Ruhr Smog - Pictures and Descriptions Wanted

In this case though we're dealing with potentially different types of particles and possibly a bit different behavior in terms of vertical distribution. Those potential differences and how they play out are something I'm fairly ignorant of. I'm pretty familiar with modern vehicle emission smog and how it looks from the air, though not to the extent that it makes visual navigation any harder. Typically you will have hazy visibility at low altitude that gradually tends to worsen somewhat as you climb, but it usually has a well defined more or less flat top caused by changes in the temperature gradient preventing continued rising of the air, and above that altitude visibility improves markedly.

What I have not seen is this kind of extremely heavy, mainly coal-produced kind of smog. The easy part is getting it to look thick and bad when you're in it. The more important part is to get how it looks when you are outside of the smoggy area and seeing it in the distance. How's the vertical distribution? Is there much noticeable variation in density in the smog when viewed over a large area, or is it uniform? What about the edges of the area? Is there a noticeable border, or not? That's what I don't currently have a handle on. I'm trying to find period pictures of daylight raids to these areas that might give some insight.
 
gecko said:
In this case though we're dealing with potentially different types of particles and possibly a bit different behavior in terms of vertical distribution. Those potential differences and how they play out are something I'm fairly ignorant of. I'm pretty familiar with modern vehicle emission smog and how it looks from the air, though not to the extent that it makes visual navigation any harder. Typically you will have hazy visibility at low altitude that gradually tends to worsen somewhat as you climb, but it usually has a well defined more or less flat top caused by changes in the temperature gradient preventing continued rising of the air, and above that altitude visibility improves markedly.

What I have not seen is this kind of extremely heavy, mainly coal-produced kind of smog. The easy part is getting it to look thick and bad when you're in it. The more important part is to get how it looks when you are outside of the smoggy area and seeing it in the distance. How's the vertical distribution? Is there much noticeable variation in density in the smog when viewed over a large area, or is it uniform? What about the edges of the area? Is there a noticeable border, or not? That's what I don't currently have a handle on. I'm trying to find period pictures of daylight raids to these areas that might give some insight.
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The problem is that WRT coal/industrial smog, not much around for quite a few decades in the West, but still plenty in India and China, even though mixed with vehicle pollution. The latter, unless trapped in a 'bowl, does seem to disperse re;natively quickly.
Have not found any really good high aerial pics from then.


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The Story of the Great Smog of London

From 5 to 9 December 1952, a thick, toxic smog blanketed London.
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British R26 airship flying over London, WW1 Stock Photo - Alamy

Download this stock image: British R26 airship flying over London, WW1 - DRHYRD from Alamy's library of millions of high resolution stock photos, illustrations and vectors.
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This more vehicular
www.gettyimages.com

'Toxic Charge' for older cars entering London's Congestion Charge...

'Toxic Charge' for older cars entering London's Congestion Charge Zone announced; 'Toxic Charge' for older cars entering London's Congestion Charge Zone announced; LIB / Smog clouds around City of...
www.gettyimages.com
 
Image Collections That Show Various Conditions

Typically tall stacks are attempting to inject their exhaust high enough to avoid having it trapped in the surface layer smog, and to provide wider dispersion of the particulates. The tallest stacks are only 1,300 ft, so individual chimney smoke columns over Essen would likely reach up to about 3,000 ft at most before clear air would predominate. The thickest smog layer would probably be limited to about 1,000 ft.

Looking down from above has much less impact than looking horizontally through smog because of the difference in distances you're see through. Local chimney smoke is completely opaque compared to the somewhat translucent area smog so the direction your seeing is from makes little difference.
 
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MajorMagee said:
Image Collections That Show Various Conditions

Typically tall stacks are attempting to inject their exhaust high enough to avoid having it trapped in the surface layer smog, and to provide wider dispersion of the particulates. The tallest stacks are only 1,300 ft, so individual chimney smoke columns over Essen would likely reach up to about 3,000 ft at most before clear air would predominate. The thickest smog layer would probably be limited to about 1,000 ft.

