PROVISION OF VISIOMETERS

The Met Office has a requirement to measure and record the Meteorological Optical Range (MOR) at airfields and at manned and automatic weather stations. The Met Office now wishes to replace the current network of visiometers.

The new instrument will make use of the plinths and power currently used by the exiting visiomete estate, and provide MOR measurement accuracy and data resilience of sufficient quality and standard to meet user requirements at these sites. The intended lifetime of a new instrument will be 10-15 years.

There are two distinct types of sites where new visiometers are required: LOT 1 Safety Critical sites (e.g. airfields) where human safety is vital, and where very high integrity is required by local users. Lot 1 places emphasison a track record of use by 'safety critical' users or at Regional Basic Synoptic Network (RBSN) baseline sites LOT 2 General Network sites which are primarily sites with automatic instruments, and where data quality andresilience specifications will be balanced against other factors such as economy of whole life costs.