A versatile, refrigerant- and cryogen-free cryofocusing-thermodesorption unit for preconcentration of traces gases in air

We present a compact and versatile cryofocusing– thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in situ measurements, in situ monitoring and laboratory operation for the analysis of flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. -80°C) and subsequently desorbed by rapid heating of the adsorptive material (e.g. 200°C). The set-up involves neither the exchange of adsorption tubes nor any further condensation or refocusing steps. No moving parts are used that would require vacuum insulation. This allows for a simple and robust design. Reliable operation is ensured by the Stirling cooler, which neither contains a liquid refrigerant nor requires refilling a cryogen. At the same time, it allows for significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography – mass spectrometry (GC–MS) for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately -80 to +150°C and a substance mixing ratio range of less than 1 ppt (pmol mol−1)to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of analyte breakthrough during adsorption, repeatability of desorption and analyte residues in blank tests. Examples of application are taken from the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC–MS instruments and by data obtained during a research flight with our in situ aircraft instrument GhOSTMS (Gas chromatograph for the Observation of Tracers – coupled with a Mass Spectrometer)

A versatile, refrigerant- and cryogen-free cryofocusing-thermodesorption unit for preconcentration of traces gases in air

We present a compact and versatile cryofocusing–thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in situ measurements, in situ monitoring and laboratory operation for the analysis of flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. −80 °C) and subsequently desorbed by rapid heating of the adsorptive material (e.g. +200 °C). The set-up involves neither the exchange of adsorption tubes nor any further condensation or refocusing steps. No moving parts are used that would require vacuum insulation. This allows for a simple and robust design. Reliable operation is ensured by the Stirling cooler, which neither contains a liquid refrigerant nor requires refilling a cryogen. At the same time, it allows for significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography – mass spectrometry (GC–MS) for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately −80 to +150 °C and a substance mixing ratio range of less than 1 ppt (pmol mol⁻¹) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of analyte breakthrough during adsorption, repeatability of desorption and analyte residues in blank tests. Examples of application are taken from the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC–MS instruments and by data obtained during a research flight with our in situ aircraft instrument GhOST-MS (Gas chromatograph for the Observation of Tracers – coupled with a Mass Spectrometer)

Impact of Global Earth Observation – Systemic view across GEOSS Societal Benefit Areas

Global Earth Observation (GEO) is perceived as instrumental to attain sustainable development goals and to be a major driver of how the society–technology–environment system is managed. However, appropriate scientific methodologies to assess the benefits of GEO and validate investments in earth observation infrastructure development have been missing. This paper presents the systems approach to measure and analyze the impact of Global Earth Observation across nine GEOSS Societal Benefit Areas. The described methodology framework was used as part of global-wide earth observation assessment conducted during the European Commission sponsored project “Global Earth Observation – Benefit Estimation: Now, Next and Emerging” (GEOBENE). The applied systems approach enabled integration and aggregation of GEOBENE project findings. Apart from the assessment framework, there are described specific tools used for the GEO’s impact assessment, i.e. system dynamics model and based on it freely available simulator, as well as some assessment results. Although the total system benefits are strongly policy scenario dependent it was found that improved data due to use of Global Earth Observation and the data availability for community has a great potential in shaping the sustainable future of our planet

Distribution of hydrogen peroxide over Europe during the BLUESKY aircraft campaign

