Brian Sandle wrote:
Øyvind Seland wrote:


Part 1: Solid fuel rockets emit chlorine compunds in the stratosphere,
which depletes ozone.

They don't until they have been activated. They emit HCl. Someone said

Yes, I know, but when you are looking at total ozone depletion
a simplification is too look at the amount of halocarbons release
in the stratosphere. Most of the chlorine released from CFC etc, reacts
rapidly into reservoir species HCl and ClNO3.


The rockets also produce a lot of water which may be used to produce the
PSC.

The water vapor released by the rockets are quite small 10-4 times
the natural and wator vapor is generally not the restricting factors for
PSC unless we are talking about orders of magnitude more than the rockets
release. The increase in water may have some other, albeit minor effects
on ozone though.

The chlorine emitted near the ground
are not different from the chlorine emitted from the solid fuel rockets,

From near the ground comes HCl form of chlorine, as from rockets, too, but
also halocarbons, which do not come from rockets.

I was thinking about the chlorine atoms themselves. More exact
description / hypothesis. The effects on ozone from HCl are the same
regardless of whether the HCl molecules comes from the space shuttle
or from produced from CFCs if the production happen to be in the same
height as the shuttle emissions.

There is a certain height variance, with the ozone depletion efficiency
being most efficient at 15-20 km height, but not so large that
the relatively small contribution from the space shuttle should be
the most important factor regardless of the height you put it into.

so whether something is transported across the tropopause or emitted
in situ have no effect on the total ozone depletion.

Excuse me but is that tested or hypothesis?

As long as we are talking about the same height, yes it is tested.
The comparison
with tropopause transport was an approximation, which for this purpose
should be more than exact enough. The former hold from basic physics.
There are no imeasurements showing a noticeable different isotopic
composition between the chlorine in rocket fuel compared to CFCs,
or for that matter any major effect on the isotopic composition
on the reactions themselves.


An idea is to look at time of launch. Then see what heppens when the rest of
the hours of sunlight have had their effect, maybe with stratospheric cloud
present, added to a night and what happens the next morning.


There are no PSCs over Florida.

The increase in space shuttle flights and use of CFC and other halocarbons have
just come at more or less within the same time frame.

All those things are changing together. One technique of finding out is to do
actual experiments in which two variables are physically held constant and
what happens to the other two is examined. That is quite often possible in
physical sciences, though rather less so in earth sciences on the whole.

Why bother? There is already a perfectly good hypothesis. The ozone
concentration decrease because of an increase in the concentrations
of halocarbons. Good correlation, measurements of concentrations
and few needed asumptions of thresholds. (There is one measured
threshold connected to temperature and PSCs, which has to be taken into
account when calculating "the ozone hole")

And to emphasis the earlier mentioned webpage, no it is not a new idea,
and people have been worried. There are no indications though that this
is an important part of the problem.




Øyvind Seland