The long-term variation of the Intermediate Water in the Philippines Sea

The dimensional and temporal distribution of Antarctic Intermediate Water (AAIW) and North Pacific Intermediate Water (NPIW) in the Philippines Sea were explored using Argo profiles. As the salinity minimum of intermediate water from mid-high latitude of the southern and northern hemisphere of the Pacific Ocean, the properties of AAIW and NPIW merges at about 10°N with different properties in the Philippine Sea. The core of AAIW is located below 600dbar with potential density of 27≤σ_θ≤27.3 kg m^-3 and salinity of 34.5≤S≤34.55 psu. The core of NPIW is located between 300-700dbar with potential density of 26.2≤σ_θ≤27 kg m^-3 and salinity of 34≤S≤34.4 psu. The volume of AAIW and NPIW during January 2004 to December 2017 is negative correlated.  The time series of AAIW and NPIW is dominated by semi-annual signals. The variations of AAIW and NPIW was mainly affected by volume transport through 130°E section by North Equatorial Current (NEC) and North Equatorial Undercurrent (NEUC).