ATMOSPHERIC CO2 GROWTH-RATE ANOMALIES IN 2002-03
Description:
We examine the growth-rate of atmospheric CO2
in 2002 and 2003. Observations show consecutive increases of greater than 2 ppmv
per year for the first time on the Mauna Loa
record. We use a statistical regression to show that increasing anthropogenic emissions
and ENSO activity are unable to
account for the CO2 growth-rates of 1992 and 1993 following the
Pinatubo volcanic eruption, or the anomalously high growth-rate of 2003. Increased
forest fires in the northern hemisphere, consistent with remote-sensing and
carbon monoxide measurements, seem likely to have contributed significantly to
the 2003 anomaly. We hypothesise that the hot and dry Eurasian summer of 2003
led to an increase in forest fire emissions from Siberia,
and may also have directly suppressed land-carbon uptake. Model results lead us
to expect a steady increase in airborne fraction as climate change weakens the
natural carbon sink and accelerates CO2 rise.
Author's Names: Chris Jones, Peter Cox, Peter Simmonds, Alistair Manning
Filesize: 150.29 Kb
Added on: 29-Jul-2005 Downloads: 23
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REGIONAL BOMB-PRODUCED RADIOCARBON INVENTORIES AND THE AIR-SEA GAS TRANSFER VELOCITY
Description: Two major problems in carbon cycle research are that the current
data-based budget of artificially-produced radiocarbon is unbalanced and that
the air-sea gas transfer piston velocity remains uncertain. In this study, the
regional distribution of bomb-produced radiocarbon inventories in the ocean and
their dependencies on the piston velocity is analysed within a seasonal, 3-d
frictional-geostrophic balance ocean model. Model results and data-based reconstructions
are compared to evaluate the consistency between the applied piston velocity
field and data-deduced ocean inventories. Bomb-radiocarbon inventories in the
GEOSECS and WOCE era are predominantly governed by the applied piston velocity.
Here, the piston velocity field provided by the Ocean Carbon Cycle
Intercomparison Project (OCMIP-II) were prescribed and scaled by a globally
constant factor in a range of sensitivity simulations.
Author's Names: S. A. Müller, F. Joos and G.-K. Plattner
Filesize: 31.44 Kb
Added on: 29-Jul-2005 Downloads: 19
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MARINE PRODUCTIVITY ESTIMATES FROM O2 AR RATIOS AND OXYGEN ISOTOPES IN THE EQUATORIAL PACIFIC
Description: Upwelling of high-nutrient waters in the
equatorial Pacific gives rise to a band of enhanced primary production around
the equator that stretches from Peru almost to Indonesia. It has been suggested
that this oceanic region accounts for a large part of global net production.
The equatorial Pacific is also thought to be the largest oceanic CO2
source and makes an important contribution to the atmospheric CO2
budget.
Author's Names: Jan Kaiser, Matthew K. Reuer, Bruce Barnett, et al
Filesize: 118.66 Kb
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INSIGHTS FROM SIMULATIONS WITH HIGH-RESOLUTION TRANSPORT AND PROCESS MODELS ON SAMPLING OF ...
Description:
Based on simulations with
high-resolution transport models we investigate the detectability of surface
flux signals in the atmospheric CO2 concentration and infer some
general guidelines for the sampling of the continental troposphere for the
purpose of constraining mid-latitude land carbon sinks.
Author's Names: U. Karstens, M. Gloor, M. Heimann, and C. Rödenbeck
Filesize: 66.96 Kb
Added on: 29-Jul-2005 Downloads: 20
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EVALUATION OF CO AND SF6 AS QUANTITATIVE TRACERS FOR FOSSIL FUEL CO2: THE MODELLERS VIEW
Description: Simulations
with a regional transport model are evaluated in order to determine to which
extend the indirect fossil fuel combustion tracer CO or the purely
anthropogenic tracer SF6 can be used to retrieve the contribution of
fossil fuel emissions in the atmospheric CO2 signal.
Author's Names: U. Karstens, U. Gamnitzer, and I. Levin
Filesize: 85.14 Kb
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STUDIES OF CARBON DIOXIDE, METHANE AND CARBON MONOXIDE VARIATIONS IN THE AIR NEAR THE GROUND ...
Description:
The results of atmospheric CO2,
CH4 and CO measurements are presented. The measurements were made in
air samples collected at heights of 4, 25, 100, 200 and 300 m above ground, and
in the atmospheric column in Obninsk, Russia (55.11 N, 36.57 E, 183 m asl).
Author's Names: F.V. Kashin, Yu. I. Baranov, P.P. Tans, and T.J. Conway
Filesize: 54.63 Kb
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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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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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GLOBAL OCEANIC AND LAND CARBON SINKS FROM THE SCRIPPS ATMOSPHERIC OXYGEN FLASK SAMPLING NETWORK
Description:
Measurements
of atmospheric O2/N2 ratio and CO2
concentration are presented over the period 1989 to present from the Scripps
Institution of Oceanography global flask sampling network. The data are used to
make estimates of land and ocean sinks over various time scales. The oceanic
and land biotic sinks are estimated to be 1.9±0.6 (ocean) and 1.2±0.8 Pg C/yr
(land) over the period Jan. 1990-Jan. 2000 and 2.2±0.5 (ocean) and 0.5±0.7 Pg
C/yr (land) over the period Jan. 1993-Jan. 2003. These estimates make allowance
for oceanic O2 and N2 outgassing based on observed
changes in ocean heat content and estimates of the relative outgassing per unit
warming. The recent ocean sink is consistent, to within the uncertainties, with
estimates of the accumulation of anthropogenic CO2 in the ocean
since 1800, assuming the oceanic sink varied over time as predicted by a
box-diffusion model. The possibility that the ocean sink is being reduced
slightly by climate feedbacks, as predicted by some models, is not ruled out,
however.
Author's Names: R.F. Keeling, A.C. Manning, R.C. Hamme, W. Paplawski
Filesize: 12.85 Kb
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CARBON-14 CONSTRAINTS ON THE LATITUDINAL DISTRIBUTION OF AIR-SEA GAS EXCHANGE
Description:
The
air-sea gas exchange rate is important for modeling and verifying ocean CO2
uptake, but remains subject to considerable uncertainty. The widely assumed
quadratic or cubic dependence of the exchange rate on windspeed together with
the latitudinal pattern of mean windspeed implies that exchange is much faster
at high compared with low latitudes. This should affect the pattern of ocean
uptake of bomb carbon-14 as well as the rate of decline of and latitudinal
gradients in atmospheric Δ14CO2. We evaluate the
constraints on the windspeed dependence of the exchange rate offered by
available isotopic measurements, discuss the major uncertainties, and suggest
observational strategies to reduce these uncertainties.
Author's Names: N. Y. Krakauer, J. T. Randerson, F. W. Primeau
Filesize: 85.91 Kb
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