Cirrus type vs cumulus type contrails?

[Trailblazer]

Today most of the persistent contrails in my area seem to be quite dense and "puffy" or "woolly", like altocumulus cloud texture. Other days they are thinner, more hazy and more cirrus like.

Does anyone know what factors affect this? I'm assuming it's something to do with altitude and temperature, as altocumulus clouds are generally lower than cirrus.

From what I have read, altocumulus cloud is made of supercooled water droplets whereas cirrus is made of ice crystals. Does that mean that these contrails are liquid water rather than ice? And if so how does that affect the persistence? Do we need to consider RHw rather than RHi?

 

[Mick West]

I think those are cirrocumulus clouds. However, it could be that some trails are aerodynamic trails, which we've observed at much lower altitudes than exhaust contrails.

 

[Trailblazer]

I think those are cirrocumulus clouds. However, it could be that some trails are aerodynamic trails, which we've observed at much lower altitudes than exhaust contrails.

You are probably right, the trails that turned into these clouds were at about 27-29,000 feet and appeared to be aerodynamic. Here's a new one forming at around 28,000ft.

Perhaps it's the presence of supercooled liquid droplets as well as ice that accounts for the denser appearance compared to the more normal contrail clouds?

 

[Jay Reynolds]

Aerodynamic trails form from wing surfaces, while exhaust contrails form from the engine exhaust. You might expect the different way that each forms to influence the eventual look of the trail.

 

[Ann K]

Does anyone know what factors affect this? I'm assuming it's something to do with altitude and temperature, as altocumulus clouds are generally lower than cirrus.

You've left out humidity, which I think (opinion) would be the defining factor.

 

[Mendel]

You've left out humidity, which I think (opinion) would be the defining factor.

He did not.

RHw (Relative Humidity with respect to Water): The ratio of water vapor pressure in the air to the saturation vapor pressure over a flat surface of liquid water.
RHi (Relative Humidity with respect to Ice): The ratio of water vapor pressure in the air to the saturation vapor pressure over an ice surface.

Google AI (yes, I had to google it) actually cited Metabunk as source for this: https://www.metabunk.org/threads/calculator-for-rhi-and-contrail-persistence-criteria.7196/