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
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VERTICAL AIRCRAFT PROFILES OVER EUROPE
Description:
Regular vertical profiles over Europe were set up in
2001 as part of the AEROCARB and Carboeurope-IP projects at five locations:
Griffin (56°36'N, 3°47'W, Scotland), Orléans (47°50'N, 2°30'E, France),
Schauinsland (47°55'N, 7°55'E, Germany), Hegyhatsal (46°57'N, 16°39'E, Hungary),
and Bialystok (53.20°N, 22.75°E, Poland). The objective of the program is to
measure CO2, CH4, N2O, SF6, CO, 13C
and 18O in CO2 vertical profiles at a bi-weekly frequency
using air samples taken up at several levels from 100m up to 3000 m above the
ground surface. One liter flasks are sampled on board small aircraft using a
standardised protocol. The samples are analysed at three laboratories (LSCE,
MPI-BGC, IUP-UHEI) which are
linked through regular intercomparison exercises. We have characterised for
each site the CO2 seasonal cycles within the atmospheric boundary
layer (ABL: 14 to 20 ppm) and the
free troposphere (FT: 10 to 13 ppm). From these signals we have calculated the
difference between ABL and FT,
known as the CO2 'jump', which will be compared to the simulations
from atmospheric transport models. We have also calculated the offset between
each airborne sampling site and the time series from Mace Head observatory,
used as a maritime reference. For CO2, the wintertime offsets at the
lowest level of the average vertical profiles are ranging from 0 ppm in Scotland
up to 10 ppm in all continental sites. Depending of the site the positive
offset due to emissions from anthropogenic and biospheric processes may extend
up to 300 to 1500 m agl. In summertime we observe a negative gradient in most
of the sites with a typical decrease of 5 ppm between 2000m and 100m agl. The
average vertical gradients will be compared to the ouput of atmospheric models,
and will be analysed with regards to the other trace gas (CO, CH4,
and CO2 isotopes).
Author's Names: M. Ramonet, L.Haszpra, K. Katrynski, I. Levin, et al
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STUDY OF ATMOSPHERIC CO2 REGIONAL VARIABILITY OVER EUROPE THROUGH THE ANALYSIS OF INTENSIVE ...
Description: We carried out airborne
campaigns over Europe in order to analyze
atmospheric CO2 variability at the regional scale. Data reveal a
higher standard variation in the planetary boundary layer (PBL) against a lower
one in the free troposphere (FT), where the air is more well mixed. Ground data
generally agree well with airborne measurements when done in the FT, but not in
the PBL where they are exposed to local disturbances. Ground stations located
in the FT are shown to be representative of a regional scale while PBL
observatories provide only locally representative measurements.
Author's Names: I. Xueref, M. Ramonet, P.Nedelec, J.A.Morgui, et al
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FIRST RESULTS FROM A 300 M TOWER ATMOSPHERIC MEASUREMENT STATION FOR GREENHOUSE ...
Description:
CHIOTTO – Continuous
HIgh-precisiOn Tall Tower Observations of greenhouse gases – is a European
Union-funded project which has as objective to build an
infrastructure for the continuous monitoring of greenhouse
gas concentrations across Europe above the surface layer using
tall towers (~300m height). For this purpose
a
new analysis system
for continuous atmospheric measurements was
built and tested at Max Planck Institute for Biogeochemistry, Jena,
Germany and was recently installed
at a 300 m tower
close to Bialystok, Poland (Lat 53°14'N, Long 23°01'E, Alt 180m),
as part of the “CHIOTTO”
tall tower network.
Since July
2005 this
system is measuring
quasi-continuously the atmospheric concentration of CO2,
CH4,
CO, N2O,
SF6
and the O2/N2
ratio as well as meteorological
parameters (atmospheric pressure,
temperature, humidity; wind speed and direction) from 5
heights on the tower ranging from 5 to 300 m.
The measurement devices
are: an
Oxzilla O2 fuel cell analyzer, a
LiCor 7000
NDIR CO2 analyzer, an
Agilent
gas chromatograph (GC) with flame ionization
detector (FID) and electronic
capture detector (ECD) for CH4, CO, N2O, SF6. The
challenge was to build a reliable automatic system which can run continuously
with very little maintenance and to fulfill at the
same time the high precision requirements for all the measured species prescribed
by the CHIOTTO project goals. The high
temporal resolution achieved will
capture
short
term events and diurnal variability. In addition, the
system is planned to run for at
least several years in order to observe long-term trends
as well.
We describe
the technical setup of the measurement system, the region of
influence of the station and present the first months of
data if available: correlations between species,
observed short term variability patterns and their relation to meteorology and
air parcel paths.
Author's Names: E.Popa, A.C.Manning, M.Gloor, U.Schultz, et al
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CARBON CYCLE INVERSION VALIDATION USING PROFILE AND OTHER NON-SURFACE OBSERVATIONAL DATA
Description:
We present preliminary results of a
modeling experiment that compares observed vertical profiles of CO2
with those generated by an atmospheric transport model (ATM). The ATM is driven
by CO2 flux fields generated from the inversion of monthly averaged
CO2 surface data (GLOBALVIEW). We note large differences between the
best fit to the observations produced in the inversion and the same quantity
simulated by the forward model. This difference arises from the nonlinearity of
the advection scheme used in the transport model. When comparing with vertical
profiles, we note that much of the difference between simulated and observed
concentration has the same structure as the impact of this nonlinearity.
Inversion schemes must therefore take nonlinearity into account. Despite these
differences, the profiles are able to distinguish among inversions that fit
subsets of the surface data, suggesting they are a useful validation dataset.
Author's Names: C.A. Pickett–Heaps, P.J. Rayner, R.M. Law, P. Peylin, et al
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TOP-DOWN REGIONAL CO2 FLUXES FOR NORTH AMERICA ESTIMATED FROM NOAA-CMDL CO2 OBSERVATIONS
Description:
We present an analysis of terrestrial net CO2 fluxes from North America for the period 2000-2004. These fluxes
consist of hourly maps at ~70km×100km resolution that are consistent with
observed atmospheric CO2 mixing ratios, as well as with varying
climatic conditions across different ecosystems as observed from space. The
flux maps are created in a newly developed ensemble data assimilation system
that consists of the atmospheric Transport Model v5 (TM5), the Vegetation
Photosynthesis Respiration Model (VPRM), and an efficient Bayesian
least-squares algorithm to optimize the fluxes from different biomes in VPRM
against CO2 mixing ratios from the NOAA-CMDL
observing network. The stochastic nature of the ensemble data assimilation
system allows us to consistently include uncertainty on net CO2 fluxes from the neighboring oceans and more distant continents
in the flux estimates for North America.
Author's Names: Wouter Peters, Lori Bruhwiler, John Miller, et al
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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
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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
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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
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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
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