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Journal articleChawner H, Saboya E, Adcock KE, et al., 2024,
Atmospheric oxygen as a tracer for fossil fuel carbon dioxide: a sensitivity study in the UK
, Atmospheric Chemistry and Physics, Vol: 24, Pages: 4231-4252, ISSN: 1680-7316We investigate the use of atmospheric oxygen (O2) and carbon dioxide (CO2) measurements for the estimation of the fossil fuel component of atmospheric CO2 in the UK. Atmospheric potential oxygen (APO) – a tracer that combines O2 and CO2, minimizing the influence of terrestrial biosphere fluxes – is simulated at three sites in the UK, two of which make APO measurements. We present a set of model experiments that estimate the sensitivity of APO simulations to key inputs: fluxes from the ocean, fossil fuel flux magnitude and distribution, the APO baseline, and the exchange ratio of O2 to CO2 fluxes from fossil fuel combustion and the terrestrial biosphere. To estimate the influence of uncertainties in ocean fluxes, we compare three ocean O2 flux estimates from the NEMO–ERSEM, the ECCO–Darwin ocean model, and the Jena CarboScope (JC) APO inversion. The sensitivity of APO to fossil fuel emission magnitudes and to terrestrial biosphere and fossil fuel exchange ratios is investigated through Monte Carlo sampling within literature uncertainty ranges and by comparing different inventory estimates. We focus our model–data analysis on the year 2015 as ocean fluxes are not available for later years. As APO measurements are only available for one UK site at this time, our analysis focuses on the Weybourne station. Model–data comparisons for two additional UK sites (Heathfield and Ridge Hill) in 2021, using ocean flux climatologies, are presented in the Supplement. Of the factors that could potentially compromise simulated APO-derived fossil fuel CO2 (ffCO2) estimates, we find that the ocean O2 flux estimate has the largest overall influence at the three sites in the UK. At times, this influence is comparable in magnitude to the contribution of simulated fossil fuel CO2 to simulated APO. We find that simulations using different ocean fluxes differ from each other substantially. No single model estimate, or a model estimate that assumed zero oce
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Journal articleHuang J, Kasper JC, Larson DE, et al., 2024,
Parker Solar Probe Observations of High Plasma β Solar Wind from the Streamer Belt (vol 265, 47, 2023)
, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, Vol: 271, ISSN: 0067-0049 -
Journal articleMitchell DG, Hill ME, Mccomas DJ, et al., 2024,
Likely Common Coronal Source of Solar Wind and <SUP>3</SUP>He-enriched Energetic Particles: Uncoupled Transport from the Low Corona to 0.2 au
, ASTROPHYSICAL JOURNAL, Vol: 965, ISSN: 0004-637X -
Journal articleEriksson S, Swisdak M, Mallet A, et al., 2024,
Parker Solar Probe Observations of Magnetic Reconnection Exhausts in Quiescent Plasmas near the Sun
, ASTROPHYSICAL JOURNAL, Vol: 965, ISSN: 0004-637X -
Journal articleBowen TA, Bale SD, Chandran BDG, et al., 2024,
Mediation of collisionless turbulent dissipation through cyclotron resonance
, NATURE ASTRONOMY, Vol: 8, Pages: 482-490, ISSN: 2397-3366 -
Journal articleFiedler S, Naik V, O'Connor FM, et al., 2024,
Interactions between atmospheric composition and climate change - progress in understanding and future opportunities from AerChemMIP, PDRMIP, and RFMIP
, GEOSCIENTIFIC MODEL DEVELOPMENT, Vol: 17, Pages: 2387-2417, ISSN: 1991-959X -
Journal articleStephenson P, Galand M, Deca J, et al., 2024,
Cold electrons at a weakly outgassing comet
, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 529, Pages: 2854-2865, ISSN: 0035-8711 -
Journal articleSishtla CP, Pomoell J, Magyar N, et al., 2024,
Validity of using Elsasser variables to study the interaction of compressible solar wind fluctuations with a coronal mass ejection
, ASTRONOMY & ASTROPHYSICS, Vol: 683, ISSN: 0004-6361 -
Journal articleRojo M, Persson M, Sauvaud J-A, et al., 2024,
Electron moments derived from the Mercury Electron Analyzer during the cruise phase of BepiColombo
, ASTRONOMY & ASTROPHYSICS, Vol: 683, ISSN: 0004-6361 -
Conference paperBeth A, Galand M, Modolo R, et al., 2024,
Ionospheric environment of Ganymede during the Galileo flybys
