Vertical and horizontal sounding of the planetary boundary layer can be complemented by unmanned aerial vehicles (UAV). Utilizing a multicopter-type UAV spatial sampling of air and simultaneously sensing of meteorological variables is possible for the study of surface exchange processes. During stable atmospheric conditions, vertical methane gradients of about 300 ppb were found. This approach extended the vertical profile height of existing tower-based infrastructure by a factor of five.

Vertical air motion retrievals from 3DVAR multiple distributed scanning Doppler radars are compared against collocated profiling radars and retrieved from an upward iteration integration iterative technique to characterize their veracity. The retrieved vertical air motions are generally within 1–2 m s⁻¹ of agreement with profiling radars and better solution than the upward integration technique, and therefore can be used as a means to improve parameterizations in numerical models moving forward.

Accurate knowledge of water vapor (WV) is vital for global climate studies. The Global Navigation Satellite System (GNSS) has been used as an emerging tool for sensing integrated WV (IWV). In the determination of PWV, surface pressure is required. However, few GNSS stations were installed with meteorological sensors back in the 1990s. Our research indicates that the ERA-Interim-derived pressure has the potential to be used to obtain high-accuracy IWV on a global scale for climate studies.

This work compares three methods to determine the optimal approach for quantifying the total oxidative potential (OP) of fine particles collected with filters using the dithiothreitol (DTT) assay. An automated system has been developed to facilitate the total OP measurements for use in generation of large data sets needed for epidemiology studies. The results from this study show that the water-insoluble components contribute to PM_2.5 OP and the related DTT-active species are largely secondary.

Different Aethalometer correction schemes were compared to a multi-wavelength absorption reference measurement. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for aerosol scattering properties in the correction is crucial to retrieve the proper absorption Ångström exponent (AAE). We found that the raw AAE of uncompensated Aethalometer attenuation significantly correlates with a measured reference AAE.

We have compared techniques used by several PEARL instruments to measure atmospheric water vapour. No single instrument can comprehensively map the atmosphere. We documented how well these techniques perform and quantified the agreement and biases between them. This work showed that new FTIR datasets at PEARL capture accurate measurements of High Arctic water vapour.

Wind turbine wakes have considerable impacts on downwind turbines in wind farms, given their slower wind speeds and increased turbulence. Based on lidar measurements, we apply a quantitative algorithm to assess wake parameters for wakes from a row of four turbines in CWEX-13 campaign. We describe how wake characteristics evolve, and for the first time we quantify the relation between wind veer and a stretching of the wake structures, and we highlight different results for inner and outer wakes.

Aerosol mass spectrometers (AMS) from ARI are used widely to measure the non-refractory species in PM1. Recently, a new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction in the commonly used standard vapourizer (SV) installed in AMS. To test the CV, the fragments, CE and size distributions of four pure inorganic species in the CV-AMS are investigated in various laboratory experiments. Results from the co-located SV-AMS are also shown as a comparison.

Mineral dust is one of the most abundant aerosol species at the global scale and an accurate estimation of its absorption at solar wavelengths is crucial to assess its impact on climate. In this work we provide an estimate of the Aethalometer multiple scattering correction for mineral dust aerosols at 450 and 660 nm. Our results suggest that the use of an optimized correction factor can lead to up to 11 % higher absorption coefficient and to 3 % higher single scattering albedo for mineral dust.

Oil and gas extraction activity can cause air quality issues through emission of reactive chemicals. VOCs related to extraction operations in the United States were measured by PTR-ToF-MS from aircraft during the SONGNEX campaign in March–April 2015. The detailed analysis in this work provides a guide to interpreting PTR-ToF measurements in oil- and gas-producing regions, and it includes fundamental observations of VOC speciation and mixing ratios.

Based on measurements with a ceilometer and from an air quality network, the relationship between the mixing layer height (MLH) and near surface concentrations of pollutants was investigated for summer 2014 in Berlin. It was found that the heterogeneity of the concentrations exceeds the differences due to different MLH retrievals. In particular for PM₁₀ it seems to be unrealistic to find correlations between MLH and concentrations representative for an entire metropolitan area in flat terrain.

Meteoric metals form metal layers in the upper atmosphere anandplay a role in the formation of middle-atmospheric clouds and aerosols. However, the total metal influx rate is not well known. Global Na datasets from measurements and a model are available, which had not been compared yet on a global scale until this paper. Overall the agreement is good, and many differences between measurements are also found in the model simulations. However, the modeled layer altitude is too low.

This work involves a first analysis of the systematic errors observed in the AOD retrieved at nighttime using the Sun–sky–lunar CE318-T photometer. In this respect, this paper is a first attempt to correct the AOD uncertainties that currently affect the lunar photometry by means of an empirical regression model. We have detected and corrected an important bias correlated to the Moon's phase and zenith angles, especially at longer wavelength channels.

Three different techniques for measuring turbulent quantities from a single Doppler lidar are evaluated against in situ observations for verification. A six-beam method generally produced the most accurate measurements of the turbulence quantities evaluated. Generally, turbulence kinetic energy can be accurately measured across all scales from a Doppler lidar. Individual velocity variances are measured less accurately, and velocity covariances are shown to be difficult to measure.

Measurements of ice cloud particle populations are needed to improve climate and weather prediction. This paper makes a comparison between ice cloud particle populations measured using two different airborne cloud particle probes. It is concluded that measurements of particle populations from older probes are similar to those from newer probes, except in total numbers of particles counted. Therefore, more airborne studies of ice clouds need to be made using newer cloud particle probes.

A large number of radiometers used to measure solar and terrestrial broadband radiation are traceable to World Standard Groups at PMOD/WRC in Davos, Switzerland. A small correction of each group may be required in the future, and this study examines the methods and implications of this on data sets collected at four remote baseline stations since the 1990s. The goal is to develop a better estimate of the solar and terrestrial radiation budget at the Earth's surface.

Cavity ring-down spectrometers (CRDS) can make accurate measurements of trace gases when the inert gas background is constant but are prone to errors when the background is variable. Here, we report that in one CRDS analyzer (L2120-i, Picarro), these errors result from broadening, narrowing, and shifting of the target absorption lines as well as neighboring lines. New spectral acquisition and analysis strategies are needed to make CRDS measurements robust to variable backgrounds.

We discuss a technique to extract the hydroxyl (OH) airglow signal from routine astronomical spectroscopic observations from the Nordic Optical Telescope. Emission spectra from the vibrational manifold from v′ = 9 down to v′ = 3. The fitted rotational temperature distribution with v′ agrees with model conditions and the preponderance of previous work. We highlight the potential for archived and future observations with unprecedented spatial and temporal resolutions.

The mathematical formulation for the optical setup of a typical EARLINET lidar system is given here. The equations describing a lidar system from the emitted laser beam to the projection of the telescope aperture on the final receiving unit (i.e., photomultiplier or photodiode) are presented, based on paraxial approximation and a geometric optics approach. The evaluation of the formulation is performed with ray-tracing simulations on a real system.