Re: [Phys-L] Earth as a "heat engine"

[John Denker <jsd@av8n.com>]

On 10/9/19 8:28 AM, Francois Primeau wrote:

> the ocean is heated and cooled at
> the surface, which is roughly a surface of constant gravitational potential
> energy, 

OK.....

> and therefore does little to directly drive ocean currents.

I wouldn't have said that.  Thermohaline circulation in the
oceans is a big deal.  In particular, you have to account for
the fact that there is more heating at some latitudes and less
at others -- leading to verrrry large-scale convection:

 https://en.wikipedia.org/wiki/Thermohaline_circulation

> Rather, the ocean currents are driven mechanically by the wind stress at
> the surface.

That's quite an overstatement.  *Some* currents (e.g. the
Gulf Stream) are primarily wind-driven ... but others are
not.