FORUM‐AE FORUM on Aviation and Emissions FP7 Coordination Action – GA 605506 ‐ www.forum‐ae.eu Partners: SN, AI, DLR, DLH, ECATS, FZAG, IFPEN, MMU, NLR, ON, RR, RRD, SENASA, ECTL, JRC, TM Climate Change Impact “Aviation impact on climate change – role of NO x emissions and contrail cirrus” WORKSHOP PROCEEDINGS Workshop held at DLR, Oberpfaffenhofen (Germany) on April 2 nd –3 rd , 2014 DLR‐Institute of Atmospheric Physics Hosted by DLR Deliverable D1.4
27/02/2015 1.7 KG, SM Final draft (including Annexes)
1 R=Report, P=Prototype, D=Demonstrator, O=Other 2 PU=Public, PP=Restricted to other programme participants (including the EC), RE=Restricted to a group specified by the
Consortium (including the EC), CO=Confidential, only for members of the Consortium (including the EC)
Climate impact and which metric to use Climate impact of aviation emissions – modelling and observations Discussion on state-of-the-art knowledge and gaps in understanding
Addressing these topics is fully in the scope of the FORUM‐AE coordination action, and more
particularly of the project’s workpackage (WP1) focused on improved understanding of
environmental impact of aviation emission. The technical organization of the workshop was
coordinated by Sigrun Matthes (DLR), co‐leader of workpackage WP1.
The subsequent chapters in the current document of workshop proceedings include the list of
workshop participants in Chapter 2, the FORUM‐AE workshop agenda in Chapter 3, and the summary
of all the technical presentations of the workshops and of the discussion they motivated in Chapter
4. The presentations themselves are gathered in appendix. Chapter 5 eventually outlines the
conclusions based on the final discussion of the day. They are the main outcome of the workshop in
addition to all the technical material made available.
10.10-10.30am Why is it important to know ice crystal number of a contrail cirrus? – Lisa Bock (DLR)
10.30-11.00am Coffee Break
Recent results from campaigns and modelling studies, climate impact of contrails
11.00-11.20am How do aircraft type and properties affect contrail evolution? – Norman Görsch (DLR)
11.20-11.40am Optical properties of contrails and contrail ice crystals- consequences on their climate impact – Valerie Shcherbakov (LaMP)
11.40-12.00am Aircraft and soot dependent radiative forcing by aviation induced cirrus - estimates from observations and model studies – Ulrich Schumann (DLR)
12.00am-1.00pm Buffet Lunch Provided by DLR
1.00-1.20pm Results of TC2 (Traînées de Condensation et Climat) project – Daniel Cariolle (CERFACS)
1.20-1.40pm On uncertainties regarding contrail and contrail cirrus climate impact – K. Gierens (DLR)
1.40-2.00pm Coffee Break
Discussion, Questions and Answers, Open research issues, Conclusion
2.00pm Questions and Answers – recommendations for proceedings
2.30pm Open research issues: Future work – research requirements, roadmap
3.30pm Conclusions (top 5 issues) Klaus Gierens and Sigrun Matthes (DLR)
S1.1–Aviationclimateimpactandworkshopobjectives‐SigrunMatthes(DLR)Sigrun Matthes opens the workshop and welcomes all participants. She presents objectives of
(CA, FP7) brings together technical specialists in this European network covering all relevant
competencies, including academic and industrial partners, linked to key environmental technical
issues on aviation emissions. In this scope, the activity includes the organization of such focused and
high quality workshops. This allows monitoring major European R&T programs, by invitation of
relevant experts.
S1.2–ScientificIntroduction:Climateimpactwhatreallymatters–LingLim(MMU)Ling Lim gives an overview on a current update of the Lee et al. [2009] assessment of climate impact
of aviation. It comprises estimates of two additional effects, compared to earlier assessments, which
are primary mode ozone (PMO) and H2O from CH4 reduction. So‐called primary mode ozone is
caused by a reduced ozone formation, associated with a lower methane concentration, hence it
counteracts on a longer timescale warming effect of short‐term ozone. Estimates of future scenarios
with different demands, technologies and operation efficiencies are undertaken. In this context, it is
important to decide and develop common understanding on the question, which species are
important for an assessment and for evaluating and comparing mitigation options. Here, when
calculating radiative transfer in the atmosphere, choice of background concentrations plays an
important role for radiative impact. Finally, evaluation and priorities how short‐term effects are
assessed versus long term climate effects is crucial.
S1.3–StatusoncurrentACARESRIArecommendations‐XavierVancassel(ONERA),OlivierPenanhoat(Snecma)Xavier Vancassel presents an overview on ACARE Strategic Research and Innovation Agenda (SRIA),
which indicates on time horizon 2050 to 2000 in detail changes per pax‐km. ACARE has set the target
to reduce passenger kilometer CO2 by 75%, NOx emission by 90%, noise by 65%. Additionally,
stronger focus should be given to recyclable vehicles.
Important topics: Knowledge, Monitoring air vehicle environment, Aircraft‐Atmosphere
S2.1–Manufacturersperspectiveonclimateimpactofaviation–RainervonWrede(Airbus)Rainer van Wrede gave an overview on AIRBUS objectives and open questions. AIRBUS was involved in the past in atmospheric research, such as the MOSAIC monitoring system. AIRBUS will continue this involvement, since it is also driver for future development. Motivation for their involvement, is the question what AIRBUS can do to reduce the air traffic impact on environment. The resulting question is, whether, they need to make changes to the aircraft design in order to mitigate climate change.
Paul Madden, and Thomas Dörr, and Peter Swann provided an overview on Rolls‐Royce objectives. Their major intent is to improve engine fuel efficiency, while developing ultra low‐NOx engines. They ask the question, in particular for counteracting emission compounds, to know, which specie is more important to work on, i.e. to minimize, is it particulate matter or NOx emissions. For all these questions, one needs to keep in mind that development time‐scales (development and operation) are pretty long, in the order of decades.
Joseph Burguburu from SNECMA added that an important issue is to agree on regulatory issues, in particular regarding particulate matter indices, i.e. mass versus number density.
Alternative fuels:
Rainer van Wrede expects that alternative fuels will have a significant share in future. The question is if the certification needs to be adapted to low aromatic fuels. And what impacts would such fuels have on supply and operation?
Paul Madden points out that nowadays a maximum of 50% blend is possible. However, overall life cycle assessment is difficult, and remains an issue. From a technical point of view, engine manufacturers can adapt to alternative fuels, if there is an overall society attitude to move onward in this direction.
S2.2–ClimateMetrics:Overviewandnewapproaches–MarianneLundCICEROMarianne Lund gave an overview on metrics which allow to provide a quantitative measure of climate impact. Metric are as well used as an exchange rate to convert any impact to equivalent CO2 emissions. Taking a closer look at IPPC reports on this issue, show a change from fourth Assessement report (AR4) to Fifth Assessment report (AR5). While AR4 point out “GWP remains the recommended metric” in the later AR5 report is noted “No single metric is adequately representing all climate impacts”.
The first question is what the impact of interest is, when talking about changes and damages. Among those metrics commonly used, are GWP (global warming potential) and GTP (global temperature potential), but they are very different one from the other. When searching for an exchange rate between individual components, in particular non‐CO2 components, it is often proposed to use CO2 as exchange rate. However, this raises the question, if CO2 really is the right basis for the “exchange rate”. New approaches and recent development in metrics now consider regional effects instead of only providing global mean values or combine various impacts in one estimate.
S2.3–Areclimatemetricsambiguous?‐KatrinDahlmann,VolkerGrewe,(DLR) Katrin Dahlmann provides an overview on how climate impact metrics needs to be designed in order to reflect underlying societal (or strategic) question. Katrin shows that different climate change aspects and different objectives lead to different combinations of emissions scenarios, metrics and time horizons. Uncertainties in the climate assessment of air traffic do not limit the assessment of new aircraft technologies with regards to more favorable (climate‐optimal) option, since many uncertainties are correlated and can be handled by Monte‐Carlo simulations. Such statistical approaches allow generating robust estimates of overall climate impact.
S3.1–NOximpactsandaltitudevariations–AmundSovde,LingLim,SigrunMatthesAmund Søvde presented results from the REACT4C project, where beside identification of climate‐
optimal routing strategies, an atmospheric multi‐model study on general changes of the air traffic
cruise altitude was performed. This study [Sovde et al., 2014] provides a quantitative estimate how
climate impact changes (i.e. mitigation potential) with regards to climate impact of NOx emissions
when aircraft generally “flying lower” or “flying higher”.
