THE SUMMER BUOYANCY DYNAMICS OF A SHALLOW MEDITERRANEAN ESTUARY AND SOME EFFECTS OF CHANGING BATHYMETRY - TOMALES BAY, CALIFORNIA

A numerical study is presented of the summer buoyancy dynamics of Toma les Bay (California, U.S.A.) which is an example of a shallow mediterr anean estuary. Tomales Bay lies along the line of the San Andreas faul t, and the resultant unidirectionality of the estuary greatly simplifi es its hydrodynamics. The numerical model hindcasts the temperature an d salinity of Tomales Bay from 1987 to 1993 using detailed hydrologica l and meteorological data, and the results are compared with held obse rvations made during that 7-year period. A second simulation is made o ver the same 7-year period but using the bathymetry for 1861 when the estuary was longer and deeper. This allows an analysis to be made of t he effects on the summer buoyancy dynamics of anthropogenic bathymetry changes. The model predicts that the historical estuary experienced g reater negative buoyancy inputs during the late summer periods, and be came more inverse with faster dispersion near the head of the basin. ( C) 1997 Academic Press Limited.