STUDY ON THE REQUIRED ACCURACY LEVEL OF MEASUREMENTS OF TEMPERATURE, SALINITY AND DEPTH IN SHALLOW SEA WATERS

This paper investigates the accuracy of the measurements of temperature, chlorinity and depth in shallow seas less than 100 meters deep, which are necessary to meet the need of the required accuracies ±1×10^-5 of the calculated values of the anomaly of specific volume of sea water and of specific volume itselfy.The ranges of measurements of temperature, chlorinity and depth are -2℃-30℃, 5‰-20‰ and 0m-100m respectively. In general, the accuracy of temperature measurement necessary to meet the required accuracy ±1×10^-5 of the calculated value of anomly of specific volume, is leaver in the low temperature and low chlorinity case than in the high temperatre and high chlorinity case;however, the necessary accuracy of the measurments of chlorinity is higher in the low temperature and low chlorinity case than in the high temperature and high chlorinity case. Generally speaking the accuraces necessary to meet the required accuracy ±1×10^-5 of the calculated value of specific volume of both the temperature and chlorinity increases as the accuracy of measurements of depth decreases either in lower temperature and lower chlorinity case or in higher temperature and higher chlorinity case.