Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the definition of atmospheric pressure?
Answer
The force per unit area exerted against a surface by the weight of the air above that surface.
Question
What is the average atmospheric pressure at sea level expressed in millibars (mb)?
Answer
$1013.25$ mb
Question
What is the standard height of a mercury column in a barometer at sea level in millimetres?
Answer
$760$ mm
Question
How does atmospheric pressure change as altitude increases?
Answer
Atmospheric pressure decreases with height.
Question
What are the lines on a weather map that join places with the same barometric pressure called?
Answer
Isobars
Question
Name the two primary types of barometers mentioned in the text.
Answer
Fortin's Barometer and Aneroid Barometer.
Question
Why is air density highest at the Earth's surface?
Answer
The pull of the Earth's gravity is strongest at the surface.
Question
What is the medical term for the decompression sickness experienced by scuba divers who surface too quickly?
Answer
The bends
Question
How does an increase in temperature typically affect atmospheric pressure?
Answer
Pressure decreases because air expands and becomes less dense.
Question
Compare the molecular weight of water vapour to the average molecular weight of dry air.
Answer
Water vapour ($18$ g/mol) is lighter than dry air (about $29$ g/mol).
Question
How does high humidity affect the pressure exerted by a volume of air?
Answer
Humid air is less dense and exerts less pressure than dry air.
Question
How many distinct pressure belts are identified on the Earth's surface?
Answer
Seven
Question
Which pressure belt is located between $0^{\circ}$ and $5^{\circ}$ North and South of the Equator?
Answer
Equatorial Low Pressure Belt
Question
What is the 'Doldrums' a common name for?
Answer
Equatorial Low Pressure Belt
Question
At what approximate latitude are the Sub-tropical High Pressure Belts found?
Answer
$30^{\circ}$ North and South
Question
What is the common name for the Sub-tropical High Pressure Belt?
Answer
Horse latitude
Question
Where are the Circum-polar Low Pressure Belts located?
Answer
Between $60^{\circ}$ and $70^{\circ}$ latitude in each hemisphere.
Question
What causes the seasonal shifting of pressure belts?
Answer
The Earth's inclination of $23 \frac{1}{2}^{\circ}$ towards the sun.
Question
In which direction do pressure belts shift on 21 June?
Answer
$5^{\circ}$ northward
Question
In which direction do pressure belts shift on 22 December?
Answer
$5^{\circ}$ southward
Question
What is the difference between 'wind' and 'air current'?
Answer
Wind is horizontal air movement, while air current is vertical or nearly vertical movement.
Question
The decrease in pressure per unit distance in the direction where pressure decreases most rapidly is called the _____.
Answer
Pressure gradient
Question
What does a close spacing of isobars on a weather map indicate?
Answer
A strong pressure gradient and high wind speed.
Question
What is the Coriolis Effect?
Answer
A force caused by the Earth's rotation that deflects the direction of winds.
Question
In the Northern Hemisphere, the Coriolis Effect deflects winds to the _____.
Answer
Right
Question
In the Southern Hemisphere, the Coriolis Effect deflects winds to the _____.
Answer
Left
Question
Where on Earth is the Coriolis deflection the least?
Answer
The Equator
Question
Where on Earth is the Coriolis deflection the greatest?
Answer
The Poles
Question
What are 'Permanent Winds'?
Answer
Winds that blow throughout the year from one latitude to another in response to latitudinal pressure differences.
Question
From which pressure belt do the Trade Winds originate?
Answer
Sub-tropical High Pressure Belt
Question
What is the meaning of the German word 'trade' in the context of Trade Winds?
Answer
Track (to blow steadily in the same direction).
Question
Why do the western margins of continents within the tropics often suffer from aridity?
Answer
Trade winds blow parallel to the shores (off-shore) and do not bring rainfall there.
Question
Between which latitudes do the Westerlies blow?
Answer
$35^{\circ}$ and $60^{\circ}$ North and South.
Question
Why are the Westerlies stronger in the Southern Hemisphere than in the Northern Hemisphere?
Answer
The absence of large landmasses reduces friction.
Question
What are the winds that originate in the Polar High Pressure Zones and blow towards the Circum-polar Lows?
Answer
Polar Easterlies
Question
Define 'Periodic Winds'.
Answer
Winds that blow at regular intervals or in regular cycles, resulting from localised differences in pressure and temperature.
Question
What causes the occurrence of Sea Breezes?
Answer
The land heating faster than the sea during the day, creating low pressure over land.
Question
At what time do Land Breezes typically occur?
Answer
At night
Question
What is the etymology of the word 'monsoon'?
Answer
Derived from the Arabic word 'Mausim', meaning 'season'.
Question
During which months do the Summer Monsoons typically develop over India?
Answer
May, June, and July.
Question
What is the 'Loo' in the context of local winds?
Answer
A very hot and dry wind that blows from the west in the plains of northern India and Pakistan during summer afternoons.
Question
Which local wind is known as the 'snow eater' in the USA and Canada?
Answer
Chinook
Question
What are the characteristics of the 'Mistral' wind?
Answer
A local cold wind originating over snowcapped mountains that blows down the valley towards the Mediterranean Sea.
Question
Concept: Cyclone
Answer
Definition: A portion of the atmosphere where pressure is lowest in the centre, with winds blowing inward.
Question
In which direction do winds circulate in a cyclone in the Northern Hemisphere?
Answer
Anti-clockwise
Question
What is the calm region at the centre of a tropical cyclone called?
Answer
The eye
Question
Which type of cyclone is larger: Tropical or Temperate?
Answer
Temperate cyclones (they occupy areas measuring thousands of kilometres).
Question
In which direction do Temperate Cyclones generally travel?
Answer
West to east
Question
What is a 'Tornado'?
Answer
A tropical cyclone occurring over land, appearing as a dark, funnel-shaped cloud with very strong inward-blowing winds.
Question
How does the wind circulation in an Anticyclone differ from a Cyclone in the Northern Hemisphere?
Answer
Anticyclones circulate clockwise, whereas Cyclones circulate anti-clockwise.
Question
What are 'Jet Streams'?
Answer
Concentrated bands of rapid air movement found at the tropopause, typically $10$ to $15$ km above the Earth's surface.
Question
List one benefit of Jet Streams for the airline industry.
Answer
Flying within the jet stream reduces flight time and fuel consumption.
Question
How do Jet Streams assist meteorologists?
Answer
Weather systems are moved forward with the jet stream, helping to forecast future weather events.
Question
What is the typical diameter of a Tornado?
Answer
Hardly $300$ or $400$ metres.
Question
Why is air pressure an important parameter for predicting weather?
Answer
Falling pressure usually indicates stormy weather, while rising pressure indicates fair weather.