Atmospheric moisture over deserts
 

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.
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) 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
yesterday afternoon's ocean-derived moisture.
Anyone have any opinions on this? jack

Atmospheric moisture over deserts
 

wrote in message
...
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.
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) 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
yesterday afternoon's ocean-derived moisture.
Anyone have any opinions on this? jack

I would imagine you're not getting the same air back - or at least it has
mixed with "continental" air that has much lower humidity. In fact, after
thinking about it, it's hard to how it would not mix with other air.
cheers
Bill

Atmospheric moisture over deserts
 

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.

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.

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
yesterday afternoon's ocean-derived moisture.
Anyone have any opinions on this?

S*
jack

Atmospheric moisture over deserts
 

On Sun, 13 Jan 2008 14:25:29 +1100, "Landy" wrote:


wrote in message
.. .
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.
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) 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
yesterday afternoon's ocean-derived moisture.
Anyone have any opinions on this? jack

I would imagine you're not getting the same air back - or at least it has
mixed with "continental" air that has much lower humidity. In fact, after
thinking about it, it's hard to how it would not mix with other air.
cheers
Bill

Thanks Bill, I agree, but my question was more to a simple easterly
gale overnight and morning (and we have thousands of miles of desert
out there) and a sea breeze (gale) in the afternoon. No rain has
occurred, but the desert wind is much much drier than the sea breeze.
Or are you saying that the reason that winds off the desert are dry is
because they MUST have dropped their moisture as precipitation
somewhere? I'm just asking the question whether deserts can have some
drying effect by way of being a dessicant or some other non-rain
moisture loss. jack

Atmospheric moisture over deserts
 

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

Atmospheric moisture over deserts
 

Uzytkownik napisal w wiadomosci
...
On Sun, 13 Jan 2008 11:28:51 +0100, "Szczepan Bialek"
wrote:

.
And here was I trying to engineer a way for the moisture to go the
other way down to the great artesian basins :)

Probably some percent of water migrate down (in the soil) and some up.

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?

It is known that air which is not dry discharge charged bodies. Electrons
and water molecules make an aggregates (we can say droplets). In the Earth
electric field one electron can lift 10^8 water molecules. UV radiation and
high temperature do the work.

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.

It is possible if no electrons and when "the air is not spending much time
away from the sea ". But I am not an expert.

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

The wind speed can have something to do also.
S*

Atmospheric moisture over deserts
 

Atmospheric moisture over deserts
 

wrote in message
...
On Sun, 13 Jan 2008 14:25:29 +1100, "Landy" wrote:


wrote in message
. ..
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.
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) 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
yesterday afternoon's ocean-derived moisture.
Anyone have any opinions on this? jack

I would imagine you're not getting the same air back - or at least it has
mixed with "continental" air that has much lower humidity. In fact, after
thinking about it, it's hard to how it would not mix with other air.
cheers
Bill

Thanks Bill, I agree, but my question was more to a simple easterly
gale overnight and morning (and we have thousands of miles of desert
out there) and a sea breeze (gale) in the afternoon. No rain has
occurred, but the desert wind is much much drier than the sea breeze.
Or are you saying that the reason that winds off the desert are dry is
because they MUST have dropped their moisture as precipitation
somewhere? I'm just asking the question whether deserts can have some
drying effect by way of being a dessicant or some other non-rain
moisture loss. jack

Jack,
No - I'm just saying that because the high-humidity air that blew in from
the sea mixed with very low-humidity air in the desert, the resulting
humidity of the mixed air that blows back out will be lower. It's a matter
of mixing ratios. I guess the absolute moisture loss (of the air that blows
back) has been to the desert air - it doesn't have to have precipitated. I
think if you did humidty measurements inland in the deserts on evenings
following the sea breezes versus days without, you would see the difference.
I hope this makes sense.
cheers
Bill

Atmospheric moisture over deserts
 

"Landy" wrote
...

wrote

I'm just asking the question whether deserts can have some
drying effect by way of being a dessicant or some other non-rain
moisture loss. jack

Jack,
No - I'm just saying that because the high-humidity air that blew in from
the sea mixed with very low-humidity air in the desert, the resulting
humidity of the mixed air that blows back out will be lower. It's a
matter of mixing ratios. I guess the absolute moisture loss (of the air
that blows back) has been to the desert air - it doesn't have to have
precipitated. I think if you did humidty measurements inland in the
deserts on evenings following the sea breezes versus days without, you
would see the difference. I hope this makes sense.

"At high altitudes, the difference between between high pressures from warm
tropical air and low pressures from cold polar air try to force air from the
tropics toward the poles, but the Earth's rotation diverts this flow to the
east, resulting in the high velocity west-to-east jet stream flows at
mid-latitudes." It is from:
http://aes.gsfc.nasa.gov/vis/a000000/a003200/a003203/

Jack lives on the western edge of Australia. So the water which migrate very
high above the desert flows to the east and we have "absolute moisture
loss".
But what things are on the eastern edge of Australia?
S*