Since the eighteenth century, weather balloons have been used as a carrier platform to make observations of the weather in our atmosphere. Fundamental discoveries about the structure of the atmosphere were made by early investigators. Atmospheric processes such as the electrification in thunderstorms and the thickness of the ozone layer have been observed using balloon-borne instrumentation.
On a daily basis, hundreds of weather balloons are launched by meteorological organizations across the world to observe the state of the atmosphere, providing the initial conditions for weather forecasts. Weather balloons are also used during field campaigns as an essential tool for studying the atmosphere. A modern weather balloon system consists of a balloon supporting a radiosonde. The radiosonde is a small device which contains a radio transmitter, weather sensors, GPS and batteries. Its radio link relays weather data to a ground station, making the device disposable. Radiosondes are rarely used for anything more than standard weather measurements. Other than a small percentage used to routinely measure the thickness of the ozone layer, weather balloon are an under-exploited measurement platform in the scientific community. Weather balloons that have the potential to carry ozone sensors have an interface to send additional information via the radiosonde for relay to the ground station. For little extra cost it is possible to add other sensors to this interface. In the Department of Meteorology at the University of Reading, a simplified data connection system has been developed allowing multiple sensors to be interfaced and powered with the radiosonde. The additional data is relayed over the existing radio link, hence no additional receiving hardware is required. Software installed at the ground station combines the standard weather data with the additional sensor data. Small disposable sensors have been developed to measure turbulence, solar radiation, optical properties of clouds, and high-energy particle concentration. The automated disposable nature of the radiosonde allows additional measurements to be made with minimal cost when compared to that of a research aircraft. During hazardous conditions for aircraft, weather balloons provide a low-risk method to obtain measurements, which was demonstrated by the proposers during the 2010 and 2011 Icelandic volcano eruptions. This project proposes to develop a multi-sensor miniature laboratory to sample hazardous volcanic plumes. The package of five bespoke sensors will measure ash, SO2, ice, electrification, and turbulent mixing. The sensor package will be carried by weather balloons and aims to improve the quality of decision-making and the predictive skill of forecast models, when a volcanic ash cloud next threatens international airspace.