TREND OF THE TOTAL INORGANIC CARBON INCREASE IN THE SUBTROPICAL WESTERN NORTH PACIFIC SINCE ...
Description:
High-quality data of
total inorganic carbon (TCO2)
and other oceanographic parameters have been acquired repeatedly between 1994 and
2003 along 137ºE (WOCE P9) in the western North Pacific. They indicate the significant
increase in TCO2,
apparent oxygen utilization (AOU) and preformed TCO2
in the water columns between 20ºN and 30ºN, in particular, in the North Pacific
Subtropical Mode Water (NPSTMW). The increase in the preformed TCO2 suggests the 0.9 to 1.1 mol m-2
yr-1 accumulation of the anthropogenic CO2 in this region.
However, the change in the preformed TCO2
associated with the change in the formation region and/or advection of NPSTMW
is also suggested.
Author's Names: M.Ishii, S.Saito, S.Masuda, A.Nakadate, et al
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TROPICAL DROUGHT AND THE CARBON CYCLE: C3-C4 PLANT FRACTIONS, ROOT-ZONE STRESS AND THE USE OF ...
Description: Tropical
drought can significantly impact inter-annual variations in the terrestrial CO2
fluxes. Concentrations and carbon
isotope ratios of atmospheric CO2 can help to quantify this impact,
however, their use requires a model estimation of the terrestrial isotope
disequilibirum, i.e. the difference between the isotopic signature of
photosynthesis and respiration, which can only be achieved by accurately accounting
for changes in relative contributions of C3 and C4 plants (C4 fraction) and
physiological effects of root-zone water stress.
Author's Names: N.S. Suits, A.S. Denning, and J.B. Miller
Filesize: 225.80 Kb
Added on: 08-Aug-2005 Downloads: 20
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TWO DECADES OF OCEANIC CO2 VARIABILITY AND THE INFLUENCE OF WIND AND STORMS ON AIR-SEA FLUX IN ...
Description: Two decades of continuous oceanic CO2
observations in the North Atlantic Ocean near Bermuda at Hydrostation S
(32°50'N, 64°10'W; 1983-1988) and BATS (Bermuda Atlantic Time-series Study;
32°10'N, 64°30'W; 1988-2003) sites are examined for long-term trends, changes
in the oceanic sink of CO2, and the influence of atmospheric changes
and short-term hurricane wind events. Over the 1983-2003 period, surface DIC
and alkalinity increased at a rate of +1.18 + 0.19 µmoles kg-1 year-1
and +0.69 + 0.14 µmoles kg-1 year-1, respectively. The
observed rate of surface ocean salinity normalized DIC (nDIC) was +0.79 + 0.13
µmoles kg-1 year-1 and similar to that expected from
oceanic equilibration with increasing CO2 in the atmosphere. The
upward trend in oceanic p CO2 (1.53 + 0.13 µatm year-) is also
identical to the rate of atmospheric CO2 increase (1.59 + 0.02 µatm
year-1) over the last 20 years. The ocean near Bermuda
has also become more acidic, with a decrease in seawater pH of 0.0012 + 0.0006
pH units year-1.
Author's Names: N.R. Bates
Filesize: 15.80 Kb
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UPDATE ON ATMOSPHERIC O2/N2 MEASUREMENTS, FROM 1994 TO 2002
Description: Our current understanding of the global carbon
cycle has greatly benefited from atmospheric O2 measurements,
pioneered by R.F. Keeling and collaborators in 1990. Our parallel sampling program, with sampling
locations added periodically beginning in 1991, now includes Point Barrow
(Alaska), Sable Island (Eastern Canada), American Samoa (Tropical South
Pacific), Amsterdam Island (Indian Ocean, French station), Cape Grim (Tasmania,
Australia), Macquarie Island (subantarctic Australian station), and Syowa
(Antarctic Japanese station). Samples
are also routinely collected on Ka’imimoana, a U. S. NOAA ship operating in the
equatorial Pacific.
