Temperature and Humidity

Temperature and humidity are measured by one Oregon Scientific THGR918-S device.  This sensor is mounted in the shade of the protective fencing around the data center air conditioning engines.

This location is away from the building itself and not affected by the airflow around the air conditioning units themselves.  The transmission unit is mounted along side that of the rain gauge roughly 3 meters away in full sun.

Limitations

Although the temperature sensor is mounted in the shade and stands away from the fencing, there is a chance in very strong sunshine the fencing itself will radiate heat to the sensor.  There is also the possibility that the moisture content of the wooden fencing may affect the humidity readings in warmer weather. Note: the sensor has been relocated since the this photo was taken so that it is not affected by solar radiation.

Atmospheric Pressure

Atmospheric pressure is measured inside the main office of the DC away from all machinery by an Oregon Scientific BTHR918N unit.  This unit also provides data on temperature and humidity within the office, as well as some simple weather forecasting (based on pressure trends) and comfort information (based on relative humidity).

Wind Speed and Direction

Wind speed and direction are measured by an Oregon Scientific WGR918N sensor.  This provides data on average wind speed, maximum gust speed and current direction.

The sensor is mounted roughly 3 meters above ground level with it’s transmission unit mounted in full sun just above half way up the mast.

The unit is located away from the DC building and as far from other obstructions as possible.

Limitations

The height of the anemometer is not standard for aviation/meteorological applications (10 meters above ground level).  Additionally, while all efforts have been made to site the unit in free air, due to the nature of the site there may be some interference from surrounding buildings and trees.

Precipitation

Rainfall is measured by an Oregon Scientific RGR918-S gauge.  The sensor is mounted on top of a stay for the protective fencing around the data center air conditioning engines.  It is out of the rain shade of the DC building and away from all possible sources of run off.

Limitations

The rain gauges accurate only to 1mm of rainfall.  Additionally, the gauge is not fitted with a heating element, and so there will be a thaw delay in obtaining readings relating to snow and hail fall.