Global Wind Patterns

Activities to try

1. 1

   Build the planet's circulation from two dials: heating and spin

   Why it works: Large-scale wind bands are the emergent OUTPUT of two interacting drivers — uneven heating by latitude and the planet's rotation. The single convection loop you expect splits into three cells once spin is added, and the bending of the winds is an apparent deflection that only appears once the planet turns beneath the moving air, not a sideways push.

   1. Starting with the planet's spin set to zero, increase the equator-to-pole heating contrast and observe a single giant convection loop per hemisphere form: warm air rising at the equator, drifting poleward aloft, sinking, and returning along the surface.
   2. Now increase the spin dial up to Earth's rotation rate and observe the single loop break into three side-by-side cells per hemisphere, arranged by latitude, with surface wind belts drawn beneath (trade winds, westerlies, polar easterlies).
   3. Use a 'launch a parcel' tool to fire a puff of air poleward and watch its path curve — to the right in the Northern Hemisphere, to the left in the Southern.
   4. Slide a real world map underneath and check where the circulation's branches land: rising equatorial air over the rainforests, descending ~30° air over the Sahara and Australian deserts.
   5. As an extension, toggle a jet-stream ribbon at a cell boundary and observe how this fast high-altitude river of air steers weather systems along its path; then explore a 'wavier jet' slider and reason about what a more meandering, 'stuck' jet might do to the weather beneath it.
2. 2

   Spin a globe and launch parcels across it (spatial Coriolis)

   Why it works: Circulation wraps a rotating sphere; seeing a straight-intended path curve on a surface you can spin makes the apparent (frame-dependent) nature of Coriolis concrete, and the opposite deflection in each hemisphere follows from the direction of rotation seen from each pole.

   1. On a spinnable 3D globe, launch a 'straight' path from the equator toward a pole and watch the trace curve relative to the rotating surface: in both hemispheres, a parcel moving toward the pole arcs eastward. On a physical turntable/lazy-Susan, which stands for one hemisphere seen from above its pole, draw a straight line with a pen across the spinning disc and watch the trace curve.
   2. Compare launches in the Northern Hemisphere (path curves right) and the Southern Hemisphere (path curves left), and say why the two differ.
   3. Peel back or tilt to view the three cells as latitude bands girdling the planet, and view the jet stream as a meandering ribbon from a polar vantage.
3. 3

   Consolidate: match, sequence, predict, and locate

   Why it works: Secure the discriminations after exploring the model: naming cells and belts, predicting deflection direction, locating deserts/rainforests from the circulation, and linking the westerlies to west-to-east weather turn the model into reliable, transferable knowledge.

   1. Match each cell to its latitude band (Hadley 0–30°, Ferrel 30–60°, polar 60–90°) and each surface belt to its wind direction (trade winds easterly/equatorward, mid-latitude westerlies, polar easterlies).
   2. Sequence the causal chain: equator heated most → air rises → drifts poleward → sinks near 30° → returns as surface wind belt.
   3. Given a poleward-launched parcel, draw or select its correctly curved path in each hemisphere (right in N, left in S).
   4. Categorise named regions as wet-equatorial (rising air) or dry-subtropical (descending air at ~30°), e.g. placing the Sahara and Australian deserts under descending air.
   5. Explain in your own words why the equator is hottest — sunlight strikes it more directly, concentrating energy over less area — rather than because it is closer to the Sun.