<jats:p>The Galileo spacecraft flew by Ganymede, down to 0.1 RG from the surface for the closest, six times giving us insight into its plasma environment. Its ionosphere, made of ions born from the ionisation of neutrals present in Ganymede&#8217;s exosphere, represents the bulk of the plasma near the moon around closest approach. As it has been revealed by Galileo and Juno, near closest approach the ion population is dominated by low-energy ions from the water ion group (O+, HO+, H2O+) and O2+. However, little is known about their density, spatial distribution, and effect on the surface weathering of the moon itself. Galileo G2 flyby has been extensively studied. Based on a comparison between observations and 3D test-particle simulations, Carnielli et al. (2020a and 2020b) confirmed the ion composition (debated at the time), highlighted the inconsistency between the assumed exospheric densities and the observed ionospheric densities, and derived the contribution of ionospheric ions as an exospheric source. However, other flybys of Ganymede are also available (e.g. G1, G7, G8, G28, and G29) providing in-situ measurements at different phases of Ganymede around Jupiter or jovian magnetospheric conditions at the moon. We extend the original study by Carnielli et al. to other flybys, and compare our modelled ion moments (ion number density, velocity, and energy distribution) with Galileo in-situ data. We discuss our results and contrast them with those obtained for the G2 flyby.&#160;&#160;</jats:p>
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Conference paperLewis Z, Beth A, Galand M, et al., 2024,
Constraining ion transport in the diamagnetic cavity of comet 67P
<jats:p>Comets are small icy bodies originating from the outer solar system that produce an increasingly dense gas coma through sublimation as they approach perihelion. Photoionisation of this gas results in a cometary ionosphere, which interacts with the impinging solar wind, leading to large scale plasma structures. One such structure is the diamagnetic cavity: the magnetic field-free inner region that the solar wind cannot penetrate. This region was encountered many times by the ESA Rosetta mission, which escorted comet 67P/Churyumov-Gerasimenko for a two-year section of its orbit.Within the diamagnetic cavity, high ion bulk velocities have been observed by the Rosetta Plasma Consortium (RPC) instruments. The fast ions are thought to have been accelerated by an ambipolar electric field, but the nature and strength of this field are difficult to determine analytically. Our study therefore aims to model the impact of various electric field profiles on the ionospheric density profile and ion composition. The 1D numerical model we have developed includes three key ion species (H2O+, H3O+, and NH4+) in order to assess the sensitivity of each to the timescale of plasma loss through transport. NH4+ is of particular interest, as it has been previously shown to be the dominant ion species at low cometocentric distances near perihelion. It is only produced through the protonation of NH3, a minor component of the neutral gas, and we show that this makes it particularly sensitive to the electric field.We also compare the simulated electron density to RPC datasets, to find the electric field strength and profile which best recreate the plasma densities measured inside the diamagnetic cavity near perihelion. From this, we also constrain the radial bulk ion speed that is required to explain the observations with the model.</jats:p>
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Journal articleJohnson M, Rivera YJ, Niembro T, et al., 2024,
Helium Abundance Periods Observed by the Solar Probe Cup on Parker Solar Probe: Encounters 1-14
, ASTROPHYSICAL JOURNAL, Vol: 964, ISSN: 0004-637X -
Journal articleKellogg PJ, Mozer FS, Moncuquet M, et al., 2024,
Heating and Acceleration of the Solar Wind by Ion Acoustic Waves-Parker Solar Probe
, ASTROPHYSICAL JOURNAL, Vol: 964, ISSN: 0004-637X -
Journal articleHeinemann SG, Sishtla C, Good S, et al., 2024,
Classification of Enhanced Geoeffectiveness Resulting from High-speed Solar Wind Streams Compressing Slower Interplanetary Coronal Mass Ejections
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 963, ISSN: 2041-8205 -
Journal articleCoburn JT, Verscharen D, Owen CJ, et al., 2024,
The Regulation of the Solar Wind Electron Heat Flux by Wave-Particle Interactions
, ASTROPHYSICAL JOURNAL, Vol: 964, ISSN: 0004-637X -
Journal articleLiu YD, Zhu B, Ran H, et al., 2024,
Direct In Situ Measurements of a Fast Coronal Mass Ejection and Associated Structures in the Corona
, ASTROPHYSICAL JOURNAL, Vol: 963, ISSN: 0004-637X -
Journal articleKuhlbrodt T, Swaminathan R, Ceppi P, et al., 2024,
A glimpse into the future: the 2023 ocean temperature and sea ice extremes in the context of longer-term climate change
