@article{fdi:010063695,
  title = {{N}ew processing approaches on the retrieval of water levels in {E}nvisat and {SARAL} radar altimetry over rivers : a case study of the {S}ao {F}rancisco {R}iver, {B}razil},
  author = {{M}aillard, {P}. and {B}ercher, {N}. and {C}almant, {S}t{\'e}phane},
  editor = {},
  language = {{ENG}},
  abstract = {{R}adar-based satellite altimetry is well recognized for oceanographic applications. {F}or continental hydrology, its use is complicated by a number of environmental factors such as river width and shape, land cover type in the vicinity of the river banks, and the topography of the relief. {T}hese factors make precision vary significantly. {L}ocations where the satellites cross the river can be used as "virtual gauging stations" that can complement the existing network of in situ stations. {T}his article describes processing techniques that take some of these environmental factors (river shape and width) into account to improve the precision of altimetry measurements of the water level. {T}hese techniques are based on some a priori information about the river banks and on modeling a phenomenon called "off-nadir hooking". {T}his approach is tested on the {S}ao {F}rancisco {R}iver in {B}razil, which for most of its path is considered narrow for satellite altimetry applied to hydrology. {D}ata from {E}nvisat cover the period 2002-2010 while the recently launched {SARAL} satellite provided data for 2013. {T}he results show that the accuracy varies significantly depending on a number of environmental factors some of which are discussed in depth. {I}n about one-half of the 16 satellite water gauging stations, the {RMS} errors are lower than 60 cm and in some cases better than 30 cm. {T}hese variations could not be directly related to the river width, but appear to be mostly related to the land cover and to the processing chain that often extracts altimetry points from an off-nadir location. {A}ll processing is fully described and the results are presented for both the {E}nvisat/{RA}-2 and {SARAL}/{A}ltika altimeters.},
  keywords = {{R}adar altimetry ; {W}ater level ; {E}nvisat ; {SARAL} ; {H}ydrology ; {BRESIL}},
  booktitle = {},
  journal = {{R}emote {S}ensing of {E}nvironment},
  volume = {156},
  numero = {},
  pages = {226--241},
  ISSN = {0034-4257},
  year = {2015},
  DOI = {10.1016/j.rse.2014.09.027},
  URL = {https://www.documentation.ird.fr/hor/fdi:010063695},
}