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Journal articleBandyopadhyay R, Meyer CM, Matthaeus WH, et al., 2023,
Estimates of Proton and Electron Heating Rates Extended to the Near-Sun Environment
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 955, ISSN: 2041-8205 -
Journal articlePaouris E, Vourlidas A, Kouloumvakos A, et al., 2023,
The Space Weather Context of the First Extreme Event of Solar Cycle 25, on 2022 September 5
, ASTROPHYSICAL JOURNAL, Vol: 956, ISSN: 0004-637X -
Journal articleZhou Y-J, He F, Zhang X-X, et al., 2023,
A radial standing Pc5-6 wave and its energy coupling with field line resonance within the dusk-sector magnetosphere
, JGR: Space Physics, Vol: 128, ISSN: 2169-9402Global ultra-low frequency (ULF) oscillations are believed to play a significant role in the mass, energy, and momentum transport within the Earth's magnetosphere. In this letter, we observe a ∼1.2 mHz radial standing wave in the dusk-sector magnetosphere accompanied by the field line resonance (FLR) on 16 July 2017. The frequency estimation from the simple box model also confirms the radial standing wave. The essential characteristics of FLR are concurrently identified at the dusk-sector magnetosphere and the conjugated ground location. Further, the radial standing wave dissipates energy into upper atmosphere to enhance the local aurora by coupling itself to the FLR. The magnetospheric dominant 1.2/1.1 mHz ULF waves plausibly correspond well with the discrete ∼1 mHz magnetosheath ion dynamic pressure/velocity oscillation, suggesting this radial standing wave and FLR in the flank magnetosphere may be triggered by the solar-wind and/or magnetosheath dynamic pressure/velocity fluctuations.
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Journal articleColomban L, Agapitov OV, Krasnoselskikh V, et al., 2023,
Reconstruction of Polarization Properties of Whistler Waves From Two Magnetic and Two Electric Field Components: Application to Parker Solar Probe Measurements
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 128, ISSN: 2169-9380- Cite
- Citations: 5
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Journal articlePookkandy B, Graven H, Martin A, 2023,
Contemporary oceanic radiocarbon response to ocean circulation changes
, Climate Dynamics, Vol: 61, Pages: 3223-3235, ISSN: 0930-7575Radiocarbon (14C) is a valuable tracer of ocean circulation, owing to its natural decay over thousands of years and to its perturbation by nuclear weapons testing in the 1950s and 1960s. Previous studies have used 14C to evaluate models or to investigate past climate change. However, the relationship between ocean 14C and ocean circulation changes over the past few decades has not been explored. Here we use an Ocean-Sea-ice model (NEMO) forced with transient or fixed atmospheric reanalysis (JRA-55-do) and atmospheric 14C and CO2 boundary conditions to investigate the effect of ocean circulation trends and variability on 14C. We find that 14C/C (∆14C) variability is generally anti-correlated with potential density variability. The areas where the largest variability occurs varies by depth: in upwelling regions at the surface, at the edges of the subtropical gyres at 300 m depth, and in Antarctic Intermediate Water and North Atlantic Deep Water at 1000 m depth. We find that trends in the Atlantic Meridional Overturning Circulation may influence trends in ∆14C in the North Atlantic. In the high-variability regions the simulated variations are larger than typical ocean ∆14C measurement uncertainty of 2–5‰ suggesting that ∆14C data could provide a useful tracer of circulation changes.
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Journal articleVuorinen L, Hietala H, Lamoury AT, et al., 2023,
Solar Wind Parameters Influencing Magnetosheath Jet Formation: Low and High IMF Cone Angle Regimes
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 128, ISSN: 2169-9380 -
Journal articleFletcher LN, Cavalié T, Grassi D, et al., 2023,
Jupiter science Enabled by ESA's Jupiter Icy Moons Explorer
, Space Science Reviews, Vol: 219, ISSN: 0038-6308ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet.
