@article{fdi:010070664,
  title = {{R}ecent advances in wavelet analyses: {P}art 2 - {A}mazon, {P}arana, {O}rinoco and {C}ongo discharges time scale variability},
  author = {{L}abat, {D}. and {R}onchail, {J}osyane and {G}uyot, {J}ean-{L}oup},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his paper is devoted to illustrating new wavelet analysis methods in the field of hydrology. {N}ew wavelet indicators are applied to long-term hydrological and climatologic proxies. {T}hey are first applied to four {A}tlantic large river monthly discharges ({A}mazon, {P}arana, {O}rinoco and {C}ongo) and then applied to two well-known long-term climatologic indexes: the {S}outhern {O}scillation and the {N}orth {A}tlantic {O}scillation. {T}his approach makes it possible to suggest physical explanations for time-scale dependant relationships. {S}ix-month variability is present in all the rivers except in the {P}arana. {I}n the {C}ongo {R}iver this signal is near stationary with strong entropy. {T}he strength of this scale coincides with higher discharge variability before 1920 and over the {O}rinoco basin with higher discharge values between 1940 and 1955. {A}n annual cycle is present in all the rivers but is much stronger, along with the entropy, in the rivers with a large tropical basin, as in the {A}mazon and the {O}rinoco. {T}his annual signal is not permanent in the {C}ongo and much more intermittent in the {P}arana where the annual recharge appears as very irregular. {A} quasi biennial variability is apparent in all the equator ward rivers and a nearly permanent 2-year coherence is found between {S}ol and the {A}mazon discharge. {A} 3-6year oscillation typical of {ENSO} variability is observed in all the rivers. {I}t is intermittent, observed before 1930 in all the rivers and after 1980 mostly in the {A}mazon {R}iver. {T}hese peaks of activity correspond to periods of major {S}ol variability. {A}n 8-year variability is particularly strong in the {P}arana {R}iver before 1940 and around 1970 and to a lesser extent in the {O}rinoco {R}iver during the low {NAO} index period, between 1940 and 1970. {T}he {C}ongo {R}iver exhibits that time-scale around 1970. {A} 13-year variability common to {S}ol, {NAO} and the {S}outh {A}tlantic {O}cean circulation is observed in the {P}arana and {C}ongo discharges. {I}n all the rivers the greatest entropy is observed at bi and multi decadal time scales with the greatest coherence with both {NAO} and {S}ol. {A} near 20-year time-scale is observed in most of the series around 1970, although it is strongest in {A}mazon and {P}arana discharges. {F}inally, a 30-year time-scale is observed between 1940 and 1970. {I}t is to be noted that most of the time-scale dominant activities, in all the rivers, may have been influenced by the interdecadal shifts that took place around 1940 and 1970 in the {P}acific and in the {A}tlantic.},
  keywords = {wavelet analyses ; time scale relationship ; global hydrology ; {A}mazon ; {O}rinoco ; {P}arana ; {C}ongo ; {ENSO} ; {NAO} ; {AMAZONIE} ; {CONGO} ; {PARANA} ; {ORENOQUE} {COURS} {D}'{EAU}},
  booktitle = {},
  journal = {{J}ournal of {H}ydrology},
  volume = {314},
  numero = {1-4},
  pages = {289--311},
  ISSN = {0022-1694},
  year = {2005},
  DOI = {10.1016/j.jhydrol.2005.04.004},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070664},
}