Flying at 35,000 ft over Quebec in winter, I am most likely in the:

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Thermosphere

Answer: (B)

Flying at 35,000 ft over Quebec in winter means you are likely in the stratosphere. The stratosphere begins at about 30,000 feet and extends to approximately 50,000 feet. This layer of the atmosphere is characterized by a temperature inversion, where temperatures increase with altitude, contrasting with the troposphere, where temperatures generally decrease with rising altitude.

At this altitude, you would be above the troposphere, where most weather events and turbulence occur, and thus experiencing more stable air conditions typical of the stratosphere. Additionally, the presence of the jet stream, which is often located near the top of the troposphere and can influence flight routes, further supports that you are flying within the stratospheric layer during winter, when strong upper-level winds typically prevail.

The other atmospheric layers, such as the mesosphere and thermosphere, begin at altitudes much higher than 35,000 feet, making it improbable for a winter flight in Quebec to be within those layers.