Heating by solar radiation is the dominant error source for daytime temperature measurements by radiosondes. This paper describes a new laboratory setup (SISTER) to characterise this radiation error for pressures and ventilation speeds that are typical for the conditions between the surface and 35 km altitude. This characterisation is the basis for the radiation correction that is applied in the GRUAN data processing for the RS41 radiosonde. The GRUAN data product is compared to that of Vaisala.

Radiosonde descent data could provide extra profiles of the atmosphere for forecasting and other uses. Descent data from Vaisala RS41 radiosondes have been compared with the ascent profiles and with ECMWF short-range forecasts. The agreement is mostly good. The descent rate is very variable and high descent rates cause temperature biases, especially at upper levels. Ascent winds are affected by pendulum motion; on average, the descent winds are smoother.

Modern radiosonde balloons fly from ground level up to the lower stratosphere and take temperature measurements. What is the uncertainty of interpolated values in the resulting atmospheric temperature profiles? To answer this question, we introduce a general statistical–mathematical model for the computation of interpolation uncertainty. Analysing more than 51 million measurements, we provide some understanding of the consequences of filling missing data with interpolated ones.

This paper describes GRUAN's strategy for a network-wide change of the operational radiosonde from Vaisala RS92 to RS41. GRUAN's main goal is to provide long-term data records that are free of inhomogeneities due to instrumental effects, which requires proper change management. The approach is to fully characterize differences between the two radiosonde types using laboratory tests, twin soundings, and ancillary data, as well as by drawing from the various fields of expertise available in GRUAN.

Radiosondes are one of the primary sources of upper-air data for weather and climate monitoring. In the last two decades, technological progress made available automated radiosonde launchers (ARLs), which are able to replace measurements typically performed manually. This work presents a comparative analysis of the technical performance of the ARLs currently available on the market and contribute to define a strategy to achieve the full traceability of the ARL products.