Satellite-observed contrail coverage over Europe and the North Atlantic in 2023

Geostationary satellite observations enable continuous monitoring of contrail coverage and its associated radiative effects, capturing their diurnal and seasonal variability over extensive spatial domains. In this work, we investigate linear contrails over the Euro--Atlantic region using Meteosat Second Generation (MSG) observations throughout 2023. Contrails are detected using a neural network trained on manually labeled satellite imagery, cloud properties are derived from MSG retrievals calibrated through an empirical linear regression model, and radiative forcing is estimated using radiative-transfer lookup tables. The results reveal contrasting regional diurnal patterns in contrail coverage, with two daily maxima over the North Atlantic and a dominant morning peak over continental Europe. Seasonally, coverage peaks in spring and decreases by $37%$ in summer, despite $16%$ higher cruise traffic. To quantify the associated radiative forcing, the proposed retrieval method estimates mean contrail cloud-top height, optical depth, and effective ice-crystal radius of 11.57~km, $0.309$, and 28.8~, respectively. The annual mean net forcing across contrail pixels is -1.4~W\,m⁻² during daytime and +32.7~W\,m⁻² at night, resulting in a coverage-weighted annual mean of $+2.85~[1.09$--6.21]~mW\,m⁻² over the study region. Atlantic waters account for approximately $78%$ of this warming, suggesting a disproportionate contribution from transatlantic traffic. Overall, the findings reveal substantial regional differences in satellite-observed contrail coverage and radiative forcing, motivating further investigation into the influence of atmospheric conditions and air traffic in the reported trends.