OBSERVED RESPONSE OF THE CO2 GROWTH RATE TO CLIMATE VARIATIONS
Description:
The world is moving in a direction of managing the carbon
cycle in order to limit the forcing of earth's climate by CO2 as
well as to limit acidification of the oceans.
We may expect limitations on emissions, sequestration of carbon and
enhancements of natural sinks. It would
be important to be able to observe and quantify the impact of any such measures
on the growth rate of CO2. Until now it has been difficult to
quantify changes of the growth rate of CO2 with confidence due to
the large year to year variations that are caused by climate variations. A statistical method has been developed to
predict the growth rate of CO2 based on observed variations of
climate parameters.
Author's Names: Pieter Tans
Filesize: 16.25 Kb
Added on: 08-Aug-2005 Downloads: 24
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CLIMATE AND DISTURBANCE EFFECTS ON GROSS ECOSYSTEM FLUXES ASSESSED BY MODEL-DATA FUSION
Description:
We
implement a model-data fusion method to determine the gross flux components
contributing to the net ecosystem exchange of a Ponderosa pine forest in Oregon. This site-level
investigation represents a test-run of the method, which will later be applied
to all of Oregon and north California.
Author's Names: J.M. Styles, B.E. Law, D. Turner, W. Cohen, and G. Whitley
Filesize: 48.86 Kb
Added on: 08-Aug-2005 Downloads: 51
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SOIL MOISTURE INCREASES IN A TROPICAL SAVANNA UNDER FREE AIR CO2 ENRICHMENT
Description:
Soil
moisture measurements in an Australian tropical savanna show accumulating soil
water under three years of Free Air CO2 Enrichment (FACE). Most of this accumulation is occurring below
the rooting depth of grasses. Although
this increase in stored soil water is only a fraction (< 0.3% yr-1)
of annual rainfall, it is cumulative and may advantage deep-rooted woody
plants.
Author's Names: C.J. Stokes, A.J. Ash, and J.A.M. Holtum
Filesize: 93.97 Kb
Added on: 08-Aug-2005 Downloads: 20
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AEOLIAN INPUT OF BIO-AVAILABLE IRON TO THE OCEAN
Description:
Atmospheric
deposition of mineral dust aerosols supplies the essential nutrient of iron to
the ocean. However, only the readily soluble
iron is available to biological uptake while the insoluble iron precipitates to
the ocean bottom. Here we present a
global model simulation of Aeolian iron input to the ocean, considering
hematite dissolution in mineral dust aerosols catalyzed by nitric and sulfuric
acids. Our model suggests that atmospheric
deposition of soluble iron to the oceans is much larger than previous model
results in high nitrate low chlorophyll (HNLC) regions.
Author's Names: S.-M. Fan, W. J. Moxim, and H. Levy II
Filesize: 482.29 Kb
Added on: 05-Aug-2005 Downloads: 70
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IMPACT OF CO2, CLIMATE AND O3 ON FUTURE LAND-ATMOSPHERE CARBON EXCHANGE
Description:
In this study we evaluate the individual and combined impacts
of CO2, climate and Ozone on future terrestrial carbon storage using
the computationally efficient GCM analogue model coupled to the MOSES/TRIFFID
land surface carbon cycle model. Ozone is modelled to have a significant
detrimental effect on future plant productivity and hence terrestrial carbon
storage, opposing the enhanced production and terrestrial carbon storage
associated with elevated atmospheric CO2 concentrations.
Author's Names: S. Sitch, B. Collins, P. Cox, N. Gedney, D. Hemming, et al
Filesize: 22.92 Kb
Added on: 04-Aug-2005 Downloads: 20
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DGVMII – QUANTIFYING UNCERTAINTIES IN THE FUTURE LAND-ATMOSPHERE EXCHANGE
Description: In recent years attention has focused on the
role of terrestrial biosphere dynamics in the climate system, and the
possibility of large land-atmosphere carbon cycle feedbacks under human-induced
future climate warming. During the 1990s rapid development of Dynamic Global
Vegetation Models (DGVMs) led a growing community to soon recognize the need
for model evaluation and intercomparison. In Cramer et al. 2000 six DGVMs were
run using identical forcing data based on the HadCM2 GCM climatology
(1860-2100) and the IS92a emission scenario.
