HR: 1330h
AN: OS23A-03    [Abstracts]
TI: Variability of Chlorophyll-a From Ocean Color Images in the La Plata Continental Shelf Region
AU: * Garcia, C A
EM: dfsgar@furg.br
AF: Federal University of Rio Grande (FURG), Dept. of Physics, Av. Italia, Km 8, Rio Grande, RS 96201-900 Brazil
AU: Garcia, V M
EM: docvmtg@furg.br
AF: Federal University of Rio Grande (FURG), Dept. of Oceanography, Av. Italia, Km 8, Rio Grande, RS 96201-900 Brazil
AB: Ocean color data from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) have been used to investigate temporal and spatial variability of chlorophyll-a concentration over the La Plata continental shelf zone (25-40^oS and 60-45^oW). Our analysis is based on 276 weekly images (9km x 9km resolution) which span from October 1997 to September 2003. We separated the log-transformed chlorophyll concentration time signal into 12 harmonics and their amplitudes and phases were determined using Fourrier analysis. The time-series for each pixel has been reconstructed by using the known amplitudes and phases. Then it was calculated the percentage explained by one or a composition of several harmonics in the time series for each pixel. Results of the analysis show that the annual cycle is the most dominant signal, especially in the area over the Brazilian continental shelf (25-35^oS). Regions close to the coastline and areas directly influenced by La Plata River show the weakest relation to annual cycle. An analysis of the spatial variability of amplitude and phase for each or a composition of several harmonics is also presented in this work. We conclude that SeaWiFS time-series satellite data can provide relevant information about biological cycles and their spatial extent over the La Plata region
DE: 3360 Remote sensing
DE: 4219 Continental shelf processes
DE: 4227 Diurnal, seasonal, and annual cycles
DE: 4815 Ecosystems, structure and dynamics
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly