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-131The 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:

      Element

      statistic
      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