Numerical analysis of contrail formation process and climate impact by aviation-induced cirrus by emissions from aircraft with alternative aviation fuels

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201C35

Subject Category: Aeronautical Technology

Responsible Representative: Atsushi Kanda, Aviation Technology Directorate, Aviation Environmental Sustainability Innovation Hub
Contact Information: Keiichi Okai, Aviation Technology Directory(okai.keiichi@jaxa.jp)
Members: Keiichi Okai, Takuma Tadokoro, Shun Amari, Jonas Andreas Erbesdobler, Shinji Nakaya

Abstract

In recent years, carbon neutrality has been declared in the aviation sector. As one of the greenhouse effects of aircraft exhaust gas, persistent contrail and contrail cirrus formation have been recognized as quite important most recently due to its expected large effects in radiative forcing. The present study investigates the effects of fuel characteristics of the major alternative aviation fuels (SAF and hydrogen) on the radiative forcing of contrails using a global climate model.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

The global atmospheric calculations with additional contrail microphysics model require large computational resources.

Achievements of the Year

Based on the evaluation of contrail radiative forcing from conventional jet fuel, we are currently investigating the impact of varying exhaust characteristics on radiative forcing when using alternative fuels such as Sustainable Aviation Fuel (SAF) and hydrogen. In parallel with the ongoing modeling and validation of contrails for these alternative fuels, we conducted a one-year simulation under conditions identical to those of previous studies that also utilized the Community Atmosphere Model version 6 (CAM 6) for evaluating Effective Radiative Forcing (ERF). The resulting annual mean ERF distribution was nearly identical to that reported in the earlier research (Fig. 1). Furthermore, our calculations successfully reproduced the seasonal variations in global monthly mean ERF consistent with the previous findings (Fig. 2). These results demonstrate the validity of our methodology and establish a robust foundation for analyzing and discussing future simulations involving model refinements or scenario analyses with varied parameters, such as fuel types and cruise altitudes.

Fig.1: Annual mean Effective Radiative Forcing (ERF) due to contrails in 2019.

Fig.2: Seasonal variations in monthly mean Effective Radiative Forcing (ERF) due to contrails in 2019.

Publications

- Oral Presentations

Takuma Tadokoro, Ryo Yoshida, Koichi Omi, Keiichi Okai, Shinji Nakayam Mitsuhiro Tsue. A Numerical Study on the Effects of Aircraft Soot Emissions from HEFA on Contrail Radiative Forcing Using CAM6. 63th Airplane Symposium, Oct, 2025, Okinawa, Japan.

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: N/A
Number of Processes: 720
Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.28

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

Computational Resources
System Name	CPU Resources Used (Core x Hours)	Fraction of Usage*2(%)
TOKI-SORA	0.00	0.00
TOKI-ST	2399663.58	2.48
TOKI-GP	0.00	0.00
TOKI-XM	0.00	0.00
TOKI-LM	1394.37	0.11
TOKI-TST	7797.41	0.13
TOKI-TGP	0.00	0.00
TOKI-TLM	0.00	0.00

File System Resources
File System Name	Storage Assigned (GiB)	Fraction of Usage*2(%)
/home	1024.00	1.64
/data and /data2	102400.00	0.67
/ssd	30720.00	1.87

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	1.63	0.00

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

ISV Software Licenses Used

ISV Software Licenses Resources
	ISV Software Licenses Used (Hours)	Fraction of Usage*2(%)
ISV Software Licenses (Total)	0.00	0.00

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.