Satellite observations of seasonality and long-term trends in cirrus cloud properties over Europe: investigation of possible aviation impacts

Abstract 2 emissions and flight densities in Europe. In this study, 10-year lidar measurements with CALIPSO are analysed to determine the seasonality and long-term trends in cirrus clouds as well as their correlations with the ambient temperatures and air traffic. The results show that there is a distinct seasonal cycle in the occurrence rates (ORs) and particle linear depolarization ratio (PLDR) of cirrus clouds. In addition, cirrus clouds appear within a broader altitude range in winter than in summer and they are characterized by larger OR and PLDR values in winter than in summer. The monthly medians of PLDR as well as their deseasonalized time series in the 10-year period before COVID-19 both show positive trends, which are statistically significant according to the Mann–Kendall (MK) significance test. However, the ORs of cirrus clouds show a negative trend, which might be connected with the background meteorological conditions. Since the cirrus PLDR strongly depends on the ambient temperatures, the contributions induced by temperature are further removed from the cirrus PLDR with a simple linear regression model. The derived residuals show significant positive trends according to the MK test. To compare the cirrus PLDR and air traffic (with the CO2 emissions from aviation as a proxy), the deseasonalization of both datasets were previously conducted since the seasonal cycles in both are not consistent. The deseasonalized time series determined for the cirrus PLDR and CO2 emissions from aviation both show increasing trends and their correlation coefficient is r = 0.54 at the confidence level above 99.5 %. Finally, comparisons between the cirrus PLDR and aviation in every season were made and revealed a strong correlation in other seasons than in summer.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Satellite observations of seasonality and long-term trends in cirrus cloud properties over Europe: investigation of possible aviation impacts ; volume:22 ; number:24 ; year:2022 ; pages:15963-15980 ; extent:18 ; Atmospheric chemistry and physics ; 22, Heft 24 (2022), 15963-15980 (gesamt 18)

Contributors, Places and Time

• Creator: Li, Qiang ; Groß, Silke

Further information

• DOI: 10.5194/acp-22-15963-2022
• URN: urn:nbn:de:101:1-2022122204175257661352
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:35 AM CEST