BODC PROJECT DOCUMENT NO. 12764 Applies to BODC Series Ref. Nos.: 33816, 33828, 33841, 33853, 41183, 41275 Joint North Sea Data Acquisition Project for 1976 (JONSDAP 76) This is the third phase of the cooperative data collection programme JONSDAP, begun in 1970 by the countries bordering the North Sea. It consists of two intensive measurement programmes. FLEX - the Fladen Ground Experiment - to study the development of the thermocline and the dynamics of the plankton bloom in spring in relation to the physical, chemical and biological environment. Measurements are concentrated in a square of side 100km for 100 days from March to June. INOUT is concerned with the general circulation of the North Sea and the storm surge problem. Currents flowing into and out of the open boundaries as well as at discrete points within the sea, are measured concentrating on a period of 40 days in the stormy season from March to April. Some 200 current meters (most also recorded temperature) of which 30 were lost, and 5 offshore tide gauges were deployed over 83 stations and more than 10 ships collected hydrographic data. The Netherlands organised a collection of meteorological data. The northern boundary of INOUT is from Wick to 59deg 20min N, 0deg E then along this latitude to the Norwegian coast. The southern boundary crosses the English Channel from Portland to Cherbourg along the meridian 2deg W (approx). One of the most important reasons for the cooperative exercise, pooling data, was the need to provide large data sets for the evaluation and running of physical and ecosystem numerical models. Data underwent intradisciplinary processing and interdisciplinary evaluation. Intercomparison of Instruments: There was no field comparison station for moored instrumentation. Laboratory techniques in use for calibrating current meter compasses were compared and shortcomings eliminated prior to the exercise. The two main types (Plessey and Aanderaa) of current meter used in the exercise were compared in a simplistic way on four of the rigs and showed that at certain times the two types could give differing responses to the same velocity field simply because of differences in instrument and rig design. This point should be borne in mind whenever comparing data across instruments. Previous JONSDAP Exercises: The first JONSDAP: this achieved the systematic collection of data from all moored stations and coastal observation sites in the North Sea in the period 1971 to 1973. The second: JONSDAP 73 was a programme of tide and current measurement in the Southern Bight of the North Sea from September to October 1973.