On Sun, 13 Jan 2008 11:28:51 +0100, "Szczepan Bialek"
wrote:

wrote
.. .
I live on the western edge of Australia, with the Indian ocean 10 km
to the west, and the vast desert interior of Australia a few hundred
kilometers to the east.
I've been watching dew point temperature refreshed every 10 minutes on
the weather bureau's website, and I'm wondering what happens to a
moist sea breeze when it blows over the interior, and then returns
much drier. It hasn't dropped any rain, but yet it somehow dries.

I am not a meteorologist but I think that you are talking about surface
wind. This from the ocean must be wet (near the surface). Next, above the
vast desert interior, the humidity migrate up an when the aie come back the
content of the water in the surface layer is lower.

The migration ( and the "lost" of water) is possible for the following
reason:
1. During the day the temperature is higher and a thermal emission of
electrons from soil is intensive. Water droplets gain the electrons and
migrate up follows the Coulomb law. Such heavy jons do not fall down easy.
2. Water molecules always migrate up because they are lighter than the
molecules O2 and N2.
3. The water which migrate enough up do not come back because at wery high
altitudes winds do not change the directions at night.

Ahh, thanks so much for that, Szczepan, I'd not even considered the
air column behaving very differently at different altitudes. Of
course, the sea breeze loses its moisture out in the desert mainly coz
it (the moisture) moves upward and I at 6' tall only "see" the air at
my altitude.
And here was I trying to engineer a way for the moisture to go the
other way down to the great artesian basins

I was not aware of this thermal emission of electrons out in the
desert, and what water droplets would be present at such usually low
relative humidities?

If it cools below the dew point (even frost point) overnight, would it
not regain that frost/dew when the land warms up? Or would there be a
time lag, so you would get dried masses of air, that have not had the
opportunity to recapture the dew/frost and then later masses carrying
this evaporated precipitation?
Does the desert act as a dessicant at all?
Perhaps some of the dew/frost (is this called precipitation?) is lost
to lower soil profiles?
Just now, we have an easterly wind that appears to be getting
increasingly humid (specific)

But the content of water is probably lower.

No it's getting higher, (g/kg), I'm not talking relative humidity
here. But at the moment, the air passing my city is unusually moist. I
suspect it is not spending much time away from the sea with the
present patterns.

and I'm guessing that this actual air
has either not gone over much desert, or has not dropped below the dew
point overnight and is merely a returnimg sea breeze with all of
Anyone have any opinions on this?


jack