DECADAL CHANGES OF THE CO2-SYSTEM PROPERTIES IN THE SUBTROPICAL SOUTH ATLANTIC: RESULTS FROM ...
Description:
Using high-quality data
for the CO2-system and related properties obtained 10-year apart, we
estimated decadal increases of anthropogenic CO2 along the A10
section of the World Ocean Circulation Experiment (WOCE) Hydrographic Program
(WHP). Increases of anthropogenic CO2 were found down to an
isopycnal surface of 27.3σθ (approx. 1000 dbar). In the
sub-Antarctic Mode Water (SAMW), the increase was 6.9 ± 2.0 μmol kg-1
on average, while in the Antarctic Intermediate Water (AAIW), it was 4.2 ± 1.9 μmol
kg-1. The increase in SAMW was larger in the west than that in the
east of the section. No significant increases were detected in North Atlantic
Deep Water (NADW) and Antarctic Bottom Water (AABW).
Author's Names: A. Murata, Y. Kumamoto, M. Aoyama, K. Sasaki, et al
Filesize: 87.34 Kb
Added on: 03-Aug-2005 Downloads: 21
Home Page | Comment on Proceeding | Details
BOMB RADIOCARBON CONSTRAINTS ON AIR-SEA GAS EXCHANGE: A NEW PARAMETERISATION OF THE PISTON ...
Description:
We
used recent ocean bomb radiocarbon inventory estimates for the time of GEOSECS
(mid-1970s) and WOCE (mid-1990s) from Peacock
[2004] and Key et al. [2004],
corrected for missing ocean areas [Naegler
2005], to develop a new parameterisation of the piston velocity – wind speed
relationship of CO2 air-sea gas exchange. For monthly mean
climatological winds on a 1°x1° grid, this results in a gas exchange parameter
aq,660 of 0.32±0.04 (in cm hr-1 m-2 s2)
and a net oceanic CO2 uptake of 1.53±0.18 PgC/yr for the mid-1990s,
when using the Takahashi et al.
[2002] pCO2 data.
Author's Names: T. Naegler, K. Rodgers, P. Ciais and I. Levin
Filesize: 41.50 Kb
Added on: 03-Aug-2005 Downloads: 18
Home Page | Comment on Proceeding | Details
SIMULATING THE GLOBAL BOMB RADIOCARBON CYCLE: CLOSING THE BUDGET
Description:
We estimated the production of bomb radiocarbon using available
information on atmospheric nuclear bomb tests, the simple (radio-)carbon cycle
model GRACE (Global RadioCarbon Exploration Model) and atmospheric observations
as constraints. Subsequent forward simulations of the bomb radiocarbon
inventory in the different carbon reservoirs turned out to be in very good
agreement with recent observation-based estimates, therewith for the very first
time allowing to close the global bomb radiocarbon budget. Besides confirming
original stratospheric bomb 14C data published in the reports of the
Health and Safety Laboratories [Telegadas,
1971, and references therein], our results confirm recent observation-based
ocean bomb radiocarbon inventory estimates for the time of GEOSECS (1970s) and
WOCE (1990s) from Peacock [2004] and Key et al. [2004], but refute the GEOSECS ocean inventory
estimates from Broecker et al. [1985, 1995].
Author's Names: T. Naegler, V. Hesshaimer, and I. Levin
Filesize: 67.02 Kb
Added on: 03-Aug-2005 Downloads: 147
Home Page | Comment on Proceeding | Details
VARIATIONS OF OCEANIC PCO2 AND AIR-SEA CO2 FLUX IN THE GREENLAND SEA AND THE BARENTS SEA
Description:
In order to elucidate seasonal
and interannual variations of oceanic CO2 uptake in the Greenland
Sea and the Barents Sea, partial pressures of
CO2 in the surface ocean (pCO2sea)
were measured from 1992 to 2001. The values of pCO2sea
were lower than the partial CO2 pressures in the atmosphere (pCO2air) throughout the year, and the
annual net air-sea CO2 fluxes in the Greenland Sea and the Barents Sea were evaluated to be 52 ± 31 and 46 ± 27 gC m-2
yr-1, respectively, yielding a total oceanic CO2 uptake of
0.050 ± 0.030 GtC yr-1. We also found that the annual mean CO2
uptake was positively correlated with the North Atlantic Oscillation Index
(NAOI) via wind strength, but was negatively correlated with DpCO2 (pCO2air-pCO2sea) and the sea ice coverage. The
results also indicate that the wind speed and sea ice coverage play a major
role in determining the interannual variation of CO2 uptake, with DpCO2 playing a minor role.
Author's Names: S. Nakaoka, S. Aoki, T. Nakazawa, G. Hashida, et al
Filesize: 121.05 Kb
Added on: 03-Aug-2005 Downloads: 20
Home Page | Comment on Proceeding | Details
ON 18O OF COMBUSTION-DERIVED CO2
Description:
Exchange rates within the Global Carbon Cycle,
between oceans, atmosphere and terrestrial biosphere – including the anthropogenic
CO2 production – are being traced by concentration and isotope ratio
measurements of atmospheric CO2. The background value of the stable
isotope ratio of oxygen in atmospheric CO2 is determined by oxygen
exchange with the ocean surface waters. During contact with leaf water, the
signature of this then evaporation-enriched groundwater (the extent still being
dependent on plant physiological and environmental parameters), will be
imprinted on CO2 diffusing back out of the leaf stomata. From water
cycle studies the continental effect (Rayleigh-distillation) is known, leading
to precipitation strongly depleted in d18O over e.g. Siberia.
