The Bureau of Commerical Fisheries Biological Laboratory in Honolulu initiated an oceanographic investigation to gain an understanding of the mechanisms producing changes in the properties and water masses of the trade‐wind zone of the North Pacific Ocean. The Bureau undertook this study because changes in the distribution of water masses near Hawaii directly affect the availability of skipjack tuna (Katsuwonus pelamis) in a predictable manner [Seckel, 1963]. Therefore, both for ecological studies and for predicting favorable environmental conditions, it is important to understand first the basic structure and mechanism of change in the ocean.A study dealing with changes in the distribution of properties and water masses in the sea requires consideration of the theory of the distribution of variables for heat, salt, and momentum budgets [Sverdrup et al., 1942]. Involved are heat and water exchange at the sea surface, the wind stress, and the effects of water motion in advection and mixing; also essential is a knowledge of the local time change of propertie