『Abstract
　Hydrological cycle is the perpetual movement of water throughout the various component of the global Earth's system. Focusing on the land surface component of this cycle, the determination of the succession of dry and humid periods is of high importance with respect to water resources management but also with respect to global geochemical cycles.
　This knowledge requires a specified estimation of recent fluctuations of the land surface cycle at continental and global scales. Our approach leans towards a new estimation of freshwater discharge to oceans from 1875 to 1994 as recently proposed by Labat et al. [Labat,D., Godderis（eの頭に´）,Y., Probst,J.L. Guyot,J.L., 2004. Evidence for global runoff increase related to climate warming. Advances in Water Resources, 631-642]. Wavelet analyses of the annual freshwater discharge time series reveal an intermittent multiannual variability (4- to 8-y, 14- to 16-y and 20- to 25-y fluctuations) and a persistent multidecadal 30- to 40-y variability.
　Continent by continent, reasonable relationships between land-water cycle oscillations and climate forcing (such as ENSO, NAO or sea surface temperature) are proposed even though if such relationships or correlations remain very complex.
　The high intermittency of interannual oscillations and the existence of persistent multidecadal fluctuations make prediction difficult for medium-term variability of droughts and high-flows, but lead to a more optimistic diagnostic for long-term fluctuations prediction.

Keywords: global hydrologic cycle; wavelet analysis; climate variability; multidecadal oscillation』

(Introduction)
1. Continental freshwater discharge to oceans
2. Spectral analysis
3. Morlet continuous wavelet transform
4. Pulses and oscillations in the land surface hydrological cycle
　4.1. Africa freshwater discharge wavelet analysis
　4.2. Asia freshwater discharge wavelet analysis
　4.3. Europe freshwater discharge wavelet analysis
　4.4. North America freshwater discharge wavelet analysis
　4.5. South America freshwater discharge wavelet analysis
　4.6. Global water discharge to the oceans
5. Discussion
6. Conclusions
References

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