Effects of the sun on the armored combat

[edgars]

Hello!

In almost two years of frequently visiting this board, i cannot remember seeing this topic discussed. If it was, please point me to that particular thread.

Anyways, i was watching some "popular" Discovery programm about WWII air combat, and the narrator reminded about the advantage of the plane having the sun behind it, when attacking the other plane, which got me thinking about the armored combat in relation to this.

My question is, to what extent sunlight affected the armored combat? It seems that the tank with sun behind it has significant advantages in spotting enemy unit (say, due to sun glare from the optics of enemy tank) and remaining unspotted itself (due to high contrast between sky and earth).

Imagine, that in CM, in a dawn scenario (supposedly the sky is clear), the Allied units have a hard time spotting that single AT gun, which is harrasing them, because the sun is shining in their eyes, and they simply cannot make it out from the dark forrested background.

Could (and should) the effects of the sun be modelled in the engine rewrite (i suppose that is earliest chance of seeing that)? The effect would be terminal in the dusk and dawn scenarios, when the sun is low, but it would require separate dawn and dusk scenarios, for obvious reasons.

As i'm thinking of this, the tank with sun behind it, would keep its advantages only if it had some dark background (forrest, hill) behind it, which might not be the case in the steppes...

Any historical insights, comments?

[M Hofbauer]

effects of sun on armor combat:

1. there's this famous propaganda reel of the Afrika Korps, showing a tank crew doing fried eggs on the armor plate of their tank. but actually it was staged, and they had "helped" the sun by heating up the plate additionally with a blowtorch before the picture shoot.

2. sunshine means improvement of general visibility which vastly affects range estimation. in full sunshine objects seem nearer which means gunners might be led to shoot short of the target (vice versa for poor visibility during overcast, rain etc.)

edit: w/r/t your thesis, yes, sun glare definitely impacts sighting and gunnery. the problem is not as big as in aerial com,bat since ground combat takes oplace on a more 2D-plane, so the sun blind spot issue is mostly a problem in late (mostly summer) afternoons, with a low yet intense sun in the east. morning phase also a problem, but probably less, since early morning fog etc. dampens the sun's strength during the morning low-sun-phase (if I may coin that term). all this "sun-blindness" is not modeled in CM, though. (general visibility is modeled for spotting issues, though)

[ August 11, 2002, 07:20 AM: Message edited by: M Hofbauer ]

[Michael Emrys]

Referring to the Afrika Korps again, I have read that they often timed their attacks so as to have the sun behind them. I have only rarely heard of other situations where this was done. I think in the European environment reliably clear skies at either sunrise or sunset were a rarity.

It definitely makes spotting more difficult when looking into the sun's glare. But I expect that having the sun at your back is no help in spotting compared to off to the side or directly overhead. The reason is that the human eye/brain relies on shading to assist in form recognition and when the light source is directly behind you, the lighting is too flat to render shading.

Michael

[Olle Petersson]

Don't forget the effect of shadow!

With sunshine just about anything in shadow become nearly invisible from anyone outside that shadow, LOS or not.

This became very clear to me when a friend dressed in a bright yellow sweater was standing inside a patch of trees. He stood about five metres in, and I sat some 15 metres outside.

There were no interviening bushes or low branches, but I still couldn't see him.

My eyes adapted to the bright light in front of the trees, so everything in shadow was black.

Cheers

Olle

[Michael Emrys]

Yes, this is one reason why looking into the sun can make it so hard. The bright light make your irises close down and anything darker (which is practically everything) is much harder to spot.

Michael

[Michael Dorosh]

Originally posted by Michael emrys:

[QB]Referring to the Afrika Korps again, I have read that they often timed their attacks so as to have the sun behind them. I have only rarely heard of other situations where this was done. I think in the European environment reliably clear skies at either sunrise or sunset were a rarity.

The desert is flat, and in Europe there is more clutter on the horizon - blocking the sun. In the desert, the sun would be directly in the enemy's face while on the horizon, since it would be closer to the ground than in Europe.

Ugh, I stated that lousily, but hopefully you see what I mean.

