INVESTIGADORES
DRAGANI Walter Cesar
artículos
Título:
Río de la Plata estuary response to wind variability in synoptic to intraseasonal scales: 2. Currents vertical structure and its amplifications for the salt wedge structure.
Autor/es:
SIMIONATO, CLAUDIA; MECCIA, VIRNA; GUERRERO, RAUL; DRAGANI, WALTER; NUÑEZ, MARIO
Revista:
JOURNAL OF GEOPHYSICAL RESEARCH
Editorial:
American Geophysical Union
Referencias:
Año: 2007 vol. 112 p. 195 - 206
ISSN:
0148-0227
Resumen:
The first acoustic Doppler current profiler current data collected at two locations of
the Rı´o de la Plata salt wedge during a period of around 6 months and salinity profiles
gathered at and around those locations are used to study the vertical structure of
currents response to wind variability in synoptic to intraseasonal timescales and its
implications for stratification. Results indicate that the estuary rapidly responds to
prevailing southwesterlies/northeasterlies with currents that decay toward the bottom
with only little rotation in depth. For the less frequent southeasterlies/northwesterlies the
estuary develops a strong vertical structure with a defined inversion in current direction
between surface and bottom layers. These patterns derive from the estuarys geometry
and bathymetry. Results have important implications for the salinity vertical structure
that are verified on the analyzed profiles. First, the combination of the bathymetry and
coastline with the prevailing wind variability is highly favorable to the maintenance of a
salt wedge structure in this estuary. Second, weakening and eventually breakdown of
stratification can only occur for intense and/or persistent southeasterly winds, which
even can be very strong, are not frequent. This can explain why the Rı´o de la Plata
displays the unusual feature of being an area of spawning and a nursery for a number of
coastal species that use the wedge as an essential element for their reproduction. Results
show that stratification is highly affected by short-term wind variability, which is its
major characteristic in the area, changing the classical concept of summer-winter
seasonality as the main feature of estuarine variability.