A Portable and Low-Cost Recording System for Time-Series Observation of Coastal Marine Surface Water: The Case of Rhone River Dilution Plume

• Published in: Journal of coastal research 2003-06, Vol.19 (3), p.740-747
• Main Authors: ROMANO, Jean-Claude, YOUUES, Walid A. N
• Format: Article
• Language: English
• Subjects: Boats; Coastal water; Earth sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Geochemistry; Global positioning systems; Marine and continental quaternary; Mineralogy; Observational research; Physical and chemical properties of sea water; Physics of the oceans; Plumes; Salinity; Sea water; Sensors; Silicates; Surface water; Surficial geology; Technical Communications; Time series; Water geochemistry
• ISSN: 0749-0208; 1551-5036

One of the difficult tasks in coastal oceanography is to study land-sea interactions with their high levels of space and time variations. Consequences of the combination of several factors such as the climate of upstream and its influence upon the rate of freshwater inputs, coastal current regime and the annual rhythm of seawater and local meteorological conditions at small and large scales. Recent measurement technologies (e.g., moorings, towed vehicles, gliders, floaters, drifters) are now in use and can be deployed in time-series observation but they are quite expensive and not adapted for most of the coastal oceanographic research laboratories. We present here the details of a simple and relatively low-cost in-situ continuous recording system for monitoring coastal marine and estuarme surface waters. It is composed of a multiparameter probe coupled to ship-independent portable GPS. The sensors can be either towed or immersed in onboard reservoir, continuously rilled with running seawater from the ship line or independent pumping device.The synclonous data acquisition allows precise location at verious pre-identified time space itercvals following the sampling strategy. The system presents both novelty and great versatility of applications, it is portable and can be shore-based or deployed in almost all types of embarkation (outboard motor rubber boat, fishing and leisure boats and oceanographic research vessels). It is autonomous, easy to handle, independent of shipboard hardware and can provide precise datasheets and real-time simultaneous display. At fixed points, the system can be transformed into a CTD to perform vertical profiles down to 60 m and recording intervals can also be modified. It provides realtime surface water hydrological data at high frequency resolution (1 rec./min or 1 rec/250 m), mesospace scale (10 to 50 km). This recording system was applied, at a semi-monthly frequency (SORCOM time-series) from October 1995 to October 1998 (a time-series which is "yet active" in 2001), in the Mediterranean coastal waters influenced by the Rhone River, using 17 m-oceanographic research vessel. Strategy, results and some examples of other applications of the system are discussed here from an instrumental point of view for future application in time-series observation on land-sea interactions.