Met Office Cardington: cloud height measurements from a Vaisala CT25K_B Laser Ceilometer, 2015-2024

The Met Office Observation-based research Boundary Layer Facility, at the semi-rural field site (18 Ha) of Cardington (52° 06′ N, 00° 25′ W, 29 m ± 1 m amsl) in central-southern England between 2004 and 2024, operated two Vaisala CT25K ceilometers deployed at Cardington since 2014, denoted by unit numbers A and B. This dataset covers data from unit B.

The CT25K Laser ceilometer is a general-purpose cloud height sensor employing LIDAR technology for detection of clouds, precipitation and other obstructions to vision. The CT25K provides reliable determination of cloud height up to 25,000 feet (7.5 km) thus covering most heights where dense clouds appear. It is designed to detect up to three possible cloud layers.

The Vaisala CT25K laser ceilometer measures cloud height-or vertical visibility if the cloud base is obscured. The single-lens design also ensures reliable measurements in fog, rain, snow and haze.

A full list of NetCDF variables can be found in “A continuous hydrometeorological record (2004–2024) at the Met Office surface site of Cardington, UK.” Osborne et al. (2025). This paper should be referenced in any research/publications pertaining to this dataset.

To ensure optimal traceability and transparency of data, comprehensive metadata is included.