Miniaturized atmospheric ionization detector

A small scintillator-based detector for atmospheric ionization measurements has been developed, partly in response to a need for better ionization data in the weather-forming regions of the atmosphere and partly with the intention of producing a commercially available device. The device can measure both the count rate and energy of atmospheric ionizing radiation. Here we report results of a test flight over the UK in December 2017 where the detector was flown with two Geiger counters on a meteorological radiosonde. The count rate profile with height was consistent both with the Geigers and with previous work. The energy of incoming ionizing radiation increased substantially with altitude.Comment: Proc 18th Conference on Atmospheric Electricity, Nara, Japan, June 201

On the development, characterisation and applications of a balloon-borne atmospheric turbulence sensor

This thesis describes the development, characterisation and use of a dataset of measurements made using 51 radiosondes equipped with accelerometers to measure atmospheric turbulence. Atmospheric turbulence, especially Clear-Air Turbulence (CAT) is hazardous to aircraft as it cannot be observed in advance. Pilots and passengers rely on CAT forecasts, which at best, are correct 60-70% of the time. The reason for this moderate performance in turbulence forecasts is due to a lack of quantitative unbiased observations needed to improve the turbulence theory. This work seeks to improve understanding of turbulence through a standardised method of turbulence observations that span the entire troposphere. To achieve this a sensing package is developed to measure the acceleration of the radiosonde as it swings due to its carrier balloon being agitated by turbulence. The accelerometer radiosonde is then compared against multiple turbulence remote sensing methods to characterise its measurements. From a comparison with a Doppler lidar in the boundary layer a relationship in terms of the eddy dissipation rate, a meteorological measure of turbulence, is found. A further relationship is found when compared with the spectral width of an Mesospheric Stratospheric and Tropospheric (MST) radar. The full dataset of accelerometer sonde ascents is analysed and with information from instrumental comparisons a standard deviation of 5 m s−2 is defined as a threshold for significant turbulence. The dataset spans turbulence generated in meteorological phenomena such as jet streams, clouds and in the presence of convection. The analysis revealed that 77% of observed turbulence could be explained by the aforementioned phenomena. In jet streams turbulence generation was often caused by horizontal processes such as deformation. In the presence of convection turbulence is found to form when CAPE > 150 J kg−1. Deeper clouds were found to be more turbulent due to the increased intensity of in-cloud processes. The accelerometer data were used to verify the skill of turbulence diagnostics, in order to assess which diagnostics are best at forecasting turbulence. It was found that turbulence diagnostics featuring the wind speed, deformation and relative vorticity advection predicted turbulence best. This work provides a new, safe and inexpensive method to retrieve in-situ information about the turbulent structure of the atmosphere. It can inform the aviation industry on where turbulence is generated and assess which are the most skilful diagnostics to predict this

Atmospheric point discharge current measurements using a temperature-compensated logarithmic current amplifier

Measurements of atmospheric corona currents have been made for over 100 years to indicate the atmospheric electric field. Corona currents vary substantially, in polarity and in magnitude. The instrument described here uses a sharp point sensor connected to a temperature compensated bi-polar logarithmic current amplifier. Calibrations over a range of currents from ±10 fA to ±3 μA and across ±20 ◦C show it has an excellent logarithmic response over six orders of magnitude from 1 pA to 1 μA in both polarities for the range of atmospheric temperatures likely to be encountered in the southern UK. Comparison with atmospheric electric field measurements during disturbed weather confirms that bipolar electric fields induce corona currents of corresponding sign, with magnitudes ∼0.5 μA

Coordinated weather balloon solar radiation measurements during a solar eclipse

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud.Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20th March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44N, 0.94W), Lerwick (60.15N, 1.13W) and Reykjavik (64.13N, 21.90W), straddling the path of the eclipse.The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming the sensing surface becomes normal to the solar beam direction at a maximum swing. Both approaches, essentially independent,give values that agree with theoretical expectations for the eclipse-induced radiation changes

Sonning Farm fog modification experiment

An experiment investigating introducing charge into a natural fog was conducted at Sonning Farm (51.48155 °N, 0.897154 °W), University of Reading, in Spring 2020. This archive contains data files from measuring instruments deployed there, for 15th and 16th March 2020, when fog events occurred. Measurements of droplet concentration were made with a LOAC (Light Optical Aerosol Counter), atmospheric electric field with a JCI131 electric field mill, and three-dimensional wind speed with a Gill sonic anemometer. Switching times of a negative corona ion source were also recorded

