How to figure out layers of the atmosphere?
Earth's atmosphere, as you probably know, is divided into five layers - the troposphere, stratosphere, mesosphere, thermosphere and exosphere.
https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Stratification
How can I determine plausible altitudes for the boundaries of these layers for my Earth-like planet's atmosphere? I have already figured out the atmosphere's composition, pressure*, density*, and escape velocity, and I know other possibly relevant things about the planet such as mass, radius, gravity, density, surface temperature, albedo, axial tilt, orbit etc.
Are these values necessary? If so, are there any I need and don't have? Also, a couple clarifications:
I'm not necessarily looking for an empirical, universal method to precisely determine the exact figures, I just need a way to give me reasonable results,
I know that something like layers of the atmosphere might seem insignificant for worldbuilding, but I am interested in knowing this for my planet, and so I'd rather not just handwave it entirely.
*at any altitude; I have a calculator for that.
EDIT: As per Morris The Cat's request, I've shared the values regarding the planet and atmosphere. Here they are:
Mass "“ 1.2x Earth
Radius "“ 1.17x Earth
Gravity "“ 0.88x Earth
Density "“ 0.75x Earth
Semi-major axis "“ 0.92 AU
Eccentricity "“ 1.8x Earth
Periapsis "“ 0.89 AU
Apoapsis "“ 0.95 AU
Year "“ 0.8x Earth, 294 Earth days
Orbital velocity "“ 1.14x Earth
Axial tilt "“ 1.17x Earth
Albedo "“ 1.22x Earth
Escape velocity "“ 1.01x Earth
Atmosphere "“ 71.9% N, 25% O2, 1.95% Ar, 1.1% CO2, 0.05% trace gases
Atm. pressure @ sea level "“ 1.45 atm
Air density @ sea level "“ 1.7x Earth
Specifically I've compared them to Earth's corresponding values which I thought were most fit for what the comment suggested.
This post was sourced from https://worldbuilding.stackexchange.com/q/150079. It is licensed under CC BY-SA 4.0.
1 answer
The five primary layers of the atmosphere are, with increasing, altitude, the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The corresponding boundaries are the tropopause, stratopause, mesopause, and thermopause. Here's how those boundaries are defined:
- Tropopause: The lapse rate $\Gamma=-\frac{dT}{dz}$, the change in temperature with height, goes from positive in the troposphere to negative in the stratosphere, being zero at the tropopause.
- Stratopause: Temperature in the stratosphere increases with increasing altitude; the stratopause is where a temperature maximum is reached once you exit the troposphere.
- Mesopause: Temperature in the mesosphere decreases with increasing altitude; the mesopause is where a temperature minimum is reached once you exit the stratosphere.
- Thermopause: The thermopause is located at the point where the Knudsen number $\text{Kn}(z)$ is about equal to one.
Essentially, to determine most of these boundaries, you need to determine a temperature profile for the atmosphere, and from there calculate $T(z)$, $\Gamma(z)$, etc. This is typically not exactly trivial.
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