Airborne cloud observation relies on high-frequency black-and-white-image information. The study presents automatic shape recognition tools developed with machine learning techniques and adapted for this type of image. Applied on a recent field campaign, these tools produce morphology-specific size distributions that can be compared across four instruments covering different size ranges. The analysis show that the tools are performing well and are consistent across the different instruments.

This paper proposes a novel methodology for selecting sulfur-dioxide-sensitive channels from FY-3E/HIRAS-II hyperspectral IR atmospheric sensors to quantitatively monitor volcanic sulfur dioxide. This methodology considers the interference of atmospheric temperature, humidity, and surface temperature with sulfur dioxide detection and retrieval, laying the groundwork for developing a more accurate and flexible volcanic sulfur dioxide retrieval algorithm under different atmospheric conditions.

This study evaluates retrieval strategies for CH₄ and N₂O using high-resolution FTIR observations from Boulder, Colorado. By comparing results with independent AirCore and aircraft in situ measurements, the analysis validates retrieval accuracy and quantifies uncertainties. The findings highlight the benefits of updated spectroscopy and improved a priori profiles and highlight consistent agreement with in situ data.

This paper provides an overview of the CIAO Observatory in southern Italy, focusing on the upgrade of its aerosol in situ laboratory in compliance with ACTRIS standard operating procedures. The aim is to provide the aerosol research community with technical details and practical guidance for establishing an in situ aerosol observational site. The paper also discusses the importance of combining in situ and remote sensing measurements for a comprehensive understanding of atmospheric processes.

Nitrogen dioxide (NO₂) is a pollutant with a short lifetime and large variability, but there are limited measurements of its distribution in the lower atmosphere. We present a new 3-year dataset of NO₂ vertical profiles in Toronto, Canada, and evaluate it using NO₂ from satellite and surface monitoring networks and simulations by an air quality forecast model. We quantify and explain the differences among the datasets to provide information that can be used to understand NO₂ variability.

Laser desorption of individual particles prior to ionization is the key to reveal their organic composition. The CO₂ lasers required are bulky and maintenance-intensive, limiting their use in the field. We have developed a compact solid-state IR laser that is easily aligned with the particle beam. Mass spectra and hit rates are similar to those of the CO₂ laser. For combined characterization of organic and inorganic particle compositions, both lasers are superior to conventional single UV pulses.