Looking down from above has much less impact than looking horizontally through smog because of the difference in distances you're see through. Local chimney smoke is completely opaque compared to the somewhat translucent area smog so the direction your seeing is from makes little difference.
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But one must take into account that nearly all homes in conurbations had coal or coke fires for heating, although there was coke gas as well, and these did not emit smoke from high chimney stacks. My parents' home in England had coke fired stove and hot water and water radiators, while the living room had a coal fire. Most English houses used water radiators, nothing like USA HVAC systems as we have here, although now many have electrically powered water or oil based radiators..
 
I just got back from a trip to LA where I experienced smog both at ground level and from the air. As we drove South, back toward the city from the desert, we literally drove into an wall of crud at the pass through the mountains (1/4 mile visibility). It was only as we got down closer to the valley floor that you could see any distance through the yellow-brown haze across the city (5 mile visibility). In this case it was a mixture of ocean moisture, fire smoke, and auto exhaust. As our flight took off we passed up through the layers of haze (2000 ft thick) and then the blanket of crud (500 ft thick) experiencing the same pattern of visibility looking out into the smog we had in the car coming down into the city. The difference was that in the airplane I could always look down and see the ground from any altitude. Clear air started at 2500 AGL. From that altitude and above it became impossible to look out and see where you were relative to various parts of the city or the coastline, but you could always look down and see a pattern of streets and houses below you. Only the pattern of mountains sticking up above the muck gave you any sense of where you actually were above LA.
 
MajorMagee said:
I just got back from a trip to LA where I experienced smog both at ground level and from the air. As we drove South, back toward the city from the desert, we literally drove into an wall of crud at the pass through the mountains (1/4 mile visibility). It was only as we got down closer to the valley floor that you could see any distance through the yellow-brown haze across the city (5 mile visibility). In this case it was a mixture of ocean moisture, fire smoke, and auto exhaust. As our flight took off we passed up through the layers of haze (2000 ft thick) and then the blanket of crud (500 ft thick) experiencing the same pattern of visibility looking out into the smog we had in the car coming down into the city. The difference was that in the airplane I could always look down and see the ground from any altitude. Clear air started at 2500 AGL. From that altitude and above it became impossible to look out and see where you were relative to various parts of the city or the coastline, but you could always look down and see a pattern of streets and houses below you. Only the pattern of mountains sticking up above the muck gave you any sense of where you actually were above LA.
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Any pics?
 
The challenge here is the thickness of the layer. If a layer has fairly even coverage, I can't make it thin. Currently I haven't gotten good results from a layer less than 8,000ft thick. Dropping it below ground level results in some pretty ugly clipping where the sprites go into the ground in the most opaque part of the texture. Smaller sprites produce a thinner layer, but it has a lot of gaps when viewed from above. And if you fill in the gaps with more sprites, FPS tanks.
 
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Yes, even the sandstorm version I was experimenting with initially has that issue. It's going to be even more difficult to avoid clipping if the city is up in the mountains. TextureMagic.ini has the function [HighAltSprite] that can be used to set visibility boundaries for cloud/effects textures. For example 100|900 would start to become visible at 100m and be full strength above 900m. If you then set the cloud MaxAltitude in the Weather file to 1000m (Min Altitude 100m) it will make the ground intersections less noticeable as long as the city is below about 200m (Clipping would be at 12.5% visibility at 200m). Unfortunately, it's based on Altitude Above Mean Sea Level (MSL), and not Altitude Above Ground Level (AGL). Perhaps AnKor could add the capability to limit cloud base levels by AGL? that would make this a universal solution, and not just for low lying areas.
 
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MajorMagee said:
Perhaps AnKor could add the capability to limit cloud base levels by AGL? that would make this a universal solution, and not just for low lying areas.
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That's not easy. I recall finding a way to get AGL altiude in CFS3 (found it while investigating a way to render grass), but it is not practical to use it for sprites - it will be too slow. Ideally such effects should be handled by shaders internally to avoid costly workarounds, but it is too late to add anything this complex.
 
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