Sectioned metspec MET 20 radiation shield, made by Campbell Scientific Ltd, Loughborough, Leicestershire, England, 2010.

For over 150 years, climate scientists have been working to collect regular temperature records close to the Earth’s surface. The CS215 is a digital sensor used for this task. Manufactured by Campbell Scientific Ltd, the CS215 utilises a Sensirion SHT75 relative humidity and temperature element in order to provide accurate and stable measurements of the surrounding environment. For protection, the CS215 can be housed within the MET 20 radiation shield, which is also manufactured by Campbell Scientific. This shield helps to isolate the sensitive elements within the CS215 from moisture and heat, whilst allowing air to flow freely across it. Using these objects, scientists have been able to improve our understanding of the connection between the land and the air above us, providing more thorough and detailed modelling of our atmosphere. The continuity of the ground-based record also helps when analysing longer-term trends relating to climate change, with the earliest daily ground-based measurements dating back to preindustrial times.

Surrounding the sensor, the MET 20 radiation shield is made from a UV stable polycarbonate plastic that utilises a double-louvred, aspirated design. It also has a gloss white aluminum arm to attach the shield to a vertical pole or stand. Generally, unaspirated radiation shields tend to overheat when solar radiation is high and wind speed is low. The aspirated design of the MET 20 helps to overcome these issues, with the white outer reflective surface and inner non-reflective barrier also preventing sunlight from reaching the delicate sensor inside.