What We Are Thinking

Where do the winds come from?

by Ken Caldeira ·

The potential energy available to generate winds is created most strongly high above the tropical western Pacific Ocean, where the condensation of water in convective systems heats already warm air, and in the polar night, where heat radiates to space and cools already cold air.

Eva Ahbe and I wanted to know where the energy came from to make winds.

This is infeasible to directly observe in the global atmosphere. Therefore, we used a model of the atmosphere to study where the energy comes from to drive winds.

Two panels. The left shows zonal mean generation of available potential energy as a function of latitude and atmospheric pressure, with strong positive generation in a column over the equator and over both poles, and negative values in the subtropics. The right shows vertically integrated generation on a world map, with the largest values over the western tropical Pacific and around the polar regions.
Where the energy that drives the winds is generated, as Figure 3 of the paper has it. Ahbe and Caldeira (2017), Journal of Climate 30, 2089-2101. Reproduced under author reuse rights.

The potential energy available to generate winds is created most strongly high above the tropical western Pacific Ocean where the condensation of water in convective systems heats up already warm air, and also in the high polar night where heat radiates to space, cooling already cold air.

These heat fluxes create density contrasts that tend to make the tropical air rise and the polar air sink, and this is a primary driver of global winds.

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