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Journal articleCollinson GA, Hietala H, Plaschke F, et al., 2023,
Shocklets and short large amplitude magnetic structures (SLAMS) in the high mach foreshock of Venus
, Geophysical Research Letters, Vol: 50, ISSN: 0094-8276Shocklets and short large-amplitude magnetic structures (SLAMS) are steepened magnetic fluctuations commonly found in Earth's upstream foreshock. Here we present Venus Express observations from the 26th of February 2009 establishing their existence in the steady-state foreshock of Venus, building on a past study which found SLAMS during a substantial disturbance of the induced magnetosphere. The Venusian structures were comparable to those reported near Earth. The 2 Shocklets had magnetic compression ratios of 1.23 and 1.34 with linear polarization in the spacecraft frame. The 3 SLAMS had ratios between 3.22 and 4.03, two of which with elliptical polarization in the spacecraft frame. Statistical analysis suggests SLAMS coincide with unusually high solar wind Alfvén mach-number at Venus (12.5, this event). Thus, while we establish Shocklets and SLAMS can form in the stable Venusian foreshock, they may be rarer than at Earth. We estimate a lower limit of their occurrence rate of ≳14%.
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Journal articleChatoutsidou SE, Saridaki A, Raisi L, et al., 2023,
Variations, seasonal shifts and ambient conditions affecting airborne microorganisms and particles at a southeastern Mediterranean site
, SCIENCE OF THE TOTAL ENVIRONMENT, Vol: 892, ISSN: 0048-9697- Cite
- Citations: 12
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Journal articleTelloni D, Romoli M, Velli M, et al., 2023,
Energy Budget in the Solar Corona
, ASTROPHYSICAL JOURNAL, Vol: 954, ISSN: 0004-637X- Cite
- Citations: 8
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Journal articleHuang J, Kasper JC, Larson DE, et al., 2023,
The Temperature, Electron, and Pressure Characteristics of Switchbacks: Parker Solar Probe Observations
, ASTROPHYSICAL JOURNAL, Vol: 954, ISSN: 0004-637X- Cite
- Citations: 9
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Journal articleLee D, Sparrow SN, Min S-K, et al., 2023,
Physically based equation representing the forcing-driven precipitation in climate models
, ENVIRONMENTAL RESEARCH LETTERS, Vol: 18, ISSN: 1748-9326 -
Journal articleRomeo OM, Braga CR, Badman ST, et al., 2023,
Near-Sun In Situ and Remote-sensing Observations of a Coronal Mass Ejection and its Effect on the Heliospheric Current Sheet
, ASTROPHYSICAL JOURNAL, Vol: 954, ISSN: 0004-637X- Cite
- Citations: 34
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Journal articleJebaraj IC, Krasnoselskikh V, Pulupa M, et al., 2023,
Fundamental-Harmonic Pairs of Interplanetary Type III Radio Bursts
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 955, ISSN: 2041-8205- Cite
- Citations: 19
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Journal articleTelloni D, Romoli M, Velli M, et al., 2023,
Coronal Heating Rate in the Slow Solar Wind
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 955, ISSN: 2041-8205- Cite
- Citations: 10
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Journal articleAlnussirat ST, Livi R, Larson DE, et al., 2023,
Dispersive Suprathermal Ion Events Observed by the Parker Solar Probe Mission
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 954, ISSN: 2041-8205- Cite
- Citations: 4
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Journal articleBasar G, Ozturk IK, Erdogan H, et al., 2023,
New even parity fine structure energy levels of atomic vanadium
, SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY, Vol: 207, ISSN: 0584-8547- Cite
- Citations: 1
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Journal articleBoucher O, Bellouin N, Clark H, et al., 2023,
Comparison of actual and time-optimized flight trajectories in the context of the in-service aircraft for a global observing system (IAGOS) programme
, Aerospace, Vol: 10, ISSN: 2226-4310Airlines optimize flight trajectories in order to minimize their operational costs, of which fuel consumption is a large contributor. It is known that flight trajectories are not fuel-optimal because of airspace congestion and restrictions, safety regulations, bad weather and other operational constraints. However, the extent to which trajectories are not fuel-optimal (and therefore CO2-optimal) is not well known. In this study, we present two methods for optimizing the flight cruising time by taking best advantage of the wind pattern at a given flight level and for constant airspeed. We test these methods against actual flight trajectories recorded under the In-service Aircraft for a Global Observing System (IAGOS) programme. One method is more robust than the other (computationally faster) method, but when successful, the two methods agree very well with each other, with optima generally within the order of 0.1%. The IAGOS actual cruising trajectories are on average 1% longer than the computed optimal for the transatlantic route, which leaves little room for improvement given that by construction the actual trajectory cannot be better than our optimum. The average degree of non-optimality is larger for some other routes and can be up to 10%. On some routes, there are also outlier flights that are not well optimized; however, the reason for this is not known.
