Vertical profiles of aerosol properties are essential for assessing the impact of aerosols on cloud formation and the Earth's radiation budget. Lidars can provide profiles of the particle backscatter and extinction coefficients and the extinction-to-backscatter ratio (lidar ratio). An Ångström exponent has to be assumed when computing these profiles from nitrogen vibrational–rotational Raman signals. This assumption introduces uncertainties. An alternative approach is the rotational Raman lidar method, which does not need an Ångström exponent as input. This study presents a quantitative comparison between the pure rotational and vibrational–rotational Raman lidar approaches to assess the impact of the Ångström exponent assumption on the vibrational–rotational Raman lidar solutions. In this short article, we present four contrasting case studies based on observations of wildfire smoke, Saharan dust, residential wood combustion smoke, and a cirrus layer. The optical properties are derived at a wavelength of 532 nm, with the rotational Raman signals measured at 530 nm and the vibrational–rotational Raman signals measured at 607 nm. It was found that the use of an Ångström exponent, deviating by 1 from the true value, introduces relative uncertainties of 5 % and less (backscatter coefficient), 5 %–10 % (extinction coefficient), and around 10 % (lidar ratio) in the vibrational–rotational Raman lidar solutions.

In this paper we will present the design of a laboratory assembled portable EDXRF spectrometer that uses the secondary target excitation mode and its analytical performance. In secondary target configuration, the sample is excited mainly with the target material characteristic emission radiation, which allows to reduce the detected continuum background and to improve the detection limits. The instrument is based on a low power, air cooled, Ag anode X-ray tube (Eclipse III) and thermoelectrically cooled Si-PIN detector arranged in a specially built geometrical setup that allows the use of secondary targets. In our design, all spectrometer elements (x-ray tube, secondary target, sample and detector) are arranged in such a way that distances are minimal while keeping the excitation and detection angles optimal as well (φ=φ = 45°). The possibility to use different secondary targets enables the optimization of detection limits for different groups of elements in various types of samples. Examples of the application of the spectrometer for the analysis of different kind of samples will be presented.

Vertical profiles of aerosol properties are essential for assessing the impact of aerosols on cloud formation and the Earth's radiation budget. Lidars can provide profiles of the particle backscatter and extinction coefficients and the extinction-to-backscatter ratio (lidar ratio). An Ångström exponent has to be assumed when computing these profiles from nitrogen vibrational-rotational Raman signals. This assumption introduces uncertainties. An alternative approach is the rotational Raman lidar method, which does not need an Ångström exponent as input. This study presents a quantitative comparison between the pure rotational and vibrational-rotational Raman lidar approaches to assess the impact of the Ångström exponent assumption on the vibrational-rotational Raman lidar solutions. In this short article, we present four contrasting case studies based on observations of wildfire smoke, Saharan dust, residential wood combustion smoke, and a cirrus layer. The optical properties are derived at a wavelength of 532 nm, with the rotational Raman signals measured at 530 nm and the vibrational-rotational Raman signals measured at 607 nm. It was found that the use of an Ångström exponent, deviating by 1 from the true value, introduces relative uncertainties of 5 % and less (backscatter coefficient), 5–10 % (extinction coefficient), and around 10 % (lidar ratio) in the vibrational-rotational Raman lidar solutions.

Vertical profiles of aerosol properties are essential for assessing the impact of aerosols on cloud formation and the Earth's radiation budget. Lidars can provide profiles of the particle backscatter and extinction coefficients and the extinction-to-backscatter ratio (lidar ratio). An Ångström exponent has to be assumed when computing these profiles from nitrogen vibrational-rotational Raman signals. This assumption introduces uncertainties. An alternative approach is the rotational Raman lidar method, which does not need an Ångström exponent as input. This study presents a quantitative comparison between the pure rotational and vibrational-rotational Raman lidar approaches to assess the impact of the Ångström exponent assumption on the vibrational-rotational Raman lidar solutions. In this short article, we present four contrasting case studies based on observations of wildfire smoke, Saharan dust, residential wood combustion smoke, and a cirrus layer. The optical properties are derived at a wavelength of 532 nm, with the rotational Raman signals measured at 530 nm and the vibrational-rotational Raman signals measured at 607 nm. It was found that the use of an Ångström exponent, deviating by 1 from the true value, introduces relative uncertainties of 5 % and less (backscatter coefficient), 5–10 % (extinction coefficient), and around 10 % (lidar ratio) in the vibrational-rotational Raman lidar solutions.

Vertical profiles of aerosol properties are essential for assessing the impact of aerosols on cloud formation and the Earth's radiation budget. Lidars can provide profiles of the particle backscatter and extinction coefficients and the extinction-to-backscatter ratio (lidar ratio). An Ångström exponent has to be assumed when computing these profiles from nitrogen vibrational-rotational Raman signals. This assumption introduces uncertainties. An alternative approach is the rotational Raman lidar method, which does not need an Ångström exponent as input. This study presents a quantitative comparison between the pure rotational and vibrational-rotational Raman lidar approaches to assess the impact of the Ångström exponent assumption on the vibrational-rotational Raman lidar solutions. In this short article, we present four contrasting case studies based on observations of wildfire smoke, Saharan dust, residential wood combustion smoke, and a cirrus layer. The optical properties are derived at a wavelength of 532 nm, with the rotational Raman signals measured at 530 nm and the vibrational-rotational Raman signals measured at 607 nm. It was found that the use of an Ångström exponent, deviating by 1 from the true value, introduces relative uncertainties of 5 % and less (backscatter coefficient), 5–10 % (extinction coefficient), and around 10 % (lidar ratio) in the vibrational-rotational Raman lidar solutions.