Consulta: creatorFacets:"Xing, Xiaogang"
Registros recuperados: 11
Data/hora: 01/06/2024 02:38:48

A Limited Effect of Sub-Tropical Typhoons on Phytoplankton Dynamics
Provedor de dados: 5
Autores: Chai, Fei; Wang, Yuntao; Xing, Xiaogang; Yan, Yunwei; Xue, Huijie; Wells, Mark; Boss, Emmanuel.
Typhoons are assumed to stimulate ocean primary production through the upward mixing of nutrients into the surface ocean, based largely on observations of increased surface chlorophyll concentrations following the passage of typhoons. This surface chlorophyll enhancement, seen on occasion by satellites, more often is undetected due to intense cloud coverage. Daily data from a BGC-Argo profiling float revealed the upper-ocean response to Typhoon Trami in the Northwest Pacific Ocean. Temperature and chlorophyll changed rapidly, with a significant drop in sea surface temperature and surge in surface chlorophyll associated with strong vertical mixing, which was only partially captured by satellite observations. However, no net increase in vertically integrated...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00645/75667/76533.pdf

Improved correction for non-photochemical quenching of in situ chlorophyll fluorescence based on a synchronous irradiance profile
Provedor de dados: 5
Autores: Xing, Xiaogang; Briggs, Nathan; Boss, Emmanuel; Claustre, Herve.
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...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00640/75204/75335.pdf

Arctic mid-winter phytoplankton growth revealed by autonomous profilers
Provedor de dados: 5
Autores: Randelhoff, Achim; Lacour, Léo; Marec, Claudie; Leymarie, Edouard; Lagunas, José; Xing, Xiaogang; Darnis, Gérald; Penkerc’h, Christophe; Sampei, Makoto; Fortier, Louis; D’ortenzio, Fabrizio; Claustre, Hervé; Babin, Marcel.
It is widely believed that during winter and spring, Arctic marine phytoplankton cannot grow until sea ice and snow cover start melting and transmit sufficient irradiance, but there is little observational evidence for that paradigm. To explore the life of phytoplankton during and after the polar night, we used robotic ice-avoiding profiling floats to measure ocean optics and phytoplankton characteristics continuously through two annual cycles in Baffin Bay, an Arctic sea that is covered by ice for 7 months a year. We demonstrate that net phytoplankton growth occurred even under 100% ice cover as early as February and that it resulted at least partly from photosynthesis. This highlights the adaptation of Arctic phytoplankton to extreme low-light...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00652/76416/77468.pdf

Quenching correction for in vivo chlorophyll fluorescence acquired by autonomous platforms: A case study with instrumented elephant seals in the Kerguelen region (Southern Ocean)
Provedor de dados: 5
Autores: Xing, Xiaogang; Claustre, Herve; Blain, Stephane; D'Ortenzio, Fabrizio; Antoine, David; Ras, Josephine; Guinet, Christophe.
As the proxy for Chlorophyll a (Chl a) concentration, thousands of fluorescence profiles were measured by instrumented elephant seals in the Kerguelen region (Southern Ocean). For accurate retrieval of Chl a concentrations acquired by in vivo fluorometer, a two-step procedure is applied: 1) A predeployment intercalibration with accurate determination by high performance liquid chromatography (HPLC) analysis, which not only calibrates fluorescence in appropriate Chl a concentration units, but also strongly reduces variability between fluorometers, and 2) a profile-by-profile quenching correction analysis, which effectively eliminates the fluorescence quenching issue at surface around noon, and results in consistent profiles between day and night. The...
Tipo: Text
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00248/35965/36927.pdf

Correction of profiles of in-situ chlorophyll fluorometry for the contribution of fluorescence originating from non-algal matter
Provedor de dados: 5
Autores: Xing, Xiaogang; Claustre, Herve; Boss, Emmanuel; Roesler, Collin; Organelli, Emanuele; Poteau, Antoine; Barbieux, Marie; D'Ortenzio, Fabrizio.
In situ chlorophyll fluorometers have been widely employed for more than half a century, and to date, it still remains the most used instrument to estimate chlorophyll-a concentration in the field, especially for measurements onboard autonomous observation platforms, e.g., Bio-Argo floats and gliders. However, in deep waters (&gt; 300 m) of some specific regions, e.g., subtropical gyres and the Black Sea, the chlorophyll fluorescence profiles frequently reveal "deep sea red fluorescence" features. In line with previous studies and through the analysis of a large data set (cruise transect in the South East Pacific and data acquired by 82 Bio-Argo floats), we show that the fluorescence signal measured by a humic-like DOM fluorometer is highly correlated to...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00661/77327/78783.pdf

Two databases derived from BGC-Argo float measurements for marine biogeochemical and bio-optical applications
Provedor de dados: 5
Autores: Organelli, Emanuele; Barbieux, Marie; Claustre, Herve; Schmechtig, Catherine; Poteau, Antoine; Bricaud, Annick; Boss, Emmanuel; Briggs, Nathan; Dall'Olmo, Giorgio; D'Ortenzio, Fabrizio; Leymarie, Edouard; Mangin, Antoine; Obolensky, Grigor; Penkerc'H, Christophe; Prieur, Louis; Roesler, Collin; Serra, Romain; Uitz, Julia; Xing, Xiaogang.
Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world's oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradiance at three wavelengths, and photosynthetically available radiation) variables are collected in the upper 1000 m every 1 to 10 days. The database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically developed procedures and its time series is quality-assessed to identify issues...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00662/77389/79010.pdf