In this work we present airborne in situ trace gas observations of hydrogen peroxide (H$_2$O$_2$) and the sum of organic hydroperoxides over Europe during the Chemistry of the Atmosphere – Field Experiments in Europe (CAFE-EU, also known as BLUESKY) aircraft campaign using a wet chemical monitoring system, the HYdrogen Peroxide and Higher Organic Peroxide (HYPHOP) monitor. The campaign took place in May–June 2020 over central and southern Europe with two additional flights dedicated to the North Atlantic flight corridor. Airborne measurements were performed on the High Altitude and LOng-range (HALO) research operating out of Oberpfaffenhofen (southern Germany). We report average mixing ratios for H$_2$O$_2$ of 0.32 ± 0.25, 0.39 ± 0.23 and 0.38 ± 0.21 ppbv in the upper and middle troposphere and the boundary layer over Europe, respectively. Vertical profiles of measured H$_2$O$_2$ reveal a significant decrease, in particular above the boundary layer, contrary to previous observations, most likely due to cloud scavenging and subsequent rainout of soluble species. In general, the expected inverted C-shaped vertical trend with maximum hydrogen peroxide mixing ratios at 3–7 km was not found during BLUESKY. This deviates from observations during previous airborne studies over Europe, i.e., 1.64 ± 0.83 ppb$_v$ during the HOOVER campaign and 1.67 ± 0.97 ppbv during UTOPIHAN-ACT II/III. Simulations with the global chemistry–transport model EMAC partly reproduce the strong effect of rainout loss on the vertical profile of H$_2$O$_2$. A sensitivity study without H$_2$O$_2$ scavenging performed using EMAC confirms the strong influence of clouds and precipitation scavenging on hydrogen peroxide concentrations. Differences between model simulations and observations are most likely due to difficulties in the simulation of wet scavenging processes due to the limited model resolution

Tropospheric ozone production and chemical regime analysis during the COVID-19 lockdown over Europe

The COVID-19 (coronavirus disease 2019) European lockdowns have led to a significant reduction in the emissions of primary pollutants such as NO (nitric oxide) and NO$_2$ (nitrogen dioxide). As most photochemical processes are related to nitrogen oxide (NO$_x$≡ NO + NO$_2$) chemistry, this event has presented an exceptional opportunity to investigate its effects on air quality and secondary pollutants, such as tropospheric ozone (O$_3$). In this study, we present the effects of the COVID-19 lockdown on atmospheric trace gas concentrations, net ozone production rates (NOPRs) and the dominant chemical regime throughout the troposphere based on three different research aircraft campaigns across Europe. These are the UTOPIHAN (Upper Tropospheric Ozone: Processes Involving HO$_x$ and NO$_x$) campaigns in 2003 and 2004, the HOOVER (HO$_x$ over Europe) campaigns in 2006 and 2007, and the BLUESKY campaign in 2020, the latter performed during the COVID-19 lockdown. We present in situ observations and simulation results from the ECHAM5 (fifth-generation European Centre Hamburg general circulation model, version 5.3.02)/MESSy2 (second-generation Modular Earth Submodel System, version 2.54.0) Atmospheric Chemistry (EMAC), model which allows for scenario calculations with business-as-usual emissions during the BLUESKY campaign, referred to as the “no-lockdown scenario”. We show that the COVID-19 lockdown reduced NO and NO$_2$ mixing ratios in the upper troposphere by around 55 % compared to the no-lockdown scenario due to reduced air traffic. O$_3$ production and loss terms reflected this reduction with a deceleration in O$_3$ cycling due to reduced mixing ratios of NO$_x$, while NOPRs were largely unaffected. We also study the role of methyl peroxyradicals forming HCHO ($^α$CH$_3$O$_2$) to show that the COVID-19 lockdown shifted the chemistry in the upper-troposphere–tropopause region to a NO$_x$-limited regime during BLUESKY. In comparison, we find a volatile organic compound (VOC)-limited regime to be dominant during UTOPIHAN

A versatile, refrigerant- and cryogen-free cryofocusing–thermodesorption unit for preconcentration of traces gases in air

We present a compact and versatile cryofocusing– thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in situ measurements, in situ monitoring and laboratory operation for the analysis of flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. - 80° C) and subsequently desorbed by rapid heating of the adsorptive material (e.g. +200° C). The set-up involves neither the exchange of adsorption tubes nor any further condensation or refocusing steps. No moving parts are used that would require vacuum insulation. This allows for a simple and robust design. Reliable operation is ensured by the Stirling cooler, which neither contains a liquid refrigerant nor requires refilling a cryogen. At the same time, it allows for significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography – mass spectrometry (GC–MS) for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately -80 to +150° C and a substance mixing ratio range of less than 1 ppt (pmol mol$^{-1}$) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of analyte breakthrough during adsorption, repeatability of desorption and analyte residues in blank tests. Examples of application are taken from the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC–MS instruments and by data obtained during a research flight with our in situ aircraft instrument GhOSTMS (Gas chromatograph for the Observation of Tracers-coupled with a Mass Spectrometer)

