Design of a Flight Planning System to Reduce Persistent Contrail Formation Team: Harris Tanveer Jhonnattan Diaz David Gauntlet Po Cheng Yeh Sponsors: Metron Aviation Center for Air Transportation Systems Research (CATSR) to Reduce Greenhouse Effects Origin/Destination CO2 Longwave Radiation Shortwave Radiation GREAT CIRCLE Fuel Consumption: DISTANCE 4713.7 kg Contrails Form: 26.15 miles Flight Duration: 1.56 hours Weather Forecast Aircraft B737-800 ISSR PARTIAL AVOIDANCE Fuel Consumption: kg Contrails Form: miles Flight Duration: hours 4745.3 13.2 2.16 - ICE SUPER SATURATED REGION (ISSR) ISSR MOST AVOIDANCE Fuel Consumption: kg Contrails Form: miles Flight Duration: hours 4795.1 5.4 2.30
Agenda Context Stakeholder Analysis Problem, Need Statement, Mission Requirements Design Alternatives & Experiment Simulation Results Questions 2
Scheduled Passenger Traffic (Millions) 300.0 250.0 200.0 150.0 100.0 50.0 0.0 Projected Growth in Air Travel Requires Attention to Climate Impacts Projected Passenger Increase y = 4.2115x - 8317.8 R² = 0.9988 4.2 million passengers/year increase 54.85% projected increase in passengers from 2013 to 2033 2010 2015 2020 2025 2030 2035 Year Aviation Demand + + Aircraft Emissions (CO2, water vapor) + Radiative Forcing + Global Climate Change # of Flights Source: Form 41 and 298C, U.S. Department of Transportation. Lee (2009). Transport impacts on atmosphere and climate: Aviation. Atmospheric Environment. 2005: 641 Tg/yr CO2 by Aviation Industry 3
Contrail Radiative Forcing Depends on Parameters Such as Solar Zenith and Contrail Opacity Radiative Forcing (RF) - energy/area W m 2 difference between incoming shortwave radiation and outgoing longwave radiation RF due to contrails is dependent upon- Solar zenith angle Contrail opacity Ambient Temperature Zenith Longwave Radiation Shortwave Radiation θ= 80 o to 90 o (RF +) θ Schumann, U. (2011). Potential to reduce the climate impact of aviation by flight level changes. AIAA Atmospheric Space Environments Conference Schumann, U. (2012). A Parametric Radiative Forcing Model for Contrail Cirrus. 4
Contrails and Associated Clouds Cause Net Radiative Forcing Similar in Size to CO2 Effects 30 mw/m^2 CO2 SW LW Contrails + Induced Cirrus RF 30 mw/m^2 Contrails induce cirrus clouds Induced cirrus clouds may increase Total Aviation RF by 41% (0.055 Wm -2 to 0.078 Wm -2 Lee (2009). Transport impacts on atmosphere and climate: Aviation. Atmospheric Environment. 5
Atmospheric Conditions for Contrail Formation Depend on Altitude, Temperature, and Relative Humidity Schmidt-Appleman Criterion specifies critical temperature where contrail cirrus may occur Cruise Altitude: 29,000ft - 41,000ft Temperature: below -40 Humidity: RHi > 100% RHi= Ice content/ice capacity (Similar to RHw) RHi > 100% indicates Ice Super-Saturated Region (ISSR) Appleman, H., 1953. The formation of exhaust contrails by jet aircraft. Bull. Amer. Meteor. Soc. 34, 14 20. Sridhar, B., 2011. Aircraft trajectory optimization and contrails avoidance in the presence of winds. 6
% of Airspace with ISSR 14% 12% 10% 8% 6% 4% 2% 0% We Analyzed 45 Days of Detailed NOAA Weather Data to Determine ISSR Locations Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Averages Data suggests: ISSR more likely in lower altitudes from September to April ISSR more likely in higher altitudes in July and August NOAA Rapid Update Cycle- CONUS in grid Temperature and RHw data Each cell 13.54x13.54 km Created a tool (left): Red = ISSR Flight levels: 7 267 283 301 320 341 363 387 414
Operational Changes to Flight Planning Could Be Used for ISSR Avoidance Y Z RHi>100% Red: Travel Through ISSR Blue: ISSR Avoidance B Destination Origin A X Airline Dispatcher Proposed Flight Plan Accepted/Rejected Flight Plan Flight Plan http://www.faa.gov/air_traffic/publications/controller_staffing/media/cwp_2012.pdf Flight Service Stations Flight Plan ATC Vectors Flight 8
Developed Method to Perform Tradeoff Between Decrease in Contrail RF and Increase in CO2-based RF Due to ISSR Avoidance ISSR Avoidance may generate excess CO2 RF Contrails (from flying through ISSR) Depends on solar azimuth, contrail opacity, ambient temperature CO2 Longwave RF Excess CO2 (from flying around ISSR) Contributes a part of 641 Tg/yr CO2 emissions and 30 mw/m^2 RF Shortwave Earth Lee (2009). Transport impacts on atmosphere and climate: Aviation. Atmospheric Environment. Schumann, U. (2011). Potential to reduce the climate impact of aviation by flight level changes. AIAA Atmospheric Space Environments 9 Conference.
