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Journal articleSnodgrass C, Epifani EM, Tubiana C, et al., 2026,
Considerations on the process of target selection for the Comet Interceptor mission
, Icarus, Vol: 447, ISSN: 0019-1035Comet Interceptor is an ESA science mission with payload contributions from ESA Member States and with an international participation by JAXA. It is the first mission that is being designed, built, and potentially launched before its target is known. This approach will enable the spacecraft to perform the first mission to a Long Period Comet from the Oort Cloud, as these comets have fleeting visits to the inner Solar System lasting only months to years from first discovery, too short for the usual process of mission development to be followed. In this paper we describe a number of factors that need to be considered in selecting a target for the mission, including scientific, orbital, spacecraft and instrument constraints, and discussion of different prioritisation strategies. We find that, in the case where we have a choice of targets, our decisions will mostly be driven by orbital information, which we will have relatively early on, with information on the activity level of the comet an important but secondary consideration. As cometary activity levels are notoriously hard to predict based on early observations alone, this prioritisation / decision approach based more on orbits gives us confidence that a good comet that is compatible with the spacecraft constraints will be selectable with sufficient warning time to allow the mission to intercept it.
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Journal articleFargette N, Eastwood JP, Phan TD, et al., 2026,
Fluid and Kinetic Properties of the Near-Sun Heliospheric Current Sheet
, The Astrophysical Journal, Vol: 997, Pages: 174-174, ISSN: 0004-637X<jats:title>Abstract</jats:title> <jats:p> The heliospheric current sheet (HCS) is an important large-scale structure of the heliosphere, and, for the first time, the Parker Solar Probe (PSP) mission enables us to study its properties statistically, close to the Sun. We visually identify the 39 HCS crossings measured by PSP below 50 <jats:italic>R</jats:italic> <jats:sub>⊙</jats:sub> during encounters 6–21, and investigate the occurrence and properties of magnetic reconnection, the behavior of the spectral properties of the turbulent energy cascade, and the occurrence of kinetic instabilities at the HCS. We find that 82% of the HCS crossings present signatures of reconnection jets, showing that the HCS is continuously reconnecting close to the Sun. The proportion of inward and outward jets depends on heliocentric distance, and the main HCS reconnection X-line has a higher probability of being located close to the Alfvén surface. We also observe a radial asymmetry in jet acceleration, where inward jets do not reach the local Alfvén speed, contrary to outward jets. We find that turbulence levels are enhanced in the ion kinetic range, consistent with the triggering of an inverse cascade by magnetic reconnection. Finally, we highlight the ubiquity of magnetic hole trains in the high- <jats:italic>β</jats:italic> environment of the HCS, showing that the mirror mode instability plays a key role in regulating the ion temperature anisotropy in HCS reconnection. Our findings shed new light on the properties of magnetic reconnection in the high- <jats:italic>β</jats:italic> plasma environment of the HCS, its interplay with the turbulent cascade, and the role of the mirror mode instability. </jats
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Journal articleBrindley H, Di Natale G, Murray J, 2026,
Achieving consistency between in-situ and remotely sensed optical and microphysical properties of Arctic cirrus: the impact of far-infrared radiances
, Atmospheric Chemistry and Physics (ACP), ISSN: 1680-7316 -
Journal articleDai AZ, Gregory J, Ceppi P, 2026,
Understanding the Climate Response to Different Vertical Patterns of Radiative Forcing
, Geophysical Research Letters, Vol: 53, ISSN: 0094-8276The dependence of climate response on the vertical structure of radiative forcing is studied using a set of idealized experiments, with horizontally uniform and vertically confined forcings. We find for a given effective forcing magnitude, higher-altitude forcing causes a smaller global warming, owing to more negative cloud feedback. We present novel evidence relating this altitude dependence to sea-surface temperature patterns and tropospheric static stability. The imposed instantaneous forcings are horizontally uniform, but higher-altitude forcings more effectively suppress convection in the tropical warm pool, producing a more positive effective (adjusted) surface forcing in that region. This gives rise, during the subsequent climate change, to greater warming contrast between the warm pool and rest of the globe, and hence to increase in low cloud amount. Our results show that to achieve accurate climate projections under anthropogenic forcings, it is important to correctly represent the vertical structures of the applied radiative forcing.
