Yoshiyuki Takahashi

Center for Global Environmental Research, Earth System Division, National Institute for Environmental Studies

NIES research staff page: https://www.nies.go.jp/researchers-e/100114.html

National Institute for Environmental Studies

Email: cgerdb_admin(at)nies.go.jp

Fuji Hokuroku Flux Observation Site (FHK)

Location: 35.443528°N, 138.764722°E

Elevation: 1050-1150 m

Sampling height: 35, 32, 27, 22, 16, 10, 4.5, 2, 1.5, 1, 0.5, 0, -0.02, -0.05, -0.1, -0.15, -0.2, -0.3, -0.6 m

Net ecosystem CO₂ exchange flux (NEE) is measured by eddy covariance (EC) method at height of 35 m on the measurement tower over a deciduous needle-leaf plantation forest in the foothills of Mt. Fuji. Three-dimensional wind speeds and virtual temperatures were measured using a three-dimensional sonic anemometer-thermometer, and CO₂ fluctuation was measured using open-path and closed-path CO₂/H₂O analyzers. For closed-path system, sample air was pumped from the air-inlet at 35m into the gas analyzers through tubes of ca. 12 m length. The flux data were sampled and logged at frequency of 10 Hz. The vertical profile of CO₂ concentration was also measured at 10 heights from 0.5-35m, in order at a frequency of 1 cycle in 2 minutes, for 12 seconds at each altitude.

The CO₂ concentration measured by closed-path gas analyzer was calibrated once a day using two standard CO₂ gases of 320 and 420 micro mol mol^-1. The net ecosystem exchange (NEE) of CO₂ was derived from the sum of the flux measured by EC (F_EC) and the rate of change in column CO₂ storage under EC measurement height (Fs). Half-hourly mean F_EC was calculated as the covariance between fluctuations in vertical wind speed and scalar quantity of CO₂ concentration. The setting of the quality control applied to the 30-minute value of the turbulent flux is described in "3-4. Quality control" of the information file attached to this data together with the source. Half-hourly mean Fs was calculated from the vertical profile of CO₂ concentration at 10 heights.

[GCMD_Platform]

In Situ Land-based Platforms > Ground Stations

[GCMD_Science]

LAND SURFACE

[Free keywords]

Net ecosystem carbon exchange

Eddy covariance method

Micrometeorology

Deciduous needle-leaf forest

[2021/07/30]

The flux and meteorological data from 2006 to 2012 have been compiled in Asiaflux Data Base Format, as ver2.1.

Some of available parameters were changed in ver.2.1, as updating from ver.1.1. See the correspondence table for parameters in the supplementary file (Parameters_v1.1_v2.1.pdf).

[2016/10/05]

The meteorological data from 2006 to 2010 have been compiled in NASA Ames Format 1001 (text file) and original csv format, as ver1.1.

[2014/05/19]

The meteorological data from 2006 to 2010 have been compiled in csv format. ver1.0.

• Site description: SiIn_FHK_2006-2012_02-1.pdf
• Description of the flux and meteorological data for 2006-2012: FxMt_FHK_2006-2012_30ｍ_02-1.pdf
• Correspondence table for parameters between ver. 1.1 and ver.2.1: FHK_Parameters_v1.1_v2.1.pdf

• Teramoto M., Liang N., Zeng J., Saigusa N., Takahashi Y., 2017, Long-term chamber measurements reveal strong impacts of soil temperature on seasonal and inter-annual variation in understory CO₂ fluxes in a Japanese larch (Larix kaempferi Sarg.) forest. Agricultural and Forest Meteorology, 214, 194-206, DOI:10.1016/j.agrformet.2017.07.024.
• Ueyama M., Takeuchi R., Takahashi Y., Ide R., Ataka M., Kosugi Y., Takahashi K., Saigusa N., 2015, Methane uptake in a temperate forest soil using continuous closed-chamber measurements. Agricultural and Forest Meteorology, 213, 1-9, DOI:10.1016/j.agrformet.2015.05.004.
• Takahashi Y., Saigusa N., Hirata R., Ide R., Fujinuma Y., Okano T., Asarse T. 2015, Characteristics of temporal variations in ecosystem CO₂ exchange in a temperate deciduous needle-leaf forest in the foothills of a high mountain. Journal of Agricultural Meteorology, 71(4), 302-317, DOI:10.2480/agrmet.D-14-00009.

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