Melin, F, Zibordi, G, Djavidnia, S (2009). Merged series of normalized water leaving radiances obtained from multiple satellite missions for the Mediterranean Sea. ADVANCES IN SPACE RESEARCH, 43(3), 423-437.
Merging time series of ocean color-derived products provided by independent satellite missions supports related biogeochemical and environmental applications by combining temporally overlapping data sets and by increasing data coverage. The creation of a merged series of normalized water leaving radiances L-WN, the primary ocean color product, is presented for the Mediterranean Sea using the SeaWiFS and MODIS data records. The merging relies on an optically-based technique that combines the available LWN signal in a spectrally consistent way. Validation statistics indicate uncertainties associated with the merged LWN decreasing from 23% at 412 nm to 12% in the 500- to 555-nm spectral range. The inter-comparison of the sensor-specific products, conducted at the scale of the basin for daily-to-monthly time scales, indicates an overall consistency. The level of differences varies with the wavelength considered and shows a marked seasonal cycle, with differences that tend to be higher in winter. The merged series is remarkably consistent with the sensor-specific data, with average absolute percent differences lower than 10% for all wavelengths below 555 nm. The benefit of merging in terms of sampling frequency over the basin is also illustrated. A merged series of LWN data based on the two considered missions provides valid data over 36% of the basin area on a daily basis. (C) 2008 COSPAR. Published by Elsevier Ltd. All rights reserved.