Design of a Flight Planning System to Reduce Persistent Contrail Formation to Reduce Greenhouse Effects Team: • • • • Harris Tanveer Jhonnattan Diaz David Gauntlet Po Cheng Yeh Sponsors: • Metron Aviation • Center for Air Transportation Systems Research (CATSR) CO2 Shortwave Radiation Weather Forecast Longwave Radiation GREAT CIRCLE Fuel Consumption: DISTANCE kg Contrails Form: miles Flight Duration: hours Origin/Destination 4713.7 26.15 1.56 ISSR PARTIAL AVOIDANCE Fuel Consumption: 4745.3 kg Contrails Form: 13.2 miles Flight Duration: 2.16 hours Aircraft B737-800 - ICE SUPER SATURATED REGION (ISSR) ISSR MOST AVOIDANCE Fuel Consumption: 4795.1 kg Contrails Form: 5.4 miles Flight Duration: 2.30 hours Agenda • Context • Stakeholder Analysis • Problem, Need Statement, Mission Requirements • Design Alternatives & Experiment • Simulation • Results • Questions 2 Projected Growth in Air Travel Requires Attention to Climate Impacts Scheduled Passenger Traffic (Millions) Projected Passenger Increase 300.0 250.0 200.0 150.0 100.0 50.0 0.0 2010 y = 4.2115x - 8317.8 R² = 0.9988 • 4.2 million passengers/year increase • 54.85% projected increase in passengers from 2013 to 2033 2015 2020 2025 2030 2035 Year Aviation Demand + + # of Flights Aircraft Emissions (CO2, water vapor) + Radiative Forcing + Global Climate Change 2005: 641 Tg/yr CO2 by Aviation Industry •Source: Form 41 and 298C, U.S. Department of Transportation. • Lee (2009). “Transport impacts on atmosphere and climate: Aviation”. Atmospheric Environment. 3 Contrail Radiative Forcing Depends on Parameters Such as Solar Zenith and Contrail Opacity π • Radiative Forcing (RF) - energy/area 2 difference between π incoming shortwave radiation and outgoing longwave radiation • RF due to contrails is dependent upon– Solar zenith angle – Contrail opacity – Ambient Temperature Shortwave Radiation Zenith π= 80o to 90o (RF +) π Longwave Radiation 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 5 Lee (2009). “Transport impacts on atmosphere and climate: Aviation”. Atmospheric Environment. 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 -40β – 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 We Analyzed 45 Days of Detailed NOAA Weather Data to Determine ISSR Locations % of Airspace with ISSR • NOAA Rapid Update CycleCONUS in grid • Temperature and RHw data • Each cell 13.54x13.54 km • Created a tool (left): • Red = ISSR Flight levels: 14% 12% 10% 8% 6% 4% 2% 0% 267 283 301 320 341 363 Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr 387 May 414 Averages Data suggests: •ISSR more likely in lower altitudes from September to April •ISSR more likely in higher altitudes in July and August 7 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 Airline Dispatcher X Proposed Flight Plan Flight Service Stations Accepted/Rejected Flight Plan Flight Plan ATC Vectors Flight Plan Flight 8 http://www.faa.gov/air_traffic/publications/controller_staffing/media/cwp_2012.pdf 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 • RFExcess CO2 (from flying around ISSR) • RFContrails (from flying through ISSR) – Depends on solar azimuth, contrail opacity, ambient temperature CO2 Longwave – 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. 9 • Schumann, U. (2011). “Potential to reduce the climate impact of aviation by flight level changes.” AIAA Atmospheric Space Environments 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 Achieving Contrail Neutrality by 2020 Aviation Demand + + Aircraft Emissions ( CO2, water vapor) Radiative Forcing (mW/m^2) Radiative Forcing + Global Climate Change ICAO: reduce net CO2 emissions by 2050 compared to 2005 baseline and cap CO2 emissions in 2020 14.8 # of Flights 16 14 12 10 8 6 4 2 0 1980 + Estimated Radiative Forcing by Contrails 9.4 Contrail Neutral 7.06 3.5 1990 2000 2010 2020 Years Contrail Neutral 2030 2040 2050 2060 • 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 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 Explanation MR 1.0: Reduce contrail RF to 2005 baseline System shall provide ability by 2020 to reduce RF due to contrails to 2005 baseline of 7.06 mW/m^2 MR 2.0: Maintain contrail RF at 2005 baseline System shall provide ability by 2020 to maintain RF due to contrails to 2005 baseline of 7.06 mW/m^2 MR 3.0: Flight path 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 