, Bulletin of the American Meteorological Society, Vol: 105, Pages: E474-E485, ISSN: 0003-0007In the year 2023, we have seen extraordinary extrema in high sea surface temperature (SST) in the North Atlantic and in low sea ice extent in the Southern Ocean, outside the 4σ envelope of the 1982–2011 daily time series. Earth’s net global energy imbalance (12 months up to September 2023) amounts to +1.9 W m−2 as part of a remarkably large upward trend, ensuring further heating of the ocean. However, the regional radiation budget over the North Atlantic does not show signs of a suggested significant step increase from less negative aerosol forcing since 2020. While the temperature in the top 100 m of the global ocean has been rising in all basins since about 1980, specifically the Atlantic basin has continued to further heat up since 2016, potentially contributing to the extreme SST. Similarly, salinity in the top 100 m of the ocean has increased in recent years specifically in the Atlantic basin, and in addition in about 2015 a substantial negative trend for sea ice extent in the Southern Ocean began. Analyzing climate and Earth system model simulations of the future, we find that the extreme SST in the North Atlantic and the extreme in Southern Ocean sea ice extent in 2023 lie at the fringe of the expected mean climate change for a global surface-air temperature warming level (GWL) of 1.5°C, and closer to the average at a 3.0°C GWL. Understanding the regional and global drivers of these extremes is indispensable for assessing frequency and impacts of similar events in the coming years.
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Journal articleGrimmich N, Prencipe F, Turner DL, et al., 2024,
Multi Satellite Observation of a Foreshock Bubble Causing an Extreme Magnetopause Expansion
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 129, ISSN: 2169-9380 -
Journal articleFeingold G, Ghate VP, Russell LM, et al., 2024,
Physical science research needed to evaluate the viability and risks of marine cloud brightening
, Science Advances, Vol: 10, ISSN: 2375-2548Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science perspective, the consensus of a broad international group of scientists is that the viability of MCB will ultimately depend on whether observations and models can robustly assess the scale-up of local-to-global brightening in today’s climate and identify strategies that will ensure an equitable geographical distribution of the benefits and risks associated with projected regional changes in temperature and precipitation. To address the physical science knowledge gaps required to assess the societal implications of MCB, we propose a substantial and targeted program of research—field and laboratory experiments, monitoring, and numerical modeling across a range of scales.
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Journal articleMatteini L, Tenerani A, Landi S, et al., 2024,
Alfvénic fluctuations in the expanding solar wind: Formation and radial evolution of spherical polarization
, PHYSICS OF PLASMAS, Vol: 31, ISSN: 1070-664X -
Journal articleMostafavi P, Allen RC, Jagarlamudi VK, et al., 2024,
Parker Solar Probe observations of collisional effects on thermalizing the young solar wind
, ASTRONOMY & ASTROPHYSICS, Vol: 682, ISSN: 0004-6361 -
Journal articleTrotta D, Larosa A, Nicolaou G, et al., 2024,
Properties of an Interplanetary Shock Observed at 0.07 and 0.7 au by Parker Solar Probe and Solar Orbiter
, The Astrophysical Journal, Vol: 962, Pages: 147-147, ISSN: 0004-637X<jats:title>Abstract</jats:title> <jats:p>The Parker Solar Probe (PSP) and Solar Orbiter (SolO) missions opened a new observational window in the inner heliosphere, which is finally accessible to direct measurements. On 2022 September 5, a coronal mass ejection (CME)-driven interplanetary (IP) shock was observed as close as 0.07 au by PSP. The CME then reached SolO, which was radially well-aligned at 0.7 au, thus providing us with the opportunity to study the shock properties at different heliocentric distances. We characterize the shock, investigate its typical parameters, and compare its small-scale features at both locations. Using the PSP observations, we investigate how magnetic switchbacks and ion cyclotron waves are processed upon shock crossing. We find that switchbacks preserve their V–B correlation while compressed upon the shock passage, and that the signature of ion cyclotron waves disappears downstream of the shock. By contrast, the SolO observations reveal a very structured shock transition, with a population of shock-accelerated protons of up to about 2 MeV, showing irregularities in the shock downstream, which we correlate with solar wind structures propagating across the shock. At SolO, we also report the presence of low-energy (∼100 eV) electrons scattering due to upstream shocklets. This study elucidates how the local features of IP shocks and their environments can be very different as they propagate through the heliosphere.</jats:p>