Author's Names: M.L. Bender, M.O. Battle, D.T. Ho, M.B. Hendricks, et al
Filesize: 165.07 Kb
Added on: 28-Jul-2005 Downloads: 17
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USING A HIGH RESOLUTION COUPLED ECOSYSTEM-ATMOSPHERE MODEL TO EVALUATE SPATIAL, TEMPORAL, AND ...
Description:
Satellite
measurements of total column CO2 can be used in inverse models to
help isolate sources and sinks; however, using satellite concentrations in
inversions may introduce spatial, temporal, and clear-sky errors. Using a
coupled ecosystem-atmosphere model, we found that using satellite measurements
to represent temporal averages will introduce large errors into the inversion
and that inverse models must sample the concentrations at the same time as they
are measured. Spatial and local
clear-sky errors are much smaller than the instrumental errors, although they
increase with domain heterogeneity. Inverse models can minimize sampling errors
by using homogenous regions and sampling the CO2 concentrations at
the same time as the satellite.
Author's Names: K.D. Corbin, A.S. Denning, L. Lu, I. Baker, A. Wang
Filesize: 23.17 Kb
Added on: 28-Jul-2005 Downloads: 21
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USING CONTINENTAL, CONTINUOUS CO2 OBSERVATIONS IN A TIME-DEPENDENT GLOBAL INVERSION ...
Description: Spatial
and temporal characteristics of land and ocean sources and sinks of carbon
remain elusive. Better understanding of the anthropogenic influences on these
carbon cycle dynamics is a common goal. This experiment is one of the efforts
to reach a middle ground of flux estimates for regions larger than experimental
plots and flux tower footprints, but smaller than continents and ocean basins.
This work tests the hypothesis that including well-calibrated continuous North
American continental CO2 measurements in the observation data used
in a global inversion will provide a constraint that improves inversion
estimates of the source and sink regions within North America. These continuous
data are collected at tall towers and flux towers. The experiment follows the
TransCom 3 synthesis inversion framework, using the NASA Goddard Space Flight
Center Parameterized Chemistry and
Transport Model (PCTM) with Goddard Earth Observing System, version 4 (GEOS-4)
meteorological data. Seasonal fluxes are estimated for a recent year for
sub-regions within North America and at continent and basin scale globally.
Methods of preparing the continental continuous CO2 measurements for
the inversion will be tested. Initial inversion results will be presented along
with recommendations for applicability to other global regions and use of the
method to evaluate additional sites for the measurement network.
Author's Names: M.P. Butler, A.S. Denning, K.R. Gurney, S.R. Kawa, et al
Filesize: 48.98 Kb
Added on: 27-Jul-2005 Downloads: 21
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USING INVERSE MODELLING TO INVESTIGATE POTENTIAL IR MEASUREMENT STRATEGIES FOR CONSTRAINING ...
Description:
CO2
and methane are important greenhouse gases, both contributing in increasing
amounts towards positive radiative forcing. It is hence important to gain
maximum understanding of the carbon cycle in the atmosphere, and the scale of
carbon trace gas sources and sinks, not only globally but also on a more
regional level. The Orbiting Carbon Observatory (OCO) satellite, scheduled for
launch in 2008, is designed for dedicated global mapping of CO2. In
order to investigate the usefulness of a variety of methods, including
retrievals from satellite mapping, some preliminary inverse modelling using a
Bayesian synthesis technique is performed using pseudodata generated to
represent possible future measurement regimes. This study will focus on the
ability of in-situ measurements within Australia to reduce the
uncertainties in Australian continental CO2 flux estimates. The
specific measurements investigated include a Ghan railway transect between
Adelaide (34.9°S, 138.6°E) and
Darwin (12.5°S, 130.9°E), and a number of continuous permanent sites. The
reduction in flux uncertainties from additional measurements compared to a
background inversion is examined, from which it is concluded that measuring on
the Ghan railway is potentially worthwhile for reducing uncertainties
associated with flux estimates.
