YNF: Yona-Field Tower Site
General site detail (Updated 10 March 2022)
 Site name
 Yona-Field Tower Site
 AsiaFlux site code
 YNF
 Location Kunigami, Okinawa, Japan
 Position 26° 45' 3.5" N, 128° 12' 45.5" E
 Elevation 210 m above sea level
 Slope -
 Terrain type
 Ridge
 Area 0.25 ha (Tree survey plot)
 Fetch -
 Climate Humid Subtropical
 (Mild with no dry season, hot summer (Cfa))
 Mean annual air temperature
 20.7℃ (1981-2010)
 Mean annual precipitation
 2501.5 mm (1981-2010)
 Vegetation type
 Evergreen broad leaf forest
 Domestic species (Overstory)
 Castanopsis sieboldii, Rapanea neriifolia,
 llex liukiuensis, Schima wallichii

 Dominant species (Understory)
 Dwarf bamboo (Pleioblastus linearis) and ferns
 Canopy height
 About 8 m
 Age More then 75 years old
 LAI 3.6
 Soil type
 Haplic Acrisol (Ultisol)

Observations
Eddy Covariance method (CO2)
 System Open-path system (CO2 flux, sensible heat flux, latent
 heat flux)
 Wind speed
 Integrated CO2 and H2O open-path gas analyzer and
 3-D sonic anemometer (IRGASON, Campbell Scientific)
 Air temperature
 Integrated CO2 and H2O open-path gas analyzer and
 3-D sonic anemometer (IRGASON, Campbell Scientific)
 Water vapor
 Integrated CO2 and H2O open-path gas analyzer and 
 3-D sonic anemometer (IRGASON, Campbell Scientific)
 CO2 Integrated CO2 and H2O open-path gas analyzer and
 3-D sonic anemometer (IRGASON, Campbell Scientific)
 Measurement height
 16 m
 Sampling frequency
 10 Hz
 Averaging time
 30 min
 Data logger
 CR1000 (Campbell Scientific)
 Data storage
 Flash memory
 Original data
 Raw data

Meteorology
 Observation items
 Levels / Depth
 Instrument
 Global solar radiation
 (incoming)
 15 m
 4-component net radiometer
 (NR01, Hukseflux)
 Global solar radiation
 (outgoing)
 15 m
 4-component net radiometer
 (NR01, Hukseflux)
 Long-wave radiation
 (incoming)
 15 m
 4-component net radiometer
 (NR01, Hukseflux)
 Long-wave radiation
 (outgoing)
 15 m
 4-component net radiometer
 (NR01, Hukseflux)
 Net radiation
 15 m
 4-component net radiometer
 (NR01, Hukseflux)
 PPFD (incoming)
 15, 1 (two points) m
 Quantum Sensor (LI-190S, LI-COR;
 PAR-01D, Prede; MIJ-14,Environmental
 Measurement Japan)
 PPFD (outgoing)
 15, 1 m
 Quantum Sensor (PAR-01D, Prede)
 Direct/diffuse radiation
 - -
 Direct/diffuse PPFD
 - -
 Air temperature
 16, 13, 10, 2 m
 Forced ventilated air temperature and
 relative humidity sensor (HMP155D,
 Vaisala)
 Humidity 16, 13, 10, 2 m
 Forced ventilated air temperature and
 relative humidity sensor (HMP155D,
 Vaisala)
 Soil temerature
 0.05, 0.1, 0.2, 0.5,
 0.8 m depth
 Soil moisture and temperature sensor
 (CS650, Campbell Scientific)
 Soil heat flux
 0.05 m (three points)
 Heat flux plate (HFP01, Hukseflux)
 Soil water content
 0.05, 0.1, 0.2, 0.5,
 0.8 m depth
 Soil moisture and temperature sensor
 (CS650, Campbell Scientific)
 Wind speed
 16, 13, 10, 2 m
 Wind direction sensor (010C, MetOne)
 Wind direction
 16 m
 3-cup anemometer (020C, MetOne)
 Barometric pressure
 15, 2 m
 Barometer (PTB110, Vaisala)
 Precipitation 15.5, 1.5 (three
 points) m
 0.5-mm tipping backet rain gauge
 (OW-34-BP, Ota Keiki)
 Soil water potential
 0.05, 0.1, 0.2, 0.5,
 0.8 m depth
 Tensiometer (CHR-TM, Climatec)
 Spectral radiation
 (in and out)
 15 m
 Spectroradiometer (MS700, Eko)

Soil respiration
 Measurement method
 Closed dynamic chamber method
 (manual measurements)
 Reference(s) for method
 -
 Measuring system
 LI-6400 (LI-COR)
 IRGA LI-6400 (LI-COR)
 Flow control
 -
 Chamber type
 Closed dynamic chamber
 Chamber size
 95 cm internal diameter
 Number of chambers
 50
 Measuring intervals
 Uncontinuous; once or twice each month from Oct.
 2013 to Dec. 2014
 In the ground covered by show
 in winter?
 No
 Original data
 Raw data
 Temperature and air pressure
 correction
 No

Other
 Photosynthesis -
 Ecological Investigation
 Tree height, diameter, stand density (every 3 years)
 
Observation Period and Data Availability
 Measurement Period
 February 2013 to present
 Measurement Frequency
 Continuous
 Data Availability
 -

Contact
 Kazuho Matsumoto (kazuhom[at]agr.u-ryukyu.ac.jp)
 Faculty of Agriculture, University of the Ryukyus
 1 Senbaru, Nishihara, Okinawa 903-0213, JAPAN
 Tel: +81-98-895-8759   Fax: +81-98-895-8759
 Shingo Taniguchi (shingota[at]agr.u-ryukyu.ac.jp)
 Faculty of Agriculture, University of the Ryukyus
 1 Senbaru, Nishihara, Okinawa 903-0213, JAPAN
 Tel: +81-98-895-8793   Fax: +81-98-895-8793
 Atsushi Takashima (a-taka[at]agr.u-ryukyu.ac.jp)
 Yona Field, Subtropical Field Science Center,
 Faculty of Agriculture, University of the Ryukyus
 685 Yona, Kunigami, Okinawa 905-1427, JAPAN
 Tel: +81-98-041-2242   Fax: +81-98-041-2189

Infrastructure
 Tower, Electrical power (AC)

Research Fund
 -

Calibration Information
 Open-path gas analyzer was calibrated approximately every year
 with standard gases and dew point generator (LI-610, LI-COR).

Publication
 -