Cloud seeding.

[kschachn]

oh wait, you somehow think that a turbofan/turbojet aircraft = a commercial airliner.
Who mentioned commercial airliners here?

Something other than a piston engine or turboprop aircraft.

Ones that typically leave contrails at high altitudes. Altitudes where the proper clouds for seeding do not form. That’s mostly what I’m stuck on here. Pictures of persistent contrails and then claiming this is some sort of weather modification.

 

[KrisZ]

Something other than a piston engine or turboprop aircraft.

Ones that typically leave contrails at high altitudes. Altitudes where the proper clouds for seeding do not form. That’s mostly what I’m stuck on here. Pictures of persistent contrails and then claiming this is some sort of weather modification.

I thought it was a mystery. Those are some very specific details for a mystery

 

[Astro14]

I think we are confusing cloud seeding* with chemtrails.

Chemtrails are conspiracy theory catnip.

Contrails are not chemtrails, they're the ice crystals left behind when the water vapor produced by combustion freezes.

The math varies slightly, depending on the exact mix in the fuel, but roughly, kerosene is C12H26−C15H32.

That is a lot of H to combine with the O in the atmosphere. It ends up being about a pound of water to a pound of burned fuel. So, lets use that. My current airplane is burning about 100lbs of fuel every minute. Some are more, some are less. But if each airplane is putting out 100lbs of what could be shock cooled into ice crystals every minute - you're going to see that.

I've talked about this enough. We used to find the level at which we formed contrails, and stay below that for tactical reasons. The atmosphere temperature and moisture content varies.

Contrails are common. How they form is well understood. How they dissipate depends on the atmospherics as well. When you spend your time up there, it becomes very familiar. Not one bit of what anyone has posted on this site looks "abnormal".

Imagine someone who has never ridden in a boat, commenting on how wakes vary, and how some of those wakes are "suspicous". Those folks who operate boats all the time are going to laugh and move on.


*Spreading nuclei like silver iodide, in existing clouds to try and increase the amount of rain those clouds produce. Which is totally different, done by a very different set of airplanes, at different altitudes than where contrails form.

 

[kschachn]

I think we are confusing cloud seeding* with chemtrails.

Chemtrails are conspiracy theory catnip.

Contrails are not chemtrails, they're the ice crystals left behind when the water vapor produced by combustion freezes.

The math varies slightly, depending on the exact mix in the fuel, but roughly, kerosene is C12H26−C15H32.

That is a lot of H to combine with the O in the atmosphere. It ends up being about a pound of water to a pound of burned fuel. So, lets use that. My current airplane is burning about 100lbs of fuel every minute. Some are more, some are less. But if each airplane is putting out 100lbs of what could be shock cooled into ice crystals every minute - you're going to see that.

I've talked about this enough. We used to find the level at which we formed contrails, and stay below that for tactical reasons. The atmosphere temperature and moisture content varies.

Contrails are common. How they form is well understood. How they dissipate depends on the atmospherics as well. When you spend your time up there, it becomes very familiar. Not one bit of what anyone has posted on this site looks "abnormal".

Imagine someone who has never ridden in a boat, commenting on how wakes vary, and how some of those wakes are "suspicous". Those folks who operate boats all the time are going to laugh and move on.


*Spreading nuclei like silver iodide, in existing clouds to try and increase the amount of rain those clouds produce.

So what altitude is cloud seeding done, and what type of aircraft are used? Do the aircraft that leave contrails perform cloud seeding (referencing the picture posted earlier and claiming weather modification)?

And I was just rattling your cage on chemtrails, of course. I mean I've seen the switches in a cockpit but I'm sure they are disconnected

 

[KrisZ]

So what altitude is cloud seeding done, and what type of aircraft are used? Do the aircraft that leave contrails perform cloud seeding (referencing the picture posted earlier and claiming weather modification)?

+1
And if large turbofan aircraft are used, can the seeding be confused with contrails?

 

[Astro14]

So what altitude is cloud seeding done, and what type of aircraft are used? Do the aircraft that leave contrails perform cloud seeding (referencing the picture posted earlier and claiming weather modification)?

And I was just rattling your cage on chemtrails, of course. I mean I've seen the switches in a cockpit but I'm sure they are disconnected

My understanding is that cloud seeding is done at lower (mid teens, to low 20s) altitudes. Contrails don't form down there. The moisture doesn't flash freeze into ice crystals. You're not going to get rain droplets forming in the temperatures where ice crystals form instantly. The air has to be a lot warmer. It's typical -60C at cruise altitude, where contrails are forming.

 

[Astro14]

+1
And if large turbofan aircraft are used, can the seeding be confused with contrails?

NO.

Because you cannot seed clear blue skies. It is too dry.

The seeding is done at low altitude, where it is warm enough to form rain drops. In clouds, where rain drops form. You won't see a cloud seeding operation from the ground.

 

[kschachn]

My understanding is that cloud seeding is done at lower (mid teens, to low 20s) altitudes. Contrails don't form down there. The moisture doesn't flash freeze into ice crystals. You're not going to get rain droplets forming in the temperatures where ice crystals form instantly. The air has to be a lot warmer. It's typical -60C at cruise altitude, where contrails are forming.

That makes sense to me. After all, isn't cloud seeding just providing a nucleation for the moisture to form into a droplet? I'd think the ice crystals would do the same if they were at the proper altitude.

 

[y_p_w]

Turbojet or turbofan? Outside of fighter jets I don’t think turbojet engines are used.

But why wouldn’t they used large turbofan aircraft? If you need a large area seeded, it would only make sense.