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Journal articleKang SM, Ceppi P, Yu Y, et al., 2023,
Recent global climate feedback controlled by Southern Ocean cooling
, Nature Geoscience, Vol: 16, Pages: 775-780, ISSN: 1752-0894The magnitude of global warming is controlled by climate feedbacks associated with various aspects of the climate system, such as clouds. The global climate feedback is the net effect of these feedbacks, and its temporal evolution is thought to depend on the tropical Pacific sea surface temperature pattern. However, current coupled climate models fail to simulate the pattern observed in the Pacific between 1979 and 2013 and its associated anomalously negative feedback. Here we demonstrate a mechanism whereby the Southern Ocean controls the global climate feedback. Using climate model experiments in which Southern Ocean sea surface temperatures are restored to observations, we show that accounting for recent Southern Ocean cooling—which is absent in coupled climate models—halves the bias in the global climate feedback by removing the cloud component bias. This global impact is mediated by a teleconnection to the Southeast Pacific, where remote sea surface temperature anomalies cause a strong stratocumulus cloud feedback. We propose that this Southern Ocean-driven pattern effect is underestimated in most climate models, owing to an overly weak stratocumulus cloud feedback. Addressing this bias may shift climate sensitivities to higher values than currently simulated as the Southern Ocean undergoes accelerated warming in future projections.
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Journal articleOwens MJ, Lockwood M, Barnard LA, et al., 2023,
Annual Variations in the Near-Earth Solar Wind
, SOLAR PHYSICS, Vol: 298, ISSN: 0038-0938 -
Journal articleArcher M, Southwood D, Hartinger M, et al., 2023,
Magnetosonic ULF waves with anomalous plasma - magnetic field correlations: standing waves and inhomogeneous plasmas
, Geophysical Research Letters, Vol: 50, Pages: 1-13, ISSN: 0094-8276Ultra-low frequency (ULF) wave observations across the heliosphere often rely on the sign of correlations between plasma (density/pressure) and magnetic field perturbations to distinguish between fast and slow magnetosonic modes. However, the assumptions behind this magnetohydrodynamic result are not always valid, particularly within the magnetosphere which is inhomogeneous and supports standing waves along the geomagnetic field. Through theory and a global simulation, we find both effects can result in anomalous plasma–magnetic field correlations. The interference pattern in standing waves can lead both body and surface magnetosonic waves to have different cross-phases than their constituent propagating waves. Furthermore, if the scale of gradients in the background are shorter than the wavelength or the waves are near-incompressible, then advection by the wave of inhomogeneities can overcome the wave's inherent sense of compression. These effects need to be allowed for and taken into account when applying the typical diagnostic to observations.