Author's Names: S. Sitch, W. von Bloh, P. Ciais, P. Cox, et al
Filesize: 18.83 Kb
Added on: 04-Aug-2005 Downloads: 19
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CANOPY UPTAKE OF ATMOSPHERIC NITROGEN AT A CONIFER FOREST: ENHANCED PHOTOCHEMICAL EFFICIENCY ...
Description: A field study at the Niwot conifer forest
within
the footprint of an AmeriFlux tower site used fluorometry (chlorophyll
fluorescence) to identify a mechanism by which canopy uptake of
atmospheric/anthropogenic N deposition may influence photosynthesis
and net ecosystem
exchange (NEE). Correlation of daytime NEE with canopy N uptake (CNU)
had suggested a linkage. Strongly differing N additions were
spray
applied (simulating wet deposition) to spruce branches. Photochemical
efficiency was markedly enhanced in N-treated branches under high light
with a
concomitant reduction in foliar photodamage and/or in PAR-induced
foliar heat dissipation. Photosynthesis
and NEE enhancement were statistically related to CNU.
Author's Names: H. Sievering, T. Tomaszewski, and R. Boyce
Filesize: 84.50 Kb
Added on: 04-Aug-2005 Downloads: 42
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THE WINTER ARCTIC OSCILLATION, THE TIMING OF SPRING, AND CARBON FLUXES IN THE NORTHERN HEMISPHERE
Description:
Increased winter temperatures associated with the
observed positive trend in the winter Arctic Oscillation can partially explain
trends towards earlier spring leafout in the northern hemisphere. Increased spring drawdown associated with
earlier leafout, coupled with increased winter respiration due to warmer
temperatures, indicate the trend in the winter Arctic Oscillation can help
explain observed increases in the seasonal amplitude of atmospheric CO2 concentration.
Author's Names: K.M. Schaefer, A.S. Denning, and O. Leonard
Filesize: 68.55 Kb
Added on: 04-Aug-2005 Downloads: 28
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EPISODIC ENHANCEMENTS OF CO2 AND CO AT THE SUMMIT OF MT. FUJI, JAPAN
Description: The mixing ratios of atmospheric CO2 were
observed at the summit of Mt.
Fuji by using a system
for continuous measurements during September 2002-February 2003 and May
2003-May 2004. The observed CO2 variations at Mt. Fuji
showed a seasonal cycle of the background level with a maximum around April and
a minimum around August. A lot of episodic events with a large enhancement of
CO2 were found, and the episodic enhancements of CO2 at Mt. Fuji
were well associated with increased CO peaks observed at the same time. The
enhancement ratios of CO to CO2 mixing ratios (ΔCO/ΔCO2)
mainly showed lower values of less than 0.03 due to urban/industrial sources,
while relatively higher ΔCO/ΔCO2 ratios up to 0.08 were also found
for the episodic events due to the biomass burning emissions. Three-dimensional
transport model simulations of CO suggested that the major contributions for
the increased events at Mt. Fuji were from China
(~50%) and the other major
regions were Southeast Asia and South Asia (~10%).
Author's Names: Y. Sawa, H. Matsueda, S. Taguchi, Y. Igarashi, et al
Filesize: 100.10 Kb
Added on: 04-Aug-2005 Downloads: 21
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THE MID-LATITUDE WESTERLIES, ATMOSPHERIC CO2 AND CLIMATE CHANGE DURING THE ICE AGES
Description:
An idealized general circulation model is constructed
of the ocean’s deep circulation and CO2 system that reproduces the
main features of glacial-interglacial CO2 cycles, including the
tight correlation between atmospheric CO2 and Antarctic
temperatures, the lead of Antarctic temperatures over CO2 at
terminations, and the shift of the ocean’s 13C minimum from the
North Pacific to the Atlantic sector of the Southern Ocean. The model is based
on a new idea about the nature of the glacial-interglacial cycles in which the
driving force is independent of the orbital forcing and is not in the ocean.
The key to glacial-interglacial transitions, we claim, is a relationship
between the mid-latitude westerly winds, atmospheric CO2, and the
mean state of the atmosphere. Cold glacial climates seem to have
equatorward-shifted westerlies, which allow more respired CO2 to
accumulate in the deep ocean. Warm climates like the present have
poleward-shifted westerlies that flush respired CO2 out of the deep
ocean.
Author's Names: J.R. Toggweiler, J.L. Russell, S.R. Carson
Filesize: 12.05 Kb
Added on: 04-Aug-2005 Downloads: 20
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