Technical note: Algal Pigment Index 2 in the Atlantic off the southwest Iberian Peninsula: standard and regional algorithms

Abstract. In this study, Algal Pigment Index 2 (API2) is investigated in Sagres, an area located in the Atlantic off the southwestern Iberian Peninsula. Standard results provided by the MEdium Resolution Image Spectrometer (MERIS) ocean colour sensor were compared with alternative data products, determined through a regional inversion scheme, using both MERIS and in situ remote sensing reflectances (Rrs) as input data. The reference quantity for performance assessment is in situ total chlorophyll a (TChl a) concentration estimated through a phytoplankton absorption coefficient (i.e. equivalent to API2). Additional comparison of data products has also been addressed for TChl a concentration determined by high-performance liquid chromatography. The MERIS matchup analysis revealed a systematic underestimation of TChl a, which was confirmed with an independent comparison of product map analysis. The study demonstrates the importance of regional algorithms for the study area that could complement upcoming standard results of the current Sentinel-3/OLCI space mission.

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Technical Note: Algal Pigment Index 2 in the Atlantic off the Southwest Iberian Peninsula: standard and regional algorithms

10.5194/os-2016-41 ◽

2016 ◽

Author(s):

Priscila Costa Goela ◽

Sónia Cristina ◽

Tamito Kajiyama ◽

John Icely ◽

Gerald Moore ◽

...

Keyword(s):

Iberian Peninsula ◽

High Performance ◽

Space Mission ◽

Technical Note ◽

Medium Resolution ◽

Algal Pigment ◽

Data Products ◽

Index 2 ◽

Pigment Index

Abstract. In this study, Algal Pigment Index 2 (API2) is investigated in Sagres, an area located in the Atlantic off the southwestern Iberian Peninsula. Standard results provided by MEdium Resolution Image Spectrometer (MERIS) ocean color sensor were compared with alternative data products, determined through a regional inversion scheme, using both MERIS and in situ remote sensing reflectances (Rrs) as input data. The reference quantity for performance assessment is in situ total chlorophyll a (TChla) concentration estimated through phytoplankton absorption coefficient (i.e., equivalent to API2). Additional comparison of data products has also been addressed to TChla concentration determined by High Performance Liquid Chromatography. The MERIS matchup analysis revealed a systematic underestimation of TChla, which was confirmed with an independent comparison of product maps analysis. The study demonstrates the importance of regional algorithms for the study area that could complement upcoming standard results of the present Sentinel-3/OLCI space mission.

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Assessment of MERIS ocean color data products for European seas

Ocean Science Discussions ◽

10.5194/osd-10-219-2013 ◽

2013 ◽

Vol 10 (1) ◽

pp. 219-259 ◽

Cited By ~ 5

Author(s):

G. Zibordi ◽

F. Mélin ◽

J.-F. Berthon ◽

E. Canuti

Keyword(s):

Imaging Spectrometer ◽

Medium Resolution ◽

Data Products ◽

Geographically Distributed ◽

Corrected Data ◽

Color Data ◽

Resolution Imaging ◽

Data Update ◽

Pigment Index ◽

European Seas

Abstract. The accuracy of marine data products from the Medium Resolution Imaging Spectrometer (MERIS) operated onboard the Envisat platform, is investigated with the aid of in situ geographically distributed measurements from different European seas. The assessment focusses on standard products from the 2012 data update commonly identified as 3rd Reprocessing. Results indicate atmospherically corrected data affected by a negative bias of several tens percent at the 413 nm center-wavelength, significantly decreasing to a few percent at 560 nm and increasing again at 665 nm. Such an underestimate at the blue center-wavelengths leads to an average overestimate of the algal-1 MERIS pigment index largely exceeding 100% for the considered European seas. A comparable overestimate is also observed for the algal-2 pigment index independently determined from top-of-atmosphere radiance through the application of neural networks.

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Assessment of MERIS ocean color data products for European seas

Ocean Science ◽

10.5194/os-9-521-2013 ◽

2013 ◽

Vol 9 (3) ◽

pp. 521-533 ◽

Cited By ~ 26

Author(s):

G. Zibordi ◽

F. Mélin ◽

J.-F. Berthon ◽

E. Canuti

Keyword(s):

Imaging Spectrometer ◽

Medium Resolution ◽

Data Products ◽

Geographically Distributed ◽

Corrected Data ◽

Color Data ◽

Resolution Imaging ◽

Data Update ◽

Pigment Index ◽

European Seas

Abstract. The accuracy of marine data products from the Medium Resolution Imaging Spectrometer (MERIS) operated on board the Envisat platform is investigated with the aid of in situ geographically distributed measurements from different European seas. The assessment focuses on standard products from the 2012 data update commonly identified as 3rd Reprocessing. Results indicate atmospherically corrected data affected by a negative bias of several tens percent at the 413 nm center wavelength, significantly decreasing to a few percent at 560 nm and increasing again at 665 nm. Such an underestimate at the blue center wavelengths leads to an average overestimate of the algal-1 MERIS pigment index largely exceeding 100% for the considered European seas. A comparable overestimate is also observed for the algal-2 pigment index independently determined from top-of-atmosphere radiance through the application of neural networks.

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High performance Nanogold™-in situ hybridzation and its use in the detection of hybridized and PCR-amplified microscopical preparations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166944 ◽

1996 ◽

Vol 54 ◽

pp. 896-897

Author(s):

G. W. Hacker ◽

I. Zehbe ◽

J. Hainfeld ◽

A.-H. Graf ◽

C. Hauser-Kronberger ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Messenger Rna ◽

High Performance ◽

Detection System ◽

Direct Methods ◽

Genetic Alterations ◽

Chain Reaction ◽

Protein Encoding ◽

Polymerase Chain

In situ hybridization (ISH) with biotin-labeled probes is increasingly used in histology, histopathology and molecular biology, to detect genetic nucleic acid sequences of interest, such as viruses, genetic alterations and peptide-/protein-encoding messenger RNA (mRNA). In situ polymerase chain reaction (PCR) (PCR in situ hybridization = PISH) and the new in situ self-sustained sequence replication-based amplification (3SR) method even allow the detection of single copies of DNA or RNA in cytological and histological material. However, there is a number of considerable problems with the in situ PCR methods available today: False positives due to mis-priming of DNA breakdown products contained in several types of cells causing non-specific incorporation of label in direct methods, and re-diffusion artefacts of amplicons into previously negative cells have been observed. To avoid these problems, super-sensitive ISH procedures can be used, and it is well known that the sensitivity and outcome of these methods partially depend on the detection system used.

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