Definitions: Modules 11-15 Flashcards
(28 cards)
winds
- air that is moving horizontally relative to Earth’s surface
- caused by the unequal heating of Earth’s atmosphere, creating a pressure gradient
- they blow in an attempt to equalize the imbalances in air pressure in the atmosphere
constant height maps
- smoothed and drawn relative to a constant elevation
- can be used to show variations in pressure at any altitude
constant pressure maps
- show variations in altitudes for a constant pressure
- high altitudes for a given pressure correspond to higher than normal pressures at a given latitude
- low altitudes for a given pressure correspond to lower than normal pressures at a given latitude
cyclone
- a centre of low pressure with a counterclockwise rotation in the Northern hemisphere and a clockwise rotation in the Southern Hemisphere
- creates surface convergence
anticyclone
- centre of high pressure with a clockwise rotation in the Northern hemisphere and a counterclockwise rotation in the Southern Hemisphere
- creates surface divergence
subgeostrophic flow
- when Coriolis force < PGF
- wind flows slowly
cyclostrophic
Coriolis force is negligible near the equator
supergeostrophic flow
- when Coriolis force > PGF
- wind flows quickly
Coriolis effect
- force caused by earth’s rotation
- only important for broad-scale winds
- northern hemisphere: Coriolis effect pulls to the right
- Southern Hemisphere: Coriolis effect pulls to the left
- with this effect, any free-moving object heading in any direction will appear to deviate from its path
one-cell model
assumes earth is covered by uniform water surface, sun’s directly overhead the equator, and earth doesn’t rotate
three-cell model
incorporates Earth’s rotation, assumes no land surface
polar front
polar jet occurs here, warm air from the Ferrell cell meets cold air from the Polar cell
ekman spiral
generated by surface currents that don’t move in the same direction as the wind and whose speed and direction isn’t uniform with depth
gyres
large-scale circular currents bounded by continents and turn under the Subtropical highs
thermohaline circulation
- slow circuit of deep currents, starting from 1km below the surface to the ocean bottom
- begins as surface currents reach the waters near Greenland
- it becomes colder, saltier, and more dense
- then water sinks to ocean depths in the high latitude waters of the North and South Atlantic
- forms deep water currents, coupled with slow surface circulation
deep water circulation
- North Atlantic deep water goes south of Africa and joins water from South Atlantic
- then it meets the Antarctic Intermediate Water and the Antarctic Bottom Water
- eventually it makes its way back to the Atlantic
El Nino
- coincides with a time of unusually warm water off the coat of Peru
- occurs approximately every 3-8 years
El Nino conditions
- decrease in differences in ocean temperatures, decrease in pressure gradients
- warm water pod approaches South American coast
- absence of cold upwelling increases warming
- warmer air extends out East, causing air to rise, decreasing pressure
air mass
- extremely large body of air whose temperatures and humidity are uniform horizontally and vertically
- classified by latitude and surface type
source regions
- areas of the globe where air masses form
- usually have a flat and uniform composition and light surface winds
temperature regime
annual cycle of temperature at a place due to its latitude and location
climograph
shows the climate of a given location or region using two or more variables
moist climate
- soil remains moist all year round
- hosts perennial streams and supports forests or tall grasses
dry climate
- evaporation exceeds precipitation by a lot
- can be further split into steppe climate and arid climate