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Journal articleLi Y, Tang Y, Wang S, et al., 2023,
Recent increases in tropical cyclone rapid intensification events in global offshore regions
, Nature Communications, Vol: 14, ISSN: 2041-1723Rapid intensification (RI) is an essential process in the development of strong tropical cyclones and a major challenge in prediction. RI in offshore regions is more threatening to coastal populations and economies. Although much effort has been devoted to studying basin-wide temporal-spatial fluctuations, variations of global RI events in offshore regions remain uncertain. Here, we show that compared with open oceans, where the annual RI counts do not show significant changes, offshore areas within 400 km of the coastline have experienced a significant increase in RI events, with the count tripling from 1980 to 2020. Furthermore, thermodynamic environments present more favorable conditions for this trend, and climate models show that global ocean warming has enhanced such changes. This work yields an important finding that an increasing threat of RI in coastal regions has occurred in the preceding decades, which may continue under a future warming climate.
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Journal articleMurray-Watson R, Gryspeerdt E, Goren T, 2023,
Investigating the development of clouds within marine cold air outbreaks
, Atmospheric Chemistry and Physics, Vol: 23, Pages: 9365-9383, ISSN: 1680-7316Marine cold air outbreaks are important parts of the high-latitude climate system, and are characterised by strong surface fluxes generated by the air-sea temperature gradient. These fluxes promote cloud formation, which can be identified in satellite imagery by the distinct transformation of stratiform cloud ‘streets’ into a broken field of cumuliform clouds downwind of the outbreak. This evolution in cloud morphology changes the radiative properties of the cloud, and therefore is of importanceto the surface energy budget. While the drivers of stratocumulus-to-cumulus transitions, such as aerosols or the sea surface temperature gradient, have been extensively studied for subtropical clouds, the factors influencing transitions at higher latitudes are relatively poorly understood. This work uses reanalysis data to create a set of composite trajectories of cold air outbreaks moving off the Arctic ice edge and co-locates these trajectories with satellite data to generate a unique view of liquid-dominated cloud development within cold air outbreaks.The results of this analysis show that clouds embedded in cold-air outbreaks have distinctive properties relative to clouds following other trajectories in the region. The initial strength of the outbreak shows a lasting effect on cloud properties, with differences between clouds in strong and weak events visible over 30 hours after the air has left the ice edge. However, while the strength (measured by the magnitude of the marine cold-air outbreak index) of the outbreak affects the magnitude of cloud properties, it does not affect the timing of the transition to cumuliform clouds nor the top-of-atmosphere albedo. In contrast, the initial aerosol conditions do not strongly affect the magnitude of the cloud properties, but are correlated to cloud break-up,leading to an enhanced cooling effect in clouds moving through high aerosol conditions due to delayed break-up. Both the aerosol environment and the strength and
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Journal articleTrotta D, Pezzi, Burgess D, et al., 2023,
Three-dimensional modelling of the shock-turbulence interaction
, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 525, Pages: 1856-1866, ISSN: 0035-8711 -
Journal articleHorbury T, Bale S, mcmanus M, et al., 2023,
Switchbacks, microstreams and broadband turbulence in the solar wind
, Physics of Plasmas, Vol: 30, ISSN: 1070-664XSwitchbacks are a striking phenomenon in near-Sun coronal hole flows, but their origins, evolution, and relation to the broadband fluctuations seen farther from the Sun are unclear. We use the near-radial lineup of Solar Orbiter and Parker Solar Probe during September 2020 when both spacecraft were in wind from the Sun's Southern polar coronal hole to investigate if switchback variability is related to large scale properties near 1 au. Using the measured solar wind speed, we map measurements from both spacecraft to the source surface and consider variations with source Carrington longitude. The patch modulation of switchback amplitudes at Parker at 20 solar radii was associated with speed variations similar to microstreams and corresponds to solar longitudinal scales of around 5°–10°. Near 1 au, this speed variation was absent, probably due to interactions between plasma at different speeds during their propagation. The alpha particle fraction, which has recently been shown to have spatial variability correlated with patches at 20 solar radii, varied on a similar scale at 1 au. The switchback modulation scale of 5°–10°, corresponding to a temporal scale of several hours at Orbiter, was present as a variation in the average deflection of the field from the Parker spiral. While limited to only one stream, these results suggest that in coronal hole flows, switchback patches are related to microstreams, perhaps associated with supergranular boundaries or plumes. Patches of switchbacks appear to evolve into large scale fluctuations, which might be one driver of the ubiquitous turbulent fluctuations in the solar wind.