Main requirements for a coordinated multi‐model studies are:
• All models include stratospheric and tropospheric chemistry
• NOx changes are similar in all models, global aviation NOx emission ~0.7Tg[N]/a
Climate impact of generally flying at different altitudes can be described as follows:
• Flying higher/lower: Larger/smaller climate impact from NOx (O3+CH4)
The set of models calculates for aircraft NOx emissions an associated radiative forcing RF (climate
impact) from 0.8 to 8.0 mW/m2. Climate impact of NOx emissions originates from changes in
atmospheric ozone and methane concentrations, associated changes in radiative balance. On a
global scale, if aircraft generally fly lower, the climate impact of NOx emissions would decrease
aviation climate impact, by about ‐2.8 to ‐0.8 mW/m2, while flying higher would increase it by about
0.8 to 3.0 mW/m2.
S3.2–WeatherdependentimpactsofNOxemissions–SabineBrinkop,VolkerGrewe(DLR)Volker Grewe shows results from the REACT4C project indicating the chemical impact of a locally
confined emission on the chemical composition in a realistic weather situation.
• Initial meteorology seems to control the fate of emitted species.
Climate impact of aviation emissions depends on initial meteorology, offering an mitigation
potential, when specifically taking into account atmospheric sensitivity of atmosphere, as undertaken
in the collaborative project REACT4C (FP7).
S3.3–GlobalWarmingPotential(GWP)ofaviationNOx‐AgniezskaSkowron(MMU)Agnieska Skowron presented results derived with the MOZART model and REACT4C emission data.
• NOxGWP decreases with increasing NOx emissions.
• Ozone production efficiency decreases with NOx emission increase
• NOx‐O3‐CH4 nonlinearities different in different world regions
S3.4–Atmosphericobservationsonscheduledflights:CARIBIC2–GretaStratmann(DLR)Greta Stratmann introduces the CARIBIC‐project. The CARIBIC project collects on‐board
measurements of atmospheric trace compounds on scheduled aircraft.
• Long time series available of measurements along aircraft tracks,
• Analysis shows seasonal cycle in NOy concentrations, with lower stratosphere showing
larger values than upper troposphere, which is an indication that many fresh plumes are
S3.5–Observations,modellingandproofofevidence–SigrunMatthes(DLR)Sigrun Matthes introduces the model initiatives to support measurement campaigns within a DLR
project WeCare, in order to investigate possibilities how to best measure atmospheric effects of
aviation, e.g. increase of atmospheric ozone concentration.
In this discussion session a review results and implications takes place, which can be derived from
programmes, but also discuss on gaps within current understanding and strategic topics and priorities
on recommendations how aviation can further evolve in order to become sustainable. Governing
questions in are the following:
What are the current understanding and uncertainties associated with atmospheric composition
changes and climate impacts due to aviation
What are the metric(s) that can best capture impacts on different space and time‐scales?
How will the climate impacts depend on changes in emissions and operations?
What are the best approaches for climate impact analysis (for policy)?
3.5Session5:ContrailsIntroductionandfundamentals
S5.1–Contrailformation:Physicalbasics–KlausGierens(DLR)Klaus Gierens presented a complete derivation of the Schmidt‐Appleman criterion in terms of basic
physics, conservation laws of energy, momentum and mass applied to an aircraft and its engines. The
motivation for such a talk is the surprise that engineers often show when it is stated that modern
engines with higher overall propulsion efficiency, , produce more contrails than older engines with
lower . He made the following statements:
• Dynamic and thermodynamic aspects of contrail formation are very good understood, as
these follow straightforward from basic physical conservation principles of mass,
momentum and energy.
• Microphysical details of contrail formation are less well understood, for instance what
exactly happens on soot surfaces, how many soot particles contribute to ice formation,
etc. However, initial number of ice crystals is known up to a factor of 2‐3.
• Contrail formation and persistence conditions are fairly well known.
• Contrail and contrail cirrus properties depend on initial conditions at formation and on
many other ambient parameters. Large variability.
This final large variability contributes potentially a large share to the overall large uncertainty
in the global and annual average Radiative Forcing of contrails which gives them an IPCC rating of
(very) low level of scientific understanding.
S5.2–Fromcontrailformationtocontrailcirrus–SimonUnterstrasser(DLR)Simon Unterstrasser reviewed the evolution of contrails from formation to contrail‐cirrus under a
modelling perspective. He introduced the three phases of contrail development and connected them
to those physical processes that are important in the respective phase. These processes determine
essential contrail characteristics that later play a role for contrail lifetime and optical properties, i.e.
local effect on the radiation field (individual RF). S.U. showed examples of simulations with cloud
resolving numerical models, under a great variety of ambient situations. This again results in a large
variability of contrail properties, as mentioned before. Finally, a simulation of a contrail cluster was
shown, a complexity that is important, i.e. it occurs often and is relevant, when a statement from
Burkhardt and Kärcher (2009) is true, viz. that contrail outbreaks (i.e. clusters in large ISSRs)
contribute a large share to the global contrail coverage and RF.
S5.3–MERMOSEprojectresults:particlesatengineexit–OlivierPenanhoat(Snecma)Next, Olivier Penanhoat reported on rig‐based measurements of particle emissions at engine exit in
the framework of the MERMOSE project. MERMOSE aims to provide a modern aircraft engine
emission dataset and to study ice nucleation on emitted soot particles. The project has the following
goals:
• Complete characterisation of fine particles behind a modern SaM146 turbofan from
SNECMA and a tubular combustor representative of this turbofan combustor.
• Fundamental characterisation of soot particles and their impact on ice crystal formation.
• To provide valuable information for a future non‐volatile particulate matter international
ICAO standard.
O. P. showed results on particle morphology, structure, size distribution (dependent on power
setting), emission mass and number concentrations (i.e. emission indices). Overall, the project was
considered successful.
S5.4–Whyisitimportanttoknowicecrystalnumberofacontrailcirrus?–LisaBock(DLR)Lisa Bock touched upon a modern topic, namely biofuels, showing how the probably reduced
number of emitted soot particles (compared to engine burning kerosene) will lead to contrails with
less ice crystals, thus less optical effects and lower lifetime. For this purpose she assumed in the
framework of a global climate model that all contrails have initially 80% less ice crystals than in a
corresponding contrail run (standard kerosene case). The result of the “biofuel” experiment
comprised reduced ice mass in contrails, larger crystals, and thus reduced optical thickness. While
total (globally integrated) contrail coverage did not decrease, that of optically thicker contrails
(>0.05, i.e. visible) did, sometimes dramatically. Thus, introduction of biofuels can potentially lead
to a shift from visible to invisible contrails with correspondingly smaller radiative forcing on climate.
However, the overall effect might be smaller than assumed in the model.
S6.1–Howdoaircrafttypeandpropertiesaffectcontrailevolution?–NormanGörsch(DLR)Norman Görsch presented results from a modelling study of contrails from different aircraft within
the same meteorological situation. Six different aircraft ranging from the small regional airliner
Bombardier CRJ to the largest aircraft Airbus A380 have been considered. Differences in wake vortex
properties and fuel flow lead to considerable variations in the early contrail geometric depth and ice
crystal number. Larger aircraft produce contrails with more ice crystals than small aircraft. These
initial differences are reduced in the first minutes, as the ice crystal loss during the vortex phase is
stronger for larger aircraft. In supersaturated air, contrails of large aircraft are much deeper after 5
min than those of small aircraft. It is important to know whether such initial differences have a long‐
lasting effect on the developing contrail‐cirrus. Quantitative differences between the contrail cirrus
properties of the various aircraft remain over the total simulation period of 6 h. The total extinctions
of A380‐produced contrails are about 1.5 to 2.5 times higher than those from contrails of a
Bombardier CRJ, which translates approximately to a higher individual climate effect by the same
factor.
S6.2–Opticalpropertiesofcontrailsandcontrailicecrystals‐consequencesontheirclimateimpact–ValerieShcherbakov(LaMP)Valery Shcherbakov showed measurements of ice crystal scattering phase functions measured with
the LaMP Polar Nephelometer. These measurements have been taken during the Concert 1 and 2
airborne campaigns. Analysis of the huge number of available nephelometer measurements allow
statistically robust statements to be made on typical crystal forms and optical properties in young or
old contrails, man‐made or natural ice clouds, or particles from mixed phase clouds and volcanic ash
clouds. All these show distinct optical characteristics. Even crystal aging (growth) has a signature in
the nephelometer measurements. He concluded stating that contrail optical‐characteristics depend
on weather conditions, contrail age, aircraft engines, and so on, and so he made another statement
on the large natural variability of contrails and their properties which renders it difficult to come up
with a narrow uncertainty margin for the climate impact in IPCC like charts. However, the Polar
Nephelometer is a powerful tool to provide statistically significant data which can be employed
synergistically with particle‐counting probes, trace‐gas and aerosol measurements to narrow down
the uncertainty ranges.
