Physical processes analysis of contrails formation over the South Brazil Region

Contrails are clouds in the shape of condensation trails formed from hot air and particles exiting the engines of airplanes. These clouds form from the isobaric mixing of hot and humid air masses emitted by airplanes with cold ambient air. Their formation can alter the sky through cirrus clouds and the radiation balance. In this study, photographic images, satellite data and atmospheric reanalysis and radiosonde data were used to assess the occurrence of these events in the South Brazil region. The results showed that there were observed several cases of contrails in the region, mainly when the upper layer where the aircraft passed was colder and moister. Initially, several cases were selected from the observations and the Terra, Aqua and Suomi satellite images. Also, radiosonding data from Curitiba, Florianópolis and Porto Alegre were applied to the thermodynamic Appleman diagram to study the physical processes involved. The results showed that temperatures below -50 °C from cold advection and moister air at the cruising level of airplanes contribute to formation of more persistent contrails and cirrus clouds. Therefore, monitoring the environmental conditions may improve the prediction of contrails formation and better understanding the impacts on the radiation balance and climate.