@article{fdi:010072778,
  title = {{V}alidation of {J}ason-3 tracking modes over {F}rench rivers},
  author = {{B}iancamaria, {S}. and {S}chaedele, {T}. and {B}lumstein, {D}. and {F}rappart, {F}. and {B}oy, {F}. and {D}esjonqueres, {J}. {D}. and {P}ottier, {C}. and {B}larel, {F}. and {N}ino, {F}ernando},
  editor = {},
  language = {{ENG}},
  abstract = {{S}atellite nadir radar altimeters have been widely used to measure river and lake surface water elevations. {T}hey can now retrieve the elevations of some rivers < 200 m wide. {H}owever, as these satellite missions are primarily designed to observe ocean surface topography, they are not always able to observe continental surfaces. {F}or steep-sided rivers (i.e. in river valleys no more than a few km wide and surrounded by slopes over 50 m high), altimeters tend to observe the top of the surrounding topography rather than the river itself. {T}he {J}ason-3 altimetry mission, launched in {J}anuary 2016, has an alternative instrument operation mode, the so called {O}pen-{L}oop ({OL}) or {D}igital {E}levation {M}odel ({DEM}) tracking mode. {T}his mode is intended to help overcome this issue, by using an on-board {DEM}. {H}owever it was not used in 2016 as the operational mode because of difficulties in defining an accurate on-board global-scale {DEM}. {M}ainland {F}rance has been chosen to test the {OL} tracking mode, as water masks and {DEM}s of sufficient accuracy are available. {F}ollowing the launch of {J}ason-3, {J}ason-2 (its predecessor) was maintained on the same nominal orbit as its follow-on, for more than 6 months. {D}uring this tandem period, data from the first 10 {J}ason-3 cycles (a {J}ason-2/-3 cycle corresponds to 10 days) were acquired in the traditional {C}losed-{L}oop ({CL}) tracking mode. {J}ason-3 data from the last 13 cycles were acquired in {OL} tracking mode. {J}ason-2 was always in {CL} tracking mode. {C}ompared to nearby in situ gages and for river wider than 100 m, {J}ason-3 water elevation anomalies have a {RMSE} between 0.20 and 0.30 m for most reaches. {J}ason-3 performance over narrow rivers is similar to that of {J}ason-2. {I}n {CL} tracking mode, {J}ason-3 altimeter tends to be locked over the surrounding topography more frequently than {J}ason-2 (due to the specific post-launch {J}ason-2 altimeter tuning). {T}his study shows that {J}ason-2 observed 60% of river reaches studied (48 of 86 reaches), whereas {J}ason-3 in {OL} tracking mode was able to measure all river reaches for every cycle. {T}his result clearly highlights the significant advantages of the {OL} tracking mode for observation of steep-sided rivers. {H}owever, further investigations are required to compute an accurate on-board global-scale {DEM} and to determine those locations where the use of {OL} tracking mode is or is not appropriate.},
  keywords = {{J}ason-3 ; {A}ltimetry ; {R}ivers ; {O}pen-{L}oop/{DEM} tracking mode ; {FRANCE}},
  booktitle = {},
  journal = {{R}emote {S}ensing of {E}nvironment},
  volume = {209},
  numero = {},
  pages = {77--89},
  ISSN = {0034-4257},
  year = {2018},
  DOI = {10.1016/j.rse.2018.02.037},
  URL = {https://www.documentation.ird.fr/hor/fdi:010072778},
}