Contrail detection on SEVIRI images and 1-year study of their physical properties and the atmospheric conditions favoring their formation over Europe

Kurzfassung

Condensation trails (contrails) from aircraft exhausts and contrail cirrus clouds play a significant role in the atmosphere's radiation balance and the climate. The aim of this study is to analyse the physical properties of contrails with the use of satellite data and determine the atmospheric conditions favoring their formation and persistence. The contrails are detected on satellite images provided by the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) radiometer onboard the Meteosat Second Generation (MSG) satellites, using a modified version of the contrail detection algorithm by Mannstein et al. Int J Remote Sens 20(8):1641-1660. (1999) for the year 2016. The study area covers central and western Europe. Five contrail detection hotspots are located, with contrail density depending on time of day and season. The length of the detected contrails ranges between 225 and 292.5 km and the mean width between 5.1 and 8.1 km. The spatial contrail cover reaches up to 0.085% of the scene, with larger values being detected between 8 and 10 UTC and during winter. Results of the comparison with the ERA-5 reanalysis database show that contrail formation and persistence is favored in ice saturated areas (RHI=~100%), when the air temperature is between 204 and 232 K (- 69.2 to - 41.2 °C) and the specific humidity between 0.025 and 0.0625 g/kg. The favorable wind direction and speed lie between W and SW (240-300°) and 10 and 30 m/s, respectively.