A New Method of Measuring Atmospheric Refractivity – Physics – PhD (Funded)

Project Description

A new method is proposed to obtain very large volumes of information on the structure of the atmosphere at low cost. The technique envisages deployment of a network of interferometers to measure the angle that routine navigational radio broadcasts from aircraft are received at the ground. Knowledge of the position of the aircraft (from GPS) then gives the amount the radio signal has been refracted by the atmosphere (the bending angle), which is a function of the atmospheric pressure, temperature and humidity along the ray path. If successfully developed, this new source of data should improve the initialisation of the numerical weather prediction models and could significantly improve the quality of weather forecasts in the UK and around the world. The purpose of the PhD is to carry out research that will further develop the technique and assess its potential value.

The work will involve data modelling and simulation, as well some practical work in the laboratory and in the field, as detailed below:

Data Modelling and Simulation
• Through data modelling and simulation, to examine the measurement requirements in terms of measurement precision and accuracy; the likely information content of the data obtained from a single interferometer; and a notional UK network of interferometers.
• Explore the spatial and temporal scales of variations represented in the measurements and compare with the scales represented in other observational data and in numerical weather prediction models.
• Consider how the new data might best be exploited and how the technique can be developed to maximise the potential benefits.

Practical work and Data Analysis
• Participate in the design and construct prototype interferometer(s) to optimise the availability, accuracy and precision of angle of arrival measurements.
• Establish a comprehensive error budget for the technique, including the impact of measurement errors and aircraft positional errors on calculations of bending angle.
• Directly compare the measurements of refractivity with estimates derived from existing sources of observational data and model fields.