Barrier and compensation layers in the East China Sea

Climatology of the isothermal layer depth(ILD)and the mixed layer depth(MLD)has been produced from in-situ temperature-salinity observations in the East China Sea(ECS)since 1925.The methods applied on the global are used to compute the ILD and the MLD in the ECS with a temperature criterion ΔT=0.8 ℃ for the ILD,and a density criterion with a threshold Δσθ corresponding to fixed ΔT=0.8 ℃ for the MLD,respectively.With the derived climatology ILD and MLD,the monthly variations of the barrier layer(BL)and the compensation layer(CL)in the ECS are analyzed.The BL mainly exists in the shallow water region of the ECS during April—June with thickness larger than 15 m.From December to next March,the area along the shelf break from northeast of Taiwan Island to the northeast ECS is characterized by the CL.Two kinds of main temperature-salinity structures of the CL in this area are given.