@article{PAR00008798,
  title = {{W}heat canopy structure and surface roughness effects on multiangle observations at {L}-band},
  author = {{P}eischl, {S}. and {W}alker, {J}.{P}. and {R}yu, {D}. and {K}err, {Y}ann and {P}anciera, {R}. and {R}udiger, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he multiangle observation capability of the {S}oil {M}oisture and {O}cean {S}alinity mission is expected to significantly improve the inversion of soil microwave emissions for soil moisture, by enabling the simultaneous retrieval of the vegetation optical depth and other surface parameters. {C}onsequently, this paper investigates the relationship between soil moisture and brightness temperature at multiple incidence angles using airborne {L}-band data from the {N}ational {A}irborne {F}ield {E}xperiment in {A}ustralia in 2005. {A} forward radio brightness model was used to predict the passive microwave response at a range of incidence angles, given the following inputs: 1) ground-measured soil and vegetation properties and 2) default model parameters for vegetation and roughness characterization. {S}imulations were made across various dates and locations with wheat cover and evaluated against the available airborne observations. {T}he comparison showed a significant underestimation of the measured brightness temperatures by the model. {T}his discrepancy subsequently led to soil moisture retrieval errors of up to 0.3 m(3)/m(3). {F}urther analysis found the following: 1) {T}he roughness value {H}-{R} was too low, which was then adjusted as a function of the soil moisture, and 2) the vegetation structure parameters tt(h) and tt(v) required optimization, yielding new values of tt(h) = 0.2 and tt(v) = 1.4 from calibration to a single flight. {T}esting the optimized parameterization for different moisture conditions and locations found that the root-mean-square simulation error between the forward model predictions and the airborne observations was improved from 31.3 {K} (26.5 {K}) to 2.3 {K} (5.3 {K}) for wet (dry) soil moisture condition.},
  keywords = {{L}-band {M}icrowave {E}mission of the {B}iosphere ({L}-{MEB}) ; microwave ; radiometry ; multiangle ; {N}ational {A}irborne {F}ield {E}xperiment ({NAFE}) ; {S}oil ; {M}oisture and {O}cean {S}alinity ({SMOS})},
  booktitle = {},
  journal = {{IEEE} {T}ransactions on {G}eoscience and {R}emote {S}ensing},
  volume = {50},
  numero = {5},
  pages = {1498--1506},
  ISSN = {0196-2892},
  year = {2012},
  DOI = {10.1109/tgrs.2011.2174644},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00008798},
}