Seasonal variations of atmospheric CO2, δ13C, and δ18O at a cool temperate deciduous forest in Japan: Influence of Asian monsoon

Murayama, Shohei; Takamura, Chikako; Yamamoto, Susumu; Saigusa, Nobuko; Morimoto, Shinji; Kumakura, Hiroaki; Nakazawa, Takakiyo; Aoki, Shuji; Usami, Tetsuyuki; Kondo, Miyuki

doi:10.1029/2009jd013626

Cited by 19 publications

(21 citation statements)

References 84 publications

(134 reference statements)

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“…More detailed descriptions of the TKY site have already been given in our previous papers (e.g. Murayama et al, 2003Murayama et al, , 2010. Continuous measurements of the net CO 2 flux between the forest and the atmosphere, as well as of meteorological parameters, using a 27-m tall tower were first initiated in 1993 by employing an aero-dynamic method that was replaced in 1998 by an eddy covariance method (Yamamoto et al, 1999;Saigusa et al, 2005).…”

Section: Methodsmentioning

confidence: 99%

O2:CO2 exchange ratios observed in a cool temperate deciduous forest ecosystem of central Japan

Ishidoya

Murayama

Takamura

et al. 2013

Tellus B: Chemical and Physical Meteorology

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Detailed observations of O2:CO2 exchange ratios were conducted in a cool temperate deciduous forest located in central Japan. The exchange ratios of soil respiration and net assimilation were found to be 1.11±0.01 and 1.02±0.03 from soil chamber and branch bag measurements, respectively. Continuous measurements of the atmospheric O2/N2 ratio and the CO2 concentration, made inside the canopy during a summer season, indicated that the average exchange ratio was lower in the daytime (0.87±0.02) than in the nighttime (1.03±0.02) with a daily mean value of 0.94±0.01. The observed average daytime and nighttime exchange ratios were nearly consistent with the corresponding values obtained from a one-box canopy O2/CO2 budget model simulation of net turbulent O2 and CO2 fluxes between the atmosphere and the forest ecosystem. Our results suggest that the daily mean exchange ratios of the net turbulent O2 and CO2 fluxes depend sensitively on the forest ecosystem processes

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Section: Methodsmentioning

confidence: 99%

O2:CO2 exchange ratios observed in a cool temperate deciduous forest ecosystem of central Japan

Ishidoya

Murayama

Takamura

et al. 2013

Tellus B: Chemical and Physical Meteorology

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“…Given the quantity and diversity of observations at the Takayama site, researchers have not yet used several components of the data in modeling studies. For example, high-precision measurements of the atmospheric composition and isotopic ratios (such as, d 13 C and d 18 O of ambient CO 2 ) have been obtained at the site (e.g., Murayama et al 2005Murayama et al , 2010. Both above-and within-canopy air sampling has been conducted and these results could be used to describe local exchanges between the terrestrial ecosystem and the ambient air.…”

Section: Future Work At the Takayama Sitementioning

confidence: 99%

Synergies between observational and modeling studies at the Takayama site: toward a better understanding of processes in terrestrial ecosystems

Ito

Saitoh

Sasai

2014

Ecological Research

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This paper reviews past and ongoing ecological studies at the Takayama forest site, one of Japan's long‐term research sites with intensive studies; the emphasis here is on the synergies between observational and modeling studies. This synergism has been encouraged because global environmental change is a complicated and interdisciplinary issue that requires this type of collaboration. The increasing amount and quality of observational data available from this site helps researchers to better constrain their model simulations because substantial uncertainties remain in the behavior of models in their current form. In addition, modeling studies encourage observational research by integrating observational data within a comprehensive framework. They do this by demanding more long‐term and high‐quality data related to specific ecological processes, and by identifying high‐priority processes and parameters that should be studied. We describe the types of modeling studies that have been conducted and how observational data from the Takayama site have improved the accuracy of these models. Many terrestrial ecosystem models have been applied to data from the site, both to validate the present forms of the models and to refine the structure and parameterization of the models. The development of new or improved terrestrial ecosystem models will be further facilitated by the requirements to simulate atmosphere–ecosystem exchanges and internal biogeochemical processes, as well as simulating their responses to a changing environment. We conclude by discussing the remaining research gaps and opportunities for deepening our understanding of terrestrial ecosystems through future collaborative studies.

