Tropospheric ozone affects air quality and climate, being a pollutant and a greenhouse gas. We analyze satellite data of tropospheric ozone columns obtained by combining two types of observations: one providing stratospheric and the other total ozone. We compare common climatological features and study the influence of the tropopause (troposphere to stratosphere boundary) on the results. We also examine trends over the last 20 years and compare satellite data with ozonesondes to identify drifts.

Cloud optical parameterizations (COPs) in Radiative Transfer for TOVS are evaluated by comparing observed and synthetic visible satellite images. The optimal COP for liquid water cloud is parameterized in terms of effective diameter (D_eff) and the COP for ice cloud developed by the Space Science and Engineering Center, with D_eff for ice cloud parameterized in terms of ice water content and temperature. The findings will benefit the remote sensing and data assimilation community.

Accurate measurements of ice water content (IWC) and snowfall rate (SR) are challenging due to high spatial variability and limitations of our measurement techniques. Here, we present a novel method to derive IWC and SR from W-band cloud radar observations, considering the degree of riming. We also investigate the use of the liquid water path (LWP) as a proxy for the occurrence of riming. LWP is easier to measure, so that the method can be applied to both ground-based and space-based instruments.

In this paper, we propose a data fusion method to obtain the no-blind-zone wind speed profiles covering the whole atmospheric boundary layer based on the joint measurements of coherent Doppler lidar (CDL), radar wind profiler (RWP) and automatic weather station (AWS). Since the above instruments are widely deployed in China, we believe this method has broad application prospects for the improvement of the boundary layer parameterization scheme in numerical forecast models. 

Optical detectors have a maximum signal (saturation). Exceedance means that the measurement has to be discarded. We investigate where saturation will occur for the future European satellite mission dedicated to CO₂ monitoring (CO2M) and strategies to avoid saturation. Saturation impacts coverage and precision, both of which are important for estimation of local CO₂ emissions. We find that taking two pictures per sampling should be sufficient to avoid saturation for CO2M, with some impact on CO₂ precision.

This paper describes the operational method of extracting meteorological information from all airborne aircraft in the European airspace every 20 s to 1 min. The methodology is described, and the quality of the wind and temperature observations is evaluated against radiosonde and other aircraft observations.

This paper describes an airborne radio occultation (ARO) observation system installed on a reconnaissance aircraft that uses GPS signal refraction in the atmosphere to retrieve information about the temperature and moisture in the storm environment as far away as 400 km surrounding the flight track. The characteristics and quality of 1700 ARO refractivity profiles were assessed. These observations are collected to help understand atmospheric rivers and improve their forecasting.

Remote sensing measurements of scattered sunlight use the atmospheric absorption of O₂–O₂ (or O₄) to derive cloud and aerosol properties. However, inconsistencies between measurements and radiative transfer simulations were found recently, and, so far, there has been no consensus on how to deal with these appropriately. In this study, long-term long-path differential optical absorption spectroscopy (LP-DOAS) observations were analysed and very good agreement with laboratory measurements was found.

This study explores nitrous oxide (N₂O) fluxes from a nutrient-poor sub-Arctic peatland. N₂O is a potent greenhouse gas; understanding its fluxes is essential for addressing global warming. Using a new instrument and flux chambers, we introduce a system to reliably detect low N₂O fluxes and provide recommendations on chamber closure times and flux calculation methods to better quantify N₂O fluxes. We encourage researchers to further investigate N₂O fluxes in low-nutrient environments.

Acetylene mole fraction measurements from the Picarro G2203 were characterised. Abnormal sensor behaviour was observed in wet conditions. A dry linear calibration was derived, although this was invalid below 1.2 ppb due to unstable measurements. The instrument was used to measure acetylene as a methane tracer at a landfill site. Fluxes were derived from 14 downwind transects using both raw and calibrated acetylene mole fraction, with raw measurements resulting in 8 % flux underestimation.

Planetary boundary layer height (PBLHT) is an important parameter in atmospheric process studies and numerical model simulations. We use machine learning methods to produce a best-estimate planetary boundary layer height (PBLHT-BE-ML) by integrating four PBLHT estimates derived from remote sensing measurements. We demonstrated that PBLHT-BE-ML greatly improved the comparisons against sounding-derived PBLHT.

Understanding the lowest layers of the atmosphere is crucial for climate research, especially in the Arctic. Our study introduces the T-Bird, an aircraft-towed platform designed to measure turbulence and aerosol properties at extremely low altitudes. Traditional aircraft cannot access this region, making the T-Bird a breakthrough for capturing critical atmospheric data. Its first deployment over the Arctic demonstrated its potential to improve our understanding of polar processes.

Contrails, the clouds formed by aircraft, are have a substantial climate impact. Determining which flight formed each contrail is a critical step to decreasing this impact. We introduce a dataset of synthetic contrail observations with known flight attributions that can be used to develop and assess geostationary-satellite-based contrail-to-flight attribution systems. We additionally introduce a new attribution algorithm and show that it outperforms previous methods.

When deriving a geophysical variable from remote sensors, the uncertainty and information content are critical. The latter quantify specifies what fraction of a real perturbation would be observed in the derived variable. This paper outlines, for the first time, a methodology for propagating the information content from multiple remote sensors into a derived product using horizontal advection as an example.

This study provides insight into how individual ions measured by proton-transfer-reaction (PTR) mass spectrometry are produced by multiple volatile organic compounds (VOCs). A reference table is provided for attributing the PTR signal to contributing VOC species. The signals are grouped according to the complexity of their potential identities. We find that a number of signal ions such as C₆H₇⁺ for benzene and C₅H₉⁺ for isoprene merely give an upper limit of their corresponding concentrations.

Measurements of methane with vehicle-based sensors are an effective method to identify and quantify leaks from urban gas distribution systems. We deliberately released methane in different environments and calibrated the response of different methane analysers when they transected the plumes in a vehicle. We derived an improved statistical function for consistent emission estimations using different instruments. Repeated transects reduce the uncertainty in emission rate estimates.

The Atmospheric Sounder Spectrometer by Infrared Spectral Technology (ASSIST) is a commercially available ground-based infrared spectroradiometer. It is designed for automated and passive measurement of the thermal radiation emitted by the atmosphere, providing information about the vertical distribution of temperature and humidity, trace gases, clouds, and aerosols in the boundary layer. In this paper, we outline the key characteristics of the ASSIST hardware and signal processing algorithm that yields downwelling radiance spectra in near real-time.