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| Titel |
Trends and Intra-annual variations of spectral biases in multi-mission remote sensing primary ocean color products at a coastal site |
| VerfasserIn |
G. Zibordi, F. Mélin, J.-F. Berthon |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250061065
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| Zusammenfassung |
| The assessment of uncertainties and biases affecting remote sensing products is a pre-condition for an effective exploitation of these data in climate studies. Within such a context, this work presents and discusses the trends and intra-annual variations of spectral biases in primary satellite ocean color products (i.e., normalized water-leaving radiance, Lwn, and aerosol optical thickness, ta) at a coastal site in the northern Adriatic Sea for the period 2002 - 2010. The analysis is performed using in situ data from the Ocean Color component of the Aerosol Robotic Network (AERONET-OC) and, satellite data products from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the Moderate Resolution Imaging Spectroradiometer (MODIS-A and MODIS-T) onboard the Aqua and Terra platforms. Results from intra-annual analysis indicate larger biases in fall and winter traceable to high sun zenith values. Results from trend analysis do not indicate any statistically significant bias of Lwn when restricting the investigated period to May 2002 – April 2010 for SeaWiFS and MODIS-T, and July 2002 – June 2008 for MODIS-A. Absolute biases, determined at around the middle of the considered period, exhibit values from -0.4 to +7.7 % for SeaWiFS and from -1.9 to +4.6% for MODIS-T in the 412-555 nm spectral interval. Higher and systematically negative biases from -15.4 to -6.2 % are observed for MODIS-A in the same spectral interval. Statistically appreciable trends are observed for ta from SeaWiFS at 443 and 490 nm (approximately +1% per year) and from MODIS-A at 667 nm (+4.7% per year). Very high are the biases for both MODIS-A and MODIS-T ta products in the 412-555 nm spectral interval (on average 21 and 16%, respectively) when compared to SeaWiFS (exhibiting values in the range of -1 and +2.5%). |
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