TY  - CONF
AU  - Li, Yun
AU  - Mahnke, Christoph
AU  - Rohs, Susanne
AU  - Bundke, Ulrich
AU  - Spelten, Nicole
AU  - Dekoutsidis, Georgios
AU  - Groß, Silke
AU  - Voigt, Christian
AU  - Schumann, Ulrich
AU  - Petzold, Andreas
AU  - Krämer, Martina
TI  - Observational evidence of contrail cirrus in slightly ice-subsaturation
M1  - FZJ-2023-05681
PY  - 2023
AB  - Contrail cirrus, including line-shaped contrails, has a net warming effect on theEarth’s climate. Of great importance to estimate their radiative effect is the coverageand mean optical thickness, which are closely associated with the conditions affectingthe formation and microphysical properties of contrail cirrus.This study focuses on cirrus observations over central Europe and the NortheastAtlantic from the airborne ML-CIRRUS campaign in 2014. Contrail cirrus inthe cirrus dataset is identified using: (1) the Schmidt-Appleman-Criterion, whichdetermines whether the environmental conditions are suitable for contrail formation,(2) an aircraft plume detection algorithm that helps identify if a measured airmass originated from aircraft exhaust, and (3) statistical analysis that generates adescription of the general characteristics of contrail and natural cirrus.The microphysical properties (mass mean radius Rice, ice crystal number Nice andice water content IWC) of contrail cirrus and natural cirrus will be described in thiswork together with their occurrence conditions. The preferred atmospheric conditionsof contrail cirrus occurrence are identified. Of particular interest is the existence ofcontrail cirrus in slightly ice-subsaturated environments, where the relative humiditywith respect to ice (RHice) centres around 90 % instead of ice supersaturation, asbelieved hitherto. This also differs from 100 % RHice in natural cirrus. Inspectingthe occurrence frequencies of air masses with RHice > 90 % compared to RHice >100 % from passenger aircraft observations above Europe and the North Atlanticduring the IAGOS-MOZAIC period from 1995 to 2010, about 43 % of the air massesare prone to contrail cirrus formation instead of 32 % found in ice-supersaturatedenvironments. Our findings imply that the avoidance of slight ice-subsaturation to ice-supersaturation at cruising altitudes might further reduce the occurrence of contrailcirrus, thus diminishing the climate impact of contrail cirrus.
T2  - Workshop "Clouds Containing Ice Particles"
CY  - 23 Jul 2023 - 26 Jul 2023, Mainz (Germany)
Y2  - 23 Jul 2023 - 26 Jul 2023
M2  - Mainz, Germany
LB  - PUB:(DE-HGF)6
UR  - https://juser.fz-juelich.de/record/1019850
ER  -