| Methods: |
In the summer of 1987 a weather station was placed on an old floodplain terrace about 200 m from the Sagavanirktok River. The site is vegetated by dwarf shrubs of Ericads and Betula. Initially the station was operational from late May/early June through August. In 1993 the station became year round. Any missing May through October average air temperature data were estimated using regressions with the Toolik Field Station weather station (68 degrees 38'N, 149 degrees 36'W). For a description of the site see Shaver, et al. 1996.
In addition to air temperature and wind speed which are reported here, global incoming radiation, photosynthetically active radiation (PAR), soil temperatures and wind direction were recorded. See the hourly data files.
Sensors information:
TEMPERATURE AND RELATIVE HUMIDITY:
Campbell Scientific, Model 207 Temperature and Relative Humidity Probe. Temperature sensor is a Fenwall electronics thermistor and the Relative Humidity sensor is a Phys-chemical Research sensor. Specs: Temp: Accuracy over the range -40 to 56°C is 1.0°C. RH: for a range of 12 - 100% the percentage error is 3. Upper temperature limit is 79°C.
WIND DIRECTION:
MET-ONE, (supplied by Campbell Scientific) Wind direction use a light weight, air foil vane and a potentiometer to produce an output that varies proportional with wind direction. Specs: Minimum Wind speed to get accurate reading = 1.0 mph. Accuracy ±5° Temperature range -50 to 70°C.
WIND SPEED:
MET-ONE, (supplied by Campbell Scientific) Wind speed sensor Model 014A. Sensor uses a 3-cup anemometer assembly and simple magnet-read switch assembly to produce a series of contact closures whose frequency is proportional to wind speed. Specs:
Operating Range - 0 to 125 mph or 0-60 m/s. Accuracy ±1.5% or 0.25 mph. Working temperature range -50 to 85°C.
PYRANOMEETER:
Li-Cor, Pyranometer: Model LI-200SB- Pyranometer is calibrated to detect most the daylight spectrum (sunlight and PAR). Specs: Sensitivity - 80mA per 1000 Watts m-2. Absolute error max ±5% but typically ±3%.
QUANTUM:
Li-Cor, Quantum. Model LI-190SB. Quantum measure photosynthetically active radiation (PAR) in mEinsteins S-1 m-2. Specs: range 400-700nm wavelength. Sensitivity 8mA/1000 mE s-1 m-2. Relative error less then ±10% for plant canopies or less then ±5% for growth chambers.
RAIN GAUGE:
Texas Electronics, Inc. (supplied by Campbell Scientific) Tipping Bucket Electric Rain Gauge. A complex spun collector funnel with a knife edge that diverts the water to a tipping bucket mechanism. For each tip a magnet causes an electronic pulse that is recorded. Each alternate tip occurs for each 0.01 inch of rainfall. Specs: Accuracy 1% at 2 inches/hr or less. Accurate Temperature Range: 0 - 37°C.
Notes: Wind speeds less than .447 are considered calm.
Air temperature at 5 meters is measured using Campbell’s 207 probes. The thermisters’ range only goes to -40 Celsius, therefore temperatures below - 40 are inaccurate.
For additional notes check the Comment variable in the dataset.
Reference Citations: Gilbin, A. E., K. J. Nadelhoffer, G. R. Shaver, J. A. Laundre and A.J. McKerrow. 1991. Biogeochemical diversity along a riverside toposequence in arctic Alaska. Ecological Monographs, 61(4):415-435.
Shaver, G. R., J. A. Laundre, A. E. Giblin, and K. J. Nadelhoffer. 1996. Changes in live plant biomass, primary production, and species composition along a riverside toposequence in arctic Alaska., U.S.A. Arctic and Alpine Research. 28(3):363-379.
Sampling Description.
None
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