MONITORING AIRCRAFT CONDENSATION TRAILS

Transcription

1 MONITORING AIRCRAFT CONDENSATION TRAILS Frank Jelinek EUROCONTROL Experimental Centre, Bretigny sur Orge, B.P.15, FRANCE, ABSTRACT Recent publication of atmospheric researchers (Minis et al. 2003, Garber et al. 2004, Sausen, et. all 2004) indicate the Radiative Forcing of aviation triggered cirrus clouds to be as large as the estimate (IPCC) on the RF of the total of all other pollutants. The ESA sponsored project CONTRAILS aimes to create a better clarity on three main related core aspects: Is there a real significant correlation between air traffic movements, contrails and cirrus cloud coverage? Are mathematical contrail models reliable enough to consider them as a starting point for a potential future contrail forecasting service? Is it possible to further improve Contrail Satellite Earth Observation and automatic contrail detection algorithms (CDA) to imagine the feasibility of a contrail monitoring service? 1. INTRODUCTION established for the period of the next 25 years and beyond. Air traffic management and airline operations would require forecasting and monitoring systems which would allow to mitigate the risk of contrail building already during the flow management and fight planning step. With such systems ATM would have two options to guide aircraft operations aiming to avoid contrail production: 1. Fly lower 2. Fly around Studies on the Fly lower option indicate that this would cause higher fuel burn and increased emission output of fuel burn proportional pollutants, e.g. CO 2, H 2 0, SO x of about 4% (Noland et. al 2003) and as well increased NO x emissions. To avoid such drawback from required lower cruise speeds at lower altitudes a radically changed aircraft and wing design would be required. Dependent on the atmospheric conditions, aircraft provoked condensation trails (contrails) may remain persistent. Those persistent contrails can evolve into cirrus clouds. Recent publications of atmospheric research express the hypothesis of an increased contribution of aviation triggered cirrus clouds to radiative forcing than estimated earlier. Where in the past the main focuss in terms of global aviation emissions was mainly on CO 2 and NO x, this focus might need to be changed to H 2 0 emissions. If this need is confirmed, a paradigm shift in the discussion around aviation and environment might become necessary. 2. TECHNICAL AND OPERATIONAL CONSEQUENCES The technical and operational consequences of such paradigm shift would be important. Engine and airframe manufactures would need to significantly rethink their technology development roadmaps already J.Bauch,TU Braunschweig 1993 Fig. 1. Lower altitude operation aircraft design From the moment the decision is taken to implement such technology it would require about 25 years to change the global aircraft fleet to such new design aircrafts. Studies on the Fly around option indicate that this would cause higher fuel burn and increased emission output of fuel burn proportional pollutants, e.g. CO 2, H 2 0, SO x of even 8-10% (EEC/PRU KPI studies; 2002) and as well increased NO x emissions in a similar manor. Proc. of the 2004 Envisat & ERS Symposium, Salzburg, Austria 6-10 September 2004 (ESA SP-572, April 2005)