Agenda Context Stakeholder Analysis Problem, Need Statement, Mission Requirements Design Alternatives & Experiment Simulation Results Questions 10
Primary Stakeholders & Interactions Currently no incentive to change High level Triple Bottom Line* perspective: Congress incentivizes Airline participation Win-Win Public has clean environment They have goodwill to elect officials who lower taxes Participating airlines have more revenue Invest in greener technology More jobs *Stoner, J., Wankel, C., & Malleck, S. (2008). Global Sustainability Initiatives: New Models and New Approaches. Charlotte, N.C.: Information Age Pub.. 11
Agenda Context Stakeholder Analysis Problem, Need Statement, Mission Requirements Design Alternatives & Experiment Simulation Results Questions 12
Radiative Forcing (mw/m^2) Achieving Contrail Neutrality by 2020 Aviation Demand + 16 14 12 10 8 6 4 2 0 + # of Flights Aircraft Emissions ( CO2, water vapor) 3.5 9.4 + Radiative Forcing + 7.06 Marquart et al., 2003: Future development of contrail cover, optical depth, and radiative forcing: Impacts of increasing air traffic and climate change. 13 http://www.icao.int/environmental-protection/37thassembly/a37_res19_en.pdf 14.8 Contrail Neutral 1980 1990 2000 2010 2020 2030 2040 2050 2060 Years Global Climate Change ICAO: reduce net CO2 emissions by 2050 compared to 2005 baseline and cap CO2 emissions in 2020 Estimated Radiative Forcing by Contrails Contrail Neutral
Problem & Need for ISSR Avoidance Problem: Integrated across all flights and all conditions, contrail effects lead to a net positive radiative forcing (warming effect). Lack of system negotiating stakeholders needs in order to provide flight paths avoiding ISSR while accounting for tradeoffs between Excess distance flown Excess fuel consumption Radiative from excess CO2 emissions RF from contrail formation Need flight planning system to avoid ISSR while accounting for tradeoffs between Excess distance flown Excess fuel consumption RF from excess CO2 emissions RF from contrail formation Royal Commission on Environmental Pollution, The Environmental Effects of Civil Aircraft in Flight, London, UK, 2002. http://www.rcep.org.uk/avreport.htm. 14
Mission Requirements MR Summary MR 1.0: Reduce contrail RF to 2005 baseline MR 2.0: Maintain contrail RF at 2005 baseline MR 3.0: Flight path Explanation System shall provide ability by 2020 to reduce RF due to contrails to 2005 baseline of 7.06 mw/m^2 System shall provide ability by 2020 to maintain RF due to contrails to 2005 baseline of 7.06 mw/m^2 System shall provide alternative flight paths for ISSR avoidance 15
Agenda Context Stakeholder Analysis Problem, Need Statement, Mission Requirements Design Alternatives & Experiment Simulation Results Questions 16
Operational Concept for ISSR Awareness in Dispatcher Interaction with Flight Planning System Weather Forecast 1. User inputs O/D and Aircraft info Origin/Destination Aircraft B737-800 2. System Retrieves ISSR Information 3. System outputs flight path info No ISSR Avoidance Fuel Consumption: 4713.7 kg Contrails Form: Flight Duration: 26.15 1.56 miles hours Partial ISSR Avoidance Fuel Consumption: 4745.3 kg Contrails Form: Flight Duration: 13.2 2.16 miles hours Complete ISSR Avoidance Fuel Consumption: 4795.1 kg Contrails Form: 5.4 miles - ICE SUPER SATURATED REGION (ISSR) Flight Duration: 2.30 hours 17
ISSR Avoidance Alternatives- Pairing Avoidance Aggressiveness with Flight Lengths Design Alternative Avoidance Aggressiveness 1 No Avoidance Short Flight Length 2 No Avoidance Medium 3 No Avoidance Long 4 Partial Avoidance Short 5 Partial Avoidance Medium 6 Partial Avoidance Long 7 Complete Avoidance Short 8 Complete Avoidance Medium 9 Complete Avoidance Long Y Flight Length: Short: < 500 nm Medium: 500 1000 nm Long: > 1,000 nm Z ISSR B Destination *Complete avoidance attempted, unless origin/destination located in ISSR Origin A 18 X
Experiment to Analyze Feasibility of ISSR Avoidance Aggressiveness for Flight Lengths Avoidance Aggression No Avoidance Partial Avoidance Complete Avoidance Independent Variables Flight Type Short Medium Long Short Medium Long Short Medium Long Atmospheric Configurations 45 days of weather from NOAA Outputs Fuel Burn CO2 emissions Radiative Forcing (Contrails and CO2) Flight Distance Flight Duration %Distance in ISSR Used representative sample of 400 flights, which resulted in 54,000 combinations 19
Agenda Context Stakeholder Analysis Problem, Need Statement, Mission Requirements Design Alternatives & Experiment Simulation Results Questions 20