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Journal articleEastwood JP, Phan TD, Drake JF, et al., 2026,
Magnetic reconnection energy fluxes in the near-sun heliospheric current sheet as observed by parker solar probe
, The Astrophysical Journal, Vol: 996, ISSN: 0004-637XThe Heliospheric Current Sheet (HCS) is a fundamental feature of the heliosphere, playing a key role organizing the magnetic structure of the solar wind. In contrast to observations previously made through the majority of the heliosphere, Parker Solar Probe has recently revealed that the HCS is typically reconnecting in the inner heliosphere. This provides a new opportunity to study reconnection dynamics in large-scale current sheets and assess how this is different from smaller systems such as Earth’s magnetosphere. We use Parker data to explore HCS reconnection energy partition in two case studies from Encounter 07 and 08. In both cases, we find that in the exhaust, the proton enthalpy flux density is largest, with significant contributions from the proton kinetic energy flux density and electron enthalpy flux density. In contrast, the exhaust Poynting flux density is small in both events. The size and stability of the HCS allows for a control volume analysis to be performed, thus allowing us to estimate changes in energy flux during reconnection. This analysis shows that energy is primarily transferred from the magnetic field to the protons, manifested as the kinetic energy of the exhaust and proton heating. Although the exhaust electron enthalpy flux density is significant, the incoming and outgoing electron enthalpy fluxes are found to be similar, and there is minimal electron heating. The small contribution of the Poynting flux in the outflow may be an important feature of HCS reconnection, with implications for reconnection in large-scale solar and astrophysical current sheets more generally.
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Journal articleBerland GD, Hill ME, Kouloumvakos A, et al., 2026,
Parker Solar Probe Observations of Suprathermal and Energetic Particles during Orbits 18 and 19
, ASTROPHYSICAL JOURNAL, Vol: 996, ISSN: 0004-637X -
Journal articleBadman ST, Fargette N, Matteini L, et al., 2026,
Properties of Magnetic Switchbacks in the Near-Sun Solar Wind
, Space Science Reviews, Vol: 222, ISSN: 0038-6308<jats:title>Abstract</jats:title> <jats:p> Magnetic switchbacks are fluctuations in the solar wind in which the interplanetary magnetic field sharply deflects away from its background direction so as to create folds in magnetic field lines while remaining of roughly constant magnitude. The magnetic field and velocity fluctuations are extremely well correlated in a way corresponding to Alfvénic fluctuations propagating away from the Sun. For a background field which is nearly radial this causes an outwardly propagating jet to form. Switchbacks and their characteristic velocity jets have recently been observed to be nearly ubiquitous by Parker Solar Probe with <jats:italic>in situ</jats:italic> measurements in the inner heliosphere within 0.3 AU. Their prevalence, substantial energy content, and potentially fundamental role in the dynamics of the outer corona and solar wind motivate the significant research efforts into their understanding. Here we review the <jats:italic>in situ</jats:italic> measurements of these structures (primarily by Parker Solar Probe). We discuss how they are identified and measured, and present an overview of the primary observational properties of these structures, both in terms of individual switchbacks and their collective arrangement into “patches”. We identify both properties for which there is a strong consensus and those that have limited or qualified support and require further investigation. We identify and collate several open questions and recommendations for future studies. </jats:p>
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Journal articleCohen CMS, Alterman BL, Baker DN, et al., 2026,
IMAP's Role in Understanding Particle Injection and Energization Throughout the Heliosphere.
