This paper presents a novel methodology for radar data processing, the path-Columnar Vertical Profile, or pCVP, based on the EVP/CVP (enhanced/column vertical profile) method. pCVP utilizes vertical profiles from EVP/CVP, but in the height vs. location format at a single volume time along the arbitrary path instead of the height vs. volume time format at a single location, as in EVP/CVP.

Once Aura is decommissioned, the multi-decadal microwave limb sounder (MLS) record of stratospheric HNO₃ will end. This paper presents the retrieval of stratospheric HNO₃ from nadir infrared sounders. We demonstrate the retrieval of stratospheric HNO₃, independent of tropospheric signal and noise, that broadly reflects the variation captured by MLS. This novel retrieval approach improves upon the status quo and lays the foundation for validation studies and product roll-out in future.

We studied methane emissions in Arctic Alaska using satellite observations to assess how well they can monitor this important greenhouse gas. We found that emission estimates varied depending on the satellite data product and were strongly affected by assumptions in the model. Our results highlight the need for careful interpretation of emissions from Arctic satellite data and thorough testing of models, with implications for reliable climate monitoring.

Stray light is an error source in all optical instruments. In passive remote sensing observations of greenhouse gases, it creates false patterns in gas concentration maps. In this work, the impact of stray light in the full processing chain from measured spectra, retrieved concentration maps, to emission rate estimates using measured and simulated data is analysed for MAMAP2D-Light. Additionally, a hardware improvement mitigates stray light for onward missions.

This paper proposes a new, fast and accurate method for estimating the cloud optical depth (τ_c) from photovoltaic (PV) power measurements under overcast sky conditions. The method performs very well with the European Centre for Medium-Range Weather Forecasts (ECMWF) products as inputs describing the state of the atmosphere. The method exhibits a better performance than published state-of-the-art methods when compared to ground and satellite-based τ_c retrievals serving as reference.

This experiment tested the ability of different technologies to detect and measure methane emissions. Participating teams used satellites, drones, and other systems to estimate methane leak rates without knowing the true rate. Some systems were more accurate than others, and wind and other environmental conditions made measurements harder. Our findings help improve these tools and support efforts to track and reduce methane emissions as new environmental rules take shape in Europe and beyond.

In this study three-dimensional cloud fields with different macro- and microphysical properties are generated and used to simulate the top of atmosphere short wave radiances and fluxes. The simulations are compared to two radiance-to-irradiance conversion approaches. Especially for viewing angles in the backscattering direction the approach that is aware of the cloud microphysics results in better flux estimates.

The atmosphere hosts a multitude of waves, among which Atmospheric Gravity wave separation from satellite measurements requires removal of global scale waves and tides. The present study describes the open access software GLOFI (GLObal wave FIt) which uses the 2D spectral decomposition to perform this removal. It is validated on simulated temperature observations synthesised for ESA (European Space Agency) Earth Explorer 11 candidate CAIRT (Changing-Atmosphere Infra-Red Tomography Explorer).

This manuscript details laboratory and field-based testing of a tower-based methane and ethane measurement system to address the challenge of separating methane sources in oil and gas basins. We describe methods for managing water vapor, calibration, and estimating the various components of measurement uncertainty. With appropriate engineering and calibration, the instrument shows the capability to measure CH₄ and C₂H₆ with sufficient stability to distinguish regional methane emission sources.

We examine four equations for calculating infrared radiation (3–50 mm) measured with an Eppley PIR (Precision Infrared Radiometer) pyrgeometer. These equations are used to transfer calibrations from our standards calibrated at the World Radiation Center in Davos, Switzerland, to our field PIR pyrgeometers. A clear choice in terms of the most precise method to follow emerges from this study. Further, we evaluate the stability of the Eppley PIR, necessary for long-term trend analysis.

The submarine eruption of the Hunga volcano released water vapor and sulfur dioxide directly into the stratosphere. The sulfur dioxide formed sulfuric acid aerosols leading to increased scattering of solar ultraviolet radiation (UV), interfering with satellite ozone retrievals. We present a new satellite technique for deriving the amount and height of Hunga aerosols from UV measurements, revealing an unusually low sulfuric acid concentration due to the water-rich conditions in the fresh plume.

We describe a new humidity probe designed for flight to characterize the very dry air at 10–12 km where jet aircraft can form persistent contrail clouds. These clouds trap heat and contribute to warming the planet. The laser-based system precisely measures water molecules in air, enabling accurate predictions of contrail formation to help reduce aviation's climate impact.

We developed a new method to better detect and study small-scale gravity waves in the middle atmosphere using lidar data. This technique more clearly reveals wave patterns than older methods and gives more accurate energy estimates, especially high up near the stratopause. Our approach helps scientists understand how these waves behave and interact across different scales, improving knowledge of atmospheric dynamics.

An attention-augmented ResNet and a transfer training are implemented to derive diurnal variations in near-global planetary boundary layer height. The transfer-trained model shows superior performances compared to conventional algorithms and non-transfer trained mode. The model predicted more reliable diurnal behaviors, with daily amplitude and peak timing approaching radiosonde results.

We improved the accuracy of low-cost particulate matter sensor (PMS5003/6003) measurements under dust-dominated conditions common in arid regions. By applying sensor-specific particle mass ratios and a relative humidity cutoff, dust-influenced measurements were identified and PM_2.5 concentrations corrected, reducing bias by ~ 50 % relative to regulatory monitors. This method enables real-time PM_2.5 correction where reference data are unavailable.

We constructed and characterized a Fluorinert multi-channel Condensation Particle Counter for aircraft applications that comprises three channels and a pressure regulation system to measure nucleation mode particles in the upper troposphere. The cutoffs were determined at several ambient and internal pressures and sample flows. During the first aircraft campaign TPEx we were able to identify possible new particle formation events.

The Fugitive Emission Distributed Sampling (FEDS) system is used to measure emissions from local-scale sources (up to ~1×1 km). FEDS uses a state-of-the-art gas analyser linked to many sampling locations. Controlled amounts of methane were released to test the accuracy of the FEDS system. Results were promising even when using different models to estimate the amount of methane released. Results were better when the wind was consistent. FEDS could be used for measuring emissions over many months.