ROBUST ESTIMATES OF PREINDUSTRIAL AND ANTHROPOGENIC AIR-SEA CARBON DIOXIDE FLUX
Description:
Accurate estimates of
the spatial distribution of pre-industrial and anthropogenic air-sea carbon
fluxes are crucial to understanding the processes driving ocean carbon uptake. We
present regional anthropogenic and pre-industrial air-sea fluxes estimated
separately from their reconstructed concentrations and Ocean General
Circulation Models (OGCM). The ocean interior carbon transports required to
explain these fluxes are calculated and their implications for the global
carbon cycle are discussed.
Author's Names: S.E. Mikaloff Fletcher, N.P. Gruber, A.R. Jacobson, et al
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PRECISION REQUIREMENTS FOR SPACE-BASED XCO2 DATA
Description:
The Orbiting Carbon
Observatory (OCO) mission will deliver space-based observations of atmospheric
CO2 with the potential to resolve many of the uncertainties in the
spatial and temporal variability of carbon sources and sinks. Our assessments of the measurement
requirements for space-based remote sensing of atmospheric CO2 conclude
that the data must support retrievals of the column-averaged CO2 dry
air mole fraction, XCO2,
with precisions of 3 to 4 ppm to resolve the annually averaged gradients between the Northern and Southern hemispheres, but higher
precision (1 to 2 ppm) will be needed to resolve East-West gradients and
questions like the location and spatial extent of the Northern Hemisphere
terrestrial carbon sink. These
conclusions are derived from the results
of observational system simulation experiments (OSSEs) and synthesis inversion
models [Rayner and O’Brien, 2001; O’Brien and Rayner, 2002; Rayner et al., 2002]. The XCO2 precision
requirements also considered the OCO mission design, the amplitude of XCO2 spatial and temporal gradients, and the relationship between XCO2 data
precision and regional scale surface CO2 flux uncertainties inferred
from XCO2 data.
Author's Names: C. E. Miller, D. Crisp, P. L. DeCola, S. C. Olsen, et al
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A DECREASING TREND IN NORTHERN HEMISPHERE CARBON UPTAKE SINCE 1992
Description: Increases in the north-south gradient of
atmospheric CO2
at Northern Hemisphere measurement sites of the NOAA/CMDL Global Air Sampling
Network reveal a shrinking carbon sink.
14 of 16 low altitude sites show differences with South Pole increasing
at a faster rate than can be explained by fossil fuel emissions, resulting in
an average north-south difference at remote marine sites nearly 1 ppm larger in
2003 than in 1992. Regardless of whether
this trend will persist, it shows that large changes in the carbon cycle can
occur rapidly and is a strong indication of the tenuous nature of terrestrial
carbon sinks.
Author's Names: J.B. Miller, P.P. Tans, J.W.C. White, et al
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INTERACTION OF CARBON DIOXIDE AND METHANE IN CARBON EXCHANGE BETWEEN FLOODED RICE PADDY ...
Description:
A combined study of micrometeorological flux measurement of carbon
dioxide (CO2) and methane (CH4) and measurement of their
stable carbon isotopes at a paddy field indicated that CH4
production can affect not only greenhouse gas budget of wetland ecosystem but
also isotopic signature of respired CO2.
Author's Names: A. Miyata, G.H. Han, M. Mano, H. Yoshikoshi, et al
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INTERANNUAL VARIABILITY OF pCO2, AND CHANGES IN SURFACE SALINITY AND TEMPERATURE IN THE UPPER ...
Description:
We
investigated the interannual variability of the partial pressure of carbon
dioxide (pCO2) in the surface waters of the western subarctic gyre
(155°E to 165°E, 48°N to 53°N) and the Alaska Gyre (AG, 195°E to 210°E, 45°N to
52°N) for a period of 9 years. We used automated measurements of pCO2
in the surface water (pCO2sw) and the air (pCO2air) as
well as sea surface temperature (SST) and salinity (S) obtained from the
Japanese-Canadian joint Volunteer Observing Ship (VOS) program. We observed
annual trends in the pCO2sw and based on simple least square fit to
observed data, the surface waters in the WSG showed a gradual pCO2sw
increase of 0.4 ppm yr-1 which was three times larger than in the AG
(1.8 ppm yr-1) for the 9-year period. In the WSG, this was about
half of the estimated atmospheric pCO2 increase for the whole period
(10 ppm or 1.2 ppm yr-1), whereas gas exchange explained much of the
increase in the AG (pCO2air increased 1.6 ppm yr-1).
Interestingly, the two gyres showed opposite annual trends in the SST and
salinity and in the WSG we observed a salinity and SST increase of 0.018 yr-1
and 0.07°C yr-1 (0.56°C for the whole study period), respectively,
whereas we observed a small freshening of 0.015 yr-1 and a cooling
trend of about 0.11°C yr-1 in the AG. We examine the possible
mechanisms to explain the annual trends in pCO2, based on the
observed changes in SST and salinity as well as observations made by other
investigators.