S6.3–Aircraftandsootdependentradiativeforcingbyaviationinducedcirrus‐estimatesfromobservationsandmodelstudies–UlrichSchumann(DLR)Ulrich Schumann presented estimates from observations and CoCiP model studies on aircraft and
soot dependent radiative forcing by aviation induced cirrus. He gave the following conclusions:
• An increase in the number of ice particles in young contrails by a factor of 2 [which cannot be
excluded from recent lab and field results] causes a factor of 21/3 = 1.26 change of optical
depth for fixed ice water path and fixed radiation extinction coefficient and correspondingly
reduced effective radius (the Twomey effect). Further changes incur in relation to visible
contrail cover, contrail lifetime, width and geometrical depth. All these changes contribute to
the larger changes in RF compared to that of optical depth. Exact numbers depend on details
in the used CoCiP model.
• The relative radiative effect of two global hypothetical fleets of A380 or A319 aircraft has
been studied with CoCiP. The global simulation with CoCiP shows a change in net RF by
factors of 0.73 or 2.51, when the global fleet of aircraft is replaced by a fictive fleet in which
all aircraft are either A319 or A380 aircraft, respectively. Hence, the RF is about a factor 3.5
larger for an A380 than for an A319. This change results mainly from the larger aircraft mass
(factor 8) and the larger fuel consumption (factor 6). In terms of RF per passenger seat or RF
per passenger‐seat distance, the ratio between the simulation results for different aircraft is
closer to unity or even smaller than one, i.e. a larger aircraft may have smaller climate impact
S7.1–ResultsofTC2(TraînéesdeCondensationetClimat)project–DanielCariolle(CERFACS)Danielle Cariolle reported on the TC2 project, a French project on Traînées de Condensation et Climat
(Contrails and Climate). TC2 has the main objectives to reduce uncertainties in calculating the climate
impact associated with contrails and induced cirrus. To this end it is engaged in development and
improvement of numerical models of contrails and contrail‐cirrus, development of parameterizations
of contrails and induced cirrus for GCMs, and aircraft in‐situ measurements of contrail and contrail‐
cirrus composition. A main focus in developing the contrail model is on a proper representation of
the background turbulent fluctuations.
Next, Daniell Cariolle reported on a sister project, IMPACT (Impact of aircraft emissions on present
and future climate). The goal of this project is similar to that of TC2, namely to contribute reducing
uncertainties in calculating the climate impact of aircraft emissions and in particular those associated
with contrails and induced cirrus but also to the NOx emissions (impact on methane and ozone) and
particulates (sulfates, nitrates, soot). This goal will be achieved by development and improvement of
numerical models of atmospheric composition and climate and studies of climate perturbation due
to aircraft emissions by 2050 time horizon. A further goal is to suggest ways to develop emission
inventories associated with future fleets and specify the needs of the climate modeling in terms of
emission inventories. D.C. presented details of these developments, for instance how ice
supersaturation is represented in the GCM.
Both projects presented by Danielle Cariolle aim at reducing the uncertainty of contrail and contrail‐
cirrus RF estimates.
S7.2–Onuncertaintiesregardingcontrailandcontrailcirrusclimateimpact–K.Gierens(DLR)Klaus Gierens devoted the final presentation of this workshop to a discussion of the sources of
uncertainties of contrail and contrail‐cirrus RF estimates. He stressed the multi‐scale‐nature of the
problem (i.e. many temporal and spatial orders of magnitude involved in the phenomenon, e.g. from
nanometre to kilometre), and showed that all research modes (in‐situ and remote measurements,
local to global models) cover only a small fraction of all the scales involved. He argued that much of
the uncertainty is related to the enormous natural variability that originates from the multi‐scale‐
property and not necessarily to our inability to solve the problems.
3.8Session8:Discussion,QuestionsandAnswers,Openresearchissues,ConclusionsKlaus Gierens led into the discussion by presenting a number of research questions:
• How far is it possible to reduce the uncertainty in contrails’ RF significantly?
• Is it possible to devise meaningful mitigation measures for individual contrails if there
remains an irreducible RF for all contrails?
• Can essential input data for mitigation strategies be predicted (forecast) such that contrail mitigation can be performed in flight planning phase?
• Are model results or forecasts robust enough to base mitigation strategies upon them? If not, which parameters/parameter combinations are most important to be fixed?
Type of funding scheme: Coordination and Support Actions (Coordinating)
Duration: July 2013 – June 2017
The FORUM-AE coordination action will create a technical specialists europeannetwork with all relevant competencies, including academic and industrial partners, linked to key environmental technical issues on aviation emissions.
In this scope, the activity will consist in the organization of focused and high quality workshops and in the monitoring of major european R&T programs, both activities being carried out closely.
Environmental impacts workpackage aims at addressing main issues linked to environmental impacts from aviation emissions, in order to have clear visibility on the current knowledge, the recent results, the on-going scientific programs, the open questions, and the most strategic topics which should be further assessed or investigated by the scientific community, as well as the priorities which should be considered in the mitigation solutions of WP2.
Aviation climate impact workshop dedicated to establishing the outcomes of recent research on NOx emissions, contrail, and contrail-cirrus, and in particular research which aims to narrow the related uncertainties.
Climate impact – Motivation, which metric to use? Climate impact of nitrogen oxide emissions from aviation & observations Contrail and contrail cirrus: Introduction and fundamentals Recent results from campaigns and modelling studies, climate impact of
contrails
Workshop proceedings summarizing state of knowledge, findings and recommendations
Introduction and fundamentals 9.30-9.45am Climate workshop goals and introduction – Klaus Gierens and Sigrun Matthes (DLR) 9.45-10.15am Scientific Introduction: Climate impact what really matters – Ling Lim (MMU) 10.15-10.45am Status on current ACARE SRIA recommendations - Xavier Vancassel (ONERA), Olivier
Penanhoat (Snecma)10.45am Coffee Break
Climate impact – Motivation, which metric to use? 11.15-11.35am Manufacturers perspective on climate impact of aviation – Rainer von Wrede (Airbus) 11.35-12.00am Climate Metrics: Overview and new approaches – Marianne Lund CICERO 12.00-12.30pm Are climate metrics ambiguous? - Volker Grewe, Katrin Dahlmann (DLR)
12.30pm Buffet Lunch Provided by DLRVisit to Research Aircraft HALO
Climate impact of nitrogen oxide emissions from aviation & observations 2.00-2.25pm NOx impacts and altitude variations – Amund Sovde, Ling Lim, Sigrun Matthes (REACT4C FP7) 2.25-2.50pm Weather dependent impacts of NOx emissions – Sabine Brinkop, Volker Grewe (DLR-IPA) 2.50-3.15pm Global Warming Potential (GWP) of aviation NOx emissions - Agniezska Skowron (MMU)
3.15-3.45pm Coffee Break 3.45pm Atmospheric observations on scheduled flights:CARIBIC2 – Greta Stratmann, Helmut Ziereis (DLR) 4.15pm Observations and proof of evidenceGaseous aviation emissions – discussion, summary, feedback 4.45pm Discussion – Study results, programmes, gaps, strategic topics/priorities 5.15pm Wrap-up day 1 – Volker Grewe and Sigrun Matthes (DLR)
Contrail and contrail cirrus: Introduction and fundamentals 9.00am Contrail cirrus - general remarks 9.10-9.30am Contrail formation: Physical basics – Klaus Gierens (DLR) 9.30-9.50am From contrail formation to contrail cirrus – Simon Unterstrasser (DLR) 9.50-10.10am MERMOSE project results: particles at engine exit – Olivier Penanhoat (Snecma) 10.10-10.30am Why is it important to know ice crystal number of a contrail cirrus? – Lisa Bock (DLR)
10.30-11.00am Coffee BreakRecent results from campaigns and modelling studies, climate impact of contrails 11.00-11.20am How do aircraft type and properties affect contrail evolution? – Norman Görsch (DLR) 11.20-11.40am Optical properties of contrails and contrail ice crystals- consequences on their climate
impact – Valerie Shcherbakov (LaMP) 11.40-12.00am Aircraft and soot dependent radiative forcing by aviation induced cirrus - estimates from
observations and model studies – Ulrich Schumann (DLR)12.00am-1.00pm Buffet Lunch Provided by DLR
1.00-1.20pm Results of TC2 (Traînées de Condensation et Climat) project – Daniel Cariolle (CERFACS) 1.20-1.40pm On uncertainties regarding contrail and contrail cirrus climate impact – K. Gierens (DLR)
1.40-2.00pm Coffee Break
Discussion, Questions and Answers, Open research issues, Conclusion 2.00pm Questions and Answers – recommendations for proceedings 2.30pm Open research issues: Future work – research requirements, roadmap 3.30pm Conclusions (top 5 issues) Klaus Gierens and Sigrun Matthes (DLR)
Olivier Penanhoat (SN)Xavier Vancassel (ON)FORUM-AE CC workshopMünchen – 2-3 April 2014
1 / FORUM-AE
ACARE FRAME
FLIGHTPATH 2050 published in 2011
Europe’s Vision for Aviation Several goals to be achieved Challenge 3 : Protecting the Environment and The Energy
Supply
STRATEGIC RESEARCH & INNOVATION AGENDA (SRIA)
Roadmap for aviation research, development and innovation SRIA Vol. 1 published in Sept 2012 SRIA Vol. 2 nearly finalised Now available on line with search and sort facility:
D1.4 Climate Change Impact Proceedings V1.2, December 2014, FORUM‐AE (FP7)
Metrics: Overview and newapproaches
Marianne T. Lund, CICERO
FORUM-AE, 2-3 April 2014
Thanks to Jan Fuglestvedt for use of slides
METRICS
Tools for aggregating informationand placing emissions of different gases on a common scale, i.e. provide "exchange rate".
iAGTPiAGTP
AGWPAGWP
AGTPAGTP
GWPGWP
GTPGTPRTP (?)RTP (?)
