Lerwick Observatory in Shetland has recently celebrated its centenary. Measurements of atmospheric electricity were made at the site between 1925 and 1984. The instruments and equipment used for this are discussed and the value of the measurements obtained assessed. A major aspect of the atmospheric electricity work was explaining the dramatic changes which followed the nuclear weapons test period. Although less well known, there are strong parallels with the discovery of the ozone hole.

Weather balloons are released every day around the world to obtain the latest atmospheric data for weather forecasting. Expanding the range of sensors they carry can make additional quantities available, such as for atmospheric turbulence, cloud electricity, energetic particles from space and, in emergency situations, volcanic ash or radioactivity. An adaptable system has been developed to provide these and other measurements, without interfering with the core weather data.

A network of Rayleigh lidars have been used to infer the upper-stratosphere temperature bias in ECMWF ERA-5 and ERA-Interim reanalyses during 1990–2017. Results show that ERA-Interim exhibits a cold bias of −3 to −4 K between 10 and 1 hPa. Comparisons with ERA-5 found a smaller bias of 1 K which varies between cold and warm between 10 and 3 hPa, indicating a good thermal representation of the atmosphere to 3 hPa. These biases must be accounted for in stratospheric studies using these reanalyses.

The composition of the upper atmosphere has been difficult to measure with localised observations relying on spacecraft, suborbital rockets or measurements of airglow from ground-based observatories. The height profile of ionisation within the neutral upper atmosphere is influenced by the composition of the neutral gas. We present a method for determining the neutral upper-atmosphere composition from measurements of the ionisation profile and compare these with spacecraft measurements.

A long-standing mystery of metal ions within E_s layers in the Earth's upper atmosphere is the marked seasonal dependence, with a summer maximum and a winter minimum. We report a large-scale winter-to-summer transport of metal ions from 6-year multi-satellite observations and worldwide ground-based stations. A global atmospheric circulation is responsible for the phenomenon. Our results emphasise the effect of this atmospheric circulation on the transport of composition in the upper atmosphere.

The early 20th century voyages of the Carnegie – a floating geophysical observatory – revealed the daily rhythm of atmospheric electricity. Combined with ideas from Nobel Prize winner C. T. R. Wilson, the Carnegie curve helped answer a fundamental question, from the time of Benjamin Franklin, about the origin of Earth's negative charge. The Carnegie curve still provides an importance reference variation, and the original data, explored further here, have new relevance to geophysical change.

A network of Rayleigh lidars have been used to infer the middle atmosphere temperature bias in ECMWF ERA-5 and ERA-interim reanalyses during 1990–2017. Results show that ERA-interim exhibits a cold bias of −3 to −4 K between 10 and 1 hPa. Comparisons with ERA-5 found a smaller bias of 1 K which varies between cold and warm between 10 and 3 hPa, indicating a good thermal representation of the atmosphere to 3 hPa. These biases must be accounted for in stratospheric studies using these reanalyses.

A tethered-balloon system deployed supercooled liquid water content sondes and fiber optic distributed temperature sensing to collect in situ atmospheric measurements within mixed-phase Arctic clouds. These data were validated against collocated surface-based and remote sensing datasets. From these measurements and sensor evaluations, tethered-balloon flights are shown to offer an effective method of collecting data to inform numerical models and calibrate remote sensing instrumentation.

The variability of the Earth's ionosphere (the electrified region of the Earth's upper atmosphere) results from external forcing from above (through solar activity and space weather effects) and from below (via natural sources such as lightning storms and tectonics). Bombing raids over Europe during World War II were used to determine the quantitative impact of explosions on the ionosphere. It was found that raids using more than 300 tonnes of explosives weakened the ionosphere for up to 5 h.

Galactic cosmic rays are high-energy particles from outside of the solar system. The products of their interaction with the atmosphere are counted by a network of neutron monitors. The number of cosmic rays reaching Earth is affected by the magnetic field embedded in the solar wind. The result is a number of regular variations in the neutron monitor data, including a diurnal variation. We have found that this variation is influenced by 1–2 h by the polarity of the Sun's magnetic field.

The solar forcing dataset for climate model experiments performed for the upcoming IPCC report is described. This dataset provides the radiative and particle input of solar variability on a daily basis from 1850 through to 2300. With this dataset a better representation of natural climate variability with respect to the output of the Sun is provided which provides the most sophisticated and comprehensive respresentation of solar variability that has been used in climate model simulations so far.

We use a novel technique to infer long-term compositional changes to the thermosphere from the annual variation of the ionospheric F2 region. A global analysis of these data reveal that long-term changes differ between geographic locations in a way that is very similar to the observed variation in the ionospheric response to increased atmospheric CO2 levels. In the absence of long-term measurements of thermospheric composition, further, detailed, modelling work is required.