Can ocean color assimilation improve biogeochemical hindcasts in shelf seas?

Abstract

[1] The objective of this paper is to investigate if the assimilation of ocean color data into a complex marine ecosystem model can improve the hindcast of key biogeochemical variables in shelf seas. A localized Ensemble Kalman filter was used to make a yearlong assimilation of weekly satellite chlorophyll data into a three-dimensional ecosystem model of the western English Channel. The skill of assimilation was evaluated with respect to non assimilated in situ data using twelve time series of biogeochemical observations collected weekly at the monitoring station L4. It was found that the assimilation scheme reduced the root mean square error and increased the correlation with the spatial distributions of the assimilated chlorophyll data, with respect to the reference run. More significantly, the skill metrics for non assimilated variables indicate that the hindcast of the mean data values at L4 was improved; however improvements in the short term forecast were not discernable. On the basis of our application, we provide general recommendations for the successful application of ocean color assimilation to hindcast key biogeochemical variables in shelf seas.