It is farther away from the built-up areas of the town, so
it is cooler. Houses make heat and so do factories.



|
| Chris W writes:
|
| My dad drives along the south side of OKC to work every
day and his
| OAT in his car always goes a few degrees colder around
the where the
| extended centerline for the runways would intersect the
road. Then
| it goes right back up after he is through that area.
He thinks this
| is because the airplanes are descending from very cold
air and
| bringing down some of it with them.
|
| I would not have thought of that, but it's certainly
plausible.
| Aircraft produce a massive downwash of air behind them
that (at least
| in theory) drifts downward until it encounters the
ground. In the
| case of aircraft very near the surface (as during
landing and
| take-off), it's entirely possible that they might
produce gentle
| downdrafts of colder air that reach the ground. I think
it would take
| fairly constant traffic using the runway to make a clear
difference,
| though.
|
| It's a bit like the constant wind that one often feels
by the side of
| a highway or major city street, always in the direction
of traffic.
| Moving vehicles do displace a lot of air.
|
| He has noted that this isn't always the case
| but it often is. You would think most of the traffic
would be
| landing from the north since our winds are mostly from
the south, but
| it seems like I see a lot of traffic coming in from the
south, maybe
| because it is easier for the traffic from DFW to just
come strait in.
|
| Things like noise abatement and other concerns might
obligate the
| airport to work against the wind, at least if the wind
speed is low
| enough (less than 10 knots or so).
|
| Anyway, any one here think it is really the case that
the planes are
| causing the temperature to be lower on the approach end
of the
| runway?
|
| I think it's plausible.