[russellmz]

the heat caused by the sun causes the image of a tank far off to appear higher or lower than it actually is. something to do with the rising heat causing the light rays to bend slightly up or down when before it hits the eye.

i saw on tv they set up a reference wooden post close to the camera and far off a parked tank. as the sun rose and set during the day the tank appeared to be lower or higher than it actually was.

[Captain Wacky]

Copius amounts of squinting, making everything look green when you go inside, and if that Tiger on the horizon doesn't get you first, the melanoma surely will twenty years down the road.

[Michael Emrys]

Originally posted by Michael Dorosh:

</font><blockquote>quote:</font><hr />Originally posted by Michael emrys:

[QB]Referring to the Afrika Korps again, I have read that they often timed their attacks so as to have the sun behind them. I have only rarely heard of other situations where this was done. I think in the European environment reliably clear skies at either sunrise or sunset were a rarity.

The desert is flat, and in Europe there is more clutter on the horizon - blocking the sun. In the desert, the sun would be directly in the enemy's face while on the horizon, since it would be closer to the ground than in Europe.

Ugh, I stated that lousily, but hopefully you see what I mean.</font>

[Dirtweasle]

Originally posted by M Hofbauer:

effects of sun on armor combat:

...so the sun blind spot issue is mostly a problem in late (mostly summer) afternoons, with a low yet intense sun in the east.

How's that? I've noticed the sun to be in the West all late afternoons.

[YankeeDog]

Originally posted by russellmz:

the heat caused by the sun causes the image of a tank far off to appear higher or lower than it actually is. something to do with the rising heat causing the light rays to bend slightly up or down when before it hits the eye.

i saw on tv they set up a reference wooden post close to the camera and far off a parked tank. as the sun rose and set during the day the tank appeared to be lower or higher than it actually was.

Yep. This is caused by temperature inversion. Basically, radiation from the sun hits the ground and makes it heat up. Some of this heat is transferred to the air near the ground. As a result, the air very close the the ground is actually hotter than the air just above it. Different temperature = different density. As you'll recall from high-school physics, light waves bend (refract), or sometimes bounce (reflect) when they pass through the boundary of two materials of differing densities. IOW, it's not the 'rising' heat that causes the effect per se, it's the fact that the air close to the ground is acutally considerably hotter than the air a few feet above the ground.

The same thing causes the desert mirage, which is actually a reflection of the sky off of the hot layer of air near the desert surface.

I imagine that this could really mess up long-range targeting sometimes.

Cheers,

YD

[tools4fools]

Originally posted by Dirtweasle:

</font><blockquote>quote:</font><hr />Originally posted by M Hofbauer:

effects of sun on armor combat:

...so the sun blind spot issue is mostly a problem in late (mostly summer) afternoons, with a low yet intense sun in the east.

How's that? I've noticed the sun to be in the West all late afternoons. </font>

[Dirtweasle]

Originally posted by tools4fools:

</font><blockquote>quote:</font><hr />Originally posted by Dirtweasle:

</font><blockquote>quote:</font><hr />Originally posted by M Hofbauer:

effects of sun on armor combat:

...so the sun blind spot issue is mostly a problem in late (mostly summer) afternoons, with a low yet intense sun in the east.

How's that? I've noticed the sun to be in the West all late afternoons. </font>

[Harry Yeide]

"It is criminal of our High Command to order attacks at daylight without considering how the early morning sunlight may affect our gunnery. The problem of the sun in our eyes must certainly be evaluated since it gives an unalterable advantge to the enemy." Maj. Gen. Orlando Ward, quoted in "Notes of Major General Bradley on Visit to 1st Armored Division," attached to memorandum AG 370-Y, "Notes on Operations of 1st Armored Division," 2 April 1943.

Note that the Americans were inevitably attacking eastward at dawn. I have never seen complaint like this regarding Europe, however.

Cheers,

Harry

[Bruno Weiss]

YankeeDog wrote:

This is caused by temperature inversion. Basically, radiation from the sun hits the ground and makes it heat up. Some of this heat is transferred to the air near the ground. As a result, the air very close the the ground is actually hotter than the air just above it. Different temperature = different density. As you'll recall from high-school physics, light waves bend (refract), or sometimes bounce (reflect) when they pass through the boundary of two materials of differing densities. IOW, it's not the 'rising' heat that causes the effect per se, it's the fact that the air close to the ground is acutally considerably hotter than the air a few feet above the ground.

