HR: 09:45h
AN: OS21A-05    [Abstracts]
TI: Patos Lagoon Outflow Within the Rio de la Plata Plume Using an Airborne Salinity Mapper
AU: * Burrage, D
EM: dmburrage@nrlssc.navy.mil
AF: Ocean Sciences Branch, Naval Research Laboratory (NRL), Code 7330, Stennis Space Center, MS 39529 United States
AU: Wesson, J
EM: wesson@nrlssc.navy.mil
AF: Ocean Sciences Branch, Naval Research Laboratory (NRL), Code 7330, Stennis Space Center, MS 39529 United States
AU: Martinez, C
EM: carmar@glaucus.fcien.edu.uy
AF: Seccion Oceanologia, Programa de Ciencias del Mar y de la Atmosfera (PCMYA), Facultad de Ciencias, Universidad de la Republica, Montevideo, Uruguay
AU: Perez, T
EM: tabare@montepaz.com.uy
AF: Division de Investigacion y Desarrollo,CITMPSA, San Ramon 716 - CP 11800, Montevideo, Uruguay
AU: Moller, Jr., O
EM: dfsomj@furg.br
AF: Fundacao Universidade Federal do Rio Grande(FURG), Campus Carreiros, 96201-900, Rio Grande, RS Brazil
AU: Piola, A
EM: apiola@hidro.gov.ar
AF: Departamento Oceanografia, Servicio de Hidrografia Naval, Ciudad Autonoma de Buenos Aires, Buenos Aires, Argentina
AB: Major river systems discharging into continental shelf waters frequently form buoyant coastal currents that propagate along the continental shelf in a direction corresponding to that of coastal trapped wave propagation (with the coast on the right/left, in the northern/southern hemisphere). The combined flow of the Uruguay and Parana Rivers, which discharges freshwater into the Rio de La Plata estuary (Latitude ~36 S), frequently gives rise to a buoyant coastal current (the 'La Plata plume') that extends northward along the continental shelf off Uruguay and Southern Brazil. Depending upon the prevailing rainfall, wind and tidal conditions, the Patos/Mirim Lagoon complex (Latitude ~ 32 S) also produces a freshwater outflow plume that expands across the inner continental shelf. Under these circumstances the Patos outflow plume may be embedded in temperature, salinity and current fields that are strongly influenced by the larger Plata plume. The purpose of this paper is to present observations of such an embedded plume structure and to determine the implications for the dynamics of the smaller Patos plume. We describe the results of an airborne remote sensing and shipboard in situ study of the salinity distribution and extent of the La Plata and Patos/Mirim Lagoon plumes conducted under contrasting winter (2003) and summer (2004) conditions. The survey was conducted using an aircraft carrying NRL's Salinity, Temperature and Roughness Remote Scanner (STARRS). A series of broad-scale flights was conducted over the continental shelf off Argentina, Uruguay and Brazil, and a detailed mapping flight was undertaken over the Patos/Mirim outflow region. Their purpose was to determine the distribution and behavior of the Plata and Patos Lagoon plumes on the continental shelf under representative winter and summer conditions. The resulting airborne and shipboard hydrographic data are compared with dynamical model parameter estimates to address the following questions: What is the influence of a large-scale plume on the behavior of a smaller scale outflow embedded within it? How might the observed Patos plume be classified in comparison with other plumes, and would this classification likely change when it is embedded in the larger Plata plume? The situation of the Patos plume embedded within the Plata Plume during winter-time may be contrasted with the simpler situation in which either one of the plumes is absent. The case of a weak Plata plume being present during summer (in the absent of the Patos plume), serves as an approximation to the ambient conditions, or background state, pertaining to the embedded case.
DE: 4219 Continental shelf processes
DE: 4235 Estuarine processes
DE: 4243 Marginal and semienclosed seas
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 4528 Fronts and jets
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly