Ground-based aviation weather radar research at the Rutherford Appleton Laboratory and University College London

We present an overview of recent collaborative research, involving RAL and UCL, in the field of ground-based meteorological radar systems for weather assessment at, and in the terminal manoeuvring area (TMA) surrounding, civil airports. Three projects are briefly described. Firstly, we present the results from a design study intended to develop the specifications for a dedicated C-band weather surveillance radar covering an airport TMA. Secondly, we discuss the design of, and present some measured data from, a recently installed S-band weather radar system located at St. Andrews in Scotland. This low-cost radar uses a small antenna and low transmitted power, but is capable of providing a high-resolution display of significant precipitation within a coverage area extending to 60 km range. High sensitivity is achieved by coherent signal processing techniques. This system demonstrates that relatively inexpensive TMA weather surveillance using radar techniques is a practical proposition. Finally, we illustrate the potential of a vertically pointing millimetre-wave radar to remotely sense the height-distribution of cloud above an airport runway. Design details of a 94 GHz cloud-profiling radar system are presented, and examples of measured data from this instrument are used to show its capabilities for automatic detection of cloud-base height and cloud depth.