Formation of thermohaline front by cooling of the sea surface and inflow of the fresh water

A numerical study of characteristics of the front formed by cooling of the sea surface and inflow of the fresh water is made within a vertical two-dimensional plane without the rotation of the earth. The convective adjustment technique is employed to parameterize the small scale convective overturning process.A sharply edged shelf causing the marked difference of the heat capacity of the water columns between over the shelf (50 m depth) and in the deeper region (150 m depth), is responsible for the formation of a thermal front over the shelf edge and two cell circulations of the same sense with each other adjoining at the frontal region.Inflow of the fresh water at the upper region of the coast (which is equivalently replaced by the outflow of the salt from the same region) adds a circulation of the opposite sense to the above ones, which transports the water of low salinity and low temperature offshore and forms a sharp front both of temperature and salinity with the offshore water of high salinity and high temperature. This thermohaline front or Oceanic front has a remarkable character that the horizontal density gradient is minimal at the front due to the counteracting contributions of temperature and salinity to density. Response of this front to the sudden ceases of the surface cooling and the fresh water supply, is also studied in order to understand its transient behaviors.