Chapter 2 · Try it yourself

The Upwelling Switch

Every spring a steady wind from the northwest blows down the California coast. Thanks to the Earth’s spin, it shoves the surface water out to sea, and cold water from the deep comes up to replace it. Turn up the wind and watch the coast change.

0 to 30 knots. Use the arrow keys or drag.

Cross-section of the coast. LAND (Monterey) east → Warm surface water Cold, deep water,full of nutrients ← west, out to sea Wind blows toward you, along the coast

You are looking north, up the coast. The wind blows toward you, south along the shore. The dashed line is the boundary between warm and cold water.

Sea surface temperature at Monterey
≈ 16 °C (61 °F)

  • Nitrate at the surface
  • Phytoplankton
  • Coastal fog

Simplified model: a steady northwest wind blowing for several days. Temperatures and nitrate are typical values, not a forecast, and a real bloom takes a few days to catch up with the wind.