Automatic monitoring on an unmanned offshore platform

The study of the variability of marine environmental conditions, or, more generally speaking, of ecosystems is very important for a better understanding and forecasting of natural phenomena. To obtain short term (days to weeks) variability estimation at one reference point, advanced instrumentation for automatic measurements is needed, to be put on platforms or buoys collecting time series of parameters characterising environmental quality. About twenty-eight years ago, CNR ISDGM was given a platform, formerly used in oil drilling activity. Modified and adapted to scientific activities, the platform (the only one for oceanographic research in the Mediterranean Sea) was installed on an 18 meters depth about 8 miles offshore from Venice and used as a base for manned physico-chemical determination of sea water parameters, automatic observations of marine weather ones, and for activities performed as a part of the Sea-WiFS CAL-VAL (Data Calibration and Validation) programme. With the start of PRISMA 2 (Programma Ricerca e Sperimentazione lar Adriatico 2 Programme for Adriatic Sea Study 2), new activities began and advanced automatic instrumentation was designed to work unmanned on the platform. The paper presents the design and use of a system based on a computer co-ordinating data acquisition and transmission activities of a multiparametric CTD probe, a colorimetric Loop Flow Analyzer for nutrient determination, a thermal infrared radiometer. The data are automatically acquired in real time, stored in the control computer and transferred to the base station in an off-line way using a GSM cellular phone link. Should it be necessary, it is of course possible to collect and transmit data in full real time, and also to control the equipment status and performance. Measurement activities started during summer 1997; the system architecture and some first results are here presented.