COntrails Spreading Into Cirrus (COSIC)

Lead Research Organisation: University of Reading
Department Name: Meteorology

Abstract

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' observatins 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.

Publications

10 25 50
 
Description This project was led by the University of Leeds who report on the key findings. Reading's role was mainly to enable the science undertaken by other partners.
Exploitation Route By aviation stakeholders to understand the impact of aircraft on climate

http://www.cosic.leeds.ac.uk/stakeholder-workshop/
Sectors Aerospace, Defence and Marine,Environment

URL http://www.cosic.leeds.ac.uk/
 
Description This project was aimed at improving understanding of the impact of aviation on climate - Reading was a minor partner in this NERC grant which was led by the University of Leeds
First Year Of Impact 2011
Sector Aerospace, Defence and Marine,Environment
Impact Types Policy & public services

 
Description COSIC Stakeholder meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Discussion and interaction with diverse stakeholders from the aviation industry

Stimulus for research and interaction
Year(s) Of Engagement Activity 2011
URL http://www.cosic.leeds.ac.uk/stakeholder-workshop/
 
Description Rolls Royce Environmental Advisory Board 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Discussion with aircraft manufacturer about wider climate change issues and specific ones of interest to the aviation industry

Request for more advice on climate change issues
Year(s) Of Engagement Activity 2014
 
Description University of Reading Aviation Event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Increased interaction with aviation stakeholders

Request to organise bespoke workshop for Rolls Royce plc on water in the atmosphere
Year(s) Of Engagement Activity 2013
URL http://www.met.reading.ac.uk/Aviation_workshop/