Common scale: CO2‐eq. = Metric x emission
AbsoluteNormalized by reference (CO2)
ARTPARTP
AtmosphericConcentrations
Radiative Forcing
Climate Change
Impacts
Emissions
METRICSMeasures to quantify impact of emissions
Development of mitigation strategies, including mitigation
costs, damage costs, discount rates
Increasingpolicy relevance Increasing
uncertainty
"Metrics do not define goals and policy – they are tools that enableevaluation and implementation of multi‐component policies" (IPCC 2014)
IPCC WGI (2014)
“Although it has several known shortcomings, a multi‐gas strategy using GWPs is very likely to have advantages over a CO2‐only strategy (O’Neill, 2003). Thus, GWPs remain the recommended metric to compare future climate impacts of emissions of long‐lived climate gases.”
Statement on GWP in IPCC AR4
… The most appropriate metric and time horizon will depend on which aspects of climate change are considered most important to a particular application. No single metric can accurately compare all consequences of different missions, and all have limitations and uncertainties… Updated values are provided in this Report. {8.7}
Summary for poliymakers IPCC AR5
Choices when using emission metrics
Time frames‐ backward looking‐ forward looking (pulse, sustained or scenario emissions)‐ level or rate‐ integrated to a given point or instaneous‐ discounting of future
Type of effectRadiative forcing, temperature change, sea level rise, socioeconomic, other?
Spatial dimensionEqual mass emissions of SLCFs in different regions can give varying global‐mean responses.
D1.4 Climate Change Impact Proceedings V1.2, December 2014, FORUM‐AE (FP7)
GWP and GTP
GWPTime integrated RF due to a pulse emission relative to that of an equal CO2
pulse.
GTP The global‐mean surface temperatureresponse to an emission pulse relative to that of CO2.
IPCC WGI (2014)
Dependence on the reference gas
After 50 years: variation in GWP only due to CO2
Slide by Jan Fuglestvedt (CICERO)
CH4 BC
Variation in GWP purelydue to CO2
Uncertainties
Scientific:‐ Lifetimes and radiative efficiency‐ CO2 impulse response function‐ Ocean heat uptake‐ Climate sensitivity and efficacies‐ Inclusion of indirect effects and
feedbacks
Structural, e.g.: ‐ Time horizon‐ Impact (RF, temperature)‐ Absolute or relative
Oliviè and Peters (2013)
Joos et al. (2013)
Climate-carbon feedbacksInconsistent treatment:
SAR and TAR no coupling of carbon and climate model
AR4 carbon‐climate feedbacks included for CO2, not for non‐CO2.
AR5
IPCC WGI (2014)
New approaches/focus
Modifications to better represent: CO2 from bioenergyRegional variabilityPeak temperature limits
Alternative multi‐componentand multi‐target approaches
Different aspects of climate change lead todifferent metrics!
• What we have to understand is:• Different metrics relate to different aspects of climate change!• The wording „climate change“ is not well-defined, somehow fuzzy!
• We have to go back and consider the right questions, the appropriate objective, to which individual metrics provide an answer.
• Any climate change assessment needs a thourough consideration of thebasic objective.
• This defines the underlying scenario and metric to be used!
• Quantification of climate impact of air traffic has large uncertainties.
• Uncertainties affect both the base case scenario and the mitigationscenario. Uncertainties are correlated! Significant changes can be identified with a Monte Carlo
simulation!
The still existing large uncertainties requires adequate statisticalmethods and hence do not limit the application
Sigrun Matthes2, Agnieszka Skowron3, Daniela Iachetti4, Ling Lim3, Bethan Owen3, Øivind Hodnebrog1, Glauco Di Genova4, Gianni Pitari4, David S. Lee3, Gunnar Myhre1, Ivar S. A. Isaksen1,51 Center for International Climate and Environmental Research – Oslo (CICERO)2 Institut für Physik der Atmosph, DLR3 Dalton Research Institute, Manchester Metropolitan University4 University of L'Aquila5 University of Oslo
FORUM‐AE Workshop 2 – 2. April 2014
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
Δ(NO+NO2) – PLUS vs BASE case
JJA: ‐10 ppb to 47 ppbDJF: ‐9 ppb to 32 ppb
June‐July‐August averagesFlying higher
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
Δ(NO+NO2) – MINUS vs BASE case
JJA: ‐42 ppb to 8 ppbDJF: ‐30 ppb to 11 ppb
June‐July‐August averagesFlying lower
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
ΔO3 – BASE case vs no aircraft
JJA: up to 8.8 ppbDJF: up to 4.4 ppb
June‐July‐August averages
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
ΔO3 – PLUS vs BASE case
JJA: ‐1.9 ppb to 2.0 ppbDJF: ‐1.0 ppb to 1.2 ppb
June‐July‐August averagesFlying higher
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
ΔO3 – MINUS vs BASE case
JJA: ‐2.1 ppb to 0.9 ppbDJF: ‐1.0 ppb to 0.7 ppb
June‐July‐August averagesFlying lower
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
Radiative forcing (RF)
BASE case vs no aircraft:RF(O3 short): 16.4 to 23.5 mW/m2
RF(CH4): ‐7.1 to ‐10.7 mW/m2 (calculated from CH4 lifetime change)RF(O3 long): ‐3.6 to ‐5.4 mW/m2 (50% of RF(CH4)RF(strat H2O): ‐1.1 to ‐1.6 mW/m2 (15% of RF(CH4)
Total range 0.8 to 8 mW/m2
PLUS vs BASE case:RF(O3 short): 0.5 to 2.9 mW/m2
RF(CH4): 0.0 to 0.2 mW/m2
RF(O3 long): 0.0 to 0.1 mW/m2
RF(strat H2O): 0.0 to 0.03 mW/m2
Total range 0.75 to 3.0 mW/m2
MINUS vs BASE case:RF(O3 short): ‐2.4 to ‐0.4 mW/m2
RF(CH4): ‐0.4 to ‐0.1 mW/m2
RF(O3 long): ‐0.2 to ‐0.06 mW/m2
RF(strat H2O): ‐0.06 to ‐0.01 mW/m2
Total range ‐2.6 to ‐0.8 mW/m2
• Short term O3 is most important.• Long wave radiation more important than short wave.
Ole Amund SøvdeFORUM‐AE Workshop 2 – 2. April 2014
Conclusions
Considering only aircraft NOx• BASE vs no aircraft compares well with other studies.• Long wave & short term RF(O3) most important.• Flying higher increase O3 and RF.• Flying lower reduce O3 and RF.
Need to address other effects• Taking NOx + contrails + particles + ... into account• Study impact of changing routes horizontally,
The CARIBIC-Project – measured parameters> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Container
www.DLR.de • Folie 8
IAGOS is a European infrastructure for systematic monitoring the UTLS withmany aircrafts, several airlines, including CARIBIC
Slide: C.A.M. Brenninkmeijer
IAGOS‐CARIBICIAGOS‐CORE: instrumentation for atmospheric chemical species (O3, CO, CO2, NOy, NOx, H2O), aerosols and cloud particles for sustainable operation
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Why using Passenger Air Crafts?
• Passenger aircrafts fly regularly all over the globe over large distances.
• Passenger aircrafts close the gap between satellite observations and specific research measurement campaigns.
