Open AccessSeasonal variation of the upper-layer seawater properties in the Banda Sea: observed from an autonomous CTD Argo float
Author(s) -
Agus S. Atmadipoera,
Tri Prartono,
Indra Jaya,
Dwiyoga Nugroho,
Gentio Harsono,
Pieldrie Nanlohy,
Ariane KochLarrouy
Publication year - 2019
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.179
H-Index - 26
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/278/1/012008
Subject(s) - argo , thermocline , downwelling , upwelling , geology , oceanography , mixed layer , bathythermograph , isopycnal , climatology , temperature salinity diagrams , ekman transport , seawater , salinity
An autonomous CTD (conductivity-temperature-depth) Argo float was deployed in the deepest Weber Basin of Banda Sea to investigate seasonal changes of the upper-layer seawater properties from the first year of CTD time-series data between August 2017 and July 2018. It is found that the float trajectory formed distinct elliptical-shapes, exhibiting a new picture of deep clockwise circulation of the float parking depth at 1000 m. On seasonal scale, large fluctuation of properties, mixed-layer depth, and thermocline thickness, were associated with seasonal alternating Ekman upwelling and downwelling dynamics. Upwelling “colder” event (July-September) was characterized by outcrops of 27°C isotherm, 34 psu isohaline and 22 kg/m 3 isopycnal at sea surface and large lateral variation of salinity in the upper 50 m. In contrast, these properties lines deepen down to about 100 m depth during downwelling “warmer” event (December-February). Amplitude of seasonal temperature change in the upper-layer was about 3°C. The very fresh water episode in the upper-layer was found during the monsoon break in April.