In this work, we show how aerosol particles in city air change their ability to scatter light when exposed to humidity, which affects the climate. Using a simpler tool, we found that in Prague's suburbs, these particles showed only a small change in light scattering, likely due to carbon-rich pollution that effectively absorbs light. Our method helps to reduce certain types of measurement uncertainty and helps fill gaps in urban climate data.

This paper reports the deployment of the first narrowband sodium lidar in the low-latitude region of China. The lidar observations are compared with satellite measurements and atmospheric models, confirming the scientific credibility of these results. Calculations of vertical gravity wave heat and sodium fluxes are used to investigate the influence of the space environment. This lidar system will provide a new ground-based detection device for studying atmospheric environment above the area.

The imbalance between the energy the Earth absorbs from the Sun and emits back to space gives rise to climate change, but measuring the small imbalance is challenging. The Earth surface reflects sunlight more in some directions than in others, as with e.g. ocean sunglint. We simulate satellites to investigate how this uneven reflection impacts estimates of the imbalance. We identify orbits that cover all directions well, so that the impact is small.

We analyzed the stratospheric aerosol plume from the 2022 Hunga eruption using satellite lidar data. We implemented a method to retrieve some aerosol properties, as standard products failed in this case. We found very high optical depth values in the days following the eruption, which decreased rapidly but remained elevated for months. Our results are broadly validated, though some satellite products underestimate the values due, in part, to the unusual aerosol size distribution in the plume.

This paper presents an intercomparison of zonal winds observed by a sodium fluorescence lidar and three types of meteor radars – a multistatic meteor radar, a conventional monostatic radar, and a forward remote receiver – located near Hefei, China. The multistatic meteor radar shows the best agreement with the lidar measurements, confirming the reliability of its wind retrievals in the mesosphere and lower thermosphere and highlighting its potential for future atmospheric dynamics studies.

Wind turbine clutter (WTC) reduces the accuracy of weather radar measurements, as turbines may now be built closer to radar sites. A dynamic algorithm reliably detects WTC when wind turbine rotor speeds exceed 5 rpm. Beamblockage due to WT in the 5 km range is significant. A wind turbine-free 5 km radius is recommended.

The European Space Agency's Aeolus satellite (2018–2023) was the first mission to measure global wind profiles from space. We analysed its performance over five years to understand data quality and coverage under different conditions. By linking instrument behaviour to wind observations, we identified strengths and limitations. These results provide essential guidance for the design and operation of the operational follow-on mission Aeolus-2.

Accurate measurement of methane's isotopic fingerprint is crucial for identifying its sources. However, water vapor interference and instrument drift can cause significant errors, especially in humid air. This study evaluated two calibration methods and found that calibrating for individual methane isotopes with a water vapor correction provided accurate and stable results for both dry and humid air. This highlights the need for robust calibration to ensure reliable methane source attribution.

Water vapor is an essential climate variable in the Earth's atmosphere and plays an important role in the radiative balance, serving as the most significant greenhouse gas in the upper troposphere. Hence, high-quality and continuous measurements are required. In this paper, we present the breadboard design of a newly developed radiometer, which will retrieve vertical profiles of middle atmospheric water vapor.

In this study, we developed an improved algorithm to retrieve the sulfur dioxide plume height and column density from the spectral band 2 of the TROPOspheric Monitoring Instrument onboard the Sentinel-5 Precursor satellite. We tested its sensitivity to various conditions and applied it to real volcanic eruptions. Overall, our approach shows high precision, accuracy, and sensitivity, and the results are consistent with other satellite measurements.

We describe the use of a nearby drifting stratospheric balloon to calibrate three different radar systems. While for radars in the VHF range different calibration options exist, it is much more complicate to do this in the lower HF range. The main complication is the required distance and size of the target, which is especially challenging for vertical pointing radars. We also present the validation of proper phase calibration and the general radiation pattern.

For satellite measurements of atmospheric composition, the random uncertainty estimates provided by retrieval algorithms might be imperfect due to various approximations used in the retrievals or presence of unknown error sources. This paper presents an overview of the methods used for validation of random uncertainty estimates. All methods discussed in this study are categorized, and assumptions and limitations of each method are discussed.

Convective storms pose several hazards, like heavy rainfall, but operational short-term forecasting (nowcasting) suffers from limited models of storm development. Cell tracking, commonly used for nowcasting of convective storms and analyzing storm evolution, is complicated by splits and merges. We show how splits and merges can be integrated into cell track analysis, using case studies and analysis of split and merge events with operational data from the Swiss weather radar network.

TROPOMI (TROPOspheric Monitoring Instrument) provides daily ozone profile data from ultraviolet bands 1–2. Accurate radiometric calibration is critical below 300 nm where signals are low. A Level-2 soft calibration complements L1 calibration and reveals spectral, temporal, and across-track biases. Re-analysis of calibration data enabled improved L1 corrections to address remaining straylight and residual signal effects, reducing soft calibration magnitude by ~15–20 % and associated biases in L1b v3.0 and ozone processor v2.9.0.

We assess the representativeness of a remote ground-based station in Mindelo, Cabo Verde by utilizing continuous observations of a ground-based multiwavelength polarization Raman lidar and the LIdar climatology of Vertical Aerosol Structure (LIVAS) products. Based on a statistical analysis of the optical properties at different radii around Mindelo and case studies, we conclude that overall, the ground-based station in Mindelo can be considered conditionally representative.

This paper presents first differential absorption lidar (DIAL) measurements of isotopic ratio of CO₂ (δ¹³C) in the atmosphere in the spectral domain of 2-µm. This work investigates additional tracers of intra-atmospheric or surface-atmosphere exchanges to characterise CO₂ sources and sinks.

The development of an open detector based on absorption spectroscopy, enhanced by high-reflectivity mirrors, for the simultaneous measurement of NO₂, IO, and CHOCHO is reported. The instrument shows good correlation with a closed system during both indoor and outdoor measurements. An open system is able to measure NO₂, IO, and CHOCHO with high precision.

Airplane condensation trails trap heat, but their full warming effect is hard to measure because they blend into natural clouds. Using satellite observations, weather data, flight paths, and a causal inference framework, we isolated this effect without simulations or contrail masks. We found contrails trap 46.9 gigajoules of heat per kilometer flown over the Americas. This provides a crucially missing observation-based estimate of a major portion of aviation’s environmental impact.

We investigate which wavelengths, depending on the latitude, are required for aerosol measurements after continuous sulphur injections of 30 Tg S yr^-1 into the stratosphere, here at 19 km, in order to obtain physically meaningful stratospheric aerosol extinction profile retrieval results from the perspective of a typical satellite instrument with the so-called solar occultation geometry. Consistent with expectations, a longer wavelength is required for the latitude range of and near the injection.