Every 10 minutes we take the temperature, humidity and wind where airliners fly, work out what their trails should do, lock that prediction, and then check it against a weather satellite.
Some short, some lasting
based on 2 independent forecastsThe air is close to the line where trails start to last, or the weather sources disagree.
Peak humidity at cruise height, measured against ice: 100%. Lasting trails need 100% or more. 1 plane(s) overhead in the last 10 minutes; 0 predicted to leave a lasting trail.
Not judged yet
Our satellite trail detector failed its accuracy test. On 223 satellite images where experts had marked every trail, it flagged 54% of images that had trails, but also 47% of images that had none, and only 12% of the lines it drew were real trails. To be used, it had to flag images with trails at least 30 points more often than images without, and at least 50% of its lines had to be real trails. It managed 7 points and 12%. So we are not using it to judge the sky until a detector that clears the bar replaces it.
Top row: what the measurements predicted for each hour. Bottom row: what the satellite saw. When the two rows agree, the sky behaved the way the physics says it should. The bottom row stays empty until the satellite detector passes its accuracy test.
This comparison starts once we have a trustworthy way to see the sky. The satellite detector we built did not pass its accuracy test, so it is not used here. The predictions above are made and locked every 10 minutes regardless, so when a better detector or our sky camera comes online, every hour from now on can be checked against what was predicted for it.
Contrails form around soot and sulfur from engine exhaust, so they are not pure ice. The question here is whether the air carries anything more. We compare EPA's own chemical tests of Dallas air (the Dallas Hinton monitor, one 24-hour sample every third day) on days when the measured upper air let trails last over the city with days when no trail could last. The plan was written down and confirmed in the Bitcoin blockchain before any chemistry was read, and the day labels come from weather data only.
No chemistry read yet. The program is waiting for Bitcoin to confirm the stamp of the plan, and for EPA's data key. Meanwhile it labels past days from the weather: so far 0 lasting-trail and 0 no-trail days.
What a result can and cannot show. Particles released at cruise height mostly take days to weeks to reach the ground and land spread over hundreds of miles, and about the same number of planes fly over Dallas every day: a lasting-trail day means the upper air let trails last, not that more planes flew. A finding would mean more of a metal at ground level after lasting-trail weather than after dry weather, beyond what dust, rain, wind and season explain, and it must also pass a fake-date check (the same test with labels taken from a week or two later, which cannot have caused anything). It would not by itself show where the metal came from. No finding would mean this monitor shows no such difference; it would not rule out releases whose fall-out lands elsewhere or is too small to measure.
Every number on this page comes from public instruments, and every rule is written down in advance.