REGIONAL ECOSYSTEM-ATMOSPHERE CARBON EXCHANGE OBSERVED SIMULTANEOUSLY VIA ATMOSPHERIC INVERSIONS ...
Description:
The
overarching goal of a long-term, multi-investigator, regional study of
ecosystem-atmosphere carbon cycling in a mixed forest ecosystem in the upper
Midwest of the USA is to observe ecosystem-atmosphere exchange of carbon
dioxide at scales of relevance to the global carbon balance, while
simultaneously understanding the mechanisms governing this exchange. This
study, the Chequamegon Ecosystem-Atmosphere Study (ChEAS), brings together
multiple approaches to observing carbon fluxes, including chamber flux, sap
flux and biometric measurements at the plot scale (~1 m2), multiple
stand-level (~1 km2) eddy-covariance flux towers, landscape-scale (~10-100
km2) eddy-covariance flux measurements from the WLEF tall tower,
multiple regional (103-105 km2) atmospheric
boundary layer (ABL) budget approaches using tall tower mixing ratio
measurements, and a regional (~105 km2) ABL budget using
a network of CO2 mixing ratio measurements on communications towers.
Flux measurements have been up-scaled to the region using a variety of
approaches, and compared to the regional ABL budget methods. Top-down and
bottom-up methods fall within a range of values for growing-season flux
estimates that suggests a level of precision for regional flux estimates of
approximately 0.5 gC m-2 d-1. A multi-tower inverse study
should increase the level of precision of the ABL budget flux estimates. Interpreting
the mechanisms governing these fluxes requires plot- and stand-level data. These
data show that variability in seasonal and annual fluxes among flux towers is
large, refuting hypotheses that ecosystem-atmosphere exchange can be explained
simply by climate, or that a sparse flux tower network can be used to map
carbon fluxes over continental domains. Stand age and stand type (e.g. aspen,
wetland, northern hardwood forest) explain a large fraction but not all of the
observed variability among stands. More sophisticated land classification
schemes may be needed to improve the precision of bottom-up methods. Multi-year
records are used to examine interannual variability in the carbon balance of
the region and show that interannual variability at WLEF is clearly correlated
with climate variability. Limited multi-year records at the plot- and stand-level
partly support the hypothesis that year-to-year variability in carbon fluxes
are coherent across the region, and begin to describe the causes of the observed
interannual variability. Further study is needed to evaluate the network design
required to describe both the magnitude and mechanisms of interannual
variability in the regional carbon balance.
Author's Names: K.J. Davis, A. Andrews, J.A. Berry, P.V. Bolstad, et al
Filesize: 131.32 Kb
Added on: 28-Jul-2005 Downloads: 31
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REGIONAL-SCALE CHARACTERIZATION OF SUMMERTIME CO2 SOURCES AND SINKS OVER THE CONTERMINOUS ...
Description:
Fast-response
(1-s resolution) CO2 measurements were recorded aboard the NASA DC-8
during the Intercontinental Chemical Transport Experiment – North
America (INTEX-NA) mission.
Utilizing a non-dispersive infrared gas analyzer-based sampling
system, measurements were obtained over sparsely sampled areas of North America and adjacent ocean basins providing
valuable regional-scale information on carbon sources and sinks.
Author's Names: S.A. Vay, Y. Choi, J.-H. Woo, and K. Prasad
Filesize: 369.00 Kb
Added on: 08-Aug-2005 Downloads: 41
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ROOT AND MICROBIAL CONTRIBUTION TO THE TOTAL CO2 EFFLUX FROM SOIL AS DEPENDENT ON LAND USE
Description: The
contribution of roots to the annual CO2 emission from gray forest
and soddy podzolic soils measured in the
field experiments under crops and native vegetation varied in the wide range
from 10 to 58% of CO2 emission from the soil by mean value of 33%.
The contribution of roots to the CO2 emission from soil surface
calculated for growth season for all the ecosystems studied was equal to 44%.
