers using theoretical forward models with specificparametrization for each land cover type. The quality of the couplingequations derived is discussed in relation with different landsurface conditions using Aquarius/SAC-D observations. This is done inpreparation for SMAP and future SAOCOM data.