Abstract
The stratified intensity of water column can be estimated by measurements of temperature, salinity and density
gradients between the upper and lower water layer, but the quantitative method using the Vaisala frequency or
potential energy has been proved more efficient. The potential energy method was applied in this study for
Uranouchi Bay (southem Japan):
(1) The water column's stratified intensity was a combination of potential energy by temperature and salinity.
The latter, however, appeared to have more influence on stratification.
(2) The seasonal change in stratified intensity consisted of short (1-2 months), and long period (1 year), corresponding to salinity and temperature changes, respectively.
(3) Beside solar radiation and precipitation, mixing by intemal waves also influenced stratified intensity.
(4) The estimation of stratified intensity with potential energy is effective in expressing the phenomenon of
dissolved oxygen deficiency of bottom water.
