MIO OBSERVATION PROGRAM - ROMARIN (previously SPECIMED)

JULIO : Judicious Location for Intrusion Observation
5,255°E – 43,135°N
5° 15,28' E – 43° 8,15' N



Introduction

On the eastern side of the gulf, during specific conditions, a vein of the Northern Current can intrude on the shelf . Both in situ measurements and numerical modelling show that intrusions develop either as a part of the NC itself encroaching on the shelf or as a separated branch of the main vein of the NC (Gatti, 2008 ; Petrenko et al., 2013). These two types of intrusions can change from one type to the other, both in time and in space. Three kinds of wind events are likely to generate intrusions: the Mistral cessations, episodes of inhomogeneous Mistral or periods of East winds. In the first two cases, intrusions are due to the inhomogeneity of the wind event. The intrusions during East wind could be due to two processes: the Ekman drift and the shift of the current’s core towards the coast. Otherwise, intrusions cannot develop during homogeneous Mistral. Other factors, such as the vertical and horizontal extents of the NC as well as its degree of mesoscale instability, can also influence the development of intrusions. However, neither the NC seasonal variability nor the variation of the GoL’s water budget have an impact on the occurrence of intrusions.

Methods

Situated on the 100 m-deep isobath, the JULIO bottom-moored ADCP measures horizontal currents through the water column, to detect intrusions occurring upstream and on the eastern side of the Gulf of Lion. The ADCP (RDI Ocean Sentinel 300 kHz) provides a current time series every ½ hour and every 4m depth throughout the water column.

Three time series are available :

* from Feb. 12 to Oct 23, 2012

* from Sep. 26, 2013 to March 28, 2014

* from July 17, 2014 to April 10, 2015

last launch on Sept 23, 2016. Dragged probably 3 days after, but had stayed at the bottom. ADCP found mid-April 2017 by fishermen. ADCP ok but cage not responding to acoustic communication tests.

To obtain JULIO time series, email anne.petrenko@univ-amu.fr or connect to Site OpenDap JULIO. Special thanks to Nicolas Barrier and Maurice Libes for this OpenDap system.


Bibliography

- Barrier N., Petrenko A.A., Ourmieres Y., (2016), Strong intrusions of the Northern Mediterranean Current on the eastern Gulf of Lion: insights from in-situ observations and high resolution numerical modelling, Ocean Dynamics, 1-15. 10.1007/s10236-016-0921-7. (see Publications section of Petrenko homepage to download paper)
- Bouffard J., Meloni M., Fernandes J., Lazaro C., Casadio S., Doglioli A.M., Petrenko A., Femenias P. (Feb 2017), Coastal Altimetry in Support to Marine Observatory and Marine Observatory in Support to Coastal Altimetry: Multi-Platform Validations of Altimetry for Monitoring the Variability of Coastal Fronts. 10th Coastal Altimetry Workshop, Florence, Italy. Abstract Book
- Casella D., Meloni M., Petrenko A., Doglioli A.M., Bouffard J., (2020) Toward a New Coastal Altimetry-Based Algorithm for the Detection of Current Intrusions Into the Gulf of Lion. 12th Coastal Altimetry Workshop, Coastal Altimetry Training, 4-7 February 2020, ESA-ESRIN, Frascati (Rome), Italy.
- Declerck A., Ourmieres Y. and Molcard A. (2016), Assessment of the coastal dynamics in a nested zoom and feedback on the boundary current: the North-Western Mediterranean case. Ocean Dynamics, final revision
- Fraysse, M., Pinazo, C., Faure, V.M., Fuchs, R., Lazzari, P., Raimbault, P. Pairaud, I (2013), Development of a 3D coupled physical - biogeochemical model development around Marseille coastal area (NW Mediterranean Sea): What complexity is required in coastal zone?, PlosOne, doi: 10.1371/journal.pone.0080012
- Gatti, J., Intrusions du Courant Nord sur la partie Est du plateau continental du golfe du Lion, thesis, June 2008, 156 pp.
- Meloni, M., Bouffard, J., Doglioli, A.M., Petrenko, A.A., Valladeau, G. (2019). Toward science-oriented validations of coastal altimetry: application to the Ligurian Sea. Remote Sens.Envir., 224, 275-288, doi:10.1016/j.rse.2019.01.028. see preprint HAL
- Meloni M., Doglioli A., Petrenko A., Bouffard J., Valladeau G. (June 18), Multi-Scale Analysis and Applications of Coastal Altimetry Observations Over the Ligurian Sea. 11th Coastal Altimetry Workshop, Frascati, Italy. Abstract
- Millet B, Pinazo C, Banaru D, Pagès R, Guiart P, et al. (2018) Unexpected spatial impact of treatment plant discharges induced by episodic hydrodynamic events: Modelling Lagrangian transport of fine particles by Northern Current intrusions in the bays of Marseille (France). PLOS ONE 13(4): e0195257. https://doi.org/10.1371/journal.pone.0195257
- Petrenko, A.A., , Kersale, M., Nencioli, F., Gatti, J., Doglioli, A. M., Dekeyser, I. (2013), Coastal circulation in the Gulf of Lion, the influence of mesoscale processes on interregional exchanges, Proceedings, 40th CIESM Congress, 28 October - 1 November 2013, Marseille, France
- Petrenko A., Y. Leredde, and P. Marsaleix (2005), Circulation in a stratified and wind-forced Gulf of Lions, NW Mediterranean Sea: in-situ and modeling data. Continental Shelf Res., 25, 5-27, doi:10.1016/j.csr.2004.09.004
- Ross O.N., M. Fraysse, C. Pinazo, I. Pairaud (2016), Impact of an intrusion by the Northern Current on the biogeochemistry in the eastern Gulf of Lion, NW Mediterranean. Estuarine, Coastal and Shelf Science 170(1–9). doi:10.1016/j.ecss.2015.12.022

Localization of JULIO (from MOOSE proposition of the COM in 2008 - 2009)

JULIO mooring down at the JULIO site