Meteorological support for UK Navy operations

Atmospheric refraction effects are well known to the Royal Navy (RN) as a factor that can dramatically affect the performance of radars. The RN uses the IREPS (Integrated Refractive Effects Prediction System) operationally to predict radar performance. This system uses a single radiosonde ascent to represent the propagating environment. This is then used to calculate the predicted radar coverage. Radiosonde ascents are routinely made at 6 hourly intervals (4 per day) from 8 locations around the UK (in addition to several sites in Europe). No data are routinely available over the sea, and the spatial resolution is relatively poor. This means that the most appropriate ascent available for a specific forecast of radar propagation may be hundreds of kilometres from the operating area, and several hours old. To overcome these problems a study was carried out to investigate the possibility of using UK Met Office Mesoscale Model output, in conjunction with a PE model for forecasting radar performance.