A 50 YEAR RECORD OF THE EVOLUTION OF THE MERIDIONAL GRADIENT IN ATMOSPHERIC CO2 AND ITS ...
Description:
Measurements of atmospheric CO2 began in
1957-1958 at a wide range of locations, including at fixed stations, on ice
floes, on oceanic expeditions, and on aircraft flights, with logistical and
financial support provided by the International Geophysical Year (IGY) program.
Although the measurement effort was reduced in scope immediately following the
IGY, today, measurements are made at more than 100 locations. Over this same time interval, emissions of CO2
from fossil fuel combustion increased from 2.3 thousand million metric tons per
year (GtC/yr) in 1958 to 7.1 GtC/yr in 2003 [Marland et
al., 2005, and personal communication]. More than 90% of this CO2 was
released into the northern hemisphere where it lingered before mixing fully
world-wide. The atmospheric CO2
concentration, in response, rose faster in the northern hemisphere than in the
southern, the interhemispheric difference increasing from near zero during the
IGY to about 3 parts per million (ppm) in 2003. For all northern hemisphere
stations where our program has measured CO2, the gradient changes
relative to the South Pole are generally proportional to the rate of fossil
fuel CO2 emissions, disregarding seasonal and short term interannual
variability in the CO2 data.
Here, we use this fact to diagnose how the carbon cycle has evolved over
the past half century.
Author's Names: C.D. Keeling, S.C. Piper, and T.P. Whorf
Filesize: 40.33 Kb
Added on: 01-Aug-2005 Downloads: 164
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A BAYESIAN SYNTHESIS INVERSION OF CARBON CYCLE OBSERVATIONS: HOW CAN OBSERVATIONS REDUCE ...
Description: Current
predictions of future CO2 sink strength vary widely as a result of
different model representations of the carbon cycle. A sound characterization of these prediction
uncertainties is crucial for the design of economically efficient carbon
management strategies. We use a mechanistically sound and statistically
tractable model of the global carbon cycle to (1) assimilate historical observations
of atmospheric CO2 concentrations and oceanic CO2 fluxes,
(ii) derive probabilistic predictions of future CO2 concentrations
and fluxes, and (iii) compare the utility of terrestrial and oceanic
observations to constrain predictive uncertainties. We found that terrestrial and oceanic flux
observations have nearly equal ability to constrain these uncertainties, if
terrestrial observations include both net primary productivity (NPP) and
respiration. Model predictions are
dependent on the choice of historical land use emissions dataset. The probability density function (PDFs) of
model parameter estimates are not normally distributed, and neglecting
autocorrelation in the CO2 concentration signal during model
calibration causes overconfident results.
Author's Names: D.M. Ricciuto, K. Keller, and K.J. Davis
Filesize: 39.46 Kb
Added on: 03-Aug-2005 Downloads: 56
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A CASE STUDY IN REGIONAL INVERSE CARBON MODELING
Description:
In order to facilitate future decision-making regarding regional
carbon fluxes, it is essential to better quantify uncertainty in inverse carbon
flux models. At Colorado State University, research is being performed in order
to better quantify sources and sinks and associated uncertainties on a
mesoscale level, through a coupled atmospheric (RAMS and PCTM) and terrestrial
carbon flux (SiB3) model (Denning, 2003).
Carbon-dioxide flux and mixing ratio data were collected from a ring of
towers (WLEF tall tower and nearby smaller towers) in northern Wisconsin over the
summer of 2004. The fully coupled
terrestrial-atmospheric model, SiB/RAMS, will be forced with 2004 reanalysis
data to predict fine scale weather in the vicinity of these towers for the
summer of 2004. Relevant portions of this simulated weather, including wind
fields and pertinent turbulence components, are extracted and used to create
backward-in-time Lagrangian Particle Dispersion Modeled (LPDM) influence
functions. Pseudo spatial carbon-dioxide
mixing ratio and flux data created by SiB/Rams is then used as input to several
different estimation routines in order to try and predict pseudo tower data at
different heights. Different temporal
and spatial aggregation lengths are considered as means of data reduction.
Particular attention will be paid to Ensemble Kalman Filter (EnKF) techniques
as well as geo-statistical methods as a means of estimation.
Author's Names: A.E. Schuh, M. Ulliaz, S. Denning, and D. Zupanski
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Added on: 04-Aug-2005 Downloads: 51
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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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Added on: 02-Aug-2005 Downloads: 166
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A DIRECT CARBON BUDGETING APPROACH TO STUDY CO2 SOURCES AND SINKS
Description:
For the purpose of
exploiting upcoming measurements of atmospheric CO2 vertical
profiles by aircrafts and continuous CO2 data recorded along tall
towers as part of the North American Carbon Plan (NACP), a direct carbon
budgeting approach is being developed.