Author's Names: N.M. Deutscher, R.M. Law, D.W.T. Griffith, and G.W. Bryant
Filesize: 54.41 Kb
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VARIABILITY OF OCEAN CO2 PARTIAL PRESSURE AND AIR-SEA CO2 FLUXES IN THE SUBANTARCTIC ZONE ...
Description: Seven CARIOCA lagrangian buoys drifted in the Subantarctic Zone, SAZ, of
the Indian and Pacific Ocean between 2001 and
2005. Measurements indicate that pCO2 in sea water is undersaturated
with respect to the atmospheric value and consequently the subantartic zone of
the Southern Ocean acts as a sink for atmospheric CO2 during all
seasons. Large observed pCO2 variability is associated with mixing
close to the subantarctic front, with biological activity and local warming.
These variabilities are higher than the seasonal cycle in the studied areas.
Author's Names: J. Boutin, L.Merlivat, and K.Currie
Filesize: 92.01 Kb
Added on: 27-Jul-2005 Downloads: 136
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VARIATIONAL DATA ASSIMILATION OF HIGH DENSITY ATMOSPHERIC CO2 DATA:...
Description: High-frequency atmospheric CO2 measurements
should become increasingly available by the end of this decade from a variety
of sources, including low-Earth orbiting satellites. If of sufficient accuracy,
these should allow the functioning of the global carbon cycle to be monitored
at fine time/space resolutions using atmospheric transport inversions. Since
traditional direct inversion methods (e.g., Bayesian synthesis) become
computationally infeasible at these resolutions, we use an approximate method,
variational data assimilation, to estimate surface CO2 fluxes at
spatial resolutions ranging from 10x10 degrees to 1x1 degrees and at time
resolutions ranging from 2 weeks to 1 hour. We assess its performance using simulated
data, including the effects of realistic transport and data errors.
Author's Names: D.F. Baker, S. Doney, and D. Schimel
Filesize: 12.88 Kb
Added on: 25-Jul-2005 Downloads: 33
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VARIATIONS AND DISTRIBUTIONS OF pCO2 IN SURAFCE SEAWATER IN THE WESTERN NORTH PACIFIC ...
Description:
Measurements of the
partial pressure of CO2 in surface seawater (pCO2w)
have been made frequently and extensively in the western North Pacific (3-35°N,
132-142°E) since 1990. Based on the time series analysis of pCO2w
data, we obtained a “climatological view” of seasonal variation in pCO2w
in the western North Pacific. We have examined the relationship between pCO2w
and sea surface temperature (SST). The pCO2w–SST
relationship varies spatially and temporally. The pCO2w
showed an average growth rate of 1.6 µatm yr-1 (nearly equal to that
of the air, pCO2a) with large variability (±8.9µatm yr-1).
In 1998, larger growth rates of pCO2w occurred in the
subtropical gyre and the western equatorial Pacific, which was probably
associated with the 1997/98 El Niño phenomena. To know processes affecting
long-term variations in pCO2w, we have examined seasonal
variation in growth rate of pCO2w. The linear growth rate
of pCO2w during the winter season ranged from 1.3±0.2 to 2.1±0.2µatm yr-1 with an average of 1.7±0.2µatm
yr-1. During
spring/summer seasons, the
average growth rate of pCO2w was larger than 2µatm yr-1 north of 27°N, and within the range from
0 to 1µatm yr-1 in the North Equatorial Current. These increases were
mostly caused by the oceanic uptake of anthropogenic CO2, and to
some extent, other processes controlling the pCO2w change: thermodynamic effect, lateral
transport and vertical mixing, and biological activity.
Author's Names: H.Y. Inoue, M. Ishii, T. Midorikawa, A. Nakadate, et al
Filesize: 73.43 Kb
Added on: 29-Jul-2005 Downloads: 45
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