What they are is open to question.
My theory is:
Hydrogen/helium ice build up on the dome from gases that turned into superfluids then icicles that get too dense to hold at the top of the atmospheric stack/dome.
They break off and are caught in an atmospheric stream where they may friction burn as they hit more and more dense atmosphere higher up.
In my opinion, of course.
While ice burning up in the atmosphere sounds reasonable, I have two comments regarding it:
In 2013, a meteor exploded over the city of Chelyabinsk in Russia. Since ice would've melted or sublimated long before getting to an altitude into which pressure from the outside air would've built up in cracks and pores enough for the meteor to explode, the explanation for why it could've exploded is that it was made of rock.
This may be the case but it depends on the mindset.
You believe in space and things coming into Earth's atmosphere.
I believe we're a cell in itself, meaning space does not exist to our view or abilities to exit the cell.
Everything is contained meaning whatever falls is whatever was produced by this cell, alone.
I know that hydrogen is an explosive substance, but Earth's atmosphere is made up of around 0.000055% hydrogen (at Wikipedia's estimates). I don't think there is enough hydrogen in the Earth's atmosphere to produce an explosion of this magnitude. Yet again, this is just my speculation.
The above atmosphere would be abundant with hydrogen/helium, etc. In my opinion.
The difference is, down here we can break down gases/liquids and use them in this dense atmosphere we live under at sea level, etc.
Any substance broken down will naturally be acted upon by the denser atmosphere we live under.
However, in their rightful place those gases will be very little in terms of volatile, unless allowed to build and fall.
It's like light versions of the icicles that fall from roof's. They build and build and build depending on how little energy can reach them to friction melt them.
Down here icicles melt. Up there they would glow as they hit denser atmosphere.
My second comment regards to the fact that you said that the meteors could be "gases that turned into superfluids then icicles". Superfluids are liquids with no viscosity, meaning they are able to flow with absolutely zero difficulty.
You have rising gases then those gases enter their own stack where they are not under any real pressure or friction.
This causes them to freeze...but, in that mix of gas to freeze, you get a superfluid. A stream. A moving stream, dependent on the movement of the reflected energy of the sun/moon reflections coming from within.
With regularity you'll get many hydrogen etc, icicle break off's from the dome that will fall slowly and friction melt back into gas, high up to be no issue.
Then you'll get a larger icicle build which maybe be a massive mix of hydrogen/helium, etc that falls and friction melts much slower as it moves and falls.
The more dense atmosphere it hits the bigger the glow. The bigger the glow the more pressure created by massive expansion into the dense atmosphere, which inevitably creates a smash back or a massive clap as that dense atmosphere is displaced by the icicle.
Helium becomes this state of matter instead of turning solid. Superfluids are unable to become solids, because elements that solidify cannot become a superfluid, and vice versa.
Hard to do down here but a regularity up at the dome.
Obviously in my opinion and the fact that I obviously do not follow a global model with space.