What is the story behind the linear clouds in the sky of Tehran?
According to the Sedaye Sama News Agency, Sadegh Ziaeyan, head of the National Weather Forecasting Center of Iran’s Meteorological Organization, said regarding the linear clouds that appeared in Tehran’s sky today (Wednesday):
“These are the trails left by airplanes passing over Tehran.”
He explained: “This phenomenon depends on the vertical atmospheric profile. In other words, when the air temperature is such that the vapor produced by an aircraft turns into ice droplets, this kind of phenomenon occurs.”
He added: “When airplanes pass through the sky under conditions where the vertical atmospheric profile dominates — meaning the temperature in the lower atmospheric layers has dropped — a trail resembling linear clouds is formed.”
He further noted: “At other times, when airplanes fly at high altitudes, no visible trail remains.”
The head of the National Forecasting Center emphasized: “When the freezing level in the atmosphere drops, airplanes passing overhead cause this phenomenon. The white trail is actually from aircraft exhaust gases, which also contain water vapor. When this vapor encounters very cold air, it turns into ice crystals.”
