Aircraft condensation trails (contrails) over South Kensington

ContrailMIP

ContrailMIP is an international effort dedicated to the intercomparison of contrail models spanning scales from plume-scale processes to global climate impacts. Its findings will drive improved assessments of aviation climate impacts and mitigation strategies.

Get involved with ContrailMIP

What is ContrailMIP and why is it necessary?

Aviation condensation trails (contrails) are recognised as an important contributor to aviation's climate impact. Current evidence indicates that their overall effect is net warming, although the magnitude of this effect remains highly uncertain. Estimates of contrail climate impact vary substantially across modelling studies, reflecting differences in the representation of contrail processes, atmospheric conditions, and climate interactions.

The contrail model intercomparison project (ContrailMIP) addresses this challenge through coordinated model intercomparison, providing a systematic framework for understanding uncertainty and improving the scientific basis of contrail climate assessments.

ContrailMIP welcomes participants (learn more at Participate in ContrailMIP) and support from organisations (learn more at Support ContrailMIP).

ContrailMIP Objectives and Approach

1. Establish Common Benchmarks

 

Develop a shared framework for model evaluation through common protocols, benchmark cases, and simulation scenarios. This enables consistent comparisons across modelling approaches and scales.

 

2. Quantify Modelling Uncertainty

 

Conduct coordinated intercomparison experiments to assess disagreement between models. These comparisons provide a systematic assessment of modelling uncertainty in estimates of contrail properties, evolution, and climate impacts.

 

3. Explain Model Differences

 

Identify the physical processes, assumptions, and parameterisations that drive differences between model results. This helps determine why models produce different assessments of contrail optical properties and climate impacts.

 

4. Build a Community Standard

 

Create an open, community-driven framework for contrail model intercomparison. Publishing protocols and results will establish a lasting resource for the international research community.

 

From Contrail Formation to Climate Impact

 

ContrailMIP is organised around four scientific themes that address contrail evolution from formation behind the aircraft through to global-scale climate impacts. By comparing models at each stage, ContrailMIP seeks to understand how physical processes, model assumptions, and scale-dependent representations influence estimates of contrail climate impact and their underlying modelling uncertainties.

This effort is delivered through four Working Groups, each focused on a key stage of contrail evolution:

  • Early Plume (WG1): Contrail formation immediately behind the aircraft, including the microphysical and dynamical processes that determine initial ice crystal properties.
  • Vortex Phase (WG2): The evolution of contrails within aircraft wake vortices, including ice crystal losses and the development of contrail structure.
  • Single Plume Scale (WG3): The growth, persistence, spreading, and radiative effects of individual contrails under different atmospheric conditions.
  • Global Scale (WG4): The representation of contrails in global climate models and their contribution to aviation climate impacts.

Select a tab below to learn more about the scientific objectives, key challenges, and leadership of each Working Group.

WGTabs

Early Plume (WG1)

Early Plume (Jet) Working Group (WG1)

 

Co-chairs: Dr. Fangqun Yu, Dr. Nicolas Bonne

Key concern

Contrail formation during the jet phase is governed by a complex interaction between microphysics and fluid dynamics. The Working Group seeks to understand how factors such as fuel composition, engine design, and aircraft and meteorological conditions influence the formation of ice crystals immediately behind an aircraft.

Objective

Determine how these processes interact to influence the number, size distribution, and, where possible, origin of the ice crystal nuclei at the end of the jet phase. These properties provide the initial conditions for all subsequent stages of contrail evolution.

Participation and contact

Visit Participate in ContrailMIP for more details regarding participation, and visit Key Contacts for more details on how to get in touch with the Working Group chairs.

Vortex Phase (WG2)

Vortex Phase Working Group (WG2)

 

Co-chairs: Dr. Roberto Paoli, Dr. Simon Unterstrasser

Key concern

During the vortex phase, contrail evolution is strongly influenced by the initial ice crystal number, aircraft wake dynamics, and atmospheric stability. Understanding how these processes affect the ice crystal survival fraction and eventual structure of the contrail is essential for predicting its subsequent evolution.

Objective

Determine how initial ice crystal properties, atmospheric stability, and aircraft characteristics influence the number, size distribution, and spatial extent of ice crystals at the end of the vortex phase.

Participation and contact

Visit Participate in ContrailMIP for more details regarding participation, and visit Key Contacts for more details on how to get in touch with the Working Group chairs.

Single Plume Scale (WG3)

Single Plume Scale Working Group  (WG3)

 

Co-chairs: Prof. Manuel Soler, Dr. Sebastian Eastham

Key concern

Following vortex breakdown, contrail evolution is governed by processes including sedimentation, wind shear, the humidity distribution in the atmosphere, and synoptic-scale vertical motion. The Working Group focuses on understanding how initial contrail properties and atmospheric conditions influence a contrail's lifetime and radiative impact.

Objective

This working group conducts two complementary intercomparisons. The first assesses the degree to which plume-scale models produce different estimates of contrail ice properties under common initial and boundary conditions, and seeks to identify the modelling choices responsible for these differences. The second evaluates the degree to which different radiative transfer methodologies lead to differences in estimates of the instantaneous radiative forcing of the resulting ice crystal distributions.

Participation and contact

Visit Participate in ContrailMIP for more details regarding participation, and visit Key Contacts for more details on how to get in touch with the Working Group chairs.

Global Scale (WG4)

Global Scale Working Group (WG4)

 

Co-chairs: Dr. Ulrike Burkhardt, Dr. Alexandru Rap, Prof. Nicolas Bellouin

Key concern

Global models can produce substantially different estimates of contrail climate impact, but the causes of these differences remain poorly quantified. Potential explanations include differences in aviation emissions, the representation of contrail formation and evolution, and the treatment of climate feedbacks.

Objective

Determine how estimates of the net contrail climate effect differ between global climate models when common inputs and simulation protocols are applied. This comparison will help identify the processes and assumptions responsible for differences in estimates of contrail radiative forcing and climate impact.

Participation and contact

Visit Participate in ContrailMIP for more details regarding participation, and visit Key Contacts for more details on how to get in touch with the Working Group chairs.

Frequently Asked Questions

Who can participate?

ContrailMIP welcomes researchers working on contrail modelling, atmospheric processes, aviation systems, and climate impact assessment.

Learn more at Participate in ContrailMIP.

Can I participate without performing experiments?

Yes. Researchers unable to perform experiments can participate through data analysis, scientific assessment, protocol development, publications, and working group activities.

Learn more at Participate in ContrailMIP.

Can I participate in multiple Working Groups?

Yes. Many research topics span multiple stages of contrail evolution, and participants are welcome to engage with more than one Working Group where appropriate.

Learn more at Participate in ContrailMIP.

How can my organisation support ContrailMIP?

Organisations can support ContrailMIP through financial support, computational resources, workshop sponsorship, and research partnerships. In addition, supporting organisations join the ContrailMIP Stakeholder Board, which provides regular updates on scientific developments, emerging findings, and project activities. Learn more at Support ContrailMIP.

Organisations interested in supporting ContrailMIP or joining the Stakeholder Board are encouraged to contact the Steering Committee.

How do I get involved?

Researchers interested in participating should contact the chairs of the Working Group most closely aligned with their expertise. Learn more at Participate in ContrailMIP.

Organisations interested in supporting ContrailMIP should contact the Steering Committee. Learn more at Support ContrailMIP.