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
𝑊
• Radiative Forcing (RF) - energy/area 2 difference between
𝑚
incoming shortwave radiation and outgoing longwave
radiation
• RF due to contrails is dependent upon– Solar zenith angle
– Contrail opacity
– Ambient Temperature
Shortwave
Radiation
Zenith
𝜃= 80o to 90o
(RF +)
𝜃
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 -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
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
𝑓𝑐𝑟 = 𝐶𝑓1 1 +
𝑉𝑇𝐴𝑆
𝐶𝑓2
𝐶𝑇𝐶𝑅 ∗ 𝐶𝑇𝐶,1 1 −
𝐻𝑝
+ 𝐶𝑇𝐶,3 ∗ 𝐻𝑝2
𝐶𝑇𝐶,2
𝐶𝑓𝑐𝑟
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