Simulating Atmospheric Refraction

Hi Mick,
If I give you or link to a couple transparent PNG images, could you add a preset to the list in the refraction simulator? I can give you the details (sizes/distances) for scaling.
What I'd like to be able to do is simulate various atmospheric conditions for the scenario in a recent YouTube series I've been doing:


I can sort of make it work using one of the Hillhouse/Habitat presets, but I'd like to be able to change temperature profile up to around 300 ft or even more. (Not so great that I can't make fine tune lapse rates over short spans near the water.)

If you don't have time or just don't want to deal with special requests, no problem. Just thought I'd ask. I have a notion for a YouTube presentation and was thinking I could use your simulator to demonstrate.

Ask me again next week! I'm off to AlienCon this weekend.
 
I forgot all about following up on the request just above, but I've got another one that's probably easier (or maybe not).
I'm struggling with the simulator to get it to produce an inferior mirage similar to an observation. I'm looking at video shot over pretty calm water with the camera just around 10cm from the surface of the water. The subject is a group of kayakers that the videographer says were about 350 meters away. At that short distance, it really should matter whether the surface is flat or curved. The difference is so small.

There's a pretty good inferior mirage of the kayakers in the video clip. When I try to replicate this scenario using the refraction simulator, all I can do is produce a "sinking" effect. I tried using some of the preset scenarios, like the Bedford Level: Wallace preset, and then just modifying the Man in the Boat image settings and camera settings to match. I've tried some pretty extreme temperature profiles down in that lower few tens of centimeters, but can't seem to make the inferior mirage appear.

What might I be missing or misunderstanding?
 
There's a pretty good inferior mirage of the kayakers in the video clip. When I try to replicate this scenario using the refraction simulator, all I can do is produce a "sinking" effect. I tried using some of the preset scenarios, like the Bedford Level: Wallace preset, and then just modifying the Man in the Boat image settings and camera settings to match. I've tried some pretty extreme temperature profiles down in that lower few tens of centimeters, but can't seem to make the inferior mirage appear.

2023-04-21_04-26-19.jpg
Something like this. It's a bit fiddly with the smaller numbers.
 
That's better than what I was able to get. It's still strange though, since instead of a wider band of inverted image, there's a very narrow region that is inverted and the rest is stretched, culminating in a return to upright (but sunken) near the apparent water line.

I'll keep playing with it.
 
I think perhaps the boundary in this real-world case is very abrupt. the sim was more set up for longer distance observations. Adding a point might help.

Also 350m seems like too short of a distance.
culminating in a return to upright (but sunken) near the apparent water line.
I don't really see that. Can you point out an example?

You might see things clearer (in terms of what is being reflected) using the Andy Young Inferior preset:
https://www.metabunk.org/refraction/?~(p~'Andy*2fWalter*20Inferior)_
2023-04-21_08-26-48.jpg
The black target with the RGB text was intended to help visualize the reflection.
 
You mean 350m might be too short a distance for the simulation? Or too short a distance estimate to the kayakers?

The effect I’m trying to replicate is the inverted section of the kayakers. What I’m hoping to find is a correlation between that inferior mirage below the “fold” region and any angular displacement downward of the upright image above the mirage.

The simulator pulls the imagery down before I can get a “mirroring” effect, and the mirroring is more a stretching in the sim rendering than what we see in the video.

Even the near target in the Andrew Young target doesn’t exhibit mirage, but rather just a warping.

I can’t figure out how to replicate the kind of short range mirage seen in the video, which is very common. A section of object is duplicated and flipped, appearing below the upright section (below which the rest of ghe target is lost to sight, replaced by mirage.) But below the inverted section, where the mirage effect dissipates, we see water or surface again. We dont see the bottom of the kayaks, upright again, which is what I get with the simulator. It’s hard, even, to get the inverted image without an excessive amount of stretching distortion.

I suspect it may be the granularity of the thermal profile. I dont know.
 
You mean 350m might be too short a distance for the simulation? Or too short a distance estimate to the kayakers?
Maybe both.

