Editing Openai/680a25f8-9f18-8004-a42d-cd36374ba000 (section)

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* Your Position: You’ve been investigating why contrails (the ice clouds left behind by planes) don’t persist in direct sunlight. Your model uses basic thermodynamics to calculate how ice crystals in contrails warm up from sunlight, which increases their vapor pressure and causes rapid sublimation (the process where solid ice turns into vapor). - The crystal’s temperature rises from about -50°C to -30°C (243 K) because it absorbs both solar radiation (mainly near-infrared light) and longwave radiation from the atmosphere. - At -30°C, the vapor pressure increases, and ambient humidity (RHi) needs to be extremely high—about 373%—to prevent sublimation. This is far above the typical levels seen in the atmosphere, which are usually around 140-160%, meaning sublimation will still occur very quickly (in ~1 second).

====== Stephen initially agreed with some aspects of your model but then disagreed with certain conclusions. He claimed that: ======
* The RHi value in contrail regions is often around 140–160%, which is high enough to prevent sublimation, or even cause deposition (ice growth).
* Microenvironments in contrail plumes can increase local humidity, allowing particles to survive longer.
* He also argued that your calculation overestimated the heating of ice crystals, claiming the temperature rise would only be a few degrees, not 20 K.