Solar Radiation Shield
The Solar Radiation Shield is a chamber made from a series of fins that use the natural convection of warm air to draw fresh air into the chamber and expel the heated air. Temperature, Humidity and Pressure sensors that are placed with in the chamber will experience a flow of fresh air and so give more accurate measurements than sensors that are exposed to direct sunlight. The fins are made from spun aluminum that has been powdercoated white.
The Solar Radiation Shields shown above are connected to the L Bar Equipment Arm. This is the most convenient way of mounting the shields to a tower, post or building. The arm can also be used to house the logger used to read the sensors in the shield.
The ventilated chamber with in the Solar Radiation Shield is cylindrical in shape, 90mm high and 50mm in diameter. This chamber is surrounded by a stainless steel mesh grill to protect the sensors from insects and wind blown debris.
If sunlight falls on sensors they absorb radiant energy directly from the sunlight and are therefore at a higher temperature than the surrounding air. This causes erroneous readings. If the sensors are put into a chamber so that the direct sunlight can not strike them but the chamber and the air within it are heated this will also cause erroneous readings. If the chamber can be ventilated so that any heated air in chamber can rise and escape through convection then fresh air from the outside will be drawn in over the sensors and accurate readings of the air temperature, humidity and pressure can be made.