• Central and fundamental requirements for determining future mitigation strategies are reliable predictions of the future climate using climate models. Therefore a comprehensive trace gas dataset is needed
Iagos.fr; caribic-atmospheric.com
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
CARIBIC Data Set and Quality
Data available (CARIBIC 2) from 2005 to March 2014 360 missions
More than 2.4 mio flight km
More than 2700 flight hours
in general high quality
no data during ascent / few data during descend
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Nitrogen Oxide Measurements: Motivation
“[…] current NOx climatologies are assembled from campaigns of opportunity and do not have the necessary statistics or coverage to adequately test the models.“
Holmes et al., 2011
www.DLR.de • Folie 11 > FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
NOy Seasonal Cycles in the UTLS
www.DLR.de • Folie 12
0,0
0,5
1,0
1,5
2,0
2,5
0 5 10 15 20 25 30 35 40 45
NOy / (nmol/mol)
Region, Season
0,0
1,0
2,0
3,0
4,0
0 5 10 15 20 25 30 35 40 45
NOy / (nmol/mol)
Region, Season
Europe North Asia
South Asia
Africa
North Atlantik South
Atlantik
North America South
America
UT
LS
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
NOy mixing ratios over Europe (12 °W - 28 °E & 65 °N - 35 °N)
www.DLR.de • Folie 13
TroposphereStratosphere
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
num
ber
ofpo
ints
Noy
/(nm
ol/m
ol)
CARIBIC NOy vs. MOZAIC NOy in Europe
www.DLR.de • Folie 14
UT
LS
- CARIBIC 2005-2012:- ca. 53800 10 s data points
- MOZAIC 2002 - 2005:- ca. 110700 1 min data points
- Only data with hPa > 500
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Observation of Small Scale Signatures of Air-Traffic emissions
www.DLR.de • Folie 15
NO and NOy mixing ratiosFlight Frankfurt Denver July 2008
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Europe, St
DJF MAM JJA SON CARIBIC & EMAC (n=16/30/2/6) (mean/std/minmax) & (5, 25, 50, 75, 95%)
0.5
1.0
1.5
2.0
2.5
3.0
NO
y [p
pb]
Europe, Tr
DJF MAM JJA SON CARIBIC & EMAC (n=29/12/14/24) (mean/std/minmax) & (5, 25, 50, 75, 95%)
0.0
0.5
1.0
1.5
2.0
2.5
NO
y [p
pb]
Comparison with Model Results (EMAC2): Seasonal Cycle in Europe (12 °W - 28 °E & 65 °N - 35 °N)
CARIBICEMAC
K. Gottschaldt
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Summary
www.DLR.de • Folie 17
• Passenger aircrafts are excellent suited for large scale and long term observations of trace gases and particles in the upper troposphere/lower stratosphere
• 1998 – 2002: CARIBIC 1 ~ 80 flights
• Since 2005: CARIBIC 2 ~ 360 flights
• Today: CARIBIC 2 IAGOS-CARIBIC
• A Comprehensive nitrogen oxide dataset for the UTLS has been acquired since the last 9 years
• Small scale signatures of air traffic emissions are detected in the data
• The CARIBIC NOy mixing ratios are in accordance (5 – 26 %) with a complete independent dataset (MOZAIC NOy)
• The CARIBIC NOy mixing ratios are in accordance with the results of models (EMAC2)
> FORUM-AE Worshop > G. Stratmann • Nitrogen Oxide Measurements with IAGOS-CARIBIC > 02.04.2014
Seasonal cycle of NO and NOy
www.DLR.de • Folie 18
Europe (12 °W ‐ 28 °E & 65 °N ‐ 35 °N)
Tropospheric NOyStratospheric NOy
North Asia (30 °E – 142 °E & 70 °N – 35 °N)
> CARIBIC Meeting 2013 > G. Stratmann • The large scale Nitrogen Oxide Distribution in the UTLS > 28.11.2013
Aircraft measurement support by atmospheric modelling
Sigrun Matthes, Patrick Jöckel
Helmut Ziereis, Doreen SeiderPart of DLR Project WeCare (coordinated by Volker Grewe)
www.DLR.de • Chart 1 > Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
Motivation Air traffic and climate change• High air traffic growth rates of 3 – 5 %
per year.
• Measures required to reduce aviation climate impact to counteract this development
Climate impact mitigation options, e.g.• Use of alternative fuels• Novel engine concepts• Modification of aircraft design• Alternative routing (operations)• etc.
Impact of aviation emissions varies withgeographic position and altitude, as well astime of flight (meteorology) Atmospheric observations are
required for in-situ data and evaluation
Model studies allow to understand mechanisms and processes providing quantitative estimates
Lee et al., 2010
> Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofenwww.DLR.de • Chart 2
Aviation climate impactCO2 and non-CO2 effects
• Climate impact of non-CO2 emissions depends on
• time and position of aircraft• actual weather conditions (processes,
transport pathways, temperature, humidity)• background concentrations
Climate impact of aviation emissions (direct & indirect effects)
• A detailed investigation of the formation and the corresponding key atmospheric processes is possible in numerical models
• For this purpose models are requires – which under consideration of actual meteorological conditions investigates such species and processes in detail
• Under the light to provide a proof of concept for the detection of the aviation signal in the atmosphere within the project WeCare a dedicated atmospheric modelling is performed
www.DLR.de • Chart 4 > Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
MECO(n): MESSy-fied ECHAM and COSMO models n-times nested
- 1-way on-line nested global-regionalatmospheric model system
ECHAM5
COSMO 1 COSMO 2
COSMO 2‐1
COSMO 2‐1‐2
COSMO 2‐1‐1
COSMO 3
COSMO 3‐1
- multiple instances possibledue to client – serverarchitecture of MMD ...
Kerkweg & Jöckel, GMD, 2012a,bHofmann et al., GMDD, 2012
www.DLR.de • Chart 5 > Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
AP 4300 Prozessmodell der SimulationsketteSoftware-Infrastruktur
• Angepasste Setups und Module je nach Fragestellung
• Globale Simulationen und regionale Nest möglich
• EMAC2 und COSMO-CLM
www.DLR.de • Chart 6
Jöckel und Matthes
• Simulations-umgebung RCE
• Datentransfer
• Operationelles System
netCDF
> Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
AP 4300 Modell-System und Software-Infrastrukturwww.DLR.de • Chart 7
ECMWF MeteorologyMARS archivStart script
DLR HPC pa1Receive data
SourceData archive
Target Input data directory
File transfer (access)
Nudging data/aw formatScript:
Input format
SourceGRIB2 (ECMWF)
Target netCDF Format
Pre-processing
EMAC simulationInput: netCDF dataDirectory:
Output: netCDF dataDirectory
SourceInput data (netCDF)
TargetOutput data (netCDF)
Atmospheric modelling
Boundary conditionsRegion, season, time, focus
Namelist (setup)
SourceExp design
Target nml file
Namelist generation
WebService / LASEMAC output data WebService
Archive
SourcenetCDF format
Target IEEE, ASCII
Pre-processing
Data storage/scratch/Afterburner, cdo
/work/archive
SourceOutput data
Target Archive data
Data archive
Mission Support ToolWebServicearchive
ASCII, smallformat, jpg
SourcenetCDF format
Target data sequence
Hindcast data
EMAC CustomizingModel setup
Regional nestsBoundary data
Preparatory work(outside of RCE)
RCE Infrastructure (Middleware)
Data
Access
> Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
Campaign supporting modelling
Global atmospheric model simulation and data analysis foridentification of concept how to directly measure aviationatmospheric impact in cruise altitude
• Using measurements on scheduled aircraft (CARIBIC, MOZAIC)
• Analysis of proof of concept ofaviation impact via CARIBIC und MOZAIC measurements
• Sensitivity studies with global atmospheric model EMAC for scenarios and emissions
• EMAC & MECO(n) simulationenvironment operational available
• Employ modelling for selectedmeasurement campaigns, e.g. DC3
www.DLR.de • Chart 8
CARIBIC-2 MOZAIC
> Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
Campaign supporting modelling
• The global-regional model MECO(n) combines via nesting the regional model COSMO with the global model EMAC (linked with MESSy)
• Particular strength is that due to the modular concept in MESSystudies can be individually design to serve the study purpose,, e.g. compare different convection schemes.
• Specification can be found in: Kerkweg and Jöckel, (2012), The 1-way on-line coupled atmospheric chemistry model system MECO(n) Part 1: Description of the limited-area atmospheric chemistry model COSMO/MESSy, Geoscientific Model Development, 5, 87-110. DOI: 10.5194/gmd-5-87-2012
www.DLR.de • Chart 9
CARIBIC
Jöckel, Matthes, Ziereis
> Sigrun Matthes, Patrick Jöckel > Observation & Modelling > FORUM-AE, 2-3 April 2014 - Oberpfaffenhofen
Physical fundamentals of contrail formation the Schmidt-Appleman criterion
and the role of particles
Klaus Gierens
Institut für Physik der Atmosphäre, DLR Oberpfaffenhofen
Institut für Physik der Atmosphäre
Motivation
Schumann et al., 2000
Institut für Physik der Atmosphäre
Contents
• Derivation of the Schmidt-Appleman criterion in terms of water vapour and enthalpy budgets
• The role of particles
• Contrails from biofuels
Institut für Physik der Atmosphäre
Simple explanation
Contrail formation is like breathing on cold air; the condensation that becomes visible is due to isobaric mixing of two air masses of different temperature and different moisture content.
