Model scope and corrections — read first

Pressure belts at 0°, ±30°, ±60°, ±90° and seasonal shifts of ±5–7° are idealized patterns, not fixed global locations or universal displacements. Pressure gradients, the Coriolis force, and friction jointly affect wind direction; near-surface winds can cross isobars, while near-geostrophic winds run approximately parallel only under suitable conditions. A Coriolis on/off switch illustrates one influence rather than fully explaining monsoons. Monsoons also depend on land–sea heating contrasts, seasonal circulation, and topography. Mediterranean and savanna climates reflect several interacting factors, not just the movement of a single pressure belt.

← Back to contents
Atmospheric pressure belts andwind belts
Module 07 · Atmospheric Circulation
Key concepts
Seasonal shift
Date (day of year) 172
↑ Pressure belts shift north–south by 5–7° with the subsolar point
Layers
Standard pressure-belt latitudes (idealized)
Equatorial low-pressure belt: 0°
Subtropical high-pressure belts: ±30°
Subpolar low-pressure belts: ±60°
Polar high-pressure belts: ±90°
Actual seasonal shift: ±5~7° (following δ)
Current parameters
Solar declination δ—
Pressure-belt shift—
Pressure and wind belts (current location)
Counterintuitive insight
Northern Hemisphere trade winds arenortheasterly trade winds, not due-easterly winds — the Coriolis force deflects airflow right in the Northern Hemisphere and left in the Southern Hemisphere.

Set the date to the June solstice: the subtropical high shifts north to about 35°N, dominates the Mediterranean region, and produces dry summer conditions.