Publications

Zhao, W. J.; Wang, G. Q.; Cao, W. X.; Cui, T. W.; Wang, G. F.; Ling, J. F.; Sun, L.; Zhou, W.; Sun, Z. H.; Xu, Z. T.; Hu, S. B. (2014). Assessment of SeaWiFS, MODIS, and MERIS ocean colour products in the South China Sea. INTERNATIONAL JOURNAL OF REMOTE SENSING, 35(12-Nov), 4252-4274.

Abstract
The Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Medium Resolution Imaging Spectrometer (MERIS) remote-sensing radiometric and chlorophyll-a (chl-a) concentration products for the South China Sea (SCS) from October 2003 to May 2010 were assessed using in situ data. A strict spatiotemporal match-up method was used to minimize the temporal variability effects of atmosphere and seawater around the measurement site. A comparison of the remote-sensing reflectance (R-rs(lambda)) of the three sensors with in situ values from the open waters of the SCS showed that the mean absolute percentage difference varied from 13% to 55% in the 412-560 nm spectral range. Generally, the MERIS radiometric products exhibited higher typical uncertainties and bias than the SeaWiFS and MODIS products. The R-rs(443) to R-rs(555/551/560) band ratios of the satellite data were in good agreement with in situ observations for these sensors. The SeaWiFS, MODIS, and MERIS chl-a products overestimated in situ values by 74%, 42%, and 120%, respectively. MODIS retrieval accuracy was better than those of the other sensors, with MERIS performing the worst. When the match-up criteria were relaxed, the assessment results degraded systematically. Therefore, strict spatiotemporal match-up is recommended to minimize the possible influences of small-scale variation in geophysical properties around the measurement site. Coastal and open-sea areas in the SCS should be assessed separately because their biooptical properties are different and the results suggest different atmospheric correction problems.

DOI:
10.1080/01431161.2014.916044

ISSN:
0143-1161; 1366-5901