The European Forest and Agriculture Optimisation Model -- EUFASOM

Land use is a key factor to social wellbeing and has become a major component in political negotiations. This paper describes the mathematical structure of the European Forest and Agricultural Sector Optimization Model. The model represents simultaneously observed resource and technological heterogeneity, global commodity markets, and multiple environmental qualities. Land scarcity and land competition between traditional agriculture, forests, nature reserves, pastures, and bioenergy plantations is explicitly captured. Environmental change, technological progress, and policies can be investigated in parallel. The model is well-suited to estimate competitive economic potentials of land based mitigation, leakage, and synergies and trade-offs between multiple environmental objectives.Land Use Change Optimization, Resource Scarcity, Market Competition, Welfare Maximization, Bottom-up Partial Equilibrium Analysis, Agricultural Externality Mitigation, Forest Dynamics, Global Change Adaptation, Environmental Policy Simulation, Integrated Assessment, Mathematical Programming, GAMS

Bromine from short-lived source gases in the extratropical northern hemispheric upper troposphere and lower stratosphere (UTLS)

We present novel measurements of five short-lived brominated source gases (CH2Br2, CHBr3, CH2ClBr, CHCl2Br and CHClBr2). These rather short-lived gases are an important source of bromine to the stratosphere, where they can lead to depletion of ozone. The measurements have been obtained using an in situ gas chromatography and mass spectrometry (GC–MS) system on board the High Altitude and Long Range Research Aircraft (HALO). The instrument is extremely sensitive due to the use of chemical ionization, allowing detection limits in the lower parts per quadrillion (ppq, 10−15) range. Data from three campaigns using HALO are presented, where the upper troposphere and lower stratosphere (UTLS) of the northern hemispheric mid-to-high latitudes were sampled during winter and during late summer to early fall. We show that an observed decrease with altitude in the stratosphere is consistent with the relative lifetimes of the different compounds. Distributions of the five source gases and total organic bromine just below the tropopause show an increase in mixing ratio with latitude, in particular during polar winter. This increase in mixing ratio is explained by increasing lifetimes at higher latitudes during winter. As the mixing ratios at the extratropical tropopause are generally higher than those derived for the tropical tropopause, extratropical troposphere-to-stratosphere transport will result in elevated levels of organic bromine in comparison to air transported over the tropical tropopause. The observations are compared to model estimates using different emission scenarios. A scenario with emissions mainly confined to low latitudes cannot reproduce the observed latitudinal distributions and will tend to overestimate organic bromine input through the tropical tropopause from CH2Br2 and CHBr3. Consequently, the scenario also overestimates the amount of brominated organic gases in the stratosphere. The two scenarios with the highest overall emissions of CH2Br2 tend to overestimate mixing ratios at the tropical tropopause, but they are in much better agreement with extratropical tropopause mixing ratios. This shows that not only total emissions but also latitudinal distributions in the emissions are of importance. While an increase in tropopause mixing ratios with latitude is reproduced with all emission scenarios during winter, the simulated extratropical tropopause mixing ratios are on average lower than the observations during late summer to fall. We show that a good knowledge of the latitudinal distribution of tropopause mixing ratios and of the fractional contributions of tropical and extratropical air is needed to derive stratospheric inorganic bromine in the lowermost stratosphere from observations. In a sensitivity study we find maximum differences of a factor 2 in inorganic bromine in the lowermost stratosphere from source gas injection derived from observations and model outputs. The discrepancies depend on the emission scenarios and the assumed contributions from different source regions. Using better emission scenarios and reasonable assumptions on fractional contribution from the different source regions, the differences in inorganic bromine from source gas injection between model and observations is usually on the order of 1 ppt or less. We conclude that a good representation of the contributions of different source regions is required in models for a robust assessment of the role of short-lived halogen source gases on ozone depletion in the UTLS