30 Questions
What is the main factor that drives the movement of air on Earth?
Variations in temperature and pressure
What is the Coriolis effect responsible for?
The curving of air as it moves from high-pressure to low-pressure areas
How does topography influence atmospheric circulation?
By causing air to rise or sink, creating areas of low or high pressure
What is a factor that influences atmospheric circulation by affecting the temperature and moisture content of the air?
Ocean currents
How does the rotation of the Earth influence atmospheric circulation?
Through the Coriolis effect
What is a factor that influences atmospheric circulation by affecting the direction and strength of prevailing winds?
Topography
What is the direction of the wind in relation to the isobars in a low-pressure area?
At an angle crossing the isobars
What happens to the wind speed near a ridge or high pressure area?
It decreases
What is the result of surface divergence in the atmosphere?
Air rises to higher altitudes
What type of weather is associated with surface divergence?
Stormy weather
What is the result of surface convergence in the atmosphere?
Air sinks to the surface
What is the relationship between the centrifugal force and the Coriolis force near a trough or low-pressure area?
The centrifugal force opposes the Coriolis force
What is the term used to describe the zone of low pressure created as warm air rises from the surface?
Equatorial trough
What is the name of the prevailing winds that blow from the subtropical high-pressure systems towards the equatorial low-pressure system?
Trade Winds
What is the characteristic of the subtropical high-pressure system?
Stable and dry conditions
What is the typical direction of the wind in the mid-latitudes?
From west to east
What is the term used to describe the large-scale circulations in the mid-latitudes?
Mid-latitude Circulation
What is the name of the winds that blow from east to west in the tropics, north and south of the equator, respectively?
Tropical Easterlies
What is the primary direction of warm surface waters in the Tropical Pacific Ocean during normal conditions?
East to west
What is often associated with El Niño events in parts of Southern Africa and the western Pacific?
Below-normal precipitation
What is the result of the shift in ocean currents during an El Niño event?
Disruption of the global climate system, leading to changes in weather patterns
Which region is likely to experience above-normal precipitation during an El Niño event?
The southwestern United States
What is the effect of El Niño events on tropical cyclones in the Atlantic basin?
Increased number of tropical cyclones
What is the effect of El Niño events on the western Pacific?
Warm water flows towards the western Pacific
What is the name of the phenomenon characterized by the weakening or reversal of trade winds in the Tropical Pacific Ocean?
El Niño
What is often associated with La Niña events in parts of Southern Africa and North America?
Below-normal temperatures
What is the result of the temperature gradient across the Tropical Pacific Ocean during normal conditions?
Energy surpluses in the western Pacific
In which region can La Niña events cause above-normal precipitation?
All of the above
What is the primary factor that disrupts the global climate system during an El Niño event?
Shifts in ocean currents
What is the effect of La Niña events on tropical cyclones in the eastern Pacific?
Increased number of tropical cyclones
Study Notes
Atmospheric Circulation Factors
- Variations in temperature and pressure across the planet drive the movement of air
- Coriolis effect: apparent deflection of moving objects (including air) caused by the rotation of the Earth, creating prevailing wind patterns in each hemisphere
- Earth's rotation influences atmospheric circulation through the Coriolis effect
- Topography influences atmospheric circulation by causing air to rise or sink, creating areas of low or high pressure
- Ocean currents influence atmospheric circulation by affecting the temperature and moisture content of the air above them
- Land and sea distribution influence atmospheric circulation by affecting the temperature and moisture content of the air above them
Global Atmospheric Circulation
- Idealized vs Actual global atmospheric circulation
- Surface Divergence: air moves away from a particular point on the surface of the Earth, associated with stormy weather and precipitation
- Surface Convergence: air moves towards a particular point on the surface of the Earth, associated with high pressure and sinking air
Tropical Circulation
- Trade Winds: prevailing easterly winds that blow from the subtropical high-pressure systems towards the equatorial low-pressure system
- Tropical Easterlies: winds that blow from east to west in the tropics, north and south of the equator, respectively
- Subtropical High-Pressure System: a belt of high-pressure areas around 20-30 degrees latitude in both hemispheres, characterized by clear skies and light winds
Mid-Latitude Circulation
- Large-scale circulations in the mid-latitudes between 30 and 60 degrees latitude in both hemispheres
- Characterized by strong and variable winds, frequent storm systems, and a wide range of weather conditions
- Westerlies: prevailing winds that blow from west to east in the mid-latitudes
ENSO (El Niño-Southern Oscillation)
- Past ENSO events: listed with years
- El Niño event: warm phase of ENSO, characterized by weakening of trade winds and shifting of ocean currents
- La Niña event: cool phase of ENSO, characterized by strengthening of trade winds and shifting of ocean currents
- Implications of ENSO for weather:
- El Niño: droughts in Southern Africa and the western Pacific, floods in the southwestern United States and Peru, heat waves in Southern Africa and North America, reduced tropical cyclones in the eastern Pacific
- La Niña: increased precipitation in Southern Africa, Southeast Asia, and the southern United States, drier conditions in southern Africa and Australia, cooler temperatures in Southern Africa and North America, increased hurricane activity in the eastern Pacific and the Atlantic basin
Test your understanding of the key factors that influence atmospheric circulation, including the Coriolis effect and Earth's rotation. Learn how these factors drive global wind patterns and shape our climate. This quiz is perfect for GEOG111 students looking to reinforce their knowledge of atmospheric circulation.
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