Recent  

We have serially combined the two well-established methods for in situ real-time measurement of fine particle chemical composition, the single particle laser ablation method and the flash evaporation with electron impact ionization method, into a novel instrument. Here we present the design, instrument characteristics, as derived from laboratory and field measurements, and results from the first field deployment during the 2017 StratoClim aircraft campaign.

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, on board the European Space Agency ENVISAT satellite, level 2 version 8 database, containing atmospheric fields of pressure, temperature and volume mixing ratio of 21 trace gases, is described in this paper. The database covers all the measurements acquired by MIPAS (from July 2002 to April 2012). The number of species included makes it of particular importance for the studies of stratospheric chemistry.

Sea surface wind and waves are important ocean parameters that can be continuously observed by meteorological buoys. Meteorological buoys are sparse in the ocean due to their high cost of deployment & maintenance. In contrast, low-cost compact wave buoys are suited for deploying in large numbers. Although wave buoys are not designed for wind measurement, we found that deep learning can estimate wind from wave measurements accurately, making wave buoys a good-quality data source for sea wind.

The evolution of the atmospheric boundary layer height (ABLH) has an important impact on meteorology. However, the complexity of the phenomena occurring within the ABL and the influence of advection and local accumulation processes often prevents an unambiguous determination of the ABLH. The paper reports results from an inter-comparison effort involving different sensors/techniques to measure the ABLH. Correlations between the ABLH and other atmospheric variables are also assessed.

This study validates the concept of using the GPM spaceborne radar observations to calibrate national weather radar networks to the accuracy required for operational severe weather applications such as rainfall and hail nowcasting.

eVe lidar measures the optical properties of aerosols and clouds and is designed to provide the European Space Agency’s satellite mission of Aeolus with ground-reference measurements. The system provides linear and circular polarisation measurements, and it has also Raman capabilities. We describe the system design, as well as the polarisation calibration techniques and the developed software for the retrieval of the optical products.

Sulfuric acid is known to be a main compound in atmospheric new particle formation. Yet, its concentration is very low, which leads to challenges when detecting it. In our study, we derive the sulfuric acid concentration based on measurements of ambient ions with a mass spectrometer. Our validation shows, that the theoretical approach using the bisulfate ion and its clusters with H₂SO₄ captures the sulfuric acid concentration very well during daytime.

The remote sensing technique lidar is widely used for wind speed measurements for both industrial and academic applications. Lidars can measure wind statistics very accurately, however cannot fully capture turbulent fluctuations in the high frequency domain, since they are partly filtered out. This paper therefore investigates the turbulence spectrum measured by a short-range, continuous-wave lidar and analytically models the measurement principle with respect to the turbulence spectrum.

Winds that are crucial to weather forecasting created by two different techniques – tracking satellite images (AMVs) and direct measurement of molecular and aerosol motions by Doppler lidar (Aeolus satellite winds) – are compared. We find that AMVs correspond well with Aeolus winds. The level of agreement depends on certain conditions, e.g., scene type, region, height. For example, larger differences are found in the Southern Hemisphere due to higher wind speed and higher vertical variation of wind.

We made a humidity generator that adds water vapor to a flowing gas. Its range of humidity is useful for calibrating balloon-borne probes to the Earth's stratosphere. The generator’s novel feature is a saturator that comprises five meters of silicone tubing immersed in water. The length was enough to ensure that the saturator’s output was independent of the dimensions and permeability of the tube. This simple, low-cost design provides an accuracy that is acceptable for many applications.

This study focuses on understanding a versatile water-based condensation particle counter (vWCPC) performance under low-pressure conditions (or high altitude). A vWCPC has the advantage of avoiding health and safety concerns. However, its performance characterization under a low-pressure is rare but crucial for ensuring successful airborne deployment. This paper provides advanced knowledge of operating a vWCPC to capture the spatial variations of atmospheric aerosols.

Satellite and ground-based observations at high latitude are much sparser than at low or mid latitude, which makes direct coincident comparisons between remote-sensing observations more difficult. Therefore, a method of scaling continuous CAMS model data to the ground-based observations is developed and used for creating virtual COCCON observations. These adjusted CAMS data are then used for satellite inter-comparison, showing good agreement in both Peterhof and Yekaterinburg cities.

The emission of biogenic volatile organic compounds (BVOCs) from plant leaves is an essential part of biosphere-atmosphere interactions. Here we demonstrate how a dynamic chamber for measuring branch-scale BVOC emissions could be characterized both in the lab for adsorptive losses and in the field for ambient-enclosure environmental differences. The results also imply emission factors for terpenes might be underestimated if measured using dynamic chambers without certified transfer efficiencies.

Spectral emissivity is a key property of the Earth surface. Few measurements exist in the far-infrared, despite recent work showing its contribution is important for accurate modelling of global climate. In preparation for ESA’s EE9 FORUM mission (launch 2026), this study takes first steps towards the development of an operational emissivity retrieval for FORUM by investigating the sensitivity of the emissivity product to different physical and operational parameters.

The instrument MIPAS on board of ENVISAT satellite provided for 10 years measurements of the atmospheric emission al limb that allow the retrieval of latitude- and altitude-resolved atmospheric composition. We describe the improvements implemented in the retrieval algorithm used for the full mission reanalysis which allow to generate the global distributions of 21 atmospheric constituents plus temperature with increased accuracy with respect to previously generated data.

