FIELD SURVEY ON A RELATIONSHIP BETWEEN DEVELOPMENT AND DECAY PROCESSES OF SALINITY STRATIFICATION DUE TO FLOODS AND TURBULENT STRUCTURES IN THE NORTHERN ARIAKE SEA

Abstract

 To understand difference of density stratification due to freshwater transport from rivers through flood events and tidal range (spring tide or neap tide), four time 25 hours continuous field measurement on tidal current, CTD, turbulence micro-structure, and suspended solid (SS) particle size property were conducted at a point in the northern Ariake Sea in summer and winter in 2014. From the results, the followings were clarified: 1) sub-tidal development and decay process of saline-freshwater stratification during flood season was clearly measured; 2) Turbulent energy dissipation rate was correlated to mean flow velocity in spring tide in winter only, but not in neap tide and in stratified spring tide; and 3) Tempo-vertical profiles of eddy viscosity and dissolved oxygen were related to condition of stratification.