@article{PAR00008809,
  title = {{V}alidation of {S}oil {M}oisture and {O}cean {S}alinity ({SMOS}) {S}oil {M}oisture {O}ver {W}atershed {N}etworks in the {U}.{S}},
  author = {{J}ackson, {T}.{J}. and {B}indlish, {R}. and {C}osh, {M}.{H}. and {Z}hao, {T}.{J}. and {S}tarks, {P}.{J}. and {B}osch, {D}.{D}. and {S}eyfried, {M}. and {M}oran, {M}.{S}. and {G}oodrich, {D}.{C}. and {K}err, {Y}ann and {L}eroux, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{E}stimation of soil moisture at large scale has been performed using several satellite-based passive microwave sensors and a variety of retrieval methods over the past two decades. {T}he most recent source of soil moisture is the {E}uropean {S}pace {A}gency {S}oil {M}oisture and {O}cean {S}alinity ({SMOS}) mission. {A} thorough validation must be conducted to insure product quality that will, in turn, support the widespread utilization of the data. {T}his is especially important since {SMOS} utilizes a new sensor technology and is the first passive {L}-band system in routine operation. {I}n this paper, we contribute to the validation of {SMOS} using a set of four in situ soil moisture networks located in the {U}. {S}. {T}hese ground-based observations are combined with retrievals based on another satellite sensor, the {A}dvanced {M}icrowave {S}canning {R}adiometer ({AMSR}-{E}). {T}he watershed sites are highly reliable and address scaling with replicate sampling. {R}esults of the validation analysis indicate that the {SMOS} soil moisture estimates are approaching the level of performance anticipated, based on comparisons with the in situ data and {AMSR}-{E} retrievals. {T}he overall root-mean-square error of the {SMOS} soil moisture estimates is 0.043 m(3)/m(3) for the watershed networks (ascending). {T}here are bias issues at some sites that need to be addressed, as well as some outlier responses. {A}dditional statistical metrics were also considered. {A}nalyses indicated that active or recent rainfall can contribute to interpretation problems when assessing algorithm performance, which is related to the contributing depth of the satellite sensor. {U}sing a precipitation flag can improve the performance. {A}n investigation of the vegetation optical depth (tau) retrievals provided by the {SMOS} algorithm indicated that, for the watershed sites, these are not a reliable source of information about the vegetation canopy. {T}he {SMOS} algorithms will continue to be refined as feedback from validation is evaluated, and it is expected that the {SMOS} estimates will improve.},
  keywords = {{A}dvanced {M}icrowave {S}canning {R}adiometer ({AMSR}-{E}) ; passive microwave ; {S}oil ; {M}oisture and {O}cean {S}alinity ({SMOS}) ; soil moisture ; validation},
  booktitle = {},
  journal = {{IEEE} {T}ransactions on {G}eoscience and {R}emote {S}ensing},
  volume = {50},
  numero = {5},
  pages = {1530--1543},
  ISSN = {0196-2892},
  year = {2012},
  DOI = {10.1109/tgrs.2011.2168533},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00008809},
}