There are still a few civilian-operated aircraft with turbojets. Used to be real common in the 60s, especially with the 707 and similar aircraft. There are still some of these classic business jets.

Our Fleet - Sabreliner 65

The Sabreliner is not only an economical airplane to get you to your destination quickly with minimal cost, but it’s 8 passenger configuration allows ample.

www.americanaircharter.com

 

[MParr]

Chemtrails are conspiracy theory catnip.”

Yep.

 

[Exhaustgases]

In around 1971 I worked at an FBO that had a contract to "seed" the cloud's / fog at a major airport near by. They had charts that proved it worked, the materials used where highly hygroscopic it was sprayed out as a fine powder from a gas engine powered hopper unit inside the plane a DC-3, with distribution ducting, leading outside. I understand this sort of thing has been done way before we did it back then.

Contrails? Yes as a kid I got so mad when they disappeared so fast, as true contrails will do.
Never back in the late 1950's did the contrails turn into a cirriform type cloud like they do now.
Hmm remember LBJ's speech about controlling the weather?

Back in 1999 I remember working in construction outside and nice clear blue skys in the morning, then the contrail dusting began during the whole day, that included formation flying and even circles of contrails, that all turned into cirriform clouds as well as low level foggy haze. Many times the flights were maybe at 10,000 feet or so, the ambient temps at an altitude of 600 feet was in the 90's, we were working on a hill in the area.
Weather or geo engineering, cause something to fix something.

 

[StumblingElk]

The rumor among whom?

Cloud seeding doesn’t work.

But if a person already believes in chemtrails, well, then, that might make them susceptible to other conspiracy theories.

Cloud seeding is a thing. We've been developing its use for decades and is t a Pseudo science. Lol

Dubai does it on a regular basis, for instance.

 

[vavavroom]

I was subjected to a chemtrail in Aisle 7 at ACE yesterday. Some people!

 

[edhackett]

So what altitude is cloud seeding done, and what type of aircraft are used? Do the aircraft that leave contrails perform cloud seeding (referencing the picture posted earlier and claiming weather modification)?

Here's a link to the Desert Research Institute's cloud seeding program. There is much to learn there. The first picture is of the plane they used starting in 1966. They later used a B26(not the one pictured), which crashed and killed the cloud seeding crew in 1980, the year before I was hired at DRI. Aircraft seeding is done over the mountains in the clouds. It's very dangerous flying. After that they concentrated on ground generators and recently have successfully seeded using UAVs.

Cloud Seeding Program

DRI is science for a smarter Nevada and a smarter world.

www.dri.edu

Ed

 

[Astro14]

Cloud seeding is a thing. We've been developing its use for decades and is t a Pseudo science. Lol

Dubai does it on a regular basis, for instance.

They do it on a regular basis, but it is still not clear that it actually works. If you read the paper I linked earlier, the evidence of cloud seeding actually working is inconclusive.

If I lived in the desert, and needed rain, I might try it.

If I were a politician, in a desert community, and wanted my constituency to think I was doing a good job, I would be showing them how I supported it, because it looks like I am doing something for them.

Whether it works or not.

 

[kschachn]

Here's a link to the Desert Research Institute's cloud seeding program. There is much to learn there. The first picture is of the plane they used starting in 1966. They later used a B26(not the one pictured), which crashed and killed the cloud seeding crew in 1980, the year before I was hired at DRI. Aircraft seeding is done over the mountains in the clouds. It's very dangerous flying. After that they concentrated on ground generators and recently have successfully seeded using UAVs.

Cloud Seeding Program

DRI is science for a smarter Nevada and a smarter world.

www.dri.edu

Ed

Thanks for that, it is a good read. Especially this part:

Cloud Seeding Operations Criteria

DRI is science for a smarter Nevada and a smarter world.

www.dri.edu

 

[Astro14]

Thanks for that, it is a good read. Especially this part:

Cloud Seeding Operations Criteria

DRI is science for a smarter Nevada and a smarter world.

www.dri.edu

Ah, so they are seeding at the 700mb level - much lower than I had thought. Nominally, 10,000 feet.

Certainly far below where contrails are formed, and they are seeding in clouds, so, the seeding operation won’t be visible.

 

[StumblingElk]

They do it on a regular basis, but it is still not clear that it actually works. If you read the paper I linked earlier, the evidence of cloud seeding actually working is inconclusive.

If I lived in the desert, and needed rain, I might try it.

If I were a politician, in a desert community, and wanted my constituency to think I was doing a good job, I would be showing them how I supported it, because it looks like I am doing something for them.

Whether it works or not.

You were comparing a legitimate endeavor (cloud seeding) to kooky conspiracy theories. That was my point

 

[Astro14]

You were comparing a legitimate endeavor (cloud seeding) to kooky conspiracy theories. That was my point

That’s a good point. I wasn’t fair in how I said it. Cloud seeding may, or may not, work.

Problem for me, and everyone else reading this thread, is that cloud seeding has been conflated with some kind of atmospheric control, and so have contrails. I was objecting to the conspiracy theories that sprout up in threads discussing contrails, and cloud seeding, and link all three.

So, there are, in fact, three distinct subjects being discussed. Cloud seeding. Contrails. Secret government projects to control weather.

I’m not convinced the cloud seeding works, but I recognize that there are people doing it, for legitimate reasons.

I don’t think there are any government projects to control the weather - that is conspiracy theory. In the early parts of this thread, there were people stating that cloud seeding was a secret way of the government controlling the weather, the Russian parade example, as one.

Then people started pointing to contrails as evidence of that secret control.

So, contrails have nothing to do with cloud seeding, because the altitudes are so very different. Further, contrails do not support the espoused conspiracy theories.