Define the Scale of Atmospheric Motions Flashcards

smallest scale atmospheric motion, short lived 1km, lasting only a few minutes; Example: Individual thunderstorms, clouds, and local turbulence

Atmospheric motions ranging from a few km to ~100km, lasting many minutes or hours. Example: Complex thunderstorms, squall lines, fronts, mountain waves and sea and land breezes.

Circulation that dominates regions of hundreds to thousands of km and typically last days or weeks. Example: Events like High and Low weather systems, ridges, and frontal zones.

Friction- the drag exerted on the air by the earth's surface (e.g., plants, trees, buildings, mountains, etc.). Friction always acts opposite to air motion and, hence, reduces wind speed. Its greatest effect is near the earth's surface and rapidly decreases with height (within lowest 1 km).

· Surface obstructions slow surface winds, which due to viscosity creates eddies of whirling winds. · Solar heating of the ground during sunny days cause thermals of warmer air to rise, these thermals are large eddies. · Frictional drag on the air flowing over the ground causes wind shears to develop.