This signal is also transferred into plant material. These main mechanisms
within the 18O-cycle are known or under investigation. The d18O
source
term for atmospheric CO2 derived from biomass burning and
anthropogenic fossil fuel combustion, however, is less well-known.
Author's Names: R.E.M. Neubert, M. Schumacher, H.A.J. Meijer
Filesize: 49.85 Kb
Added on: 03-Aug-2005 Downloads: 19
Home Page | Comment on Proceeding | Details
THE EFFECT OF SEA-ICE GROWTH ON CO2 EXCHANGE BETWEEN THE SEA AND THE OVERLYING AIR ON THE BASIS ...
Description:
We have carried out the tank experiment
in the low-temperature room to clarify the CO2 gas exchange mechanism
between the sea and the overlying air during the sea-ice formation process. The
air CO2 concentration in the headspace of the tank began to increase
simultaneously with the sea-ice formation and growth. The CO2 flux
was with in the range from 2.1x10-4 to 4.5x10-4 g-C m-2
hour-1 at ice thickness of 5cm. The CO2 flux was
mainly dependent on the brine salinity in the upper layer of sea-ice, which
suggests that CO2 was released from the brine in the sea-ice, and
transported to the atmosphere.
Author's Names: D. Nomura, H. Yoshikawa-Inoue, and T. Toyota
Filesize: 60.69 Kb
Added on: 03-Aug-2005 Downloads: 18
Home Page | Comment on Proceeding | Details
CARBON DIOXIDE UPTAKE IN THE SOUTHERN OCEAN AND THE FORMATION OF ANTARCTIC INTERMEDIATE WATER ...
Description:
The
formation of Antarctic Intermediate Water is investigated in a state of the art
numerical model. Results are compared with a previous, lower resolution version
of the model, and with data from the World Ocean Circulation Experiment.
Author's Names: N.M.A. Nunes, D.C.E. Bakker, K.J. Heywood, et al
Filesize: 15.49 Kb
Added on: 03-Aug-2005 Downloads: 20
Home Page | Comment on Proceeding | Details
INCREASE OF NORDIC SEAS ANTHROPOGENIC CO2 INVENTORY OVER THE LAST TWO DECADES AS OBSERVED FROM ...
Description:
This
paper presents estimates of the 13C Suess effect and anthropogenic
carbon concentration increase in the Nordic
Seas since 1981.
Author's Names: A. Olsen, A.M. Omar, R.G.J. Bellerby, et al
Filesize: 37.34 Kb
Added on: 03-Aug-2005 Downloads: 22
Home Page | Comment on Proceeding | Details
SYNOPTIC SCALE CO2 VARIABILITY SIMULATED WITH GLOBAL HIGH RESOLUTION ATMOSPHERIC TRANSPORT MODEL
Description:
We present a new version of the global
atmospheric tracer transport model driven by analyzed meteorology with
diurnally varying mixing in the boundary layer capable of running globally at
resolutions up to quarter degree longitude-latitude or higher. The impact of
the higher resolution model can be visible in resolving city plumes, airmass
boundaries, diurnal cycle, fronts and synoptic scale events often observed in
continuous CO2 monitoring site data.
Author's Names: S. Maksyutov, R. Onishi, G. Inoue, P.K. Patra, et al
Filesize: 53.22 Kb
Added on: 03-Aug-2005 Downloads: 29
Home Page | Comment on Proceeding | Details
ASSESSMENT OF AIR-SEA CO2 EXCHANGE RATES IN THE WORLD’S OCEANS USING BOMB 14C INVENTORIES
Description:
The inventory of nuclear bomb produced 14C
(bomb 14C) in the ocean is a major constraint of CO2
exchange between the atmosphere and ocean in numerical models and analytical
estimates of gas exchange. New 14C data in the ocean, improved
methods of separating the bomb 14C from the natural background of 14C
in the ocean, and reassessment of previous inventories are challenging the
canonical estimates of the air-sea gas transfer. An improved method of
separating natural 14C from the observed 14C distribution
is being used to estimate the bomb 14C distribution and inventory.
We use GEOSECS 14C data to represent the global distribution in
1975, and the new WOCE dataset for 1995 to get two time representations of
inventory. To reduce the bias error for averaging zonal bomb 14C
inventories from limited observation stations during the GEOSECS times, we use
zonal averages given by Peacock [2004] for re-evaluation of 1975 air-sea CO2
exchange rates. Zonal inventories for 1995 will be from GLODAP mapping results
using WOCE data [Key et al. 2004]. Lateral
transport models developed by Broecker et al. [1985] are used to assess the
regional air-sea CO2 exchange rates as well as an appropriately
weighted global mean. Four independent methods of estimating bomb 14C
inventory in the ocean show that the original estimate by Broecker et al. [1995]
could be about 25% too high, the air-sea CO2 exchange rates derived
from this original bomb 14C inventory could also be too high by a
similar amount. Results of this assessment will be presented.
Author's Names: T.-H. Peng, R. Wanninkhof, R.M. Key, A. Macdonald
Filesize: 16.72 Kb
Added on: 03-Aug-2005 Downloads: 24
Home Page | Comment on Proceeding | Details