COntrails Spreading Into Cirrus (COSIC)

Lead Research Organisation: University of Manchester
Department Name: Earth Atmospheric and Env Sciences


BACKGROUND In the last fifty years aviation has experienced very rapid development, with air traffic recording an almost 9% yearly growth rate in the first half of the period (approximately 2.5 times the average GDP growth rate) and approximately 5% yearly growth rate in the second half of the period. According to the most recent estimates, aviation climatic impact amounts to 2-8% of the global radiative forcing associated with climate change. As a result of the expected increase in air traffic in the next decades, the relative importance of air traffic on climate change is expected to increase significantly. THE NEED FOR COSIC AND AIMS One of aviation's largest effects is likely to be that due to contrails and their spreading into cirrus. This could be considerably larger than the effects of increased CO2 emissions but this contrail-cirrus remains unquantified. Previous estimates of combined aviation induced cloudiness suggest that spreading contrails could be important. However, these studies rely on correlating air traffic with cirrus coverage and have large uncertainties and methodological problems. The ultimate aim of this proposal is, for the first time, to build a physically based parameterisation of contrail-cirrus - to determine its role in climate change, testing whether it has a larger role than line-shaped contrails. To achieve this ultimate goal, observations of contrail properties and their spreading will be made with FAAM (research aircraft) flights and satellite observations. Then a hierarchy of models will be used to develop a contrail-cirrus cloud parameterisation within the Met Office Unified Model, working closely with both the Met Office and the Deutsches Zentrum für Luft- und Raumfahrt (DLR) partners, and constraining the developed parameterisations by the observations made by University of Manchester and Met Office researchers during the aircraft campaign. WORKPLAN WP1 will perform an aircraft campaign making 6 'case study' observations of spreading contrail during 2009 in an area out of the flight corridor to the southwest of the UK . We will use a novel 'figure of eight' flight pattern to make and monitor our own contrail and, in particular, track its evolution into cirrus. We will measure its radiative forcing by flying cross sections above and below and by monitoring from space using the GERB and SEVIRI geostationary instruments. We will make use of state-of-the-art observations made by the Met Office and University of Manchester groups. We will also rely on ice supersaturation forecasts supplied by the University of Reading group using European Centre forecasts. WP2 will use idealised modelling data supplied by DLR and the detailed observations made during WP1 to simulate specific case studies observed during the aircraft campaign. Particular attention will be made to the later stages of contrail lifecycle. WP3 will again make use of idealised DLR data and our own (and others) case-study data to build a prognostic contrail-cirrus scheme for the Met Office Unified Model. WP4 will employ the Unified Model with this parameterisation to predict the radiative forcing and climate impact from contrail-cirrus, comparing its climate impact to that estimated for line-shaped contrails.


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Le Breton M (2012) Airborne observations of formic acid using a chemical ionization mass spectrometer in Atmospheric Measurement Techniques

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O'Shea S (2016) Airborne observations of the microphysical structure of two contrasting cirrus clouds in Journal of Geophysical Research: Atmospheres

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Stopford, C. (2015) AIITS: Preliminary light scattering data from Tropical Tropopause Layer cirrus in Composition and Transport in the Tropical Troposphere and Lower Stratosphere Meeting, Boulder, Colorado, United States

Description Forecast models were utilised to determine flight regions suitable for contrail formation and sampling; regions that were both free of cloud but showed a high probability of occurrence of air mass being supersaturated with respect to ice. The FAAM research aircraft, fitted with cloud microphysics probes and remote sensing instruments, formed a distinctive spiral-shaped contrail in the predicted area by flying in an orbit over the same ground position as the wind advected the contrails to the east. Parts of these contrails were sampled during the completion of four orbits, with sampled contrail regions being between 7 and 30 min old. Lidar measurements were useful for in-flight determination of the location and spatial extent of the contrails, and also to report extinction values that agreed well with those calculated from the microphysical data. A shortwave spectrometer was also able to detect the contrails, though the signal was weak due to the dispersion and evaporation of the contrails. Post-flight the UK Met Office NAME III dispersion model was successfully used as a tool for modelling the dispersion of the persistent contrail; determining its location and age, and determining when there was interference from other measured aircraft contrails or when cirrus encroached on the area later in the flight.

