Exam 1: Earth and Its Atmosphere

A) burning fossil fuels
B) lightning
C) deforestation
D) photosynthesis

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A) methane
B) argon
C) helium
D) nitrogen

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A) nitrous oxide
B) carbon dioxide
C) ozone
D) chlorofluorocarbons

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The stratosphere is an inversion layer b...

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A) pressure
B) density
C) temperature
D) weight

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A) prominences
B) flares
C) solar wind
D) aurora

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A) in the northern and southern hemispheres near the equator
B) in the northern and southern hemispheres at high latitudes
C) in the northern hemisphere and southern hemispheres in the polar regions
D) in the northern hemisphere and southern hemispheres at low latitudes

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A) They tend to remain stable.
B) They tend to go up and down.
C) They tend to keep decreasing.
D) They tend to keep increasing.

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A) It makes clouds white
B) It is semi-transparent
C) It colours the sky blue
D) It is invisible

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A) rapid change in atmospheric pressure
B) extreme cold
C) combined effects of heat and humidity
D) lack of oxygen to the brain

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The thermosphere is the hottest atmosphe...

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A) about 75%
B) about 25%
C) about 10%
D) about 50%

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D

A) Calgary
B) Toronto
C) Montreal
D) Halifax

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A

A) the outgassing produced by volcanoes
B) nitrous oxide
C) condensation on a drinking glass
D) the stratosphere

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The tropopause is the boundary layer between the troposphere, which is the lowest layer of the Earth's atmosphere, and the stratosphere above it. The troposphere is where most of the Earth's weather phenomena occur, and it contains approximately 75-80% of the atmosphere's mass and water vapor. There is very little water vapor above the tropopause in the stratosphere for several reasons: 1. Temperature Inversion: The tropopause acts as a barrier because of the temperature inversion that occurs at this boundary. In the troposphere, the temperature generally decreases with altitude, but at the tropopause, this trend reverses, and the temperature starts to increase with altitude in the stratosphere. This temperature inversion prevents the convective uplift of air and moisture from the troposphere into the stratosphere. 2. Condensation and Freezing: As air rises in the troposphere, it cools and expands. When it cools to the dew point, water vapor condenses into water droplets or ice crystals, forming clouds and precipitation. By the time air reaches the tropopause, most of its moisture has already condensed out and fallen back to the surface as precipitation. 3. The Brewer-Dobson Circulation: This is a large-scale atmospheric circulation that moves air from the tropical tropopause up into the stratosphere and towards the poles. While this circulation does transport some water vapor into the stratosphere, it is minimal because the rising air must pass through the cold trap of the tropical tropopause, where temperatures are extremely low and any remaining water vapor is likely to freeze out and precipitate. 4. Stratospheric Dryness: The stratosphere itself is inherently dry because it lacks the mechanisms for producing and retaining moisture that are present in the troposphere, such as evaporation from oceans, transpiration from plants, and the aforementioned convective processes. 5. Photodissociation: In the rare instances when water vapor does make it into the stratosphere, it can be broken down by the intense ultraviolet (UV) radiation from the sun in a process called photodissociation. This further reduces the amount of water vapor that can exist in the stratosphere. Due to these factors, the stratosphere contains only a tiny fraction of the water vapor found in the troposphere, leading to very dry conditions above the tropopause.

A) 21%
B) 43%
C) 78%
D) 84%

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A) water vapour
B) nitrous oxide
C) carbon dioxide
D) methane

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A) frictional heating caused by meteorites
B) absorption of ultraviolet radiation by ozone
C) chemical reactions between ozone and chlorofluorocarbons
D) release of latent heat energy during condensation

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