Semi-annual Salinity Propagation in the Arabian Sea
[28-Aug-2018] Menezes, V.V.
Presented at the 2018 Ocean Salinity Science Team and Salinity Continuity Processing Meeting
The Arabian Sea exhibits the highest salinity of the Indian Ocean with values above 36.5 (psu), being a source of salt for the entire basin in several time scales. Despite the Arabian Sea to be a central region to understand the salinity dynamics of the Indian Ocean, the time scales of variability of sea surface salinity (SSS) in this region is not fully known due to the historical lack of in situ
observations in basin scale with relatively high temporal resolution. In the present work, Aquarius and SMAP satellite and Argo SSS data are used to characterize these scales. A novel finding is the presence of the propagating features on the semi-annual band. These features have wavelengths around 15° (1500 km) and amplitudes around 0.4 (psu). The perturbations propagate into a north-westward direction from the southern tip of the Indian subcontinent to the Gulf of Aden, with a discontinuity in phase speed just downstream of the shallow Chagos Laccadive Ridge at about 73°E. This wave might be related to the monsoonal wind regime forcing.