It was once suggested that photodissociation of water followed by the escape of hydrogen was a significant source of oxygen in the atmosphere.

]]>In your one-dimensional transparent isothermal atmosphere, what happens to the top of the atmosphere? I was wondering if it might disappear:

1) If it existed, there would be an abrupt boundary transition from the isothermal temperature of the atmosphere to the absolute zero temperature of deep space. This seems contrary to to the idea of maximum entropy.

2) If the molecules at the top of the atmosphere are just as kinetically active as those on the surface, then there is nothing really stopping them from moving further out beyond any supposed top of the atmosphere.

This seems to imply that there is no top to the atmosphere. However if that were so then I think it would mean the atmosphere has actually dispersed throughout deep space.

]]>If that would not be the case, it would be possible to build a machine that makes mechanical energy from a single source of heat.

Can you explain this in more detail or do you have a link that might explain it?

]]>“”A column of dry air in hydrostatic equilibrium ….. bounded by two ﬁxed values of the pressure, and the question is asked, what vertical temperature proﬁle maximizes the total entropy of the column? Using an elementary variational calculation, it is shown how the result depends on what is kept ﬁxed in the maximization process. If one assumes that there is no net heat exchange between the column and its surroundings—implying that the vertical integral of the absolute temperature remains constant—an ISOTHERMAL proﬁle is obtained in accordance with classical thermodynamics and the kinetic theory of gases”

http://www.nioz.nl/public/fys/staff/theo_gerkema/jas04.pdf

If that would not be the case, it would be possible to build a machine that makes mechanical energy from a single source of heat. This goes against the 2nd law of thermodynamics.

The natural intuition that the temperature must be warmer at the bottom, because molecules gain energy, when falling, is wrong because it’s exactly compensated by another phenomenon: Those molecules that have little energy cannot go up as well as those with more energy.

This is not to deny that the sudden imposition of a gravitational field on a column of gas would

indeed set up a temperature gradient. It would – but it wouldn’t persist. It would

quickly be homogenized and the column would become isothermal.

So if a column of gas behaves this way would a GH free atmosphere behave the same way too? I think it might. Without the driving force of IR radiation from the upper reaches of the atmosphere there would be very little net heat flux in our column of air. There would be no re-radiation of course and very little convection. A GH free atmosphere would be very different from our present one and approximately much more closely to an isothermal state.

]]>You might get yourself an account on e.g. dropbox (you can get 2GB storage per month free).

It lets you upload any type of file and create a url pointing to them, which you can then insert into your blog..

For example here’s an AWK program that does anomalization. The urls are even relatively human readable.

]]>Here is the code for define_atmos_0_2 – as a word doc, just rename the file .m.

=======define_atmos_0_2.m =========

function [pr Tr rhor ztropo] = define_atmos_0_2(zr, Ts, ps)

% Calculate pressure, pr; temperature, Tr; density, rhor; from height, zr;

% surface temperature, Ts; and surface pressure, ps

% By assuming a standard temperature profile to a fixed tropopause temp

% zr is a linear vector and starts at the surface

pr=zeros(1,length(zr)); % allocate space

Tr=zeros(1,length(zr)); % allocate space

rhor=zeros(1,length(zr)); % allocate space

% first calculate temperature profile

lapset=6.5/1000; % lapse rate in K/m

Ttropo=215; % temperature of tropopause

htropo=10000; % height of tropopause

% Tstrato=270; % temperature of stratopause

Tstrato=215; % temperature of stratopause – making stratosphere isothermal

zstrato=50000; % height of stratopause

ztropo=((Ts-Ttropo)/lapset); % height of bottom of tropopause in m

for i=1:length(zr)

if zr(i)=ztropo && zr(i)(ztropo+htropo) && zr(i)<zstrato)

Tr(i)=Ttropo+(zr(i)-(ztropo+htropo))*(Tstrato-Ttropo)/(zstrato-(ztropo+htropo)); % stratosphere

else

Tr(i)=Tstrato; % haven't yet defined temperature above stratopause

% but this prevents an error condition

end

end

% pressure, p = ps * exp(-mg/R*integral(1/T)dz) from 0-z

mr=28.57e-3; % molar mass of air

R=8.31; % gas constant

g=9.8; % gravity constant

intzt=0; % sum the integral of dz/T in each iteration

dzr=zr(2)-zr(1); % dzr is linear so delta z is constant

pr(1)=ps; % surface condition

for i=2:length(zr)

intzt=intzt+(dzr/Tr(i));

pr(i)=ps*exp(-mr*g*intzt/R);

end

% density, rhor = mr.p/RT

rhor=mr.*pr./(R.*Tr);

end

==== end of code ===========

]]>I am trying to run your scripts, but I am missing an updated version of define_atmos

where could I get: define_atmos_0_2 ?

]]>