In agroecosystems the contribution of roots was strongly related to the length
of crops growth. CO2 emission during dormant periods of the year was
greatly controlled by the decomposition of surface litter and detritus in the
soil than by respiration of roots and soil microorganisms.
Author's Names: A. Larionova, V. Lopes de Gerenju, D.Sapronov, I. Yevdokimov
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Added on: 01-Aug-2005 Downloads: 19
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SATELLITE-BASED MODELING OF GROSS PRIMARY PRODUCTION OF DECIDUOUS FOREST AND GRASSLAND SITES ...
Description: The
satellite-based Vegetation Photosynthesis Model (VPM) that estimates seasonal
dynamics of gross primary production (GPP) of vegetation was applied to 5
European forest and grassland sites. The relatively simple VPM model is based
upon light absorption by leaf chlorophyll, leaf water content and leaf age. The
current version of the VPM model relates the Enhanced Vegetation Index (EVI) to
light absorption by leaf chlorophyll and the Land Surface Water Index (LSWI) to
leaf water content, modifying implied functional relationships within the model
according to daily air temperature and photo-synthetically active radiation
input. We used site-specific climate data and CO2 flux data of the
year 2002 from three beech forest sites and two grassland/cropland sites of the
CARBOEUROPE network for testing.
Author's Names: Xiangming Xiao
Filesize: 11.46 Kb
Added on: 09-Aug-2005 Downloads: 25
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SEASONAL AND INTERANNUAL VARIABILITY IN NET ECOSYSTEM CO2 EXCHANGE IN SIX FOREST FLUX SITES IN JAPAN
Description: Eddy covariance measurements of CO2 were
taken for five years above six forests distributed from the northern to
southernmost main islands of Japan.
These forests included cool- and warm-temperate deciduous and coniferous
forests. The climate of Japan
is characterized by apparent seasonal changes and adequate precipitation affected
by the East Asian monsoon. In this report, we compared net ecosystem production
(NEP) among forests using the eddy
covariance method and analyzed the climatic factors that affect seasonal and
inter-annual changes in NEP in
relation to forest type. The observed annual NEP
from 2000 to 2002 ranged from 286 to 566 gCm-2yr-1, and
this basically increased with decreasing latitude. The observed maximum 10 days
mean NEP was about 1.5 times
larger in the deciduous sites, although the growing period was more than 2
times longer in the coniferous sites.
Author's Names: Y. Ohtani, Y. Yasuda, Y. Mizoguchi, T. Watanabe, et al
Filesize: 31.36 Kb
Added on: 03-Aug-2005 Downloads: 97
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SEASONAL CHANGE OF CO2 FLUX ABOVE A JAPANESE BEECH FOREST
Description:
Forestry
and Forest Products Research Institute erected a CO2 flux observation
tower at a Japanese beech forest, and have measured CO2 flux with
closed-pass eddy covariance method for 5 years. During the observation period, 2003
was the most CO2 absorbed year, and the amount was 1.9 times larger
than 2004, which was the least CO2 absorbed year. To investigate the
cause of the smaller CO2 absorption in 2004, we referred some
meteorological factors in 2003 and 2004.
Solar radiation (during green-leaved season) was larger in 2004 than
2003, in contradiction to CO2 absorption. On the other, air temperature was higher in 2004
than 2003 (both in green-leaved and defoliated season). We assumed that larger
respiration in 2004 effected the depression of annual CO2
absorption. At our research site, annual
mean air temperature in 2004 was 0.95 degree centigrade warmer than 2003. The result of this study suggests the
tendency that warmer climate may cause less CO2 absorption in this
Japanese beech forest.
Author's Names: T. Saito, Y. Ohtani, Y. Mizoguchi, T. Morisawa
Filesize: 84.05 Kb
Added on: 04-Aug-2005 Downloads: 20
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SEASONAL VARIATION AND PARTITIONING OF NOCTURNAL FOREST LEVEL RESPIRATION IN A MIXED BROADLEAVED ...