, Space Sci Rev, Vol: 222, ISSN: 0038-6308The payload of the Interstellar Mapping and Acceleration Probe (IMAP) includes sophisticated in situ instruments to measure solar wind plasma and magnetic fields, suprathermal and energetic particles at 1 au as well as unprecedented remote sensing instruments to observe the energetic neutral atoms (ENAs) in the outer heliosphere and the ultraviolet glow of the interstellar neutral H interacting with the three-dimensional solar wind. This unique combination of sensors on a single platform allows connections to be made between the inner and outer heliosphere to an extent never before possible. This article focuses on the scientific theme of connecting the physics of particle acceleration and transport throughout the heliosphere. Such studies enabled by IMAP are organized into three broad categories: i) fundamental particle acceleration and transport processes, ii) heliospheric variability that affects those processes, and iii) inner heliospheric science.
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Journal articleBadman ST, Stevens ML, Bale SD, et al., 2025,
Multispacecraft Measurements of the Evolving Geometry of the Solar Alfvén Surface over Half a Solar Cycle
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 995, ISSN: 2041-8205 -
Journal articleBowen TA, Ervin T, Mallet A, et al., 2025,
Stochastic Heating in the Sub-Alfvénic Solar Wind
, Physical Review Letters, Vol: 135, ISSN: 0031-9007Collisionless dissipation of turbulence is important for heating plasmas in astrophysical, space physics, and laboratory environments, controlling energy, momentum, and particle transport. We analyze Parker Solar Probe observations to understand the collisionless heating of the sub-Alfvénic solar wind, which is connected to the solar corona. Our results show that linear resonant heating through parallel-propagating cyclotron waves cannot account for turbulent dissipation in the sub-Alfvénic region, which observations suggest may dissipate turbulence at distances further from the Sun. Instead, we find that stochastic heating can account for the observed ion energization; however, because the dominant contributions arise from infrequent, large-amplitude events, turbulent intermittency must be explicitly incorporated. These observations directly connect stochastic heating via breaking of the proton magnetic moment with the intermittent and inhomogeneous heating of turbulence reported in many previous studies. Our identification of stochastic heating as a dynamic mechanism responsible for intermittent heating of the solar wind has significant implications for turbulent dissipation in the lower corona, other astrophysical environments, and laboratory plasmas.
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Journal articleSharan S, Pais A, Amit H, et al., 2025,
Fluid flow at the top of Jupiter's dynamo region
, Journal of Geophysical Research: Planets, ISSN: 2169-9097The magnetic main field (MF) and secular variation (SV) models for Jupiter can be used to gain insights about the internal dynamo and the flow that drives the field. We use two such models computed from Juno observations up to spherical harmonic degrees 16 and 8 for the MF and SV, respectively. We solve the radial magnetic induction equation in the frozen-flux approximation, at the dynamo region outer boundary assuming zero radial velocity for four large-scale physical flow assumptions- unconstrained, toroidal, tangentially geostrophic and columnar. We find flows with root mean square velocity varying between 100 and 400 km/yr (0.3-1.3 cm/s) when the dynamo region spherical boundary is taken at 0.83 Jupiter radius. Equatorially symmetric, toroidal and non-zonal velocity components are larger than the anti-symmetric, poloidal and zonal components, respectively, for almost all cases. Toroidal and tangentially geostrophic flows display similar velocity values and patterns, despite relying on different physical assumptions. The four inverted solutions indicate that the Jovian interior has dominant eastward flows nearthe Great Blue Spot, in agreement with previous studies. In addition, our more complex flow models shed light on some new features such as a large non-zonal component,meridional flows in the southern hemisphere and field-aligned flows in the north. Finally, our unconstrained flow solution suggests upwelling near the south pole, consistent withn thermal wind theory.
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Journal articleRiddell-Young B, Michel SE, Lan X, et al., 2025,
Microbial driver of 2006-2023 CH4 growth indicated by trends in atmospheric δD-CH4 and δ13C-CH4.