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Journal articleZazzeri G, Graven H, Xu X, et al., 2023,
Radiocarbon measurements reveal underestimated fossil CH₄ and CO₂ emissions in London
, Geophysical Research Letters, Vol: 50, ISSN: 0094-8276Radiocarbon (14C) is a powerful tracer of fossil emissions because fossil fuels are entirely depleted in 14C, but observations of 14CO2 and especially 14CH4 in urban regions are sparse. We present the first observations of 14C in both methane (CH4) and carbon dioxide (CO2) in an urban area (London) using a recently developed sampling system. We find that the fossil fraction of CH4 and the atmospheric concentration of fossil CO2 are consistently higher than simulated values using the atmospheric dispersion model NAME coupled with emission inventories. Observed net biospheric uptake in June–July is not well correlated with simulations using the SMURF model with NAME. The results show the partitioning of fossil and biospheric CO2 and CH4 in cities can be evaluated and improved with 14C observations when the nuclear power plants influence is negligible.
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Journal articleLivi S, Lepri ST, Raines JM, et al., 2023,
First results from the Solar Orbiter Heavy Ion Sensor
, ASTRONOMY & ASTROPHYSICS, Vol: 676, ISSN: 0004-6361- Cite
- Citations: 20
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Journal articleLewis HC, Stawarz JE, Franci L, et al., 2023,
Magnetospheric Multiscale measurements of turbulent electric fields in earth's magnetosheath: how do plasma conditions influence the balance of terms in generalized Ohm's law?
, Physics of Plasmas, Vol: 30, ISSN: 1070-664XTurbulence is ubiquitous within space plasmas, where it is associated with numerous nonlinear interactions. Magnetospheric Multiscale (MMS) provides the unique opportunity to decompose the electric field (E) dynamics into contributions from different linear and nonlinearprocesses via direct measurements of the terms in generalized Ohm’s law. Using high-resolution multipoint measurements, we compute the magnetohydrodynamic (EMHD), Hall (EHall), electron pressure (EPe ), and electron inertia (Einertia) terms for 60 turbulent magnetosheath intervals, to uncover the varying contributions to the dynamics as a function of scale for different plasma conditions. We identify key spectral characteristics of the Ohm’s law terms: the Hall scale, kHall, where EHall becomes dominant over EMHD; the relative amplitude of EPe to EHall, which is constant in the sub-ion range; and the relative scaling of the nonlinear and linear components of EMHD and of EHall, which are independent of scale. We find expressions for the characteristics as a function of plasma conditions. The underlying relationship between turbulent fluctuation amplitudes and ambient plasma conditions is discussed. Depending on the interval, we observe that EMHD and EHall can be dominated by either nonlinear or linear dynamics. We find that EPe is dominated by its linear contributions, with a tendency for electron temperature fluctuations to dominate at small scales. The findings are not consistent with existing linear kinetic Alfven wave theory for isothermal fluctuations. Our work shows how contributions to turbulent dynamics change in different plasma conditions, which may provide insight into other turbulent plasma environments.
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Journal articleZhu X, He J, Duan D, et al., 2023,
Non-field-aligned Proton Beams and Their Roles in the Growth of Fast Magnetosonic/Whistler Waves: Solar Orbiter Observations
, ASTROPHYSICAL JOURNAL, Vol: 953, ISSN: 0004-637X- Cite
- Citations: 5
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Journal articleHeyns MJ, Lotz SI, Cilliers PJ, et al., 2023,
Adaptations to a geomagnetic field interpolation method in Southern Africa
, ADVANCES IN SPACE RESEARCH, Vol: 72, Pages: 854-865, ISSN: 0273-1177- Cite
- Citations: 2
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