Author's Names: C. Crevoisier, E. Gloor, J. Sarmiento, L. Horowitz, et al
Filesize: 70.64 Kb
Added on: 28-Jul-2005 Downloads: 154
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A FRAMEWORK FOR INTEGRATED GLOBAL ATMOSPHERIC CARBON OBSERVATIONS: IGCO AND IGACO
Description:
A
major challenge in reaching a better understanding of global change is the
integration of global carbon observations at different scales, made in the
atmosphere, ocean and terrestrial domains.
This is essential to optimize efforts supporting national, regional and
international policy related to the global carbon cycle. The partners of the Integrated Global
Observing Strategy (IGOS-P) representing all players in carbon cycle research
and monitoring recognised this and produced, with the help of an international
panels of experts, published theme reports on the Carbon Cycle (IGCO) and on
Atmospheric Chemistry (IGACO). These
themes contain recommendations on how to more effectively coordinate and fill
gaps in global Earth observations.
Author's Names: P. Ciais, L. Barrie and R. Dargaville
Filesize: 120.85 Kb
Added on: 28-Jul-2005 Downloads: 34
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A HINDCAST OF SURFACE OCEAN PCO2 AND AIR-SEA CO2 FLUX PRODUCED BY A DATA-ASSIMILATING OGCM ...
Description:
The primary aim of the Centre for
Observation of Air-sea Interactions and Fluxes (CASIX) is to estimate
accurately the air-sea fluxes of CO2. Under CASIX, a high resolution
ocean general circulation model, coupled to an ocean biogeochemistry model, has
been used to provide estimates of surface ocean pCO2 and air-sea
fluxes of CO2 for the year 2003. An initial global simulation was
run at 1 degree horizontal resolution, providing boundary conditions for a
limited area North Atlantic model at 1/3
degree resolution. Observed temperature and salinity data were assimilated into
the model. Temporal variability in the resulting pCO2 fields are
compared to observations, and the primary production and pCO2 results
of the two different resolution runs are compared.
Author's Names: S.K.Liddicoat, R.M.Barciela, J.C.P. Hemmings, et al
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Added on: 01-Aug-2005 Downloads: 36
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A REGIONAL ATMOSPHERIC CONTINUOUS CO2 NETWORK IN THE ROCKY MOUNTAINS ...
Description:
We
are establishing a continuous CO2 observing network in the Rocky Mountains, building on technological and modeling
advances made during the Carbon in the Mountains Experiment (CME), to improve our understanding of regional
carbon fluxes and to fill key gaps in the North American Carbon Program (NACP).
We will present a description of the Rocky RACCOON network and early results
from the first three sites.
Author's Names: B.B. Stephens, S. De Wekker, D. Schimel, and A. Watt
Filesize: 159.78 Kb
Added on: 04-Aug-2005 Downloads: 44
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A REGIONAL-SCALE ANALYSIS OF THE ANTHROPOGENIC CONTRIBUTIONS TO CO2 IN THE MIDWEST: ...
Description:
Atmospheric observations obtained during intensive
field experiments are used to characterize regional sources and test data
assimilation techniques. In this study, the STEM-2K1
(Sulfur Transport Eulerian Model, version 2K1) and its adjoint model are applied
to the analysis of observations from aircraft platforms made during the summer
2004 ICARTT (International Consortium for Atmospheric Research on Transport)
experiment. Observed ratios between CO2 and tracers and model
derived airmass markers are used to identify emission signatures, indicating
the influence of different sources. Model derived influence functions along
with assimilated transport model results of anthropogenic tracers are used to
characterize the anthropogenic CO2 emissions in the Midwest during the summer 2004 period. This analysis
gives an initial look at the Midwest domain
which is the focus of the expansion of NOAA Climate Monitoring and Diagnostic
Laboratory’s tall tower observation network and the upcoming Mid-Continent NACP
Intensive Campaign.
Author's Names: J.E. Campbell, C.O. Stanier, G.R. Carmichael, et al
Filesize: 13.03 Kb
Added on: 27-Jul-2005 Downloads: 39
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A SIMULATION OF CARBON CYCLE EMPLOYED BY A 2-D ATMOSPHERIC TRANSPORT MODEL
Description:
Carbon flux distribution was
simulated between 90°S and 90°N during from 1981 to 1997. It was confirmed there was a terrestrial C
sink in the area of mid-high latitude of north hemisphere. Some effect factors
to Carbon flux, as ENSO, volcano
activity, surface temperature etc. were analyzed also.
Author's Names: L. Xu, C. Li, M. Shao, R.J. Zhang and M.A.K., Khalil
Filesize: 95.35 Kb
Added on: 09-Aug-2005 Downloads: 40
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