Mixing of air masses can lead to condensation because the saturation pressure of water vapour decreases almost exponentially with decreasing temperature. Isobaric mixing thus can end up in a supersaturated state even if none of the two mixed air masses was saturated before.
This mixing trajectory and the saturation pressure curves of water vapour are displayed in a Schmidt-Appleman diagram. Isobaric mixing is represented by a straight line in such a diagram (pressure vs. temperature).
Institut für Physik der Atmosphäre
Schmidt-Appleman diagram
Isobaric mixing of hot exhaust gases of high absolute humidity with cold ambient air of low absolute humidity.
Schmidt (1941), Appleman (1953), Schumann (1996)
Institut für Physik der Atmosphäre
Derivation of the Schmidt-Appleman theory in terms of engine mass and enthalpy flows (1)
The slope G of the mixing trajectory is simply
Index E: Environment
Index P: Plume at engine exit, i.e. engine and fuel dependent
e is water vapour partial pressure, T is static temperature
It is practical to use mass mixing ratio q instead of partial pressure./
p is air pressure, ε 0.622(ratio of molar masses of water and air).
Derivation of the Schmidt-Appleman theory (2):Water mass budget
the water vapour mixing ratio at engine exit is determined from the mixing ratios in the air streams and the water vapour from burning the fuel. Instantaneous mixing of core and bypass streams gives
with : emission index for water vapour
(1.25 for kerosene, higher values for methane and liquid hydrogen)
The nominator in the slope factor G is thus
Institut für Physik der Atmosphäre
Derivation of the Schmidt-Appleman theory (3):Overall propulsion efficiency
The continuous loss of momentum due to drag and friction dP/dt
has to be replaced by the thrust F of the engines:
⁄
Thus, work has to be applied with a rate FVwhich has to be taken from the fuels chemical energy, that is
Q:lower heat value of fuel, :overall propulsion efficiency
V:aircraft speed
Institut für Physik der Atmosphäre
Derivation of the Schmidt-Appleman theory (4):Conservation of momentum
Momentum conservation (actio=reactio) requires that the airstreams get the same momentum in the opposite direction:
, , ,
here is the velocity of the airstream relative to the ground at engine exit
Institut für Physik der Atmosphäre
Derivation of the Schmidt-Appleman theory (5):Conservation of energy
Energy conservation (reference frame fixed to the ground):
the chemical energy of the fuel is converted into work against drag, into kinetic energy and thermal energy of the exhaust
2 , 2 , 2 , ,
, , ,
Note: , the rest is thus 1 .
Note: kinetic energy is 104 J/kg ,thermal energy is 107 J/kg .
Thus thermal energy 1 .
Institut für Physik der Atmosphäre
Derivation of the Schmidt-Appleman theory (6):Enthalpy budget
Assuming again instantaneous mixing of core and bypass air at engine exit we arrive at the following enthalpy
, ,
which can be rewritten using the energy conservation from above as
1
thus the denominator of G is1
Institut für Physik der Atmosphäre
Derivation of the Schmidt-Appleman theory (7)Slope factor
• Note that particles are not even mentioned in the Schmidt-Appleman theory.
• However, particles are necessary for droplet and crystal formation as nucleation centres.
• How does this fit together?
• Without any particles, neither in the air nor in the exhaust, the SAC would not work at all, because then nucleation would need several 100% of supersaturation to commence.
• If soot were perfect ice nuclei, ice saturation would probably suffice instead of water saturation for contrail formation.
• Sulfuric acid covered soot is bad ice nuclei, but there are plenty of these particles such that contrail formation is never constrained by lack of nucleation sites. Therefore particles need not to be mentioned in the SAC.
Institut für Physik der Atmosphäre
Contrail properties depend on particle emission, contrail formation does not
soot emission index by number
ice
crys
tal n
umbe
r co
ncen
trat
ion
Kerosene
Fischer-Tropsch blends
results of AAFEX campaignsand calculations by Kärcher and Yu, 2009
Institut für Physik der Atmosphäre
Conclusion
• Dynamic and thermodynamic aspects of contrail formation are very good understood, as these follow straightforward from basic physical conservation principles of mass, momentum and energy.
• Microphysical details of contrail formation are less well understood, for instance what excactly happens on soot surfaces, how many soot particles contribute to ice formation, etc. However, initial number of ice crystals is known up to a factor of 2-3.
• Contrail formation and persistence conditions are fairly well known.
• Contrail and contrail cirrus properties depend on initial conditions at formation and on many other ambient parameters. Large variability.
relative humidity wind shear temperature radiation depth of supersaturated layer contrail properties after vortex
phase interaction with natural cirrus interaction with other contrails
Partly answered in Unterstrasser & Gierens, ACP, 2010a & b, Jensen et al, JGR,1998
www.DLR.de • Chart 20
Dispersion Phase – Contrail to cirrus transition
- EULAG-LCM can serve as benchmark model for simplied model CoCiP- Both models simulate individual contrails- Compare models for a multitude of atmospheric scenarios
Validation along model chain: EULAG-LCM -> CoCip -> GCM
Individual contrailsLarge scale
EULAG-LCM CoCiP
Model purpose:EULAG-LCM: high resolution simulations for selected cases with detailed dynamics and ice microphysicsCoCiP: coarser simulations for global scale applications
Dispersion phase – Contrail cluster formation
Evolution of eight contrails in a supersaturated layer with background vertical wind shear over 4 hours.
www.DLR.de • Chart 21
Dispersion phase – Contrail cluster formation
Formation of contrail cluster: Saturation effects in regions with dense air traffic
Non-linear scaling of contrail climate with air traffic density
2 Mermose & cruise particles – FORUM‐AE CC Workshop – 2&3 April 2014
Mermose project
Impact of aviation on global warming is a major concern. In this context, theFrench DGAC is funding four projects in order to provide a betterunderstanding of contrail formation, a better evaluation of their impact onclimate, and new detection and avoidance management means.
MERMOSE, the first of these projects, led by ONERA, and with SNECMA aspartner, aims to provide a modern aircraft engine emission dataset and tostudy ice nucleation on emitted soot particles.
The project is 2 folds: one part with complete characterisation of fine particlesbehind a modern SaM146 turbofan from SNECMA and a tubular combustorrepresentative of this turbofan combustor ; a second part with fundamentalcharacterisation of soot particles and their impact on ice crystals formation.
In parallel to its scientific objective, this project provides valuable informationin the frame of the current work to propose a future nvPM (non volatileparticles matter) international ICAO standard.
3 Mermose & cruise particles – FORUM‐AE CC Workshop – 2&3 April 2014
Engine Campaign / Tested engine
The campaign was performed on a SaM146‐1S17 engine (PowerJet).
This engine developed by SNECMA in collaboration with NPO Saturn wascertified by Snecma in June 2010.
It is a modern mixed flow Turbo‐fan with an optimised RQL single annularcombustor ; For ‐1S17: OPR = 21,9 & BPR = 4,42 & F00 = 69.21kN
This engine equips the Russian regional jet Sukhoi Superjet 100.
4 Mermose & cruise particles – FORUM‐AE CC Workshop – 2&3 April 2014
Engine Campaign / General data
The campaign was performed at Snecma Villaroche.
The measurements were performed in June 2014 with Onera, IRSN, CNRS andSnecma teams.
The engine tested was an un‐mixed flow configuration, in the same way it wasfor the pollution certification of SaM146 (it enables to realize representativesampling in the primary nozzle exit).
The sampling system was the one used for the SaM146 pollution certification:it is a single orifice probe moved by a robot.
2 chains were used: the Snecma gaseous pollutant chain which was fullycompliant to ICAO Annex 16 Vol. 2, and the Onera fine particles chain whichwas partially compliant to SAE‐E31 AIR6241.
5 Mermose & cruise particles – FORUM‐AE CC Workshop – 2&3 April 2014
Engine Campaign / Test bench
Snecma/gaseous pollutants
Chain
Onera/fine particles
Chain
P2
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Results / Emissions indices gradients
Number & Mass emission indices at 85%:
– CPC concentration values exploited for number
– Pegasor concentration values exploited
– up to ~25% variation observed both for number and mass
– Fine radial measurement shows smooth evolution for number (not performed for mass)
y = ‐1E‐05x2 + 0,0022x + 0,8886
7,00E‐01
7,50E‐01
8,00E‐01
8,50E‐01
9,00E‐01
9,50E‐01
1,00E+00
1,05E+00
50 100 150 200 250
Ein (136°)
EIn traverse (45°)
Ein traverse (135°)
Ein traverse (‐135°)
Ein traverse (‐45°)
Check
Traverse and fine radial measurements at 85% ‐ EIn (adim)
EIn (#/kg) ‐adim
7,00E‐01
7,50E‐01
8,00E‐01
8,50E‐01
9,00E‐01
9,50E‐01
1,00E+00
1,05E+00
50 70 90 110 130 150 170 190 210 230
EIn traverse (45°)
Ein traverse (135°)
Ein traverse (‐135°)
Ein traverse (‐45°)
Check
Traverse and fine radial measurements at 85% ‐ EIm(adim)
EIm (g/kg) ‐adim
radiusRadius (mm) (mm)
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Results / Emissions indices
Average emission indices in mass and in number were obtained for all engine powers except 7%.