, Proc Natl Acad Sci U S A, Vol: 122Methane (CH4) is the second most important greenhouse gas and has been rising following a brief period of stabilization from 1999 to 2006. Determining the cause of this rise is critical for reducing emissions and predicting future climate sensitivity. The carbon and hydrogen stable isotopic composition of atmospheric CH4 is controlled by variability in isotopically distinguishable emission categories and fractionating sink processes. While most studies using atmospheric δ13C-CH4 data suggest a dominantly microbial source for recent CH4 growth, this understanding is not uniform, and uncertainties remain [S. Schwietzke et al., Nature 538, 88-91 (2016), S. Basu et al., Atmos. Chem. Phys. 22, 15351-15377 (2022), J. Thanwerdas, M. Saunois, A. Berchet, I. Pison, P. Bousquet, Atmos. Chem. Phys. 24, 2129-2167 (2024)]. Here, we present a harmonized global measurement record of atmospheric δD-CH4 and estimate emissions from 1999 to 2022 with global isotope mass balance calculations using both carbon and hydrogen isotopic ratios. We conduct thorough uncertainty analyses to separate absolute magnitude and emission trend uncertainties and find with high confidence that trends in δ13C-CH4 and δD-CH4 observations are both consistent with an entirely microbial emission driver of the post-2006 CH4 rise, while fossil fuel emissions have remained relatively stable.
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Journal articleNakamura R, Dudok de wit T, Jones GH, et al., 2025,
Establishing a European Heliophysics Community (EHC)
, Annales Geophysicae, Vol: 43, Pages: 855-879, ISSN: 0992-7689Europe hosts a large and highly active community of scientists working in the broad domain of Heliophysics. This broad discipline addresses plasmas in the regions of space and atmosphere influenced by the Sun and solar wind. However, this community has historically been fragmented, both geographically and thematically, which has limited the potential for strategic coordination, collaboration, and growth. This has recently prompted a grass-roots community-building effort to foster communication and interactions within the European Heliophysics Community (EHC). This white paper outlines the motivation, priorities, and initial steps towards establishing the EHC, and presents a vision for the future of Heliophysics in Europe. As a crucial first step of this endeavour, a dedicated EHC website is now available: https://www.heliophysics.eu/ (last access: November 2025).
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Journal articleWong HL, Palacios R, Gryspeerdt E, 2025,
rojak: A Python library and tool for aviation turbulence diagnostics
, Journal of Open Source Software, Vol: 10, ISSN: 2475-9066Aviation turbulence is atmospheric turbulence occurring at length scales large enough (ap proximately 100m to 1km) to affect an aircraft (Sharman, 2016). According to the National Transport Safety Board (NTSB), turbulence experienced whilst onboard an aircraft was theleading cause of accidents from 2009 to 2018 (NTSB, 2021). Clear air turbulence (CAT) is a form of aviation turbulence which cannot be detected by the onboard weather radar. Thus, pilots are unable to preemptively avoid such regions. In order to mitigate this safety risk, CAT diagnostics are used to forecast turbulent regions such that pilots are able to tactically avoidthem.rojak is a parallelised Python library and command-line tool for using meteorological data to forecast CAT and evaluating the effectiveness of CAT diagnostics against turbulence observations. Currently, it supports,1. Computing turbulence diagnostics on meteorological data from the European Centrefor Medium-Range Weather Forecasts’s (ECMWF) ERA5 reanalysis on pressure levels(Hersbach, 2023). Moreover, it is easily extendable through a software update to supportother types of meteorological data.2. Retrieving and processing turbulence observations from Aircraft Meteorological DataRelay (AMDAR) data archived at the National Oceanic and Atmospheric Administration(NOAA)(NCEP Meteorological Assimilation Data Ingest System (MADIS), 2024) andAMDAR data collected via the Met Office MetDB system (Met Office, 2008)3. Computing 27 different turbulence diagnostics, such as the three-dimensional fronto genesis equation (Bluestein, 1993), turbulence index 1 and 2 (Ellrod & Knapp, 1992),negative vorticity advection (Sharman et al., 2006), and Brown’s Richardson tendencyequation (Brown, 1973).4. Converting turbulence diagnostic values into the eddy dissipation rate (EDR) — the International Civil Aviation Organization’s (ICAO) official metric for reporting turbulence (Meteorological Service for International Air Navigati
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Journal articleWarwick L, Oetjen H, Murray J, et al., 2025,
In situ measurements of ice and snow emissivity in the far-infrared
, Earth and Space Science, Vol: 12, ISSN: 2333-5084This paper describes the first field deployment of the Far INfrarEd Spectrometer for Surface Emissivity far-infrared Fourier transform spectrometer to an Arctic environment and shows retrievals of the emissivity of ice and snow in the wavenumber range 400–1,200 cm−1 at viewing angles of 35° and 50°. The retrieved ice emissivity shows a variation of 0.05 between the peak value at around 950 cm−1 and the minimum value at around 750 cm−1. The emissivity is also between 0.01 and 0.02 lower for the higher viewing angle. The emissivity of snow is higher and shows less variation with both viewing angle and wavenumber but it is 0.01 less than one below 900 cm−1. This has implications for remote sensing and climate modeling in this wavenumber range as it implies that both the spectral and angular variation of emissivity must be taken into account. The retrieved ice emissivity agrees well with the emissivity modeled using Fresnel equations. The retrieved snow emissivity agrees well with modeled snow emissivity but further independent measurements of the snow physical properties are needed to test the performance of the model in the far infrared.