The persistent contrails were found to consist of small (~10 µm) plate-like crystals where growth of ice crystals to larger sizes (~100 µm) was typically detected when higher water vapour levels were present. Using the cloud microphysics data, extinction co-efficient values were calculated and found to be 0.01-1 km-1. The contrails formed during the flight (referred to as B587) were found to have a visible lifetime of ~40 min, and limited water vapour supply was thought to have suppressed ice crystal growth.
Exploitation Route COSIC aims to quantify the climate impact of spreading contrails by making direct observations with dedicated research flights, analysis of data and climate modelling. This Leeds led project links with the Universities and Manchester and Reading, it is also utilizes the UK atmospheric science research aircraft, supported by NERC and the Met Office. It also engages with stakeholders.
Sectors Environment,Transport

Description Contrails and especially their evolution into cirrus-like clouds are thought to have very important effects on local and global radiation budgets, though are generally not well represented in global climate models. Lack of contrail parameterisations is due to the limited availability of in situ contrail measurements which are difficult to obtain. Here we present a methodology for successful sampling and interpretation of contrail microphysical and radiative data using both in situ and remote sensing instrumentation on board the FAAM BAe146 UK research aircraft as part of the COntrails Spreading Into Cirrus (COSIC) study. Expertise developed from this project has been used to improve analysis of global cirrus databases e.g. that provided by the IAGOS In-service Aircraft for Glbal Observing System - This work generated our inclusion in the Global Research Infrastructure IAGOS by which we are now providing global cirrus data products to new UK Industrial programmes such as DE-ICER lead by Rolls Royce and GKN Aerospace.
First Year Of Impact 2018
Sector Aerospace, Defence and Marine,Construction,Education,Energy,Environment,Transport
Impact Types Societal,Economic

Description Airborne Holographic Imaging Probe
Amount £106,020 (GBP)
Funding ID NE/T009144/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 09/2019 
End 03/2020
Description Characterisation and Modelling of Climatically Relevant Primary Biogenic Ice Nuclei in the BEACHON Southern Rocky Mountain Project
Amount £244,499 (GBP)
Funding ID NE/H019049/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 03/2011 
End 09/2013
Description Demonstration of an Aircraft System for Real-Time Discrimination & Reporting of Dust, Volcanic Ash, Ice and Super-cooled Water Particles.
Amount £142,070 (GBP)
Funding ID NE/I023058/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 10/2011 
End 08/2014
Description Microphysics of Antarctic Clouds
Amount £469,667 (GBP)
Funding ID NE/K01482X/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 05/2014 
End 02/2019
Description Cloud Microphysics Data Analysis Workshop - ICCP 2016 Manchester 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact This workshop, hosted and funded by the International Conference on Clouds & precipitation and EUFAR was an Expert Workshop on Data Processing, Analysis & Presentation of Software of Cloud Probes.
The International Commission on Clouds and Precipitation (ICCP) together with the EUFAR Expert Working Group dedicated to In Situ Characterisation of Cloud and Precipitation Particles are organising a 2-day workshop on data processing, analysis and presentation of software of cloud probes, prior to the 17th International Conference on Clouds & Precipitation.
The workshop took place in Manchester from 23 to 24 July 2016. Click here to see the workshop agenda.
The previous 2014 workshop on analysis of cloud measurements confirmed that there is a serious lack of consistency in not only what correction/analysis algorithms are applied to cloud measurements but also in how they are implemented. An informal poll at the close of the meeting indicated that the majority of the participants were supportive of action to bring consensus, when possible, to issues related to "best practices" when processing data and reporting results. This is the motivation for this workshop.

The particular objectives of the 2016 meeting were as follows:
1. Identify those processing algorithms that are critical for producing results with the
lowest uncertainties.
2. Reach consensus on optimum practices for as many of these algorithms as possible, including all aspects of their implementation and documentation.
3. Identify aspects of algorithms that cannot be optimised in general and that must be set for individual probes or individual datasets

4. Organise a working group (similar to or possibly complementary to the EUFAR EWG group) that will oversee the development and maintenance of a data base of processing algorithms and, if supported by community consensus, direct the development of a common data processing and analysis package that will incorporate all the algorithms identified in objective (1)


The outcomes of the meeting were:

A document describing approved processing algorithms by the consensus of participants at the meeting and via a questionnaire sent to the cloud physics community at large.
A new working group whose responsibilities will be clearly defined. Some members will be drawn from participants at the workshop while others may come from the cloud physics community at large.
A new data processing and analysis system will be defined with an outline of its future structure and implementation based on discussion of this document.
Research students were engaged at the highest level with respect to approved data analysis techniques and approaches for their cloud microphysics research relevant to their approved practice for inclusion in PhD theses and their publications.
Year(s) Of Engagement Activity 2016