@article{fdi:010049157,
  title = {{T}he {GHYRAF} ({G}ravity and {H}ydrology in {A}frica) experiment : description and first results},
  author = {{H}inderer, {J}. and de {L}inage, {C}. and {B}oy, {J}.{P}. and {G}egout, {P}. and {M}asson, {F}. and {R}ogister, {Y}. and {A}malvict, {M}. and {P}feffer, {J}. and {L}ittel, {F}. and {L}uck, {B}. and {B}ayer, {R}. and {C}hampollion, {C}. and {C}ollard, {P}. and {L}e {M}oigne, {N}. and {D}iament, {M}. and {D}eroussi, {S}. and de {V}iron, {O}. and {B}iancale, {R}. and {L}ernoine, {J}.{M}. and {B}onvalot, {S}ylvain and {G}abalda, {G}erminal and {B}ock, {O}. and {G}enthon, {P}ierre and {B}oucher, {M}. and {F}avreau, {G}uillaume and {S}eguis, {L}uc and {D}elclaux, {F}ran{\c{c}}ois and {C}appelaere, {B}ernard and {O}{\¨ie}, {M}onique and {D}escloitres, {M}arc and {G}alle, {S}ylvie and {L}aurent, {J}.{P}. and {L}egchenko, {A}natoli and {B}ouin, {M}.{N}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his paper is the first presentation of a project called {GHYRAF} ({G}ravity and {H}ydrology in {A}frica) devoted to the detailed comparison between models and multidisciplinary observations (ground and satellite gravity, geodesy, hydrology, meteorology) of the variations of water storage in {A}frica from the {S}ahara and part to the monsoon equatorial part. {W}e describe the various actions planned in this project. {W}e first detail the actions planned in gravimetry which consist in two main surface gravity experiments: on the one hand the periodic repetition of absolute gravity measurements along a north-south monsoonal gradient of rainfall in {W}est {A}frica, going from {T}amanrasset (20 mm/year) in southern {A}lgeria to {D}jougou (1200 mm/year) in central {B}enin; on the other hand the continuous measurements at {D}jougou ({B}enin) with a superconducting gravimeter to monitor with a higher sampling rate the gravity changes related to an extreme hydrological cycle. {A}nother section describes the actions planned in {GPS} which will maintain and develop the present-day existing network in {W}est {A}frica. {T}he third type of actions deals with hydrology and we review the three sites that will be investigated in this joint hydrogeophysics project namely {W}ankama (near {N}iamey) and {B}agara (near {D}iffa) in the {N}iger {S}ahelian zone and {N}alohou (near {D}jougou) in the {B}enin monsoon zone. {W}e also address the question of the ground truth of satellite-derived missions: in this context the {GHYRAF} project will lead to test the hydrology models by comparison both with in situ and satellite data such as {GRACE}, as well as to an important increase of our knowledge of the seasonal water cycle in {A}frica. {W}e finally present preliminary results in {GPS} based on the analysis of the vertical motion of the {D}jougou site. {T}he resulting absolute gravity changes related to the 2008 monsoon are finally given.},
  keywords = {{G}ravity ; {GPS} ; {W}ater storage ; {S}ahel ; {M}onsoon ; {AFRIQUE} {SUBSAHARIENNE} ; {SAHEL}},
  booktitle = {},
  journal = {{J}ournal of {G}eodynamics},
  volume = {48},
  numero = {3-5},
  pages = {172--181},
  ISSN = {0264-3707},
  year = {2009},
  DOI = {10.1016/j.jog.2009.09.014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010049157},
}