ESS228
Prof. Jin-Yi Yu
Purpose of Rigid Lid Approximation
•Rigid lid approximation: the upper surface was held
fixed but could support pressure
changes related to waves of lower speed
and currents of interest.
•Ocean models used the
"rigid lid" approximation to eliminate high-speed external gravity waves and allow a longer
time step.
•As a result, ocean tides and other waves having the
speed of tsunamis were filtered
out.
•The rigid lid
approximation was used in the 70's
to filter out gravity wave
dynamics in ocean models. Since then, ocean model have evolved to include a free-surface allowing
fast-moving gravity wave
physics.