eastern part of the area, deepest in the northwestern pertion,
and of intermediate depth at Bikini.
Water masses in the area
ah”
are primarily Equatorial Pacific, North Pacific Intermediate,
and West North Pacific Central.
Underwater sound propagation conditions at depths <ehove
the thermocline are good, out will become less favorable as
summer progresses.
Propagation in the deep water is bottom
limited where Gepths ere less than 1000 fathoms.
The axis of
the deep sound channel is found at 800 to 1200 meters (1.3 to
1.5 tines as deep as off the U. S. West Coast).
Tre physical hydrozraphy of Bikini ITagoon is simtlar to
that obtained at CHOSSROA0S.
Surface waters move dewnwind,
and deep waters ficw in the ovposite direction to complete a
cellular circulation.
At the uswind end the deep waters are
diverted both north and south into two seccndaryv horizontal
cells.
During moderate to strong trades, water flows into the
lagoon along the windward reefs and flows~out through Enyu
Flaws out
channel and.at the leeward reefs and channels.
With southerly
and southeasterly winds most of the inflow occurs through knyu
channel.
Speed of the surface current was measured to be about
1.6% of the wind speed instead of 3% as previously found.
The
aeep flow was apnarently more variable in direction and of con-
siderably less speed than that obtained during previous inves*igations,
4s the trade winds materially decrease, the surface
5
COPIED/DOE
LANL RG 7
ete ten
est) at depths of 50 to 175 meters, being shoalest in the south-
what
waters are most stratified (i.¢., density gradients are great~