Pressure on the boiling point

The record-high pressures from the January 2020 anticyclone were sufficient to measurably change the boiling point of water

Developing the hertz art–science project to allow inaudible sounds of the Earth and cosmos to be experienced

The Earth and atmosphere are in constant motion. Volcanoes, glaciers, earthquakes, thunderstorms, and even the aurora borealis produce powerful low-frequency sounds known as infrasound. Infrasound is constantly passing through our atmosphere at frequencies of less than 20 Hz, below the range of human hearing, which is effectively an inaudible symphony. Inspired by wanting to allow physical access to this natural phenomenon, a collaboration between the worlds of contemporary art and meteorology has been developed. This led to a project called hertz, named after the 19th century physicist Heinrich Hertz, whose surname provides the scientific unit (Hz) for frequency. Hertz explores the manifestation of the hidden vibrations of our own planet and the secret harmonies of our stars. The manifestation of the hidden vibrations of our own planet was principally achieved using a subwoofer and furniture adapted to vibrate to the amplitude of infrasonic waves from pre-recorded sources and in real time. The project's motivations are to explore new methods for experiencing and re-engaging with parts of our planet through this phenomenon. Hertz has had a UK national tour in which 7000 people interacted with the piece, of which approximately 85 % felt more reconnected to the environment after interacting with the installation. This paper describes the concepts, creative ideas, technology, and science behind the project. It addresses its development, including the steps to make it accessible for all, and examines its impact on those who created and interacted with the work

A self-calibrating wide range electrometer for in-cloud measurements

Charge is observed in clouds of all forms, which influences their development and properties. In-cloud charge measurements require a wide dynamic range instrument, extending from charge in aerosols and dusts to that present in thunderstorms. Unexpectedly large charge densities (>200 pCm-3) have recently been detected in layer clouds using balloon-carried linear electrometers. These, however, lead to instrument saturation if sufficient sensitivity for aerosol and droplet charge is maintained. Logarithmic electrometers provide an alternative, but suffer strong non-linear thermal effects. This is a limitation for balloon-carried instruments which encounter temperature changes up to ~100 °C, as full thermal compensation requires complexity inappropriate for disposable devices. Here, a novel hybrid system is described, combining linear and logarithmic electrometers to provide extended dynamic range (±50 pA), employing the negligible (±4%) total temperature drift of the linear device to provide in situ calibration of the logarithmic device. This combination opens up new measurement opportunities for charge in clouds, dusts and aerosols

A self-calibrating wide range electrometer for in-cloud measurements

Charge is observed in clouds of all forms, which influences their development and properties. In-cloud charge measurements require a wide dynamic range instrument, extending from charge in aerosols and dusts to that present in thunderstorms. Unexpectedly large charge densities (>200 pCm-3) have recently been detected in layer clouds using balloon-carried linear electrometers. These, however, lead to instrument saturation if sufficient sensitivity for aerosol and droplet charge is maintained. Logarithmic electrometers provide an alternative, but suffer strong non-linear thermal effects. This is a limitation for balloon-carried instruments which encounter temperature changes up to ~100 °C, as full thermal compensation requires complexity inappropriate for disposable devices. Here, a novel hybrid system is described, combining linear and logarithmic electrometers to provide extended dynamic range (±50 pA), employing the negligible (±4%) total temperature drift of the linear device to provide in situ calibration of the logarithmic device. This combination opens up new measurement opportunities for charge in clouds, dusts and aerosols

A miniature oscillating microbalance for sampling ice and volcanic ash from a small airborne platform

A lightweight and low power oscillating microbalance for in situ sampling of atmospheric ice and volcanic ash is described, for airborne platforms. Using a freely-exposed collecting wire fixed at only one end to a piezo transducer, the instrument collects airborne material. Accumulated mass is determined from change in natural frequency of the wire. The piezo transducer is used in a dual mode to both drive and detect the oscillation. Three independent frequency measurement techniques are implemented with an on-board microcontroller: a frequency sweep, a Fourier spectral method, and a phase-locked loop. These showed agreement to ±0.3 Hz for a 0.5 mm diameter collecting wire 120 mm long, flown to 19 km altitude on a weather balloon. The instrument is well suited to disposable use with meteorological radiosondes, to provide high resolution vertical profiles of mass concentration