Forcing, how can it be directly measured?

[hgerh...@yahoo.co.uk]

One idea is to measure heat up take by the oceans, which will give a
figure in W/m2 for the radiation imbalance; but why can we not measure
it directly, ie compare the incoming and outgoing radiation in W/m2?

http://en.wikipedia.org/wiki/Radiative_forcing

And what's the tropopause got to do with it? The heat capacity of the
air is essentially zero for periods longer than a few weeks, so if
there's imbalance in W/m2 it's got to a) go into the ocean and b)
it'll be the same right across the atmosphere, or not?

A few weeks ago I asked about averaging according to 4th powers, but
thinking it through again, as long as the albedo of the Earth stays
the same and solar insolation stays the same, the average temperature
of the Earth determining the outgoing radiation stays the same; what
changes is that the temperature gradient between where the incoming
radiation is absorbed and where it is re-emitted to space goes up.

The point being, why should the transport between those two points go
according to 4th powers? Eg, some of the transport should be in the
form of convection or water evaporating at the surface of the oceans
and condensing higher up in the atmosphere. And convection (hot air
rising in the tropics say and falling over the arctic), while
temperature dependent in some fashion, is not a straight 4th power
function of surface temperature.

[James Annan]

hgerh...@yahoo.co.uk wrote:
> One idea is to measure heat up take by the oceans, which will give a
> figure in W/m2 for the radiation imbalance; but why can we not measure
> it directly, ie compare the incoming and outgoing radiation in W/m2?

We can and indeed have (google ERBE), but it's difficult to do accurately.

James

[Eric Swanson]

I think that there's the notion the the lapse rate between the surface
and the tropopause will remain the same, mol. Thus, warming at the
surface would cause the altitude of the tropopause to rise. I recall
a report which showed that the height of the freezing level in the
atmosphere has increased, which would be consistent with an expansion
of the atmosphere as the result of an net warming of the air.

E. S.
---

[Alastair]

On Apr 8, 2:17 pm, "hgerhau...@yahoo.co.uk" <hgerhau...@yahoo.co.uk>
wrote:

> A few weeks ago I asked about averaging according to 4th powers, but
> thinking it through again, as long as the albedo of the Earth stays
> the same and solar insolation stays the same, the average temperature
> of the Earth determining the outgoing radiation stays the same; what
> changes is that the temperature gradient between where the incoming
> radiation is absorbed and where it is re-emitted to space goes up.
>
> The point being, why should the transport between those two points go
> according to 4th powers? Eg, some of the transport should be in the
> form of convection or water evaporating at the surface of the oceans
> and condensing higher up in the atmosphere. And convection (hot air
> rising in the tropics say and falling over the arctic), while
> temperature dependent in some fashion, is not a straight 4th power
> function of surface temperature.

Yes.

But as Eric said "there's the notion the the lapse rate between
the surface and the tropopause will remain the same, mol." (What
does "mol." mean?)

However, that does not answer your objections. It is yet
another "constant".

What everyone is missing is that the model being used is wrong.
It is not the radiation which changes. It is the albedo!

Increasing the CO2 concentration results in raising the altitude and
latitude of the snow line. This is one reason why the Arctic sea ice
(low altitude) is melting.

No more clues :-)

Cheers, Alastair.