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Journal articleStedman M, Hunt SE, De Vis P, et al., 2025,
Impact of characterization on cross-calibration performance for multispectral sensors with SI-traceable satellite mission TRUTHS
, IEEE Transactions on Geoscience and Remote Sensing, Vol: 63, ISSN: 0196-2892A new generation of satellites designed for low-uncertainty, SI-traceable measurements—termed“SITSats”—marks a major advancement in Earth observation (EO) capability. These missions aim to enhance the performance and interoperability of the EO “system of systems.” Among them, the ESA Earth Watch Traceable Radiometry Underpinning Terrestrial- and Helio-Studies (TRUTHS) mission is designedto serve as a “gold-standard” radiometric reference for cross-calibrating EO sensors in the solar reflective domain. In this work, uncertainties in cross-calibration comparisons arising from sensor characterization and design are investigated. A processing chain to prepare collocated data for uncertainty-quantified comparison is presented. This includes steps to perform spectral band adjustment and spatial resampling. Using the TRUTHS hyperspectral imaging spectrometer (HIS)as the reference and Sentinel-2 multispectral imager (MSI) as the target, a simulation study based on high-resolution imagery assesses achievable comparison performance. A subset of uncertainty effects driven by sensor characterization is propagated through the spectral and spatial processing using a Monte Carlo approach. Sentinel-2 data are assumed at 10-m resolution, which is most sensitive to the errors considered. The results highlight the importance of sensor characterization, particularly inherent in-flight wavelength knowledge for target sensors, in such comparisons. Results from the simulation analysis give uncertainty estimates (k = 1) of 0.31% (blue), 0.50% (green), and 0.23% (red) for the combined error effectsarising from sensor characterization and geolocation uncertainty for comparisons over the Libya-4 desert pseudo-invariant calibration sites (PICS) using an instantaneous 205-m square comparison region. Results for more heterogeneous scenes, such as rainforest, still achieve uncertainties of 0.6%–1.2% for the red–green–blue (RGB) ban
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Journal articleBreul P, Ceppi P, Simpson IR, et al., 2025,
Seasonal and regional jet stream changes and drivers
, NATURE REVIEWS EARTH & ENVIRONMENT, Vol: 6, Pages: 824-842 -
Journal articleFarahat A, Oliveros JCM, Bale SD, 2025,
Simulation and Design of a CubeSat-Compatible X-Ray Photovoltaic Payload Using Timepix3 Sensors
, AEROSPACE, Vol: 12 -
Journal articleKang H, Choi Y, 2025,
Estimating Tropical Upper‐Level Cloud Feedback Based on Radiative‐Convective Equilibrium Framework
, Geophysical Research Letters, Vol: 52, ISSN: 0094-8276<jats:title>Abstract</jats:title> <jats:p> Tropical upper‐level cloud (TUC) feedback remains highly uncertain because TUC fraction and its radiative effect respond in complex ways to sea surface temperature (SST) warming. Using a radiative–convective equilibrium (RCE) model, we isolate the radiative impact of TUC changes by adjusting the relative occurrence of clouds and water vapor across the tropics. The resulting TUC feedback parameter, estimated from RCE experiments with