Figure S1. Seasonal evolution of the surface salinity observed in the climatology of
Chatterjee et al. (2012) (left) and simulated by the model (right). The tri-monthly seasons are
indicated on each frame.
Comment: The observed climatology shows the co-existence of ASHSW (SSS in excess of
36.2, in the northern and central part of the basin) and fresher waters (SSS less than 35.8) in
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the equatorial region, as well as on both eastern and western boundaries. This contrast is seen
in all seasons, although with a modulation. The salty tongue progresses southward in the
central basin (between 60°E and 70°E) from spring to summer, and retreats back northward
from fall to winter. On the western boundary, the limits between the two water masses
oscillates between a northernmost position in summer, and a southernmost position in fall and
winter. The model reproduces adequately the observed patterns throughout the seasonal cycle,
with little departures from the observations.
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