Tidal currents and mixing in the Lake Maracaibo estuarine system

The Lake Maracaibo estuarine system is a cooscillating coupled ocean-lake s ystem connected through a partially mixed estuary. In this paper we examine the low frequency movements (omega < 0.1 cycles/day) in the different wate r bodies within this system. The harmonic and rotary spectral analyses of v elocity data indicates the importance of tidal forcing within the whole sys tem and its interaction with winds and fresh water discharge. In particular , the results indicate the existence of dominant semi-monthly oscillations in Lake Maracaibo, likely of non-linear tidal origin, and suggest that vert ical stratificaction plays an important role in controlling the three-dimen sional structure of tidal currents.