Air Pressure and Wind Vocabulary

Vocabulary flashcards covering air pressure, wind forces, wind classifications, and local and global wind patterns based on the lecture notes.

Isobars

Lines on a map connecting points of equal barometric pressure.

High Pressure Cell

A heavy pressure cell represented by an $H$, characterized by surface divergence and sinking air (subsidence).

Low Pressure Cell

A light pressure cell represented by an $L$, characterized by surface convergence and rising air (uplift).

Pressure Gradient Force (PGF)

The difference in air pressure between two locations that determines wind direction and wind strength or speed.

Coriolis Force

The apparent deflection of moving objects (such as air and ocean currents) from a straight path caused by the Earth's rotation on its axis; it alters wind direction but NOT speed.

Geostrophic Winds

Upper-level winds flowing $1-2\text{ km}$ above the surface and higher, formed by Pressure Gradient Force and affected by Coriolis Force, but not ground friction.

Surface Winds

Winds flowing below $1-2\text{ km}$ altitude in contact with the Earth's surface, affected by Pressure Gradient Force, Coriolis Force, and Friction Force with the ground.

Zonal Flow

A pattern of geostrophic wind flow oriented primarily in an east-west direction.

Meridional Flow

A geostrophic wind pattern exhibiting ridges and troughs oriented north-south.

Jet Stream

A meandering river of geostrophic air $100-300\text{ miles}$ wide and $3000-7000\text{ ft}$ deep at an altitude between $25,000-35,000\text{ ft}$ above sea level, with average wind speeds between $50$ and $110\text{ mph}$.

Rossby Waves

A subset of the Polar Jet Stream stretching from one trough to another with wavelengths on the order of thousands of kilometers, forming a meridional pattern of ridges and troughs.

Anemometer

An instrument used to record wind speed in units of $\text{mph}$, $\text{kph}$, or knots.

Macroscale Winds

Wind systems classified on large scales, including Planetary ($1000-40,000\text{ km}$ across, such as the Westerlies) and Synoptic ($100-1500\text{ km}$ across, such as hurricanes).

Mesoscale Winds

Wind systems spanning $16-160\text{ km}$ ($10-100\text{ miles}$) across, such as thunderstorms.

Microscale Winds

Wind systems spanning $3.5\text{ km}$ ($2\text{ miles}$) or less, such as tornadoes and dust devils.

Land Breeze

A local wind that flows from the land toward the sea in the early morning when higher pressure forms over the cooled land and lower pressure forms over the warmer water.

Valley and Mountain Breezes

Local winds in mountainous regions formed when warm air flows up the mountain during the day and cool air flows down the mountain at night on the same side.

Chinook Wind

A warm, dry local wind occurring in the Rocky Mountains of the United States and Canada.

Santa Ana Winds

Local winds occurring in southern California created as air moving from the interior heads toward the coast.

Katabatic Wind

A flow of cold, dense air moving downslope, which can reach speeds over $100\text{ mph}$.

Northeast Trade Winds

Major global wind pattern found between $0^\text{o}-30^\text{o}\text{ N}$ latitude.

Southeast Trade Winds

Major global wind pattern found between $0^\text{o}-30^\text{o}\text{ S}$ latitude.

Westerlies

Major global wind pattern found between $30^\text{o}-60^\text{o}$ latitude in both the Northern and Southern Hemispheres.

Easterlies

Major global wind pattern found between $60^\text{o}-90^\text{o}$ latitude in both the Northern and Southern Hemispheres.