chapter - Atmospheric and Oceanic Science

Fig. 14.12. As Fig. 14.11, except for CPDO regime.
14.6. Conclusions
Low-frequency variability
Concerning the estimation of future hydro-meteorological conditions,
Robertson et al. (2001) analyzed the decadal fluctuations of the streamflow for the
Paraná River at Corrientes during the 1904-1997 period and provided indications
that these fluctuations may be partially predictable. They isolated the oscillatory
components with periods of 8 years and 17 years and constructed autoregressive
predictive models for each component. Their prediction based upon the 8 year and
the 17 year oscillatory components, including data up to the austral summer of
1999, suggested increased probability of below-average flows until 2006. Thus,
they found a high probability of drought occurrence in the region of the La Plata
River basin during the period from 2002 to 2006. However, it is worth noting that
their results are based on near-cyclic components (with periods of 8 and 17 years)
of the streamflow for the Paraná River and do not take into account the non-linear
component of this parameter relative to the PDO phases. So, the present analysis
provides another view of the interannual climate variability in the La Plata River
basin, which takes into account the non-linear aspects of the climate in the region
relative to the PDO phases and to the ENSO phases.
Comparisons between ENSO-related anomaly patterns of SSA rainfall, SST
and SLP for the WPDO and CPDO regimes show important differences which represent
the non-linear components of these composites relative to the PDO phases
(for a given ENSO phase) and relative to ENSO phases (for a given PDO phase).
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