Data/hora: 06/06/2024 03:33:21

Provedor de dados: 	5	
País: 	France	
Título: 	Improved correction for non-photochemical quenching of in situ chlorophyll fluorescence based on a synchronous irradiance profile	
Autores: 	Xing, Xiaogang; Briggs, Nathan; Boss, Emmanuel; Claustre, Herve.	
Data: 	2018-09	
Ano: 	2018	
Resumo: 	In situ chlorophyll fluorometers have been used to quantify the distribution of chlorophyll concentration in natural waters for decades. However, chlorophyll fluorescence is depressed during daylight hours due to non-photochemical quenching (NPQ). Corrections attempted to date have provided improvement but still remain unsatisfactory, often over-estimating the expected value. In this study. we examine the relationship between NPQ and instantaneous Photosynthetically Active Radiation (iPAR) using field data from BGC-Argo floats equipped with Chlorophyll-alpha fluorometers and radiometers. This analysis leads to an improved NPQ correction that incorporates both iPAR and mixed layer depth (MLD) and is validated against data collected at sunrise or sunset. The optimal NPQ light threshold is found to be iPAR = 15 mu mol quanta m(-2) S-1, and the proposed methods based on such a light threshold correct the NPQ effect more accurately than others, except in "shallow-mixing" waters (NPQ light threshold depth deeper than MLD). For these waters, an empirical-relationship-based method is proposed for improvement of NPQ correction using an iPAR profile. It is therefore recommended that, for optimal NPQ corrections, profiling floats measuring chlorophyll fluorescence in daytime be equipped with iPAR radiometers.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	https://archimer.ifremer.fr/doc/00640/75204/75335.pdf

DOI:10.1364/OE.26.024734

https://archimer.ifremer.fr/doc/00640/75204/	
Editor: 	Optical Soc Amer	
Formato: 	application/pdf	
Fonte: 	Optics Express (1094-4087) (Optical Soc Amer), 2018-09 , Vol. 26 , N. 19 , P. 24734-24751	
Fonte: 	info:eu-repo/semantics/openAccess

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