What I'm doing is trying to find a way to create an atmospheric cold trap that will maintain a temperature of approximately −200 degrees Celsius (−328 Fahrenheit).
According to Wikipedia
In astronomy, a cold trap is a close to the surface layer of the atmosphere that is substantially colder than both the deeper and higher layers. The temperature of the air drops with increasing height above the surface of the earth reaching a low point (which for the earth resides at about 20 kilometers height). It is called a trap because it keeps ascending gases with high melting points in by freezing them to a solid which then drops back to the planet surface
It's a big part of the reason that all of our water vapor hasn't broken down and had its hydrogen lost to space.
So, how could a cold trap be created that possesses the temperatures I described above while surface temperatures of the planet remain Earth-like. The cold trap doesn't have to be created naturally, nor does it need to be at the same height or anything else as ours. It merely needs to maintain those temperatures in a layer of the atmosphere. For comparison, I want the cold trap to be a little more than 3 times colder than the one here on Earth.
For anyone wondering why I'm asking this, it's a follow up of my terra-forming question here
Thank you for any help or insight!