observationally constrained versus CMIP6‐derived TUC fractions, is more negative for observational inputs (−1.66 to −1.24 W m <jats:sup>−2</jats:sup> K <jats:sup>−1</jats:sup> ) and spans a much broader range for CMIP6 inputs (−1.34 to +1.78 W m <jats:sup>−2</jats:sup> K <jats:sup>−1</jats:sup> ). The stronger negative feedback with observational inputs likely reflects a larger reduction in TUCs with SST warming. In contrast, CMIP6‐based parameters indicate weaker radiative effects of SST‐driven TUC reductions, suggesting that climate models may underestimate this negative feedback. </jats:p>
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Journal articleLivadiotis G, Cuesta ME, Khoo LY, et al., 2025,
Entropy transfer from solar radio bursts to energetic particles
, SCIENCE ADVANCES, Vol: 11 -
Journal articleWilliams RG, Goodwin P, Ceppi P, et al., 2025,
A normalised framework for the Zero Emissions Commitment
, BIOGEOSCIENCES, Vol: 22, Pages: 7167-7186, ISSN: 1726-4170 -
Journal articleLee CO, Christian ER, Sandoval L, et al., 2025,
Space Weather Science to Enhance Forecasting with the NASA IMAP Active Link for Real-Time (I-ALiRT) System
, SPACE SCIENCE REVIEWS, Vol: 221, ISSN: 0038-6308- Cite
- Citations: 1
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Journal articleDriver OGA, Stettler MEJ, Gryspeerdt E, 2025,
The ice supersaturation biases limiting contrail modelling are structured around extratropical depressions
, Atmospheric Chemistry and Physics (ACP), Vol: 25, Pages: 16411-16433, ISSN: 1680-7316Contrails are ice clouds formed along aircraft flight tracks, responsible for much of aviation's climate warming impact. Ice-supersaturated regions (ISSRs) provide conditions where contrail ice crystals can persist, but meteorological models often mispredict their occurrence, limiting contrail modelling. This deficiency is often treated by applying local humidity corrections. However, model performance is also affected by synoptic conditions (such as extratropical depressions).Here, composites of ERA5 reanalysis data around North Atlantic extratropical depressions enable a link between their structure and ISSR modelling. ISSRs are structured by these systems: at flight levels, ISSRs occur less frequently in the dry intrusion – descending upper-tropospheric air – than above warm conveyors – where air is lifted. Both ERA5 reanalysis and in situ aircraft observations show this contrast, demonstrating that the model reproduces the fundamental relationship. Individual-ISSR modelling performance (quantified using interpretable metrics) is also structured. Of the rare ISSRs diagnosed in the location associated with the dry intrusion, fewer are confirmed by in situ observations (20 %–25 % precision drop compared to the warm conveyor) and fewer of those observed were diagnosed (13 %–19 % recall drop). Scaling humidity beyond the occurrence rate bias dramatically increases the recall at low precision cost, demonstrating the potential value of scaling approaches designed with different intentions. However, the failure of scaling to improve precision, or the performance in the dry intrusion, implies that there is a need to account for the synoptic weather situation and structure in order to improve ISSR forecasts in support of mitigating aviation's climate impact.
