CEMP Instrumentation

The electronic instruments for the CEMP network consist of the following sensors:
  • RM Young Wind Monitor Model #WS5103
  • Licor Silicon Pyranometer Model #LI200X
  • CSI Temperature/Humidity Probe Model #C-50Y mounted in a 6-plate Gill radiation shield at 6 ft. height
  • Vaisala Barometric Pressure Sensor Model #BP105
  • Texas Electronics Rain Gauge Model #TE525
  • GE-Reuter Stokes Gamma Radiation Sensor Model #RSS-131

    The sensors are monitored with a Campbell Scientific Inc. (CSI) CR10X datalogger. Sensors are sampled every 3 seconds and summarized by the datalogger for each 10 minute period. Current data readings are displayed on-site with an Intermountain Environmental LCD display Model #LCD1 that has been mounted into the door of the datalogger enclosure. The on-site display is updated every 6 seconds. The current readings include: gamma radiation (uR/hr), air temperature (F), humidity (%), wind speed (mph), wind direction (direction octant), solar radiation (ly), station barometric pressure (in.Hg.), precipitation since midnight (in.), and system battery voltage (volts).

    The summarized 10-minute data (hourly for satellite telemetered stations) consists of the following parameters:



    Solar Radiation (W/m2) average
    Wind Speed (mph) average
    Wind Vector magnitude (mph) vector average
    Wind Vector direction (degrees) vector direction
    Standard deviation of direction (degrees) std. dev.
    Max. Wind Gust (mph) maximum sample (3 sec.)
    Max. Air Temperature (C) maximum
    Ave. Air Temperature (C) average
    Min. Air Temperature (C) minimum
    Max. Relative Humidity (%) maximum
    Ave. Relative Humidity (%) average
    Min. Relative Humidity (%) minimum
    Barometric Pressure (mbars) average
    Precipitation (in.) total for 10 min.
    Precipitation running total (in.), sample
    Max. Gamma Radiation (uRem/hr) maximum
    Ave. Gamma Radiation (uRem/hr) average
    Min. Gamma Radiation (uRem/hr) minimum
    Max. Battery Voltage (volts) maximum
    Ave. Battery Voltage (volts) average
    Min. Battery Voltage (volts) minimum
    Datalogger temperature (C) average
    Station ID sample

    Data telemetry from the stations occurs via conventional telephone landline, cellular phone or GOES satellite. Due to the remoteness of 5 of the ranch stations, one-way satellite telemetry was the most viable method to telemeter the data. Data for these stations are summarized into hourly periods and telemetered once every 3 hours. The GOES DCP system assigns specific transmission intervals and times to each platform. Since the satellite telemetry is one-way only, data is stored on-site for later retrieval. Hourly and 10-minute data values are stored using CSI data storage modules and downloaded monthly during a maintenance visit. The capacity of the storage modules would allow for more than 6 months of on-site data storage. After the data is retrieved, it is sent to the Western Regional Climate Center where it is archived and ingested into the database.

    Cellular phone service is used at locations where phone landlines were unavailable or installation costs would be excessive. Data retrieval from both cellular phone and landline phones occurs approximately every 3 hours. The frequency of this data calling cycle can be increased to occur every 10 minutes although a 30 minute frequency is the optimal rate to allow for connection and communication with all the CEMP sites. In the event of communication failure with a particular site during a data call, the data is stored by the datalogger and then retrieved on the subsequent call. During a normal calling cycle, each site that experiences a communication failure receives at least one call-back attempt. In case of an extensive failure in any of the communications systems on-site data storage was designed to allow for 20 days of storage on the datalogger. Telephone and cellular phone access also permit the reprogramming of the remote units without