ASSESSING SATELLITE-DERIVED VARIABLES USED IN PRIMARY PRODUCTION MODELS IN THE ARGENTINE SEA

DOGLIOTTI, A.I.; SEGURA, V.; LUTZ, V.

Ciudad de Córdoba

Congreso; Congreso Argentino de Teledeteccion 2012: El medio ambiente y sus cambios: un desafío para la información espacial (CAT-2012); 2012

IAFE

Remote sensing of ocean color is a valuable tool to provide synoptic fields of primary production on regional and global scales. Satellite data provide daily estimates of chlorophyll-a concentration (Chl-a), irradiance at surface (PAR) and attenuation coefficients (Kd), required information to compute primary production at large scales. However, other important properties also needed, such us the photosynthetic parameters (to describe the photosynthetic response to available light) and the vertical distribution of the pigment biomass, cannot be directly derived from remotely sensed data. Field measurements of bio-optical properties including primary production gathered during three cruises performed in the Argentine Sea (from 38° to 55°S and from the coast to the shelf-break) during austral spring 2005, late summer and late winter 2006 were used to evaluate satellite estimates derived from MODIS-Aqua sensor in this region. The standard Chl-a product (OC3Mv6) tended to underestimate field measurements (~-30%). Also Lee?s Kd(PAR) product showed to underestimate (~-10%) field data. Finally, PAR product showed consistently higher than measures values (~50%), while sea surface temperature (SST) showed a high correlation (r=0.98), and low bias (3.5%) and uncertainty (8.2%). Daily water-column integrated primary production modeled using a MODIS data and measured photosynthetic parameters (and assuming vertical homogeneity of the biomass profile) showed encouraging results. A slight underestimation (~-10%), and a relative low uncertainty (30.3%) indicated a good performance of the model when satellite-derived values were used as inputs. Correlations between the field photosynthetic parameters and remotely-sensed properties, such us temperature and chlorophyll-a, were tested, but no significant relationships were found.