Isn’t technology wonderful.
It gets dark and you can see everything if you fork out a couple of hundred notes for a decent Night or Thermal vision system.
Then along comes nature and screws it all up and once again I get to chuckle at high-tech.
Take night vision. We’re up to Gen 4 now, digital if memory serves me well. Crystal clear (but still in green) views of people like me stumbling around.
Only that’s not quite right is it, as night vision won’t see through fog, heavy rain, thick snow, or other obscurants like smoke.
Thermal however is brilliant (not).
It can see through plain old smoke and other obscurants, but not well through weather like driving snow or rain, or the thickest of fogs where it works, sort of, with a reduced range.
Only the chances of a user positively identifying friend or foe without a strobing IR IFF tag is remote.
The heat blob through a POS1 scope as an example.
IR strobes was something I picked up years ago and took it with me into deer stalking. Home made (as always), I had a simple clear IR LED pulsing at 5 beats a second. The idea was to let clients track me as I stalked in low light.
BUT it made me stand out on EVERYONE’S night vision.
Whoops, and the reason why IR strobes for IFF didn’t catch on in combat. Even worse, some wildlife were reacting to the IR.
I speak of mosquitoes and gad flies.
Ouch! It got so bad that I had a cloud of the little sods above my head waiting their turn to tuck in.
Defeating both is still easy though and some carry a pocket full of flares to ruin your night vision as you intently stare through the tube.
This is highly effective in fog, heavy rain, or snow as the light scatter from the flares is usually enough to swamp lesser grades of NV. Gen 0 to 2 for instance with 3-4 still unable to clearly differentiate targets if the flare is between them and you.
Note:- This might sound a bit ‘different’ but I found that those multi-shot fireworks very effective when poaching and being tracked.
The gamekeepers, farmers, and police couldn’t keep using NV and the intermittent stars and flashes ruined their natural night vision.
Plus, in the main, dogs don’t like whistles, shrieks, flashes, and bangs.
All in all about a minute of chaos to allow you to slip away.
Still back to fog and what other benefits has it when covering movement?
Sound attenuation. Yep, it does that only selectively.
Attenuation of sound waves in fog is all about the frequency, or pitch of the sound. The higher the pitch, the better the attenuation.
This is why fog horns have a very low pitch.
Now it’s not perfect but if you can dig a generator, radar or missile system, into the ground, it reduces scatter noise and it’s IR signature.
Right up until some jerk of a MOD weenie moved away from the humble IC engine and into small jet turbine powered ones. If the howl wasn’t loud enough, the expansive heat plume was spectacular on IR let alone Thermal.
Can you guess the weapon system I’m talking about??
Get close enough and you’d still be able to zero in on it.
Or if you have a dog, and they will lead you straight to it. Their hearing being way better than ours and you don’t need batteries.
Are there many types of fog?
You bet there are and in low lands it all depends on a low if nil wind speed. Fog forms when the difference between air temperature and dew point is generally less than 2.5 °C or 4 °F.
Now I had absolutely no idea that there were so many “official” types of fog.
Radiation (Winter) fog.
Clear cold night sky’s.
The ground chills down, the moisture condenses.
Rather than fog I tend to treat this like a heavy dew.
Valley or basin fog.
Think temperature inversion.
You have a cold basin of air and the wind blows warmer moisture laden air across it. It’s a bitch as unless the wind picks up a lot or the temperature increases (sunlight), it can last for days.
This is sort of the same thing without the need for valley’s or basins.
If you have snow cover which hasn’t melted, warm moisture laden air over it will chill down and drop its moisture. You also get this a lot at sea and (unfortunately) for those who live on or near water.
Is caused by cold air passing over warmer water or moist land.
Slightly different and again an inland boaters fog.
Warm river evaporating away and a cold wind over it causes the water laden moisture to condense. Thus is it possible to be on a river in fog, walk a couple of hundred yards in land and it’s gone. Your day starts damp and wet until the sun warms everything up.
Up slope fog.
That wind blowing across hills.
Warm air from below rises, it gets cold, it “rains”, or more accurately condensate.
Now here’s another a sort of fog.
High rise apartments and low altitude clouds.
Fog for the top few dwellings.
You paid all that money and all you see is damp grey. (Chuckle). Having said that it’s sort of useful for collecting water on drip clothes and nets but nearly always short-lived as the streets warm up, hot air rises and drives away the moisture laden air.
Composed of supercooled water droplets forms rime.
Fluffy soft ice that forms on all posts and lines on the windward side of things. I really hate this type of fog!
Personally I do love a good pea-souper.
Dulling noise, reducing visibility, making prey less jumpy for some reason. Like they feel safe wrapped up in the gloom I suppose.
As for foraging / scavenging. Even with IR supported CCTV security, fog is your friend. Only don’t forget some nice hot, bright, flares for when you get into the mire.
Low light and humans.
Humans are at a distinct disadvantage to many animals in low light conditions. Our eyes are more biased towards colour NOT extracting the maximum light from any scenario. I touched on animal vision and freely acknowledge that most wild life have stunning vision, just not in infinite colours, but where it matters, in low light.
|COLOR RELATIVE TO HUMANS
||ULTRAVIOLET AND GREEN
||ULTRAVIOLET, BLUE, YELLOW
||MOST SEE JUST TWO COLORS
||MOST SEE SOME COLOR
||SOME COLOR AND IR
||FIVE TO SEVEN COLORS
||POOR REDS GOOD GREENS, BLUES, UV, NO IR
||Poor colors BUT they own the night
|POOR REDS GOOD GREENS, BLUES plus UV
||BLUE AND GREEN
||POOR REDS GOOD GREENS, BLUES plus UV
||Different, NV GOOD
||BLUES AND YELLOWS
Yet it doesn’t stop there.
Gifted night vision is a given and they can detect movement (both slower and faster) better than us mere mortals. They can also pick out short (blue) and middle (green) wavelength colors, but they’re less sensitive to long wavelength colors such as red and orange.
Hang on though, less sensitive doesn’t mean they can’t see reds, it’s just they aren’t so prominent.
Plus White. Where would the world be without white?
Those eyes specially adapted for night work love white.
So either stop blinking, net up, or wear tinted glasses!
Or, as one expert put it, “In the main most animals are essentially red-green color blind,” BUT have good to excellent UV vision.
Which means, AVOID BLUE and ditch the denim jeans !
Blue is the perfect mirror for ultraviolet and as such you will stand out beautifully to a deer who also possess UV sensitivity.
Finally, do you wash your outer layers, your camouflage?
If you do you might also like to avoid using commercial washing liquids and powders. Some of them contain ultraviolet (UV) enhancers. How else can they claim their white is whiter than white!