Simulation Scope Flight Data 1 Day of Flights Continental United States Boeing 737 Constant en-route airspeed Aircraft fly only on 8 levels Jet A Fuel ($3.06/gallon)* Strategic Maneuvering Pre-takeoff planning to avoid ISSR Safety assumed to be responsibility of ATC Contrail RF ISSR always produce contrails (binary regions) Contrail properties estimated with deterministic values 80 o solar zenith angle CO2 RF Only Excess CO2 Considered Excess CO2 RF contributes to global CO2 RF of 30 mw/m^2 *http://www.eia.gov/dnav/pet/hist/leafhandler.ashx?n=pet&s=eer_epjk_pf4_rgc_dpg&f=a 21
Physical Processes Modeled Fuel Consumption f cr = C f1 1 + V TAS C f2 CO2 Emissions C TCR C TC,1 1 H p C TC,2 + C TC,3 H p 2 RHi for persistent contrail formation C fcr Eurocontrol (2011). User manual for the Base of Aircraft Data (BADA) revision 3.9 Jardine, C. (2009). Calculating the Carbon Dioxide Emissions of Flights. Sridhar, B. (2011). Design of aircraft trajectories based on trade-offs between emission sources. Radiative Forcing due to Contrails Radiative Forcing due to Excess CO2 Schumann, U. (2011). Potential to reduce the climate impact of aviation by flight level changes. AIAA Atmospheric Space Environments Conference. Lee (2009). Transport impacts on atmosphere and climate: Aviation. Atmospheric Environment. 22
I/O for Simulation to Conduct ISSR Avoidance Experiment Simulation Elements: Trajectory calculator Contrail calculator CO2 Emissions calculator RF calculator Simulation Facts: Runtime 9 days Output: 54,000 flight combinations Simulation uses modified A* routing algorithm 23
Agenda Context Stakeholder Analysis Problem, Need Statement, Mission Requirements Design Alternatives & Experiment Simulation Results Questions 24
As Avoidance Increased, % Duration in ISSR Decreased Histograms of % of Distance in ISSR by Avoidance Type 0.0 0.3 0.6 0.9 1.2 1.5 1.8 Long Flights 100 50 % DistISSR_Long, No Avoidance % DistISSR_Long, Complete 97% decrease in Average % of Distance in ISSR Medium Flights Percent 0 % DistISSR_Medium, No Avoidance % DistISSR_Medium, Complete 95% decrease in Average % of Distance in ISSR 100 50 Short Flights 100 50 % DistISSR_Short, No Avoidance % DistISSR_Short, Complete 76% decrease in Average % of Distance in ISSR 0 0 0.0 0.3 0.6 0.9 1.2 1.5 1.8 % of Distance in ISSR 25
As ISSR Avoidance Increased, RF Contrails+CO2 per Flight Path Decreased Histograms of Total RF by Flight and Avoidance Type 0.0000E+00 3.5000E-11 7.0000E-11 1.0500E-10 1.4000E-10 1.7500E-10 2.1000E-10 2.4500E-10 Long Flights 50 25 Long, No Av oidance Long, Complete 18.49% Decrease in Average TOTAL RF from None to Complete Avoidance Medium Flights Percent 0 Medium, No Av oidance Medium, Complete 18.35% Decrease in Average TOTAL RF from None to Complete Avoidance 0 Short, No Av oidance Short, Complete 50 25 Short Flights 50 25 0 0.0000E+00 18.07% Decrease in Average TOTAL RF from None to Complete Avoidance 3.5000E-11 7.0000E-11 1.0500E-10 1.4000E-10 1.7500E-10 2.1000E-10 2.4500E-10 Radiative Forcing (W/m^2) 26
Tradeoff Between RF Contrails and RF ExcessCO2 per Flight Path for Long Flights RF Contrails > RF ExcessCO2 RF Contrails <RF ExcessCO2 At 99% Avoidance- Benefits of Avoiding ISSR are Outweighed by RF from Excess CO2 for Long Flights 27
As Avoidance Increases, Cost Increases and Total RF Decreases Long Flight Medium Flight Short Flight % Decrease in Average Total RF (No Avoidance to Complete Avoidance) 18.49% 0.94% 18.35% 1.33% 18.07% 4.14% % Increase in Average Cost (No Avoidance Complete Avoidance) 28
Summary of Conclusions As avoidance increases, on average the aircraft spends less of its flight path in ISSR 97% decrease for Long 95% decrease for Medium 76% decrease for Short Avg RF Contrails is greater than Avg RF Excess CO2 for all flights until about 99% avoidance As % avoidance increases, cost increases, and Total RF decreases 29
Average Total RF vs. Average Cost (Per Flight Path) % Decrease in Average Total RF (No Avoidance to Complete Avoidance) Long Flight 18.49% 0.94% % Increase in Average Cost (No Avoidance to Complete Avoidance) Medium Flight 18.35% 1.33% Short Flight 18.07% 4.14% 30
Recommendations Accounting for tradeoff between RF Excess CO2 and RF Contrails : Conduct pilot test at 99% avoidance for all flight durations Recommend further research on: Increasing level of scientific understanding behind cloud science. Who should pay for increased fuel and crew costs as distance increases? How is passenger comfort impacted from ISSR avoidance? How can these flight paths be optimized? 31
Questions 32