Fluctuations multi-échelles et extrêmes dans les séries temporelles biogéochimiques à moyen et long terme en milieu marin côtier
Brizard Zongo, S. (2010). Fluctuations multi-échelles et extrêmes dans les séries temporelles biogéochimiques à moyen et long terme en milieu marin côtier. PhD Thesis. Université Lille 1 - Sciences et technologies: Villeneuve-d'Ascq. 308 pp. |
| Keywords | Chemistry > Geochemistry > Biogeochemistry
Time series
Turbulence
Marine/Coastal |
| Abstract | This thesis focuses on the study of biogeochemical time series medium and long term, so as to characterize their fluctuations at multiple scales, and in particular their extremes. The data come largely from MAREL and SOMLIT programs. MAREL The program was implemented by Ifremer and based on high-frequency measurements. The program is a SOMLIT Observation Service since 1997 labeled by INSU. These measurements are made every 15 days, out, at a fixed point in coastal waters in the English Channel. For the analysis of these time series, the methods used are borrowed from the fields of numerical analysis and turbulence. This study is carried out in three parts. In the first part, the analysis of the Fourier spectrum was used to measure the influence of physical forcing on the distribution of high-frequency settings. In the second part, the comparison between SOMLIT MAREL and data collected directly adjacent to Boulogne-sur-Mer was able to show complementarity but by highlighting the most informative of MAREL system. The comparison between two distinct sites in Manche (Eastern and Western) helped to identify similarities and differences in the levels of ratios (N / P / Si; COP / Chla). In the third part, it was possible to demonstrate the influence of extreme events the flow of the Seine on the distribution of certain biogeochemical parameters measured in Honfleur. We also highlighted in the context of the WFD, the influence of the study of scale on estimates of certain metrics necessary for the definition of good environmental status based on data from the high frequency. |
| Dataset | - REPHY: REPHY (2022). Dataset of French Observation and Monitoring program for Phytoplankton and Hydrology in coastal waters since 1987. SEANOE. https://doi.org/10.17882/47248, more
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