Modal Properties of Antarctic Intermediate Water in the Southeast Pacific and the South Atlantic

Abstract

Abstract Modal properties of Antarctic Intermediate Water (AAIW) are determined from bivariate distribution diagrams for two regions in the southeast Pacific and two regions in the South Atlantic. The volumetric potential temperature-salinity diagrams reveal distinct differences between the intermediate waters of the southeast Pacific and the South Atlantic. The intermediate waters of the, southeast Pacific are more homogeneous than their counterpart in the South Atlantic. The potential temperature and salinity properties of the large volume mode intermediate water in the southeast Pacific are identical to those of the coldest variety of McCartney's (1977) Subantarctic Mode Water (SAMW). It is evident from volumetrically weighted-average properties that the intermediate water of the South Atlantic is primarily colder (∼1°C), denser (∼0.1 mg cm−3) and oxygen poorer(O.5 ml ℓ−1) than the intermediate water of the southeast Pacific. If it is assumed that no AAIW formation takes place in the South Atlantic out...