Ah I bet you got that off the Weather Channel.

[YankeeDog]

Originally posted by Bruno Weiss:

Ah I bet you got that off the Weather Channel.

*ahem* I am sure my sources would prefer to remain anonymous. . .

Just call me the weather grog.

[edgars]

Originally posted by Michael Dorosh:

The desert is flat, and in Europe there is more clutter on the horizon - blocking the sun. In the desert, the sun would be directly in the enemy's face while on the horizon, since it would be closer to the ground than in Europe.

Steppes of Russia and Ukraine?

[Michael Emrys]

Originally posted by ciks:

</font><blockquote>quote:</font><hr />Originally posted by Michael Dorosh:

The desert is flat, and in Europe there is more clutter on the horizon - blocking the sun. In the desert, the sun would be directly in the enemy's face while on the horizon, since it would be closer to the ground than in Europe.

Steppes of Russia and Ukraine?</font>

[edgars]

So, basicaly, you all seem to agree that the effect is too miniscule (given the "european terrain") and/or too undeterminable to be programmed into CMx?

(I would appreciate some more historical quotes, if someone could post them.)

[Ozzy]

Originally posted by ciks:

So, basicaly, you all seem to agree that the effect is too miniscule (given the "european terrain") and/or too undeterminable to be programmed into CMx?

(I would appreciate some more historical quotes, if someone could post them.)

I can't give you historical quotes, but I live in Europe since my mom thought it was a good idea to bear me

In usual European terrain with woods, slopes, steppes, etc. I would say the effect is neclegtible except for two conditions:

- late summer/fall afternoons with bright sun deep in the west - horrible if you drive in car (and I assume not much better in a tank)

- on larger snow-/icefields. I'd say that the low sun elevation, the immense diffuse reflection of the sunlight and the reduced contrast ground/sky (grey/white) would make it a tremendous advantage having the sun in your back.

[tools4fools]

Originally posted by Dirtweasle:

</font><blockquote>quote:</font><hr />Originally posted by tools4fools:

</font><blockquote>quote:</font><hr />Originally posted by Dirtweasle:

</font><blockquote>quote:</font><hr />Originally posted by M Hofbauer:

effects of sun on armor combat:

...so the sun blind spot issue is mostly a problem in late (mostly summer) afternoons, with a low yet intense sun in the east.

How's that? I've noticed the sun to be in the West all late afternoons. </font>

[Firefly]

I'd say that it depends on latitude and time of year. In Norhern Europe the sun is quite low in the sky in winter, so it's possible to have the sun in your eyes when looking straight ahead on a sunny winter day. Of course it's more likely to be foggy, raining or snowing.

The problem in North Africa wasn't so much the sun, but that the activity of battle would whip up a sand storm, which would reduce visibility considerably. In winter this was added to by strong winds, rain or mist.

[Pak40]

Originally posted by Olle Petersson:

Don't forget the effect of shadow!

With sunshine just about anything in shadow become nearly invisible from anyone outside that shadow, LOS or not.

Very true. If you're in the middle of a field on a sunny day, a tree line 200 meters away will have a very strong shadow. Due to the brightness around you, your eyes will not be able to adjust to see much of anything in the tree line.

However, on a cloudy day that same tree line will be much clearer.

[tar]

There is one other effect that I haven't seen mentioned so far in this thread: silouhetting. Men and especially vehicles that come over a backlit ridgeline will make especially wonderful targets, so you need to be careful when the sun is behind you.

[Michael Emrys]

Silhouetting is certainly important and the reason troops and vehicles tried to stay below the military crest. Seen against a bright sky (and even a starlit sky is bright compared to the earth), units are much easier to spot and identify, especially if they are moving. However, units with the sun close to directly behind them will not be silhouetted, but instead lost in the glare. There's a fine line there, and I don't know if it is worth the computer power to include it in the game, but it could and did have effects in real life.

Michael