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Journal articlePugsley G, Gryspeerdt E, Nair V, 2025,
Cloud fraction response to aerosol driven by nighttime processes
, Proceedings of the National Academy of Sciences of USA, ISSN: 0027-8424 -
Journal articleMandikas VG, Voulgarakis A, 2025,
High-Resolution Numerical Scheme for Simulating Wildland Fire Spread
, MATHEMATICS, Vol: 13 -
Journal articleYufei Y, Timothy H, Domenico T, et al., 2025,
Ion-scale solitary structures in the solar wind observed by Solar Orbiter and Parker Solar Probe
, Astrophysical Journal Letters, Vol: 994, ISSN: 2041-8205We investigate a class of ion-scale magnetic solitary structures in the solar wind, characterized by distinct magnetic field enhancements and bipolar rotations over spatial scales of several proton inertial lengths. These structures are revisited using high-resolution data from the Solar Orbiter and Parker Solar Probe missions. Using a machine learning-based method, we identified nearly a thousand such structures, providing new insights into their evolution and physical properties. Statistical analysis shows that these structures are more abundant closer to the Sun, with occurrence rates peaking around 30 - 40 Rsun and decreasing farther out. High-cadence measurements reveal that these structures are predominantly found in low-beta (beta <1) environments, with consistent fluctuations in density, velocity, and magnetic field. Magnetic field enhancements are often accompanied by plasma density drops, which, under near pressure balance, limit field increases. This leads to small fractional field enhancements near the Sun (approximately 0.01 at 20 Rsun), making detection challenging. Magnetic field variance analysis indicates that these structures are primarily oblique to the local magnetic field. Alfvénic velocity-magnetic field correlations suggest that most of these structures, unlike most near-Sun solar wind fluctuations, exhibit sunward-directed Alfvenic polarization in the plasma frame. We compare these findings with previous studies, discussing possible generation mechanisms and their implications for the turbulent cascade in the near-Sun Alfvénic solar wind. While these structures might be Alfvénic solitons, vortices, or flux ropes, we refrain from a definitive classification pending further evidence. Further high-resolution observations and simulations are needed to fully understand their origins and impacts.
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Journal articleLi J-H, Khotyaintsev YV, Graham DB, et al., 2025,
Solar Orbiter Observations of a Self-Consistent Ion-Scale Magnetic Hole at 0.9AU
, GEOPHYSICAL RESEARCH LETTERS, Vol: 52, ISSN: 0094-8276 -
Journal articleDasgupta B, Menoud M, van der Veen C, et al., 2025,
Harmonisation of methane isotope ratio measurements from different laboratories using atmospheric samples
, Atmospheric Measurement Techniques, Vol: 18, Pages: 6591-6607, ISSN: 1867-1381Establishing interlaboratory compatibility among measurements of stable isotope ratios of atmospheric methane (δ<sup>13</sup>C-CH<inf>4</inf> and δD-CH<inf>4</inf>) is challenging. Significant offsets are common because laboratories have different ties to the VPDB or SMOW-SLAP scales. Umezawa et al. (2018) surveyed numerous comparison efforts for CH<inf>4</inf> isotope measurements conducted from 2003 to 2017 and found scale offsets of up to 0.5 ‰ for δ<sup>13</sup>C-CH<inf>4</inf> and 13 ‰ for δD-CH<inf>4</inf> between laboratories. This exceeds the World Meteorological Organisation Global Atmospheric Watch (WMO-GAW) network compatibility targets of 0.02 ‰ and 1 ‰ considerably. We employ a method to establish scale offsets between laboratories using their reported CH<inf>4</inf> isotope measurements on atmospheric samples. Our study includes data from eight laboratories with experience in high-precision isotope ratio mass spectrometry (IRMS) measurements for atmospheric CH<inf>4</inf>. The analysis relies exclusively on routine atmospheric measurements conducted by these laboratories at high-latitude stations in the Northern and Southern Hemispheres, where we assume each measurement represents sufficiently well-mixed air at the latitude for direct comparison. We use two methodologies for interlaboratory comparisons: (I) assessing differences between time-adjacent observation data and (II) smoothing the observed data using polynomial and harmonic functions before comparison. The results of both methods are consistent, and with a few exceptions, the overall average offsets between laboratories align well with those reported by Umezawa et al. (2018). This indicates that interlaboratory offsets remain robust over multi-year periods. The evaluation of routine measurements allows us to calculate the interlaborator
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Journal articleMuro GD, Cohen CMS, Xu Z, et al., 2025,
Energy-Dependent SEP Fe/O Abundances During the May 2024 Superstorm
, SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS, Vol: 23
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