VARIATIONAL DATA ASSIMILATION OF HIGH DENSITY ATMOSPHERIC CO2 DATA:...
Description: High-frequency atmospheric CO2 measurements
should become increasingly available by the end of this decade from a variety
of sources, including low-Earth orbiting satellites. If of sufficient accuracy,
these should allow the functioning of the global carbon cycle to be monitored
at fine time/space resolutions using atmospheric transport inversions. Since
traditional direct inversion methods (e.g., Bayesian synthesis) become
computationally infeasible at these resolutions, we use an approximate method,
variational data assimilation, to estimate surface CO2 fluxes at
spatial resolutions ranging from 10x10 degrees to 1x1 degrees and at time
resolutions ranging from 2 weeks to 1 hour. We assess its performance using simulated
data, including the effects of realistic transport and data errors.
Author's Names: D.F. Baker, S. Doney, and D. Schimel
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Added on: 25-Jul-2005 Downloads: 34
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TOWARDS A NEW ISOPYCNIC OCEAN CARBON CYCLE MODEL
Description: Numerical
ocean carbon cycle models are the primary tools to predict the ocean's response
to increasing atmospheric CO2 concentration. So far most of these
have been based of physical components with geometric vertical levels. While
permitting an accurate computation of the horizontal pressure gradient driving
geostrophic flow, vertical discretization on z-levels leads to spurious
diapycnal mixing and upwelling. Isopycnic ocean models have an advantage over
those with geometric vertical layers in that their vertical coordinate mimics
the real structure of the water column as stratified layers of constant
density, and thus avoid artificial mixing and advection in the ocean interior.
Their disadvantages include the problem of massless layers, the necessity to
add a mixed layer model to adequately represent surface processes, and the
induction of a horizontal pressure gradient error by the sloping density
surfaces. Models with different vertical schemes thus complement each other and
can be used as one basis for an uncertainty assessment.
Author's Names: K.M. Assmann, C. Heinze, H. Drange, M. Bentsen, and K. Lygre
Filesize: 19.62 Kb
Added on: 25-Jul-2005 Downloads: 37
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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.
Filesize: 96.36 Kb
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MONTHLY RESOLUTION FOSSIL-FUEL-DERIVED CARBON DIOXIDE EMISSIONS FOR THE COUNTRIES...
Description: Examination of national statistical databases has
allowed for the widely-used data set on annual, fossil-fuel-derived, carbon
dioxide emissions (maintained by the Carbon Dioxide Information Analysis Center
(CDIAC)) to be subdivided into monthly time intervals. This analysis focused on
statistical parameters that represent the solid, liquid, and gaseous fuels
consumed in each country at monthly time scales. An intermediate product of
this analysis was the fraction of the annual total consumption occurring in
each month for each fuel. Monthly fractions were multiplied by the annual carbon
dioxide emission value to obtain monthly emission estimates. A benefit of this
approach is monthly and annual emissions time series that are mutually
consistent. This presentation will give
monthly emissions for multiple years for the United
States, Canada,
and Mexico.
All data have been updated since the Fall 2004 AGU
presentation of this work. The monthly data by state and province provide
enough detail to begin to describe how the annual cycle of emissions varies
spatially (i.e., whether emissions peak in the summer, in the winter, or are
relatively uniform throughout the year).
Author's Names: R.J. Andres, J.S. Gregg, L.M. Losey, and G. Marland
Filesize: 40.59 Kb
Added on: 25-Jul-2005 Downloads: 29
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DETERMINING CO2 FLUX COMPONENTS IN THE DENVER URBAN ECOSYSTEM
Description: Within urban ecosystems are strong anthropogenic
emissions of CO2 as well as significant CO2 sinks
associated with vegetation. CO2 profiles and net flux of CO2
(NEE) over Denver
was measured over a multi-year period and compared with certain component
fluxes (soil surface net flux, and emissions from fossil fuel combustion). CO2
concentration and NEE typically exhibits a diurnal trend, apparently due to
emissions from transportation and sequestration by vegetation.
Author's Names: D. E. Anderson and T. Thienelt
Filesize: 22.21 Kb
Added on: 25-Jul-2005 Downloads: 38
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MODELING ATMOSPHERIC CO2 CONCENTRATION PROFILES AND FLUXES ABOVE SLOPING FORESTED TERRAIN
Description: CO2
profiles were simulated in the atmospheric boundary layer above sloping terrain
using a three dimensional transport model coupled with a vegetation sub-model.
WMO/GAW concentration monitoring site and ecosystem flux measurement site were
located inside the modeled region at the top of a hill and at boreal forest,
respectively. According to model results, the concentration measurement at hill
site was representative for continental background. However, concentration at few
meters above active vegetation represented mainly local variation.
Concentration difference between hill site and forest site was about 5 ppm
during afternoon according to both model and measurements. The hill site was
above boundary layer during night and inside boundary layer during daytime. The
regional CO2 signal dominated in both cases. The average flux to the
whole model region was about 40 % of the local flux at the forest site.
Author's Names: T. Aalto, J. Hatakka, M. Aurela, T. Thum and A. Lohila
Filesize: 40.81 Kb
Added on: 22-Jul-2005 Downloads: 40
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