American Meteorological Society Certification Atmospheric Dynamics 3

Question 1

What is the primary balance in the tropics that replaces geostrophic balance?

Accepted Answer

Cyclostrophic balance

Answer

In strong tropical vortices where Coriolis force is negligible, cyclostrophic balance between the centrifugal and pressure gradient forces dominates.

Question 2

The hydrostatic equation relates pressure change to which atmospheric quantity?

Accepted Answer

Air density and gravity

Answer

The hydrostatic equation states that the pressure decrease with height equals air density times gravitational acceleration.

Question 3

Which scale of motion is characterized by horizontal scales of 2–2000 km?

Accepted Answer

Mesoscale

Answer

Mesoscale meteorology covers phenomena with horizontal extents from roughly 2 to 2000 km, including thunderstorms and sea breezes.

Question 4

What does PVU (potential vorticity unit) measure?

Accepted Answer

Isentropic potential vorticity

Answer

A PVU (10⁻⁶ K·m²·kg⁻¹·s⁻¹) is the standard unit for potential vorticity on isentropic surfaces.

Question 5

In a barotropic atmosphere, how do pressure surfaces relate to density surfaces?

Accepted Answer

They are parallel (no solenoids)

Answer

A barotropic atmosphere has parallel pressure and density surfaces, meaning no baroclinic instability can develop.

American Meteorological Society Certification Practice Test