2 3. ECONOMICAL BACKGROUND The economical consideration is not negligible, even if one assumes that the cost on fuel contributes only for about 20% to the total cost for a flight mission, strongly tackle the economical situation of the airlines. The importance of the financial impact might even be better understood if it is known that the net result as a percentage of the revenue for all IATA airlines during the period between was only +0.4%. The economical situation of the airlines, as we all know, surely did not become better as a consequence of September 11 th, SARS, Golf war II etc. This background gives extreme importance to the ESA CONTRAIL project since it will significantly contribute to consolidate knowledge on correlation between aircraft operation, contrails and cirrus cloud coverage. In addition it will provide key information about feasibility and quality of potential future forecasting and monitoring services in support of the ATM planning process. Fig. 2. EUROCONTROL Organisation Its top priority is on aviation safety, where with its revised convention in 1997 it has adopted a strong commitment to environment. With different entities and services it actively contributes to the reduction of the aviation caused environmental impact. Route Charges Collection CRCO Director General M-UAC Maastricht UAC for DE, NL, LU, BE Only if such services are considered feasible, would it make sense to start a political discussion on the implementation of such mitigation policies. UAC for CZ, SK, HU, AU, SL, HR, BiH IFPS Flow Management R&D for ATM CEATS Praha, Budapest CFMU EEC Bretigny IANS Luxembourg EATMP Support Services Training institute Training engineering Strategy ATM Managing Agent 4. AIR TRAFFIC MOVEMENT DATA RU Regulatory Unit The core input component for atmospheric research and emission estimation for the aviation sector is the availability of realistic air traffic movement data of a statistically significant quantity. Even reference research projects and publications in the global aviation emission domain relied in the past on theoretical and simplified air traffic movement data or based their results on a rather small number of traffic days of realistic quality. Great circle flight trajectories where applied for city pairs published in global airline schedules. Theoretical vertical profiles where associated to such flight trajectories to model flight operation due to the unavailability of realistic air traffic movement data to atmospheric research. The provision of realistic air traffic movement data to the CONTRAILS project in the scientifically required granularity will be assured by EUROCONTROL. Performance Monitoring PRU SRU Safety Regulation Fig. 3. Organisational structure & entities EUROCONTROL s Environmental Domain, part of the EATMP, and the EUROCONTROL Experimental Centre (EEC) Research Area Society, Environment and Economics (SEE) investigate systematically since several years future ATC and ATM means which could be beneficial for the environment. They contribute with studies and the development of tools to the provision of reliable information concerning aviation and environment in support of the political decision making process. Large amounts of Air traffic data will be provided to the CONTRAILS project in two different forms: EUROCONTROL is the European Organisation for the Safety of Air Navigation with currently 34 Member States ( ).

3 4. 1. Air Traffic Density (ATD) Maps for each day of the year 2004 This data will be provided for the Region of Interest (ROI) (20N/80W - 75N/50E) covering complete Europe, the North Atlantic and large parts of the U.S. East Coast. Fig. 4. ROI covered by ATD Maps for 2004 Daily ATD data will be provided as Grid Maps with a grid granularity of 50 x 50km. Each grid contains the information of the total aircraft kilometer flown inside such grid. (ETFMS) is used to produce Contrail Model maps. In addition to the functionality of the former CFMU TACT system, ETFMS receives surveillance data i.e. radar derived data provided by the Air Navigation Service Providers (ANSPs), position report data provided by the aircraft operators and, meteorological data. ETFMS uses this data to update the existing data coming from flight plans and flow measures. The reception of this accurate real-time data allows ETFMS to re-calculate the current position and future trajectory of flights adding enormously to the accuracy of the data within ETFMS. ETFMS CPR data is currently the most precise representation of the real air traffic. CPR data is not yet available for complete Europe but only for a reduced coverage geographical area. To produce these ATD Maps, EUROPEAN air traffic movement data, which is provided by EUROCONTROL s Central Flow Management Unit (CFMU), will be merged with air traffic movement data provided by United States Federal Aviation Agency (FAA) to cover the complete ROI. This complete set of movement data will be processed at the EEC using the Global Aviation Emission Studies Movement database (GAES-Move) and its gridding capabilities. Fig. 6. Geographical CPR data coverage (2003) 5. CONTRAIL MODEL MAPS At the EEC this CPR data is being processed with TEA, the Toolset for Emission Analysis, to produce contrail maps. Fig. 5. Air Traffic Density Maps By comparing the Air traffic Density Maps with Cirrus cloud maps, the relationship between changes in cirrus and air traffic density shall be quantified. H 2 0 emission estimation of the Advanced Emission Model (AEM) will be produced based on the CPR data. Atmospheric conditions parameters produced with MM5 are fed into AEM and are further increasing the degree of realism of the modelling of the combustion process of the aircraft engine. H 2 O output of AEM and atmospheric condition data is passed further into the TEA Contrail model which is mainly based on the Schmitt-Appleman criterion Correlated Position Reports (CPR) Even more precise Air traffic data in the form of Correlated Position Reports, extracted out of the CFMU Enhanced Traffic Flow Management System

