THE NOAA CMDL TALL TOWER OBSERVING NETWORK: NEW RESULTS AND PLANNED EXPANSION
Description: The
National Oceanic and Atmospheric Administration’s Climate Monitoring and
Diagnostics Laboratory has been working to build a network of tall tower
monitoring sites over the US
since the early 1990’s. Tall tower CO2 mixing ratio measurements are
sensitive to upwind fluxes over scales of hundreds of kilometers. Such
measurements therefore place strong constraints on estimates of regional scale
carbon budgets. We have used the Stochastic Time Inverted Lagrangian Transport
(STILT) model to evaluate the relative contributions of upwind sources and
sinks to simulated CO2 mixing ratios at existing and proposed new
tower sites. For example, sampling footprints from STILT have been combined
with estimates of hourly ecosystem CO2 fluxes from the Simple
Biosphere (SiB) model to investigate the spatiotemporal influence of different
biomes on observed CO2 concentrations at the towers. Contributions
of fossil fuel and oceanic CO2 fluxes can also be quantified using
this method.
Author's Names: A.E. Andrews, P.S. Bakwin, P.P. Tans, J. Kofler, C. Zhao, J.
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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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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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Added on: 03-Aug-2005 Downloads: 56
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OCEANIC SOURCES AND SINKS FOR ATMOSPHERIC CO2
Description: Owing to the combination of greatly improved observational constraints
and new data analysis and modeling techniques, our ability to constrain the
role of the ocean in the global carbon cycle has made great advances in the
past decade. By combining ocean interior carbon data with ocean general
circulation models in an inverse manner, we can constrain the oceanic uptake of
anthropogenic CO2 to within an unprecedented narrow range of
2.20±0.25 Pg C yr-1 for a nominal year of 1995. The inversely
estimated pre-industrial air-sea fluxes reveal the expected pattern with CO2
outgassing in the tropics and CO2 uptake at mid to high latitudes.
The subpolar regions of the Southern Hemisphere defy this trend, exhibiting
strong outgassing of natural CO2. This outgassing nearly cancels the
large uptake of anthropogenic CO2 in this region, leading to a near
zero net contemporary flux. The contemporary air-sea fluxes from the inversion
agree reasonably well with flux estimates derived from ∆pCO2
observations, with the exception of the above subpolar regions, where our flux
estimates are three to five times smaller. When analyzed together with the
observed atmospheric CO2 gradients, our results support the
existence of a substantial sink for atmospheric CO2 in the northern
hemisphere terrestrial biosphere, and a terrestrial carbon loss in the tropics.
Author's Names: N. Gruber, S.E. Mikaloff-Fletcher, A.R. Jacobson, et al
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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
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INCREASING THE TEMPORAL AND SPATIAL RESOLUTION OF FOSSIL-FUEL CARBON EMISSIONS ESTIMATES FOR ...
Description: Numerical models of the carbon cycle are
becoming increasingly sophisticated. One result of this is that these models
now require fossil-fuel carbon-dioxide emissions data with sub-annual (e.g.,
seasonal) time resolution. They also
require finer spatial resolution than national averages (i.e., than one point
per nation). Finer spatial resolution is
especially needed for countries as large in area as the United States of
America (U.S.A.). Here we present a summary of monthly data for the entire
nation, and annual data for each state in the U.S.A.
Author's Names: T.J. Blasing, C.T. Broniak, and G. Marland
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PACIFIC DOMINANCE TO GLOBAL AIR-SEA CO2 FLUX VARIABILITY: A NOVEL ATMOSPHERIC INVERSION AGREES ...
Description:
We
address an ongoing debate regarding the geographic distribution of interannual
variability in ocean - atmosphere carbon exchange. We find that, for 1983-1998,
both novel high-resolution atmospheric inversion calculations and global ocean
biogeochemical models place the primary source of global CO2 air-sea
flux variability in the Pacific Ocean. In ocean biogeochemical models, this
variability is clearly associated with the El Niño / Southern Oscillation
cycle. Both inversion and models indicate that the Southern Ocean is the
second-largest source of air-sea CO2 flux variability, and that
variability is small throughout the Atlantic, including the North Atlantic, in
contrast to previous studies.
Author's Names: G.A. McKinley, C. Rödenbeck, M. Gloor, et al
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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
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INITIAL RESULTS FROM THE TOTAL CARBON COLUMN OBSERVING NETWORK
Description:
The
Total Carbon Column Observing Network is a new network of ground-based solar
observatories, dedicated to column measurements of greenhouse gases. We present CO2 column abundances
observed in Park Falls, Wisconsin
and Lauder, New Zealand
during May 2004 – June 2005. In Park Falls, Wisconsin,
the peak-to-peak variation of column-average CO2 is approximately 13
ppmv. In Lauder, New Zealand, the peak-to-peak
variation of column-average CO2 is approximately 4 ppmv. Assuming a secular trend of 2 ppmv yr-1,
we infer a peak-to-peak seasonal amplitude of 11 ppmv and 2 ppmv for Park Falls
and Lauder respectively. These values
are higher than model predictions by Olsen and Randerson [2003].
Author's Names: R.A. Washenfelder, V. Sherlock, B.J. Connor, et al
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OCEANIC CONSTRAINTS ON THE SIZE OF THE TERRESTRIAL CO2 FERTILIZATION SINK
Description: We have constructed an
estimate of annual-mean surface fluxes of carbon dioxide for the period 1992-6
using observational constraints from the atmosphere and from the ocean
interior. The method interprets in situ
observations of carbon dioxide concentration in the ocean and atmosphere using
transport estimates from global circulation models.
Author's Names: A.R. Jacobson, J.L. Sarmiento, M. Gloor, N. Gruber, et al
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