Values are of the same order as those observed recently on CFM56 (A‐PRIDE5)
Maximum values are achieved around 85% LTO.
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
0% 20% 40% 60% 80% 100% 120%
Eim (g/kg) ad
im
% régime
EIm (from Pegasor) ‐ adim
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
0% 20% 40% 60% 80% 100% 120%
EIn (n/kg) adim
% régime
EIn (from CPC) ‐ adim
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Cruise particles estimations?
What is the need?– EI in mass?
– EI in number?
– Size distribution?
– Reactivity?
– …
What is the origin and the uncertainty of the values currently used in inventories?
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Cruise particles estimations?
Emission Indices on the ground:– Direct measurements: few results become available (APEX, AFEX, A-
PRIDE5, Mermose…)o It is observed that EI may vary (up to 10% 20%?) at the core nozzle exit
section
– Correlation to Smoke Number:o Only proposed for EI in mass
o What is correlated is the particles mass concentration, and a second steppermits to derive the EI
o Some uncertainties attached to the SN (measurement effects, ambianteffect, jet A1 fuel effect, engine configuration effect: TF or MTF)
o Uncertainties linked to the correlation: such a correlation is insenstive to thesize distribution ; the FOA1 SN/particles concentration correlation wasmainly used up to now ; alternative has been recently proposed by Stettler &al (2013) which induces a non negligible increase.
FOA FOX
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Cruise particles estimations?
Emission Indices in cruise:– Direct measurements: chasing aircrafts (DLR campaigns, TC2…)
o Uncertainties?
– Combustor test rig measurements: o at the exit of the combustor in a test rig with actual cruise conditions in terms
– Correlation to ground values: o Stettler et al (2013) recent analysis, propose an interesting correlation of the
cruise particles concentrations to the ground concentration.
o This correlation is established for conventional combustor technology
o This analysis and its conclusions seem important material to consider.
Mermose & cruise particles – FORUM-AE CC Workshop – 2&3 April 2014
Conclusion 18/15
A successful engine campaign:
‐ Very good cooperation between all project members (ind, res. centers, ac. )
‐ Nearly 7 hours of engine run (on 4 days) providing effective nvPM measurements
‐ High experience gained and key points still investigated (inputs to AIR6241)
‐ CAER (french DGAC funded pgm): Alternative fuel also tested (30‐85‐100% LTO)
Results:
‐ First time traverse measurements of nvPMs are performed behind a turbofan engine
‐ Complete particles data for 30% to 100% T/O thrust: real‐time and laboratory ;
‐ First set of representative results of SaM146 mass and number particle emissionsindices (EIs). Focus is put here on EIs, but a huge scientific work was also performed(Onera, IRSN, CNRS) to fully characterise particles (morphology, chemistry, reactivity)and will be published.
- but fewer iceparticlesbecome larger, epecially in main flightregions
- decrease in optical depth
ice water content [mg/m3]
mean ice particle size [µm]
optical depth
240 hPa
Folie 8
Experiment: Coverage
Lisa Bock • FORUM-AE 03.04.2014
no decrease
significant changes in regions into which contrail cirrus are transported
decrease by70 %
> 0.05
total coverage
coverage of visible contrail cirrus
> 0.05
Folie 9
Experiment: Radiative Forcing
Lisa Bock • FORUM-AE 03.04.2014
change of initial ice particle number decrease of mean radiative forcing almost 60 %
radiative transfer parameterization in ECHAM5 needs to betested for small (r < 10µm) ice particles
mean: 29 mW/m2 mean: 12 mW/m2
PRELIMINARY
Folie 10
Summary
- Introduction of contrail ice particle number in the climate modelconsistent with two-moment-scheme of natural cirrus better representation of microphysical processes and better
knowledge of microphysical and optical properties of contrailcirrus
- Initial ice particle number strongly affects the microphysical and opticalproperties of contrail cirrus
- Reduction of initial ice particle number does not lead to a generaldecrease of the contrail lifetime, but the time contrail cirrus are visible( > 0.05), is shorter
Lisa Bock • FORUM-AE 03.04.2014
Thank you!
Lisa Bock • FORUM-AE 03.04.2014
FAIR
fewer aerosols fewer ice crystals decreased albedo larger sedimentation lower ice water content lower rad. effects larger ice crystals shorter life time
smaller contrail radiative forcing?
Soot‐rich regime Soot‐poor regime
soot
volatile particles
ambient liquid aerosols
liquid droplets
Dilution and cooling of jet plume
contrail iceparticles soot
volatile particles
ambient liquid aerosols
Dilution and cooling of jet plume
contrail iceparticles
liquid droplets
In soot-poor regime droplets / ice crystals are also formed on ambient andvolatile plume particles particularly at low temperatures
- vertical extent - ice crystal number- distribution of ice crystals- sensitivity to meteorological conditions- differences persist in contrail cirrus……
Summary
Aircraft type
- vertical extent - ice crystal number- distribution of ice crystals- sensitivity to meteorological conditions- differences persist in contrail cirrus- …- …
Thank you for your attention!
Norman GörschDeutsches Zentrum für Luft- und Raumfahrt e.V.
Institut fuer Physik der AtmosphäreTelephone +49 8153 28 1537
Forum AE workshop: Oberpfaffenhofen, 2 – 3 April 2014
Optical properties of contrails and contrail ice
crystals - consequences on their climate impact
A. SchwarzenboeckA. ChauvignéO. JourdanV. ShcherbakovJ.-F. GayetCh. GourbeyreG. Febvre
Laboratoire de Météorologie Physique (Laboratory of Physical Meteorology) Clermont –Ferrand, France
Forum AE workshop: Oberpfaffenhofen, 2 – 3 April 2014
Sphericalliquid particles
Typical diameteris less thanroughly 3 μm
The diameteris increasingwith the distancefrom the aircraft
Forum AE workshop: Oberpfaffenhofen, 2 – 3 April 2014
Fifth Assessment Reportof the Intergovernmental Panel on Climate Change
(IPCC 2013)
From Table 8.5: Confidence level for the forcing estimate.
Confidence
Level
Basis for Uncertainty Estimates (more certain
► less certain)
Contrails Medium
Contrails observations , large number of model estimates
► Spread in model estimates of RF and uncertainties in contrail optical properties
Contrail-induced
Cirrus Low
Observations of a few events of contrail induced cirrus
► Extent of events uncertain and large spread in estimates of ERF
Radiative Forcing (RF) Contrails from aviation +0.01 (+0.005 to +0.03) W m–2
Effective Radiative Forcing(ERF)
Combined contrail and contrail-cirrus +0.05 (+0.02 to +0.15) W m–2
Year 2011
Regional RF: ~ (global RF) x 6.
The differences in the net RF reach up to 50%.
Forum AE workshop: Oberpfaffenhofen, 2 – 3 April 2014
Cloud particles
Sampling Volume
Paraboloidal miror
Laser Beam
Symmetry axis
Photodiodes
Optic fibres
θ
The airborne Polar Nephelometer probe
Forum AE workshop: Oberpfaffenhofen, 2 – 3 April 2014
Polar Nephelometer:Measurement of the scattering phase functionof cloud particles (3 µm < D < ~ 1 mm).
Polar Nephelometer onboard the DLR Falcon aircraft
Forum AE workshop: Oberpfaffenhofen, 2 – 3 April 2014
Time series at 1s resolution for the flights 19b and 16b.(a) Extinction (in km-1) and (b) Asymmetry parameter measured by the Polar Nephelometer;(c) and concentration of nitric oxide (in ppbv) measured by chemiluminescence technique
Aircraft and soot dependent radiative forcing by aviation induced cirrus –estimates from observations and model studies
Ulrich Schumann
DLR – Institut für Physik der AtmosphäreOberpfaffenhofen
Progress in Understanding Aviation-Induced Cirrus
1. ML-CIRRUS with HALO
2. CONCERT with Falcon
3. CoCiP + Meteosat +...
4. RF as in IPCC 2013
5. Aircraft effect
6. Soot effect
ML-CIRRUS 1CONCERT References
Voigt et al., ACP, 2010: overview and CoCiP testsVoigt et al., GRL, 2011: optical depth in young contrailsKübbeler at al., ACP, 2011: Thin and subvisible cirrus Jurkat et al., GRL, 2011: HONO, H2SO4/SO2Gayet et al., ACP, 2012: aspherical particlesJessberger et al. , ACP, 2013: Aircraft ImpactSchumann et al. , GRL, 2013: Particle number and Soot Impact
New insight on contrail properties – results of CONCERT 2008
5
Contrail Cirrus Prediction Tool - CoCiP Contrail Cirrus Prediction – Example: 0600 UTC in June 2006
Based on a 3-days global simulation for March 2006
cross‐flight direction, y
*) http://de.wikipedia.org/wiki/Lufthansa
Conclusions 1: Soot has strong impact on contrail cirrus RF
• An increase in the number of ice particles in young contrails by a factor of 2 causes a factor of 21/3 = 1.26 change of optical depth for fixed ice water path and fixed radiation extinction coefficient and correspondingly reduced effective radius (the Twomey effect).
