Transcript M5.4-Gravity waves

Section 5.4 Gravity Waves
Gravity Waves
 Gravity acts as the restoring force on parcels displaced
from hydrostatic equilibrium.
 Pure gravity exists when the fluid is stably stratified.
 Two types of gravity waves:
 external gravity waves: static stability is due to the density
discontinuity at the interface between two fluids
 internal gravity waves: static stability arises from the
stable stratification, buoyancy force acts as the restoring
force
External Gravity Waves: Density
Discontinuity
Air: Small Density
h’
h’
Water: Large Density
Transverse Waves:
Waves are oscillations (in field variables,
such as velocity or pressure) that propagate
in space.
Surface (External) Gravity Waves
Tsunami: Shallow Water Waves
Gravity Waves
 Gravity acts as the restoring force on parcels displaced
from hydrostatic equilibrium.
 Pure gravity exists when the fluid is stably stratified.
 Two types of gravity waves:
 external gravity waves: static stability is due to the density
discontinuity at the interface between two fluids
 internal gravity waves: static stability arises from the
stable stratification, buoyancy force acts as the restoring
force
Internal Gravity Waves: Stable Stratification
Colder than the env.;
Downward acc.
Warmer than the env.;
Upward acc.
Vertical Velocity (w) Field During a
Model Initial Adjustment Periods
Internal Gravity Waves Generated
by Rapidly Rising Deep Convection
Mountain Waves and Clouds
Lenticular Cloud