The Atmosphere — Layers, Pressure Belts, Winds and Cyclones

Five Layers, and Only One of Them Has Weather

Every general studies paper carries two or three atmosphere questions, and they are among the cheapest marks on the sheet — because the whole chapter is built on a handful of fixed facts that never change from year to year.

The difficulty is not the concept. It is that four or five items look alike and paper-setters swap them: ozone belongs to one layer, meteors burn in another, radio waves bounce off a third. Temperature falls as you climb — but only in the bottom layer; above it, temperature starts rising again. Trade winds and westerlies both blow, but from opposite ends of the same pressure belt.

So learn this chapter as a stack, bottom to top, with one signature fact attached to each level. Then learn winds as movement from high pressure to low pressure, bent by one force. Do that and you will never again pause over which layer holds the ozone.

1. The ozone layer, which absorbs most of the Sun's ultraviolet radiation, is found in which layer of the atmosphere?

2. What is the normal lapse rate — the rate at which temperature falls with increasing height in the troposphere?

3. Meteors entering the Earth's atmosphere burn up mainly in which layer, also the coldest layer of the atmosphere?

4. The trade winds blow from which pressure belt to which?

5. Which warm, dry local wind of the Rocky Mountains region is nicknamed the 'snow eater'?

6. A tropical cyclone forming over the north-west Pacific Ocean, near China and Japan, is called a:

7. Tropical cyclones do not form within about 5° of the equator. Why?

8. Which instrument is used to measure the relative humidity of air?