4 TEA AEM MM5 CONTRAIL sensors in order to capture as best as possible the diurnal variation. In addition, cirrus cloud coverage and properties are also be mapped using EO satellite data. Through comparison of cirrus cloud maps with air traffic density maps, the relationship between cirrus and air traffic density shall be quantified. The CONTRAILS project will provide an assessment of the radiative forcing of both the contrails and the cirrus changes. Historical context for Contrails Fig. 7. Contrail Map production at EEC Output of this process are 2D gridded Contrail maps with a resolution of 0.25 to Contrails maps for the years 1985, and 2000 will be prepared aiming to provide the historical context for the one year (2004) intensive study period. Improvement/porting of CDA The existing Contrail Detection Algorithm (CDA) of DLR will be ported during the CONTRAILS project to support additional satellite sensors for which it was not adapted. With the perspective of a potentially future operational monitoring service for aviation, the CONTRAILS project aims to further increase the detection efficiency and to reduce the false detection rate of the available CDA. Details on this work are presented in an specific abstract prepared by DLR. Fig. 8. AEM/TEA Contrail Maps 6. IN-DEPTH VALIDATION PROCESS Air traffic movement data and contrail model grid maps will be compared against Earth Observation of Contrails and Cirrus clouds from several satellite sensors. EUROCONTROL air traffic data and contrail model maps are input data into the further in-depth validation process which is supported and performed by the ESA CONTRAILS project partners DLR, KNMI, DSRS. Fig. 10. EO Satellite Scans for contrails 7. CONCLUSION Fig. 9. CONTRAILS Partner During this validation process, contrails will be mapped for the entire year 2004 using several satellite The ESA project CONTRAILS will validate the most recent hypothesis on correlation between air traffic movements, contrails and cirrus cloud coverage and

5 increased cirrus cloud contribution to Radiative forcing. It will investigate key aspects concerning the feasibility and the obtainable level of quality for a contrail forecasting and monitoring service, which would be required to support a mitigation strategy for a future Air Traffic management system. By its work, the CONTRAIL project will significantly consolidate the information base for the political decision making process and provide details on impact, cost and potential benefit. 8. REFERENCES Penner, J.E., et al.: Aviation and Global Atmosphere, IPCC, Garber, P.D., Minnis, P., Costulis, P.K. 2003: A USA commercial flight track database for upper tropospheric aircraft emission studies. Chesneau, S., Fuller, I., Hustache, J-C., : ATM Flight Efficiency and its impact on environment,, EEC/SEE/2003/001 Jelinek, F., Carlier, S., Smith, J., Quesne, A.,: The EUR RVSM Implementation Project Environmental Benefit Analysis EEC/ENV/2002/008 Jelinek, F., Carlier, S., Smith, J.,: Advanced Emission Model (AEM3) v1.5, EEC/SEE/2004/004 EUROCONTROL site: EEC SEE document site: ESA CONTRAILS project site: Sausen et al.: Aviation Radiative Forcing in 2000: An Update on IPCC(1999), Draft 10.August 2004 Gardner, R.M.: ANCAT/EC2 Global Aircraft Emissions Inventories for 1991/92 and 2015, ECAC, 1998 Minnis, et al.: Contrail Coverage and Radiative Forcing Over the USA Derived from Satellite Data, NASA LRC, Atmospheric Effects of Aviation Conference, 2000 Boin, M., Levkov, L.,: Numerical simulation of the life time of contrails, GKSS Research Centre, Institute of Physics, Geesthacht, Germany, pg Appleman, H., 1953: The formation of exhaust condensation trails by jet aircraft. Bull. Am.Met.Soc., 34, ACARE, The Challenge of the Environment, Volume 2, 2003 NASA, Roadmaps to the Future, version1.0, 2002 Kluger, J., Why High-flying Planes make us less cool, Time Magazin, April 2004 Carlier, S., De Lepinay, I., Smith, J., :MFF2-FT project Global Aviation Emission Study, EEC/SEE/2004/006 Jelinek, F., Carlier, S., Smith, J.,: The Mediterranean Free Flight Programme (MFF) Environmental Benefit Analysis -EEC/SEE/2003/003