Zero-dimensional contrail models could underpredict lifetime optical depth
File(s)
Published version
Author(s)
Akhtar Martinez, Caleb
Eastham, Sebastian D
Jarrett, Jerome P
Type
Journal Article
Abstract
Proposed contrail avoidance schemes rely on being able to robustly predict which contrails cause the most climate warming. However, it has not yet been shown that different contrail models agree sufficiently to support the targeting of individual contrails by climate impact. To address this, we compare the most widespread contrail model, the Contrail Cirrus Prediction (CoCiP), to a higher-fidelity contrail model, the Aircraft Plume Chemistry, Emissions, and Microphysics Model (APCEMM), under parameterized meteorological conditions. The results show that the time-integrated total extinction (a proxy for climate impact) in APCEMM is 3.8 times that in CoCiP and that the models have opposite sensitivities of their time-integrated total extinction to relative humidity. We argue that these differences are due to the differing representations of the distribution of ice particles in space and in size across the contrails. The use of a monodisperse ice particle size distribution in a Gaussian plume means that CoCiP models the contrail exclusively as an accelerating, falling mass. The use of a spatially gridded and size-resolved aerosol scheme allows APCEMM to represent the separation of the precipitation plume from the contrail core, hence modeling behavior beyond the initial phase in which the contrail grows unconstrained. This behavior is consistent with prior large-eddy simulation studies, and it accounts for 92 % of the aggregate APCEMM time-integrated total extinction across all simulations. This suggests that models lacking a size-resolved aerosol scheme may underestimate the time-integrated total extinction. While a strategy avoiding a given proportion of persistent contrails in an unbiased way is still expected to yield a proportional reduction in the time-integrated total extinction, implementing strategies using contrail models to select the specific contrails to avoid may lead to fewer reductions in the time-integrated total extinction, primarily due to the current level of disagreement between models. We therefore recommend more research to establish confidence in model predictions at later contrail ages.
Date Issued
2025-10-17
Date Acceptance
2025-08-22
Citation
Atmospheric Chemistry and Physics (ACP), 2025, 25 (20), pp.12875-12891
ISSN
1680-7316
Publisher
Copernicus Publications
Start Page
12875
End Page
12891
Journal / Book Title
Atmospheric Chemistry and Physics (ACP)
Volume
25
Issue
20
Copyright Statement
©Author(s) 2025. This work is distributed under the Creative Commons Attribution 4.0 License.
License URL
Subjects
Environmental Sciences
Environmental Sciences & Ecology
Life Sciences & Biomedicine
Meteorology & Atmospheric Sciences
NUMERICAL SIMULATIONS
PERSISTENT CONTRAILS
Physical Sciences
REGIONS
Science & Technology
TO-CIRRUS TRANSITION
Publication Status
Published
Date Publish Online
2025-10-17