Seasonal distribution and transport of CO2 in the tropopause region based on

frequent observations in the CONTRAIL project

Yousuke Sawa (Meteorological Research Institute)

Toshinobu Machida (National Institute for Environmental Studies)

Hidekazu Matsueda (Meteorological Research Institute)

1. CONTRAIL (Comprehensive Observation Network for Trace

gases by AIrLiner) from 2005　・ Instruments description　・ flight area/data

2 ． Observed CO2 in the tropopause region

　・ Time series of CO2

　・ Distributions of CO2

3 ． Conclusions ・ Transport pathways of CO2

to the lower stratosphere

October 19-22, 2009The Extra-Tropical UTLS: Observations, Concepts and Future

DirectionsCommunity workshop at NCAR, Boulder, USA

CO2 as a transport tracer

• CO2 is very stable in the atmosphere

• CO2 has (relatively) well-known seasonal cycles depending on the latitudes

• CO2 can be used as a transport tracer

355360365370375380385

CO

2 (p

pm)

30N-25N

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CO

2 (p

pm)

20N-15N

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CO

2 (p

pm)

10N-5N

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CO

2 (p

pm)

EQ-5S

355360365370375380385

CO

2 (p

pm)

10S-15S

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CO

2 (p

pm)

20S-25S

1993 1995 1997 1999 2001 2003 2005 2007

CO2 （ 9-12km ）

(between Australia and Japan)

Matsueda et al., 2002, 2008

New instruments: development for CONTRAIL

Vertical Distribution

Vertical Distribution

Latitudinal/Longitudinal Distribution

• Ascending/descending: 10 sec average (~80m vertical)• Cruising altitudes:1 min average (~15 km horizontal)• Detailed structures

Functions:• in-situ CO2 measurement• 1-2 month continuous observation• real time control by aviation information (ARINC)• Onboard calibrations high accuracy 0.2 ppmMachida et al., 2008

Continuous CO2 Measurement Equipment (CME)

Wide range,High frequency

CONTRAIL CO2 Data set

2005 Nov. – 2009 Mar.(3212 legs)CO2 1-min data: ~1 million dataAltitude: 8-12 km

Main routes for analysis

between North America and Japan

Num

ber

of d

ata

(/da

y)

Between Europe and Japan• 680 legs• almost every day from November 2006 to Mar. 2008.

Examples of observed CO2

Meteorological Re-analysis Data (JCDAS)

2006122100UT

330K

CO2 were well corresponded to the PVs

December, 2006

Significant variationsTropospheric or stratospheric ?

Equator

North Pole

EquivalentLatitude

Analytical Methods

ΔΘ ： differences in potential temperature

Lower stratosphere

Upper troposphere

Vertical coordinate:

=0K (Tropopause =2 PVU)

=20K

=10K

=-10K

=-20K

Latitudinal coordinate:

Hoor et al., 2004 Hegglin et al., 2006

Reanalysis dataJMA Climate Data Assimilation System (JCDAS)Same system as JRA-25 (Onogi et al., 2007) T106, L40, 6hr

Vertical profiles of CO2

by reference to

Above tropopause, the CO2 shows different vertical gradients above and below of about 25K.

CO2 (ppm) CO2 (ppm)

25K

0K

(from flights between Europe and Japan)

Oct. Dec.

Mar. May

Aug. Sep.

Time series of CO2 for each binbetween Japan and Europe

between Japan and North America

Upper troposphere:a strong seasonal cycle maximum in spring minimum in summer

Lower stratosphere:a gradual decrease in winter and spring followed by a rapid increase in summer

Seasonal cycle of CO2 in LSMax.: SeptemberMin.: April

Amplitude: 1.2 ppm (=20-30K)1.8 ppm (=30-40K)

2.2 ppm (=40-50K)

July 2007

ΔΘ=0

Oct. 2006 Mar. 2007

→ Equivalent Latitude

ΔΘ=0

Pot

entia

l Tem

pera

ture Descent of

low CO2

Seasonal changes of CO2 distributions

Aug 2007

ΔΘ=0

Sep. 2007

ΔΘ=0

Rapid meridional transport of high CO2

form lower latitudes

Summer ： CO2//Θ, CO2//ΔΘ

Winter ： CO2//Θ, CO2//ΔΘ

uniformly distributed

~constant

CO2(ppm)

CO2 distributions in summer 2008

CO2 distributions in summer 2007 between Japan

and North America

between Japan and Europe

Longitudinal difference ?

10W-50E (W)

50-110E (C)

110-150E (E)

Jul. 2007 340<<360K

ECW

May Jun. Jul. Aug. Sep.

2007 Jan 2007 Mar

2007 Jul 2007 Aug 2007 Sep

Equivalent latitude→

Pot

entia

l tem

pera

ture

CONTRAIL-Transport model intercomparison

Niwa et al.CO2 by NICAM-gl6 (Niwa@CCSR/Tokyo Univ.)

the courtesy of Niwa(CCSR/Tokyo Univ.), Patra(JAMSTEC)

Conclusions ：Transport pathways of CO2 to the lower stratosphere

• Frequent CO2 observations were made in the tropopause region by using JAL airliners.

• Rapid CO2 increases were found in the summer in the lower stratosphere, followed by gradual decreases from winter to spring.

• CO2 distributions in - coordinates suggest the existence of a rapid meridional transport on potential temperature surfaces in summer, and a subsidence of air from higher altitudes in winter to spring.

• More JAL observations could provide new evidences about the meridional transport pathways, such as relationships to the monsoon circulation.

How to access CONTRAIL CO2 data-> Contact us!

CME data• request -> PIs• PIs -> data protocol -> data user• data user -> agreement, description of the study, members -> PIs• PIs -> CO2 data set -> data users• Short annual report -> PIs

• contact the PIs to discuss the results as well as co-authorship and collaboration before presentation or publication

ASE CO2 data are submitted to• WDCGG (WMO world data center for greenhouse gases)• globalview CO2 (processed by Dr. Masarie @ NOAA/GMD)

Related projects:• CONTRAIL TMI (Transport model intercomparison) among CCSR/Tokyo Univ., MRI/JMA, JAMSTEC, NIES• GOSAT validation• many Carbon cycle model studies,…

tmachida@nies.go.jphmatsued@mri-jma.go.jpysawa@mri-jma.go.jp

747-Classic1993 ～ 2005 for ASE

747-4002005 ～ for ASE and CME

777-2002006 ～ for CME

Thank you

References• Machida et al. (2008): Worldwide measurements of

atmospheric CO2 and other trace gas species using commercial airlines, J. Atmos. Oceanic. Technol. 25(10), 1744-1754, DOI: 10.1175/2008JTECHA1082.1.

• Matsueda et al.(2008): Evaluation of atmospheric CO2 measurements from new flask air sampling of JAL airliner observation, Pap. Meteorol. Geophys. 59, 1-17.

• Sawa, Y., T. Machida, H. Matsueda (2008): Seasonal variations of CO2 near the tropopause observed by commercial aircraft, J. Geophys. Res., 113, D23301, doi:10.1029/2008JD010568.

We would like to acknowledge many engineers of the Japan Airlines, JAL Foundation and JAMCO Tokyo for supporting our CONTRAIL project. The CONTRAIL project is financially supported by the Research Fund by Global Environmental Research Coordination System of the Ministry of the Environment in Japan.

Acknowledgements