Weather and Climate: Ch. 7 Flashcards
Smallest scale of motion
Microscale Systems
How long are microscale systems?
few seconds to minutes
Examples of microscale systems
wind gusts, microbursts, dust devils
Middle-sized systems less than 60 miles across, up to 600 miles wide
Mesoscale systems
How long are mesoscale systems?
few minutes to several hours
Examples of mesoscale systems
thunderstorms, tornadoes, local winds
Largest wind patterns (Macroscale Systems)
- Synoptic-scale winds
- Planetary-scale winds
Characteristics of Synoptic-scale winds
- smaller with diameters of 600 miles
- easily identified on weather maps
- midlatitude cyclones and anticyclones
Characteristics of Planetary-scale winds
- extend around entire globe for weeks
- westerlies and trade winds
Basic cause is unequal heating of surface
Global Circulation
Where are subtropical anticyclones centered?
near 30° north and south
Exentensive areas of subsiding air
Subtropical Anticyclones
What do subtropical anticyclones result in?
low RH, fair skies, calm winds, warm temps
World’s major deserts located in…
subtropical anticyclones
Subtropical anticyclones are at …
Horse Latitutdes
Results from clockwise and outward flow on north side of subtropical high
Midlatitude Westerlies
How do Midlatitude Westerlies blow?
from west to east in midlatitudes
Midlatitude Westerlies are highly ________
variable
Midlatitude Westerlies follow a _____ path due to ______ differences
wavy; temp
longest wave patterns
Rossby waves
Rossby waves are a part of …
Midlatitude Westerlies
Results from clockwise and outward flow on south side of Subtropical High
Trade Winds
How do trade winds blow?
from east (NE) to west in tropical latitudes
Doldrums are located near ________
equator
Trade winds converge (low pressure)
Intertropical Convergence Zone (ITCZ)
ITCZ is a part of ________
Doldrums
Air subsides and flows away
Polar Highs
Polar regions are _____
cold
Separates air masses of different temps
Polar Front
Colder air to north from warmer air to south
Polar Front
Area of low pressure
Subpolar Lows
Responsible for much of stormy weather in midlatitudes
Subpolar Lows
Move and vary in intensity with seasons
Semipermanent Highs and Lows
Pressure and wind belts follow vertical rays of sun
Seasonal Shifts
Seasonal Shifts shift _____ in July
north
Seasonal Shifts shift _____ in January
south
What are precipitation patterns determined by?
- Semipermanent pressure systems
- Distribution of land and water
- Air temp
- Terrain
High speed winds found in westerlies
Jet Streams
Jet Streams are _______ of miles long
thousands
Jet streams have a width of __-___ miles
60-300