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“…b Isotopic ratios in the atmosphere are representative values from the measurements of atmospheric CO 2 (Nakazawa et al, 1993;Allison and Francey, 2007), CH 4 (Umezawa et al, 2009), CO (Kato et al, 1999), and N 2 O (Ishijima et al, 2007). c Isotopic ratios of CO 2 and CO in standard gases used in this study are the means obtained from the direct measurements by mass spectrometers (Tsunogai et al, 2002;Murayama et al, 2010). Isotopic ratios of standard gas for CH 4 are the representative values of fossil fuel CH 4 (Snover et al, 2000) similar to the measurements of other JFP standard gases by T. Umezawa (personal communication, 2011).…”

Section: Analysis and Its Precisionmentioning

confidence: 99%

“…Furthermore, quick connectors (Swagelok QC series) are adopted to easily connect the sample inlet and vent tubes in the aircraft. Each flask was preconditioned by heating it at 120 • C under a vacuum condition (1 × 10 −6 Torr) for 12 h. It has been shown by Murayama et al (2003) that such treatment is effective in minimizing the CO 2 drift in flask samples. A total of 24 flasks used for each flight are distributed into 4 aluminium packages, so that they can be easily placed on or removed from the aircraft.…”

Section: Flask Air Samplingmentioning

confidence: 99%

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Evaluation of a new JMA aircraft flask sampling system and laboratory trace gas analysis system

Tsuboi¹,

Matsueda²,

Sawa³

et al. 2013

Atmos. Meas. Tech.

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We established and evaluated a flask air sampling system on a cargo C-130H aircraft, as well as a trace gas measurement system for the flask samples, as part of a new operational monitoring program of the Japan Meteorological Agency (JMA). Air samples were collected during each flight, between Kanagawa Prefecture (near Tokyo) and Minamitorishima (an island located nearly 2000 km southeast of Tokyo), from the air-conditioning system on the aircraft. Prior to the operational employment of the sampling system, a quality assurance test of the sampled air was made by specially coordinated flights at a low altitude of 1000 ft over Minamitorishima and comparing the flask values with those obtained at the surface. Based on our storage tests, the flask samples remained nearly stable until analyses. The trace gas measurement system has, in addition to the nondispersive infrared (NDIR) and vacuum ultraviolet resonance fluorescence (VURF) analyzers, two laser-based analyzers using wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) and off-axis integrated cavity output spectroscopy (ICOS). Laboratory tests of the laser-based analyzers for measuring flask samples indicated relatively high reproducibility with overall precisions of less than ±0.06 ppm for CO₂, ±0.68 ppb for CH₄, ±0.36 ppb for CO, and ±0.03 ppb for N₂O. Flask air sample measurements, conducted concurrently on different analyzers were compared. These comparisons showed a negligible bias in the averaged measurements between the laser-based measurement techniques and the other methods currently in use. We also estimated that there are no significant isotope effects for CH₄, CO and N₂O using standard gases with industrial isotopic compositions to calibrate the laser-based analyzers, but CO₂ was found to possess isotope effects larger than its analytical precision

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Seasonal variations of atmospheric CO₂, δ¹³C, and δ¹⁸O at a cool temperate deciduous forest in Japan: Influence of Asian monsoon

Cited by 19 publications

References 84 publications

O<sub>2</sub>:CO<sub>2</sub> exchange ratios observed in a cool temperate deciduous forest ecosystem of central Japan

O<sub>2</sub>:CO<sub>2</sub> exchange ratios observed in a cool temperate deciduous forest ecosystem of central Japan

Synergies between observational and modeling studies at the Takayama site: toward a better understanding of processes in terrestrial ecosystems

Evaluation of a new JMA aircraft flask sampling system and laboratory trace gas analysis system

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