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Time-Space Variability of Chlorophyll-a and Associated Physical Variables within the Region off Central-Southern Chile
Department of Oceanography, Center for Oceanographic Research in the Eastern South Pacific (COPAS), University of Concepción, Casilla 160-C, Concepción, Chile
Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Casilla 1020, Valparaíso, V Región, Chile
* Author to whom correspondence should be addressed.
Received: 10 September 2013; in revised form: 12 October 2013 / Accepted: 17 October 2013 / Published: 28 October 2013
Abstract: Time-space fluctuations of chlorophyll-a (Chl-a) within the region off central-southern Chile (33–42°S), and their association with meteorological-oceanographic conditions, were analyzed using satellite time series data (2002–2012). The mean distribution of moderate values of Chl-a (~0.5 mg∙m−3) in the northern section (33–38°S) extended out to ~200 km of the coast whereas they were restricted to a narrower band in the southern section (38–42°S). Mean wind stress and wind stress curl were upwelling favorable for most part of the year in the northern section whereas upwelling-downwelling periods were distinct in the southern section. The dominant frequency of Chl-a variability in the coastal zone and the coastal transition zone was annual, as it was for the rest of the variables, except in a transitional band between these zones and where a semi-permanent jet is located. At the annual frequency, the alongshore distribution of coastal Chl-a presented strong discontinuities, with minimum values around upwelling centers (~37 and 40°S) and higher values (> 2 mg∙m−3) in between. Also at the annual frequency, correlation analyses suggest that Ekman transport and Ekman pumping might act synchronously to extend the offshore distribution of the highest Chl-a values during the spring-summer period whereas mesoscale activity appears to contribute to Chl-a increases in the coastal transition zone. Sea surface temperature does not appear to be associated with the annual cycle of Chl-a in the coastal zone and in the coastal transition zone it might be linked to Chl-a variability through the effects of internal waves.
Keywords: satellite Chl-a; annual cycle; wind-driven upwelling; alongshore and across-shore differences; central-southern Chile
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Morales, C.E.; Hormazabal, S.; Andrade, I.; Correa-Ramirez, M.A. Time-Space Variability of Chlorophyll-a and Associated Physical Variables within the Region off Central-Southern Chile. Remote Sens. 2013, 5, 5550-5571.
Morales CE, Hormazabal S, Andrade I, Correa-Ramirez MA. Time-Space Variability of Chlorophyll-a and Associated Physical Variables within the Region off Central-Southern Chile. Remote Sensing. 2013; 5(11):5550-5571.
Morales, Carmen E.; Hormazabal, Samuel; Andrade, Isabel; Correa-Ramirez, Marco A. 2013. "Time-Space Variability of Chlorophyll-a and Associated Physical Variables within the Region off Central-Southern Chile." Remote Sens. 5, no. 11: 5550-5571.