1. User inputs O/D and Aircraft info System Weather Forecast Origin/Destination 2. System Retrieves ISSR Information Aircraft B737-800 3. System outputs flight path info No ISSR Avoidance Fuel Consumption: 4713.7 kg Contrails Form: 26.15 miles Flight Duration: 1.56 hours Partial ISSR Avoidance Fuel Consumption: 4745.3 kg Contrails Form: 13.2 miles Flight Duration: 2.16 hours Complete ISSR Avoidance Fuel Consumption: - ICE SUPER SATURATED REGION (ISSR) 4795.1 kg Contrails Form: 5.4 miles Flight Duration: 2.30 hours 17 ISSR Avoidance Alternatives- Pairing Avoidance Aggressiveness with Flight Lengths Design Alternative Avoidance Aggressiveness Flight Length 1 No Avoidance Short 2 No Avoidance Medium 3 No Avoidance Long 4 Partial Avoidance Short 5 Partial Avoidance Medium 6 Partial Avoidance Long Flight Length: •Short: < 500 nm •Medium: 500 – 1000 nm •Long: > 1,000 nm Z 7 Complete Avoidance Short 8 Complete Avoidance Medium 9 Complete Avoidance Long ISSR B Destination Y *Complete avoidance attempted, unless origin/destination located in ISSR Origin A 18 X Experiment to Analyze Feasibility of ISSR Avoidance Aggressiveness for Flight Lengths Independent Variables Avoidance Aggression Flight Type Outputs Atmospheric Configurations Short No Avoidance Medium Long Short Partial Avoidance Medium Long 45 days of weather from NOAA • • • • • • Fuel Burn CO2 emissions Radiative Forcing (Contrails and CO2) Flight Distance Flight Duration %Distance in ISSR Short Complete Avoidance Medium Long 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 – 80o 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 πππ = πΆπ1 1 + πππ΄π πΆπ2 πΆππΆπ ∗ πΆππΆ,1 1 − π»π + πΆππΆ,3 ∗ π»π2 πΆππΆ,2 πΆπππ Eurocontrol (2011). “User manual for the Base of Aircraft Data (BADA) revision 3.9” • CO2 Emissions Jardine, C. (2009). “Calculating the Carbon Dioxide Emissions of Flights.” • RHi for persistent contrail formation Sridhar, B. (2011). “Design of aircraft trajectories based on trade-offs between emission sources.” • Radiative Forcing due to Contrails Schumann, U. (2011). “Potential to reduce the climate impact of aviation by flight level changes.” AIAA Atmospheric Space Environments Conference. • Radiative Forcing due to Excess CO2 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 % DistISSR_Long, No Avoidance 100 Long Flights 0.9 1.2 1.5 1.8 % DistISSR_Long, Complete 50 Percent % DistISSR_Medium, No Avoidance % DistISSR_Medium, Complete 100 95% decrease in Average % of Distance in ISSR % DistISSR_Short, No Avoidance 100 Short Flights 0.6 97% decrease in Average % of Distance in ISSR 0 Medium Flights 0.3 50 0 % DistISSR_Short, Complete 76% decrease in Average % of Distance in ISSR 50 0 0.0 0.3 0.6 0.9 1.2 1.5 1.8 % of Distance in ISSR 25 As ISSR Avoidance Increased, RFContrails+CO2 per Flight Path Decreased Histograms of Total RF by Flight and Avoidance Type 0 00 . 0 Long, No Av oidance Long Flights 50 Percent Medium, No Av oidance Long, Complete Medium, Complete 50 18.35% Decrease in Average TOTAL RF from None to Complete Avoidance 25 Short, No Av oidance 50 Short Flights 1 1 0 0 0 0 0 -1 -1 -1 -1 -1 -1 -1 E E E E E E E 0 0 0 0 0 0 0 00 00 50 00 50 00 50 5 0 0 4 7 1 4 3. 7. 1. 1. 1. 2. 2. 18.49% Decrease in Average TOTAL RF from None to Complete Avoidance 25 0 Medium Flights 00 + E 0 0 Short, Complete 18.07% Decrease in Average TOTAL RF from None to Complete Avoidance 25 0 E 00 0 0 0. 0 +0 1 1 0 0 0 0 0 -1 -1 -1 -1 -1 -1 -1 E E E E E E E 0 0 0 0 0 0 0 00 00 50 00 50 00 50 5 0 0 4 7 1 4 . . . . . . . 3 7 1 1 1 2 2 Radiative Forcing (W/m^2) 26 Tradeoff Between RFContrails and RFExcessCO2 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 % Decrease in Average Total RF (No Avoidance to Complete Avoidance) % Increase in Average Cost (No Avoidance – Complete Avoidance) Long Flight 18.49% 0.94% Medium Flight 18.35% 1.33% Short Flight 18.07% 4.14% 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 RFContrails is greater than Avg RFExcess 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) % Increase in Average Cost (No Avoidance to Complete Avoidance) Long Flight 18.49% 0.94% Medium Flight 18.35% 1.33% Short Flight 18.07% 4.14% 30 Recommendations • Accounting for tradeoff between RFExcess CO2 and RFContrails: – 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