Long-term Observation of CO 2 concentration and its isotope ratios over the Western Pacific H. Mukai, Y. Nojiri, Y. Tohjima, T. Machida, Y. Shibata and H. Kitagawa Center for Global Environmental Researc h, National Institute for Environmental Stu dies And
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Long-term Observation of CO 2 concentration and its isotope ratios over the Western Pacific
Long-term Observation of CO 2 concentration and its isotope ratios over the Western Pacific. H. Mukai, Y. Nojiri, Y. Tohjima, T. Machida, Y. Shibata and H. Kitagawa Center for Global Environmental Research, National Institute for Environmental Studies And Nagoya University. - PowerPoint PPT Presentation
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Long-term Observation of CO2 concentration and its isotope ratios over the Western Pacific
H. Mukai, Y. Nojiri, Y. Tohjima, T. Machida, Y. Shibata and H. Kitagawa
Center for Global Environmental Research,National Institute for Environmental Studies
AndNagoya University
Monitoring by using commercial cargo ships Atmospheric CO2 samples from wide range of latitude can be
colleted.
Frequent commercial cargo ship service enable us to observed seasonal variation of CO2 in addition to long-term variation.
Japan-Oceania cruise can provide us a good chance to observe latitudinal difference in behavior of CO2 from Northern Hemisphere to Southern Hemisphere.
Relatively economic monitoring if it goes as planed.
92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07
Japan -N America(30N-55N)
Japan –Oceania(30N-35S)
NOV
Hakuba
SKAUBRYN ( Seaboard)
Southern Cross
SKAUGRAN ( Seaboard) PYXIS(TOYOFUJI)
FUJITRANS WORLD
MOL Glory
Golden Wattle(MOL)
Alligator Hope(MOL)
Trans Future
Special thanks to MOL, Toyofuji, Fuji Trans, Nihhon Usen,Seaboard International Shipping Co.
FUJITRANS WORLD
PYXIS
FUJITRANS WORD and PYXIS routes2003 Sep – 2004 Nov
1) Bottle Sampling : Stainless-steel bottle 3L (+ Glass bottle 2.5L ) ~10 times/y since 1995 ~ 3 samples / 10 degree in latitude 2) Gas analysis in the bottle: CO2, N2O, CH4 (NDIR, GC-ECD, GC-FID)
delta 13C, delta 18O (MAT252, dual inlet) 14C is measured by Accelerator MASS in NIES
Air Inlet
Temperature sensorGPS sensor
(1) Metal bellows pump
GPS receiver
(2) Cooler (-45 oC)
(3) Sampling Flask Box
Sampling Controller
CO2 analyzer
12CO213CO2
C3 plant
C4 plant
14CO2
Soil
Isotope signature of CO2 (13C, 14C, 18O)will provide important clues about CO2 budget and climatic effects on CO2 uptake mechanism
CF = anthropegenic input ( Fossil combustion and Cement production)CNs = Net Sea flux CNb = Net land biological flux CGS = Gross exchange flux between Sea and atmosphereCGb = Gross exchange flux between land biosphere and atmosphere
Isotope disequilibrium term CGs(δs –δa) + CGb(δb –δa)
Assessment of isotopic balance equationAssessment of isotopic balance equation Oceanic sink looked too variable. Oceanic sink variation = +1 PgC and decrease trend ???
c.f. Reported oceanic variation on flux is about +0.4 PgC What is possible causes ?
If we set Oceanic sink variation to be Zero How much percent we have to change the parameters such as Discrimination factor? It is most important for both disequilibrium and biological uptake term.1) Discrimination for CO2 uptake by plants fractionation factor decreases? C4 plant fraction to C3 plant increase? 2) Gross primary production decreases or increase?
-19.1
-19
-18.9
-18.8
-18.7
-18.619
95
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Dis
crim
inat
ion
expe
cted
(per
mil)
-12
-10
-8
-6
-4
-2
0
2
SO
I
0.2 per mil decrease can be possibleby high T and low humidity , but Gross primary production can not decrease by corresponding amount (over 50%)
SOI
Apparent variation of oceanic sink can be compensated by biological discrimination adjustment by up to 0.2 per mil
-1.5
-1
-0.5
0
0.5
1
1.5
219
95
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
delta
18O
tren
d (p
er m
il)
-19
-16
-13
-10
-7
-4
-1
2
-25
-15
-5
5
15
25
35
45
55
SOI
Delta 18O trend showed some increase over 10 years
SOI
El N
ino
Increase delta 18O of water? GPP decrease?
Conclusion
(1) Ten-year observation of CO2 and isotopes over Western Pacific from 30S to 50N was conducted by using 8 commercial cargo ships.
(2) By simple carbon budget equations using isotopic data, oceanic and terrestrial uptake amounts were estimated. Oceanic sink was relatively stable but still had 1Pg-C variation. Terrestrial sink seemed to decrease rapidly by higher and more dry condition at El Nino event. Apparent oceanic fluctuation may be partly caused by the change of C isotopic discrimination due to climatic condition.
(3) Oxygen isotope ratio showed increasing trends in all latitude during 10 years. It was different tendency from that of 1990’s. It may be related to high
temperature and low humidity tendency including lower GPP in recent years.
(4) Carbon-14 measurements will give an another angle to look at carbon budget. Further analysis is needed.
(5) Seasonal variations of CO2 and carbon isotope ratio were large in Northern Hemisphere but small in Southern Hemisphere. Isotope fractionation factor was about –19 per mil on average, but –14 per mil in 20S, which showed some C4 plants effect at that latitude. (not shown)