Author's Names: M. Chierici, A. Fransson, Y. Nojiri
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CARBON CYCLE DECADAL VARIABILITY IN MODE WATERS OF THE SOUTH WEST INDIAN OCEAN: ANTHROPOGENIC ...
Description:
Mode Waters provides a
privileged pathway for the transport of heat, salt and anthropogenic CO2
into the ocean interior. The carbon cycle
decadal variability in response to
environmental changes is investigated using historical and recent
data collected during the INDIGO (1985-1987) and OISO (1998-2003) oceanographic
campaigns conducted in the South West Indian Ocean, an important zone for Mode
Waters formation. The
observed change in dissolved inorganic carbon over the
15-year period was 8 µmol/kg in Subantarctic Mode Water (500-800m), which is
less than the anthropogenic carbon increase alone (13 µmol/kg). This difference
may be explained by natural or climate-induced changes in ocean processes.
Predictions from a global ocean-carbon model (OPA-PISCES) are used as a means
to help interpret changes in the controlling processes: ocean dynamics,
biological activity and air-sea interactions.
Author's Names: C. L. Monaco, N. Metzl, O. Aumont, K. Rodgers, et al
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LOOKING FOR THE MARINE CO2 PROCESSES ON LAND
Description:
Begur-Pals site (41,58ºN, 3,14ºE, Catalonia,
Spain)
is weekly sampled for CO2 and other GHG (CH4, CO, N2O,
SF6) since January 2000. This CO2 serial data shows at
the middle of each summer a sudden increase and decrease of the CO2
peak. It is a process that can be either attributed to a highest transpiration
rate than ecosystem production due to the lack of summer precipitation, to biomass
burning from Mediterranean forest fires, to tourist activities in the coast, or
to CO2 pumping from waters in the Western Mediterranean sea (according
to wind backtrajectories). A sampling strategy using sites with high towers
with continuous measurements has been developed. Sites are placed at the vortexes
of a rhombus: two extremes are continental sites in the center of the Ebro’s
watershed and a marine site is located in the Menorca Island.
The other two are high towers in the Catalonian coast.
Author's Names: J-A. Morguí, X. Rodó, A. Font, E. Martí, et al
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TEMPORAL VARIATIONS OF THE ATMOSPHERIC CO2 CONCENTRATION AND ISOTOPE RATIOS IN THE ARCTIC ...
Description:
Systematic observations of the
atmospheric CO2 concentration, and carbon and oxygen isotope ratios
of CO2 (d13C and d18O) have been maintained at Japanese Arctic Observatory
in Ny Ålesund (79°N, 12°E) and Antarctic station, Syowa (69°S, 40°E). The
interannual variations of the CO2 concentration and d13C in association with the occurrence of ENSO event were clearly observed at the both sites.
The d18O
values observed at Syowa Station showed significant increasing trend after
1999.
Author's Names: S. Morimoto, S. Aoki, T. Nakazawa, G. Hashida, et al
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LONG-TERM OBSERVATION OF CO2 CONCENTRATION AND ITS ISOTOPE RATIO OVER THE WESTERN PACIFIC
Description: Air was collected systematically
from 1995 to 2005 over the Pacific from 30S to 55N in latitude by
ships-of-opportunity to monitor global trend of CO2 concentration
and its variation in the atmosphere. The
monitoring results showed that three El Niño events during 10 years mostly
affected regional and temporal variation of CO2 growth rate and its
budget. Variation of carbon isotope ratio showed that the CO2 flux
from terrestrial biosphere seemed to rapidly increase at that time, correlated
with global temperature anomaly. Oxygen isotope ratio had increasing trend in
this period, similar to the variation of temperature. Atmospheric 14CO2
variation also seemed to be influenced by El Niño event.
Author's Names: H. Mukai, Y. Nojiri, Y. Tohjima, T. Machida, et al
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EARTH SYSTEM RESPONSE TO GLOBAL WARMING INFERRED BY SIMULATION USING A ONE-DIMENSIONAL ENERGY ...
Description: The coupled feedback processes of energy
and carbon cycles are an essential mechanism for understanding global
environmental change. We developed a simplified one-dimensional
carbon and energy cycle coupled model to quantify the feedback processes between
energy and carbon cycles. The model was calibrated
to reproduce the historical variations in temperature and
atmospheric CO2 concentration. The model results of vertical ocean
temperature profiles, and latitudinal NPP and NEP
distributions were in good agreement with the observation data and terrestrial
biosphere model results. The regional difference of terrestrial ecosystem response by
climate feedback appeared in the middle and high latitudes. The north-south distribution
is important to investigate the terrestrial ecosystem because the opposite
response appeared in the middle and high latitude. The future change of carbon
cycle and climate was also simulated up to the year 2100 based on the IPCC
scenario. The atmospheric CO2 concentration reaches 735 ppmv in 2100
and global average temperature increases 1.9 K for 2000-2100.
Author's Names: K. Murakami, T.Sasai, K.Ichii, and Y.Yamaguchi
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