• The larger RF change is a consequence of further changes:
• The model computes increases of visible contrail cover by 1.29, contrail age by 1.16, contrail width by 1.22, and contrail geometrical depth by 1.14. All these changes contribute to the larger changes in RF compared to that of optical depth.
• The quantitative model results depend on model details.
• Open: nonlinear interactions in the contrail for changes soot concentrations
• More important: Soot changes the whole cloud system
• The relative radiative effects of two global hypothetical fleets of A380 or A319 aircraft has been studied with CoCiP.
• The global simulation with CoCiP shows a change in net RF by factors of 0.73 or 2.51, when the global fleet of aircraft is replaced by a fictive fleet in which all aircraft are either A319 or A380 aircraft, respectively.
• Hence, the RF is about a factor 3.5 larger for an A380 than for an A319. This change results mainly from the larger aircraft mass (factor 8) and the larger fuel consumption (factor 6).
• These parameters cause changes in the simulated soot emissions, size-dependent mixing in the aircraft wake, and related contrail properties in the model.
• Hence, the global contrail effects depend strongly on the aircraft types.
• In terms of RF per passenger seat or RF per passenger-seat distance, the ratio between the simulation results for different aircraft is closer to unity or even smaller than one, i.e. a larger aircraft may have smaller climate impact per transport unit than a smaller aircraft.
• Development and improvement of numerical models of contrails and cirrus‐contrail;
• Development of parameterizations of contrails and induced cirrus for GCM;
• Aircraft in‐situ measurements of contrail and contrail‐cirrus composition;
Wake evolution in four regimes Gerz et al. (1998)
t = 0 s.
a few hours
t ~ 1000 s.
t ~ 100 s.
t ~ 10 s.
Vortex regime
Dissipation regime
Diffusion regime
Jet regime
~ 1 km
~50 m
Evolution of aircraft wakes
Vortex roll-up;jet/vortex interaction
Vortex descent;Crow(elliptic) instability
Stratification; vortex break-up
Atmospheric variability ... to global scales
Zw = ua/c tua/c = 250 m/s (cruise)
ZwO
Modelling the diffusion regime to obtainparameterisations for large scale models: Life time of contrails and induced cirrus Evolution of the microphysical and meanradiative properties
Development acheived: Implementation of the turbulence scheme of « Paoli and Sharif »
Idealized simulations of the diffusion regime in atmospheric
layers under several levels of turbulence
Paoli et al, ACP 2014
•Atmosphere at tropopause level: N=0.012 s-1, Sice=130%•Flight level : 11 km
The IMPACT project aims to contribute reducing uncertainties in calculating the climate impact of aircraft emissions and in particular those associated with contrails and induced cirrus but also to the NOx emissions (impact on methane and ozone) and particulates (sulfates, nitrates, soot).
• Development and improvement of numerical models of atmospheric composition and climate necessary for this problem;
• Climate impact studies appropriate to the subject and climate perturbation due to aircraft emissions by 2050 time horizon;
• Suggest ways to develop emission inventories associated with future fleets and specify the needs of the climate modeling in terms of emission inventories.
Burkhard and Karcher, 2012
1. Critical analysis of current global emissions by the fleet commonly used in models based on the existing literature but also on the basis of new measurements of emission factors.
2. Development and adaptation of the climate and chemical atmospheric composition models for use in impact studies by the aircraft fleet : representation of the region of the upper troposphere-lower stratosphere (vertical resolution, joint treatment tropospheric and stratospheric chemistry), coupling between the particles and the gas phase chemistry, coupling between chemistry and climate (direct and indirect effects of particles), radiative effect of contrails and induced cirrus.
3. The models should take into account the transient formation of contrails, cirrus and induced composition changes in the plume including ozone formation. These models must also be able to use new emission scenarios when they become available.
WP 1 : Development of the climate‐chemistry models (months 1‐30)WP 1 : Development of the climate‐chemistry models (months 1‐30)
Perturbations of the chemical composition and climate associated with aircraft emissions in the context of future IPCC simulations for present-day conditions but also for the 2050 time horizon ;
Perform sensitivity simulations with alternative future scenarios of emissions from aviation to quantify the uncertainty associated with different assumptions regarding the fleet, the engine and the fuel;
Contribution of soot emissions to contrails formation and induced cirrus and to the optical and radiative properties of clouds;
Contribution of contrails and induced cirrus to the total radiative forcing and to the climate impact ;
Use of cost / benefit climate functions integrating the time evolution of the radiative effects or of temperature changes resulting from aircraft emissions to quantify the effect of each factor to climate change functions ;
Critical analysis of future emission scenarios and recommendations in terms of possible new research programs to develop new emission inventories beyond IMPACT .
WP 2 : climate impact studies (months 18‐48)WP 2 : climate impact studies (months 18‐48) SNECMA – Emissions from the current fleetSNECMA – Emissions from the current fleet
Complete a critical revue of emission data used in previous projects.
Input : Technical reports from Quantify, scientific publications, interview of experts.
Output : Assessment Report on the hypothesis used to estimate the emissions indices (g/kg)for NOx at cruise altitude, et the indices for emitted particles (numbre/kg ou g/kg) at cruisealtitude.
Illustration of the dispersion of NOx
emission indices (Lee et al 2013) due to:
•Hypothesis on the engine behaviour;
• Various modelisation of the EINOx(at a given Qfuel ou engine regime);
•All other factors.
Version standard Ozone change : plume chemistry
CNRS/LIVE – Increased vertical resolution in LMDz‐INCA (1)
Ozone change : no plume chemistryPlume chemistry parameterisation (Cariolle et al. 2009)‐ Increase from 19 to 39 levels.
‐ Include both gas phase chemistry and aerosols (SO4, BC et OC, NO3, naturelles).
CNRS/GAME – Tropospheric chemistry in the CNRM‐CCM modelCNRS/GAME – Tropospheric chemistry in the CNRM‐CCM model
How do different research modes cope with this enormous ranges of variability?
Measurements
in situ:
Single events, questionable representativeness (thick contrails are the easiest to find and observe);
Connection with background situation generally possible and should be recorded .
satellite:
Good global coverage with low resolution, only bulk properties;
Connection with background situation perhaps possible, in particular background clouds and albedo;
Detection efficiency for optically thin contrails and contrail cirrus is low; fraction of undetected contrails depends on sensor and must be estimated with aid of global model results.
Institut für Physik der Atmosphäre
Low detection efficiency of optically thin contrails
Kärcher et al. ACP 2009
Institut für Physik der Atmosphäre
How do different research modes cope with this enormous ranges of variability?
Theory, modelling
CRM:
Good representation of and radiation;
Single situations in parameter space of many dimensions;
Mostly idealised situations.
GCM and CoCiP:
Global focus, but simplified representation of contrail Access to actual air traffic data sometimes a problem
Validation with observed cases is difficult because of the large number of relevant parameters.
Institut für Physik der Atmosphäre
Imperfection of (contrail) models
Model InadequacyModel structure differs from the structure of the modelled system per definitionem.Various reasons:• lack of knowledge: known and
unknown unknowns;• idealisation, simplified
equations;• constraints of computing time
and memory.
Model UncertaintyModel parameters; Initial and boundary conditions; Subgrid parameterisations;Non-linearity;Internal variability.
Epistemic and ontic uncertainties
Ontic (aleatory) uncertainties are irreducible.
Prediction error
Institut für Physik der Atmosphäre
Points for discussion
1. How far is it possible to reduce the uncertainty in contrails’ RF significantly?
2. Is it possible to devise meaningful mitigation measures for individual contrails if there remains an irreducible RF for all contrails?
3. Can essential input data for mitigation strategies be predicted (forecast) such that contrail mitigation can be performed in flight planning phase?
4. Are model results or forecasts robust enough to base mitigation strategies upon them? If not, which parameters/parameter combinations are most important to be fixed?
Institut für Physik der Atmosphäre
Points for discussion
5. Which approach to contrail mitigation is most promising to yield a substantial gain and least error-prone in making a wrong decision?
a. climatology based mitigation
b. individual contrail impact assessment
c. avoid only those contrails that can safely predicted to have a significant warming impact