I suspect it may be the granularity of the thermal profile. I dont know.
Yeah, since it was made in the context of flat earth, it was mostly about long distance observations as the curve is irrelevant over short distances. The common "wet road" inferior mirage can happen at very small distances, and will have a large vertical temperature change over just a few cm above the road (or water) surface. So you'd need to make the elbow quite abrupt.

The sim lacks the ability to change the range of the graphs, but you can fudge it by clicking on "PERMALINK", and then editing the URL that is generated. Like this one:

Code:
https://www.metabunk.org/refraction/?~(profile~(~21.842~0~18.163~0.909~9.316~1.483~9.359~-0.622~12.48~329.084~12.48~329.084)~side~(~21~0.5~60~30)~profileRH~(~66.258~0~58.282~8.31~50~24.725~50.0187506~15.255)~useRefraction~true~useStandard~false~showGraphRI~false~useFlat~false~useNarrow~false~useNight~false~showSideView~true~showSideGradient~true~showSideImages~false~useDebug~false~useLensView~false~showEyeLevel~false~showGeoHorizon~false~useEditRH~false~sideZoom~1~sideZoomEnable~false~visibility~10~visibilityEnable~false~useLasers~false~lasers~(~(height~5~angle~0~flip~false~color~%27*2300ff00~diameter~%272~power~100~div~1~name~%27Laser*201~offset~0))~vFOV~0.027072886662092~tilt~0.0008726646259971648~showEveryLines~10~viewerHeight~1.6~viewerOffset~10.889999999999999~minX~8.5~maxX~22.5~minY~-10~maxY~30~RH~50~wavelength~550~computedParams~false~windows~(w~1920~h~944~side~(~393.59375~4.71875~672~378)~rh~(~1497.5859375~0~384~472)~temp~(~393.59375~396.4765625~384~472)~render~(~384~0~1536~944)~info~(~1234.40625~4.71875~672~378))~name~%27Andy*2fWalter*20Inferior~src~%27AndyYoungTargetAlphaRGB.png*2cAndyYoungTargetAlphaRY.png~targets~(~(distance~1161.6~height~9.84252~name~%272km~offset~10~multiple~0~gap~0~altitude~0)~(distance~2737.152~height~9.84252~name~%273km~image~1~offset~11~altitude~0~multiple~0~gap~0)~(distance~2587.2~height~9.84252~name~%274km~offset~20~altitude~0~multiple~0~gap~0)~(distance~6623.232000000001~height~9.84252~name~%275km~image~1~offset~30~altitude~0~multiple~0~gap~0)~(distance~3379.2000000000007~height~9.84252~name~%277.5km~offset~45~altitude~0~multiple~0~gap~0)~(distance~3212.3520000000003~height~9.84252~name~%2710km~image~1~offset~70~altitude~0~multiple~0~gap~0))~targetAltitude~0)_

There I've adjusted the preset for the temp gradient editor to ~minX~8.5~maxX~22.5
with a bit of fiddling around this gives us an inferior mirage at 0.22 miles (350m)
2023-04-21_16-24-33.jpg

Note that this needs a 10°C difference between water surface and upper air temperature. Did such conditions exist? Looking at the short sleeves and sunshine it seems hard to imagine such a temperature gradient.
 
^This is more like it. Thx. I’ll play around with that “hack” method later tonight or this weekend when I’m on my computer.
 
New request for refraction simulator (if possible and not too much trouble).

Can you create another preset, basically copying one of the Hillhouse/Habitat presets (any one) but inserting a temp/elevation profile that has a greater elevation and temperature range? Something more like what you have in the Visual Obstruction Calculator preset?
 
New request for refraction simulator (if possible and not too much trouble).

Can you create another preset, basically copying one of the Hillhouse/Habitat presets (any one) but inserting a temp/elevation profile that has a greater elevation and temperature range? Something more like what you have in the Visual Obstruction Calculator preset?
If you click on permalink, you can edit the minX and maxX for temperate and minY, maxY for altitude. For example: "~minX~-20~maxX~20~minY~-10~maxY~12000"
https://www.metabunk.org/refraction...e-f.png*3f*2chabitat-f.png~targetAltitude~0)_
 
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