Do contrails affect the weather?

As a climate scientist with extensive research in the field of atmospheric physics, I can provide a comprehensive answer to your question regarding the impact of contrails on weather. Contrails, or condensation trails, are the long, thin, white clouds that form behind aircraft at high altitudes. They are formed when the hot, humid exhaust gases from an airplane's engines mix with the cold, dry air at high altitudes, leading to the condensation of water vapor into ice crystals.

Step 1: English Answer

Contrails can indeed have an impact on weather conditions, although the extent of this impact is a subject of ongoing scientific debate and research. To understand how contrails affect the weather, it is important to consider several factors, including their formation, properties, and interaction with the atmosphere.

### Formation and Persistence

Contrails form when the water vapor in the exhaust of an aircraft condenses and freezes at high altitudes, typically above 8 kilometers. The conditions required for contrail formation are quite specific, including low temperatures, high humidity, and the presence of aerosols that serve as condensation nuclei. When these conditions are met, contrails can form and persist for hours, potentially stretching across hundreds of kilometers.

### Impact on Temperature

One of the primary ways contrails can affect weather is through their impact on temperature. Contrails can act as a blanket, trapping heat from the Earth's surface and leading to a slight increase in temperature, a phenomenon known as the "contrail effect." This effect is most pronounced at night when the contrails are not being disrupted by sunlight. However, during the day, the contrails can also reflect sunlight back into space, leading to a cooling effect.

### Impact on Cloud Formation

Contrails can also influence cloud formation. The ice crystals in contrails can serve as nuclei for the condensation of water vapor, potentially leading to the formation of cirrus clouds. These clouds can then affect the Earth's radiation budget by reflecting sunlight and trapping heat. The overall impact of contrails on cloud formation is complex and depends on various factors, including the altitude, duration, and density of the contrails.

### Climate Change Considerations

The potential contribution of contrails to climate change is an area of significant concern. While contrails are short-lived compared to other forms of pollution, the large number of flights and the potential for contrails to induce cloud formation can lead to a significant impact on the Earth's climate. Some studies have suggested that contrails could contribute to a warming effect that is comparable to that of carbon dioxide emissions from aviation.

### Weather Forecasting

Regarding weather forecasting, contrails are not typically included in models due to the difficulty in predicting their formation and behavior. However, as noted by Carleton, "Weather forecasting of daytime highs and lows do not include contrails, but if they were included in areas of contrail outbreaks, they would improve the temperature forecasts." This suggests that incorporating contrails into weather models could lead to more accurate predictions, particularly in areas with high air traffic.

### Conclusion

In conclusion, contrails can affect weather by influencing temperature and cloud formation. While the exact extent of this impact is still being studied, it is clear that contrails have the potential to alter atmospheric conditions in ways that can impact weather patterns and climate change. As our understanding of these effects improves, it may become increasingly important to consider contrails in weather forecasting and climate models.

**

"Weather forecasting of daytime highs and lows do not include contrails," said Carleton. "If they were included in areas of contrail outbreaks, they would improve the temperature forecasts." Yes, contrails affect the weather. The vapour particles are nucleii for condensation of more water.Jun 25, 2015