JULIO - Judicious Location for Intrusions Observations
|Temporal extent||2012-02-12 -2012-10-23|
|Author(s)||Petrenko Anne1, Barrier Nicolas1, Libes Maurice2, Quentin Céline1|
|Affiliation(s)||1 : Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
2 : Aix Marseille Univ, CNRS, IRD, IRSTEA, OSU PYTHEAS, Marseille, France
|Note||If you use these data in publications or presentation, please acknowledge the JULIO Project Office of MIO/OSU Pytheas. Also, we would appreciate receiving a preprint and/or reprint of publications utilizing the data for inclusion in our bibliography. Relevant publications should be sent to: JULIO Project Office, Anne Petrenko, Laboratoire MIO, UMR7294, Campus de Luminy, 13288 Marseille cedex 9, France|
|Keyword(s)||acoustic, adcp, circulation, current, currents, data, depth, direction, direction_of_sea_water_velocity, doppler, Earth Science > Oceans > Ocean Circulation > Ocean Currents, eastward, eastward_sea_water_velocity, gulf of lions, intrusions, julio, latitude, longitude, magnitude, measurements|
JULIO (Judicious Location for Intrusions Observations) mooring is located close to the 100 m-deep isobath (around 5.25°E and 43.13°N), offshore Marseille. With its bottom-moored (300kHz) ADCP, it enables measuring horizontal currents (every 4 m and every ½ h) through the water column, and among others, identifying periods of exchange between the Northern Current and the continental shelf.
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.
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 5m depth (4 m until 2016) throughout the water column.
Three time series are available :
[Sept 23, 2016 launch. Dragged probably 3 days after, but stayed at the bottom. ADCP found mid-April 2017 by fishermen. ADCP ok but cage not responding to acoustic communication tests.]
* from Sep. 26, 2013 to March 28, 2014, every 4 minutes
* from Feb. 12 to Oct 23, 2012, every 4 minutes
Localization of JULIO from 2012 to 2016: 5° 15,28' E – 43° 8,15' N or 5,255°E – 43,135°N
Two incoming data series:
* from Sept 1st, 2021 to June 23, 2022, every 30', every 4 minutes
* from Dec 7, 2020 to August 31, 2021; every 30', every 5 minutes
Localization of JULIO since 2020: 5°14.074' E - 43°8.503' N or 5,235° E - 43,142° N
|Utilisation||The data may be used and redistributed for free but is not intended for legal use, since it may contain inaccuracies. Neither the data Contributor, MIO, OSU Pytheas, CNRS, nor the French Government, nor any of their employees or contractors, makes any warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, or assumes any legal liability for the accuracy, completeness, or usefulness, of this information.|
|Acknowledgements||We acknowledge the SPECIMED program (2012-2015; PI B. Quéguiner), and ROMARIN program (2013-2018; PI C. Grenz), and the Mediterranean Institute of Oceanography for their permanent support.|
A Teledyne-RDI BroadBand 307.2 kHz ADCP - Acoustic Doppler Current Profiler - was deployed bottom-moored, mounted between 90 and 100 m depth for the first three series (2012 to 2016) in an anti-trawling mooring at 5° 15,28' E – 43° 8,15' N or 5,255°E – 43,135°N since 2020, on a classical mooring (see web site :for description) at 5°14.074' E - 43°8.503' N or 5,235° E - 43,142° N
ORIGINAL ADCP DATA
The ADCP data was downloaded and converted to Matlab using the Teledyne-RDI WinADCP software.
INITIAL ADCP PROCESSING
There are 50 pings per ensemble ; each ping last 0,56 sec The ensemble lasts 50*0.56 = 28 sec. An ensemble (28 sec) + interval between ensemble (36.75 sec) = 64,75 nearly 65 sec ; hence a little more than a minute. The interval between two measurements can be found in the time series ; the time data are every 1/2 hour.