Location of Sampling Stations: Headquarters weather station (HQC).

Frequency of Sampling: Continuous sampling at headquarters weather station.

Variable Measured:

1. Air temperature at 2 m (⁰C)
2. Relative humidity at 2 m (%)
3. Solar radiation down (0.3-3.0 μm, Wm-2)
4.  Wind speed at 3 m (ms-1)
5. Wind direction at 3 m (degrees)
6. Precipitation (mm)
7. Soil temperature at 25 cm (⁰C)

Methods:

A Campbell Scientific (CR1000) data logger monitors air temperature, relative humidity, solar radiation, wind speed, soil temperature, and wind direction. Parameters are sampled once every 10 seconds. A microprocessor in the CR1000 manipulates the raw data and outputs the average air temperature, soil temperature, relative humidity, wind speed, solar radiation, and wind direction on 5 minute, hourly, and daily intervals. A separate Campbell Scientific CR800 data logger collects and stores precipitation data from an Ott Pluvio2 rainguage. The CR1000 data is accessed every 5 minutes via wireless internet, and the CR800 is accessed every 15 minutes. SAS software is used to format and output data to AWE011 (hourly) and AWE012 (daily) final storage locations.
Missing data are signified with a blank or '.'

Routine Maintenance: Weather station bi-monthly checks include:

1. Pyranometer check for level, dust accumulation, or other obstruction
2. Relative humidity dust shield check
3. Bearing check on anemometer and wind direction sensor

Biyearly maintenance includes:

1. Calibration of li200x pyranometer
2. Replace bearings and reed switch in anemometer and bearings in wind direction sensor.

Summary of All Changes:

1. Program execution interval was changed from 60 seconds to 10 on 7/17/2000. This change could significantly influence values reported for max wind speed. Caution should be used when comparing max wind speeds across this date.
2. Hourly precipitation not precise and removed after 1/1/2000. All AWE01 ppt data before 3/19/2010 was collected via tipping bucket. APT01 data should be used for more accurate precipitation values.
3. Soil Temperature data collection began in June 1992, but data are unavailable from 2001 to August 12, 2008 and December 7, 2009 to May 21, 2010.
4. Solar radiation variables were recalculated in March 2023 in order to standardize units that had been inconsistent across years.

For additional metadata information see: http://lter.konza.ksu.edu/sites/default/files/DC.pdf

For additional methods information see: http://lter.konza.ksu.edu/sites/default/files/MM.pdf