SCOR WG 142: Quality Control Procedures for Oxygen and Other Biogeochemical Sensors on Floats and Gliders. Recommendations on the conversion between oxygen quantities for Bio-Argo floats and other autonomous sensor platforms
Provedor de dados: 5
Autores: Bittig, Henry; Körtzinger, Arne; Johnson, Ken; Claustre, Herve; Emerson, Steve; Fennel, Katja; Garcia, Hernan; Gilbert, Denis; Gruber, Nicolas; Kang, Dong-jin; Naqvi, Wajih; Prakash, Satya; Riser, Steven; Thierry, Virginie; Tilbrook, Bronte; Uchida, Hiroshi; Ulloa, Osvaldo; Xing, Xiaogang.
Tipo: Text
Palavras-chave: Argo; Bio-argo; Oxygen.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00348/45915/56281.pdf

Recommendations for obtaining unbiased chlorophyll estimates from in situ chlorophyll fluorometers: A global analysis of WET Labs ECO sensors
Provedor de dados: 5
Autores: Roesler, Collin; Uitz, Julia; Claustre, Herve; Boss, Emmanuel; Xing, Xiaogang; Organelli, Emanuele; Briggs, Nathan; Bricaud, Annick; Schmechtig, Catherine; Poteau, Antoine; D'Ortenzio, Fabrizio; Ras, Josephine; Drapeau, Susan; Haentjens, Nils; Barbieux, Marie.
Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease of use, size, power consumption, and relatively low price. While in situ chlorophyll a (Chl) fluorescence is proxy for Chl a concentration, and hence phytoplankton biomass, there exist large natural variations in the relationship between in situ fluorescence and extracted Chl a concentration. Despite this large natural variability, we present here a global validation data set for the WET Labs Environmental Characterization Optics (ECO) series chlorophyll fluorometers that suggests a factor of 2 overestimation in the factory calibrated Chl a estimates for this specific manufacturer and series of sensors. We base these results on...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00384/49552/50046.pdf

Preparing the New Phase of Argo: Scientific Achievements of the NAOS Project
Provedor de dados: 5
Autores: Le Traon, Pierre-yves; D'Ortenzio, Fabrizio; Babin, Marcel; Leymarie, Edouard; Marec, Claudie; Pouliquen, Sylvie; Thierry, Virginie; Cabanes, Cecile; Claustre, Hervé; Desbruyeres, Damien; Lacour, Leo; Lagunas, Jose-luis; Maze, Guillaume; Mercier, Herle; Penkerc'H, Christophe; Poffa, Noe; Poteau, Antoine; Prieur, Louis; Racape, Virginie; Randelhoff, Achim; Rehm, Eric; Schmechtig, Catherine Marie; Taillandier, Vincent; Wagener, Thibaut; Xing, Xiaogang.
Argo, the international array of profiling floats, is a major component of the global ocean and climate observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of the French “Investissements d’Avenir” Equipex program. The objectives of NAOS were to consolidate the French contribution to Argo’s core mission (global temperature and salinity measurements down to 2000 m), and also to develop the future generation of French Argo profiling floats and prepare the next phase of the Argo program with an extension to the deep ocean (Deep Argo), biogeochemistry (BGC-Argo) and polar seas. This paper summarizes how NAOS has met its objectives. The project significantly boosted France’s contribution to Argo’s core mission by...
Tipo: Text
Palavras-chave: Profiling floats; Deep ocean; Biogeochemistry; Mediterranean Sea; Arctic; Atlantic; Argo.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00654/76584/77729.pdf

A BGC-Argo Guide: Planning, Deployment, Data Handling and Usage
Provedor de dados: 5
Autores: Bittig, Henry C.; Maurer, Tanya L.; Plant, Joshua N.; Schmechtig, Catherine; Wong, Annie P. S.; Claustre, Hervé; Trull, Thomas W.; Udaya Bhaskar, T. V. S.; Boss, Emmanuel; Dall’olmo, Giorgio; Organelli, Emanuele; Poteau, Antoine; Johnson, Kenneth S.; Hanstein, Craig; Leymarie, Edouard; Le Reste, Serge; Riser, Stephen C.; Rupan, A. Rick; Taillandier, Vincent; Thierry, Virginie; Xing, Xiaogang.
The Biogeochemical-Argo program (BGC-Argo) is a new profiling-float-based, ocean wide, and distributed ocean monitoring program which is tightly linked to, and has benefited significantly from, the Argo program. The community has recommended for BGC-Argo to measure six additional properties in addition to pressure, temperature and salinity measured by Argo, to include oxygen, pH, nitrate, downwelling light, chlorophyll fluorescence and the optical backscattering coefficient. The purpose of this addition is to enable the monitoring of ocean biogeochemistry and health, and in particular, monitor major processes such as ocean deoxygenation, acidification and warming and their effect on phytoplankton, the main source of energy of marine ecosystems. Here we...
Tipo: Text
Palavras-chave: Ocean observation; Ocean biogeochemical cycles; Sensors; Carbon cycle; Ocean optics; Best practices; Argo.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00512/62344/66607.pdf

Quality control for BGC-Argo radiometry
Provedor de dados: 5
Autores: Poteau, Antoine; Organelli, Emanuele; Boss, Emmanuel; Xing, Xiaogang.
This document is the BGC-Argo quality control manual for radiometry observations. This first version of the document is to apply an initial QC to all radiometry values. Except for data failing the following tests, all the other values will be flagged as probably good data (‘2’). Probably good data need to be validated (i.e., flagged as good “1”) in delay mode.
Tipo: Text
Palavras-chave: Argo; Physical oceanography; In-situ marine data; Profiling floats; Radiometry; Operational oceanography.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00513/62466/66773.pdf