Introduction to ocean dynamics

This first lecture sets the scene for the whole week. Nicholas Hall introduces the ocean as one of two thin envelopes of fluid – the ocean and the atmosphere – whose motion regulates our climate by moving heat from the equator toward the poles.

As you watch, you’ll explore:

• The ocean and the atmosphere – how these two fluids resemble each other, and the key differences between them (density, a free surface, salt, and what drives each one)
• Energy in the climate system – how the imbalance between incoming sunlight and outgoing radiation sets the whole system in motion
• The causes of oceanic motion – the wind, the Sun, the Moon, and the Earth itself
• Spatial and temporal scales – the enormous range of sizes and timescales on which the ocean moves, from turbulent mixing to basin-wide gyres
• Time variation in a fluid – how we describe change as we follow the flow
• Pressure and depth – why pressure rises so quickly beneath the surface, and how it balances gravity

The aim is physical intuition, not mathematics: a feel for why the ocean moves. Keep that in mind as you watch – everything else this week builds on these foundations.