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Journal articleQi Y, Ergun R, Pathak N, et al., 2024,
Investigation of a Magnetic Reconnection Event with Extraordinarily High Particle Energization in Magnetotail Turbulence
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 962, ISSN: 2041-8205 -
Journal articleLaker R, Horbury TS, O'Brien H, et al., 2024,
Using Solar Orbiter as an Upstream Solar Wind Monitor for Real Time Space Weather Predictions
, SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS, Vol: 22 -
Journal articleJones GH, Snodgrass C, Tubiana C, et al., 2024,
The Comet Interceptor mission
, Space Science Reviews, Vol: 220, ISSN: 0038-6308Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms-1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as
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Journal articleGershman DJ, Fuselier SA, Cohen IJ, et al., 2024,
Magnetic Reconnection at Planetary Bodies and Astrospheres
, SPACE SCIENCE REVIEWS, Vol: 220, ISSN: 0038-6308 -
Journal articleLouarn P, Fedorov A, Prech L, et al., 2024,
Skewness and kurtosis of solar wind proton distribution functions: The normal inverse-Gaussian model and its implications
, ASTRONOMY & ASTROPHYSICS, Vol: 682, ISSN: 0004-6361 -
Journal articleWells CD, Kasoar M, Ezzati M, et al., 2024,
Significant human health co-benefits of mitigating African emissions
, Atmospheric Chemistry and Physics, Vol: 24, Pages: 1025-1039, ISSN: 1680-7316Future African aerosol emissions, and therefore air pollution levels and health outcomes, are uncertain and understudied. Understanding the future health impacts of pollutant emissions from this region is crucial. Here, this research gap is addressed by studying the range in the future health impacts of aerosol emissions from Africa in the Shared Socioeconomic Pathway (SSP) scenarios, using the UK Earth System Model version 1 (UKESM1), along with human health concentration-response functions. The effects of Africa following a high-pollution aerosol pathway are studied relative to a low-pollution control, with experiments varying aerosol emissions from industry and biomass burning. Using present-day demographics, annual deaths within Africa attributable to ambient particulate matter are estimated to be lower by 150 000 (5th-95th confidence interval of 67 000-234 000) under stronger African aerosol mitigation by 2090, while those attributable to O3 are lower by 15 000 (5th-95th confidence interval of 9000-21 000). The particulate matter health benefits are realised predominantly within Africa, with the O3-driven benefits being more widespread - though still concentrated in Africa - due to the longer atmospheric lifetime of O3. These results demonstrate the important health co-benefits from future emission mitigation in Africa.
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Journal articleChen L, Ma B, Wu D, et al., 2024,
Weak Solar Radio Bursts from the Solar Wind Acceleration Region Observed by the Parker Solar Probe and Its Probable Emission Mechanism
, ASTROPHYSICAL JOURNAL, Vol: 961, ISSN: 0004-637X -
Journal articleWilliams RG, Meijers AJS, Roussenov VM, et al., 2024,
Asymmetries in the Southern Ocean contribution to global heat and carbon uptake
, Nature Climate Change, ISSN: 1758-678XThe Southern Ocean provides dominant contributions to global ocean heat and carbon uptake, which is widely interpreted as resulting from its unique upwelling and circulation. Here we show a large asymmetry in these contributions, with the Southern Ocean accounting for 83 ± 33% of global heat uptake versus 43 ± 3% of global ocean carbon uptake over the historical period in state-of-the-art climate models. Using single radiative forcing experiments, we demonstrate that this historical asymmetry is due to suppressed heat uptake by northern oceans from enhanced aerosol forcing. In future projections, such as SSP2-4.5 where greenhouse gases increasingly dominate radiative forcing, the Southern Ocean contributions to global heat and carbon uptake become more comparable, 52 ± 5% and 47 ± 4%, respectively. Hence, the past is not a reliable indicator of the future, with the northern oceans becoming important for heat uptake while the Southern Ocean remains important for both heat and carbon uptake.
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