Particle-phase nitrates are an important component of atmospheric aerosols and chemistry. In this manuscript, we systematically explore the application of aerosol mass spectrometry (AMS) to quantify the organic and inorganic nitrate fractions of aerosols in the atmosphere. While AMS has been used for a decade to quantify nitrates, methods are not standardized. We make recommendations for a more universal approach based on this analysis of a large range of field and laboratory observations.

FORUM is an instrument which will look at the earth atmosphere from a satellite. It will cover a spectral range which is responsible for about one half of the radiation lost by our planet. Its measurements will help predicting the climate changes, in particular the earth heating. The End-to-End simulator is a chain of codes that simulate the FORUM measurement process. The goal of the project is to study how the instrument reacts to different retrieval conditions.

Tornadic storms have been hypothesized to emit sound at frequencies below human hearing which animals and certain microphones can detect. This study covers the design, fabrication, and deployment of a specialized microphone system that can be carried by first responders and storm chasers. The study also presents real-time processing methods, analyzes several recorded severe weather events including a tornado, and introduces a real-time web interface to allow live monitoring of the mobile sensor.

The ability to measure snowfall with weather radar has greatly advanced with the development of techniques that utilize dual-polarization measurements, which provide information about the snow particle shape and orientation, and multi-frequency measurements, which provide information about size and density. This study combines these techniques with the NASA D3R radar, which provides dual-frequency polarimetric measurements, with data that was observed during the 2018 Winter Olympics.

In this study we focus on the retrieval of aerosol, NO₂ and HCHO vertical profiles from multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations for the first time over Thessaloniki, Greece. We use two independent inversion algorithms for the profile retrievals. We evaluate their performance, we intercompare their results and we validate their products with ancillary data, measured by other co-located reference instruments.

The assimilation of the GNSS data in weather models have a positive impact on the forecasts. The impact is still limited due to using only the GPS zenith-direction parameters. We calculate and validate more advanced tropospheric products from three satellite systems: the US American GPS, Russian GLONASS and European Galileo. The quality of all the solutions is comparable, however combining more GNSS systems enhances the observations geometry and improves of the quality of the weather forecasts.

Particles in the atmosphere play a significant role in climate change by scattering light back into space, reducing the amount of energy available to be absorbed by greenhouse gases. We built a new instrument to measure what direction light is scattered by particles, e.g. wildfire smoke. This is important because, depending on the angle of the sun, some particles scatter light into space (cooling the planet), but some light is also scattered towards the Earth (not cooling the planet.)

This study analyzes the quality of two versions (v3.6 and v4.1) of ozone concentration measurements from the ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer), by comparing with data from five satellite instruments between 2004 and 2020. It was found that although the v3.6 data exhibit a better agreement than v4.1 with respect to the other instruments, v4.1 exhibits much better stability over time than v3.6. The stability of v4.1 makes it suitable for ozone trend studies.

Very small CO₂ fluxes are measured at night and in Arctic regions, for example. Under these conditions, if the sensible heat flux is not close to zero, the WPL correction will take values in the order of the flux. For these cases, a special quality control is proposed.

During the VAL-OUC campaign, we established coherent Doppler lidars (CDLs) network over China to verify the L2B products from Aeolus. By the simultaneous wind measurements with CDLs at 17 stations, the L2B HLOS data from Aeolus are compared with that from CDLs. To our knowledge, the VAL-OUC campaign is the most extensive so far between CDL and Aeolus in the planetary boundary layer for different atmospheric scenes. The vertical velocity impact on the HLOS retrieval from Aeolus are evaluated.

We propose a new method to quantify particulate sodium and potassium salts (nitrate, chloride, and sulfate) by using a refractory aerosol thermal desorption mass spectrometer (rTDMS). The combination of a graphite particle collector and a carbon dioxide laser enables high desorption temperature. Laboratory experiments showed that major ion signals originating from sodium or potassium salts were clearly detected associated with the increase in the desorption temperature by laser heating.

The Global Positioning System (GPS) radio occultation (RO) technique is a satellite-based method for producing highly accurate vertical profiles of atmospheric temperature and pressure. RO profiles are used to monitor global climate trends, particularly in that region of the atmosphere that includes the lower stratosphere. Two data sets spanning 1995–1997 that were produced from the first RO satellite are highly accurate and can be used to assess global atmospheric models.

The cube root of the energy dissipation rate (EDR), as a standard reporting metric of atmospheric turbulence, is estimated using 1-Hz commercial quick access recorder data from Korean-based national air carriers with two different types of aircraft. Various EDRs are estimated using zonal, meridional, and derived vertical wind components, and the derived equivalent vertical gust. Characteristics of derived EDRs using 1-Hz flight data are examined to observed strong turbulence cases.

We developed a machine learning model to detect plumes of nitrogen dioxide satellite observations over two years. We find over 310,000 plumes, mainly over cities, industrial regions and areas of oil and gas production. Our model performs well in comparison to other datasets and in some cases, finds emissions that are not included in other datasets. This method could be used to help locate and measure emission hotspots across the globe and help inform climate policies.

A method for estimating microphysical properties of ice clouds based on the radar measurements is presented. The algorithm exploits the information provided by differences in the radar response at different frequency bands in a relation to changes in the snow morphology. The inversion scheme is based on a statistical relation between the radar simulations and the properties of snow calculated from in cloud samplings.

Aeolus is the first satellite that provides global wind profile measurements. The mission aims to improve the weather forecasts in the tropics, but also, potentially, in the polar regions. We evaluate the performance of the instrument over Northern Canada and the Arctic by comparing its measured winds in both cloudy and non-cloudy layers with wind data from forecasts, reanalysis, and ground-based instruments. Overall, good agreement was seen, but Aeolus winds have greater dispersion.