Description:
Seasonal variations in nocturnal
aboveground forest level respiration were measured using static, automated
foliage and stem chambers in the Yamashiro Experimental Forest (YEF), a
broadleaved secondary forest in Kyoto,
Japan. The
growth component of the respiration during the growing season equaled 12% of
the total annual aboveground nocturnal forest level respiration in the YEF.
These findings suggest that growth respiration is an important component of
total respiration in similar forests.
Author's Names: T. Miyama, Y. Kominami, I. Hosoda, K. Tamai, et al
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Added on: 02-Aug-2005 Downloads: 21
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SIGNALS OF PHOTOSYNTHESIS AND RESPIRATION AT BOREAL FORESTS IN RESPONSE TO ENVIRONMENT ...
Description: The isotopic composition of the ecosystem respiration (d13CER) and the isotopic
discrimination of the ecosystem (DEco) were retrieved from intensive campaigns (1998 to 2000) and
from weekly diurnal sampling (2003) at a boreal forest site (Fraserdale, Canada,
49°53'N, 81°34'W). The results show that
d13CER was less sensitive to
temperature (T) variation compared with DEco, suggesting that the photosynthesis CO2 flux
was likely more sensitive to temperature than the ecosystem respiration CO2
flux during the same period of time at the study site.
Author's Names: L.Huang, B. Chen, P.P. Tans, K.Higuchi, D.Worthy, et al
Filesize: 87.89 Kb
Added on: 29-Jul-2005 Downloads: 150
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SIMULATING EFFECTS OF LAND USE CHANGE ON CARBON FLUXES WITH A PROCESS MODEL IN SUBTROPICAL ...
Description:
A process model was used to simulate changes in the carbon fluxes and
stocks at a site that was transformed a grassland to a plantation at Qian
Yanzhou. The total carbon storage of the zonal vegetation (evergreen broadleaf
forest) was simulated and taken as the saturated carbon storage value of that site. The simulated vegetation density and soil organic
carbon (SOC) were compared with the observed. The simulates indicate
that after 20 years planting of the needle leaf forests (Pinus Massoniana, Cunninghamia lanceolata and Pinus elliottii ect) on ex-grassland, the net carbon storage increase in the plantation
was 8.03 kg
C/m2,in which the
vegetation carbon storage increased 8.5334
kg C/m2 and the soil carbon storage decreased 0.518 kg C/m2. The total
carbon storage of 20 years plantation is 58.6%
of the saturated value. The study also shows that between 0 and 7 years of land
use change the soil carbon was decreased and between 7 and 20 years it was
predicted to increase slowly.
Author's Names: M. Huang, J. Ji, M. Cao, and K. Li
Filesize: 51.59 Kb
Added on: 08-Aug-2005 Downloads: 17
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SOIL CARBON IN ABANDONED LANDS OF RUSSIA
Description:
Annual
changes in soil carbon stock are considered of the abandoned managed
agricultural lands that were under natural regrowth over the territory of Russia
within the period 1990-2002. Total area of abandoned agricultural land is 21,6
millions ha. The projections of changes in the carbon stock have been made for
the period from present to 2010. The ROTHC model was employed in the
investigation of carbon dynamics in soils. The territory of Russia
was subdivided into 40 regions. The average basic soil and climatic parameters,
as well as the annual input of organic matter into soils due to natural
succession were estimated for each region. Average annual net-emission over the
territory of abandoned lands was 2,1 ± 1,8 Tg C/yr in 1990-1999. CO2
removal from the atmosphere by soils was 5,2 ± 2,8 Tg C/yr on average in
2000-2002. A total increase in carbon stock of the abandoned lands over the
country can be as high as 153 Tg C (that corresponds to the removal of 561 Tg
of CO2 from the atmosphere) in 2010. Central regions of the European
part of Russia, south of
East Siberia and the Far East will have the
highest intensity of carbon sequestration.
Author's Names: A.A. Romanovskaya
Filesize: 36.11 Kb
Added on: 04-Aug-2005 Downloads: 22
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