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Journal articleTeixeira JCM, Burton C, Kelley DI, et al., 2026, , Earth System Dynamics, Vol: 17, Pages: 739-767, ISSN: 2190-4979
Fire schemes within Earth System Models capture long-term historical trends in burnt area, but they struggle to reproduce the pronounced decline observed over the past two decades. This study investigates whether the observed decline in global burnt area during 1998–2016 can be better represented in the JULES-INFERNO fire model by introducing a globally uniform dependence on the Human Development Index (HDI) as a proxy for socio-economic fire controls. This approach substantially reduces regional biases in annual burned area. In Temperate North America, model bias decreases from +735.57 % to +44.46 %, with similarly large reductions in Central America, Southern Hemisphere South America, Europe, and the Middle East. HDI also improves the representation of burned area trends in eight of the 14 GFED4s regions with significant negative trends in observations. However, correcting large positive regional biases removes compensating errors in the original model, leading to a stronger global negative bias, which shifts from −34.35 Mha in JULES-INFERNO to approximately −111 Mha in JULES-INFERNO with the HDI implementation. Overall, while HDI improves regional performance and better captures observed downward trends in some regions, it also reduces interannual variability and underestimates larger fires. This highlights both the potential and limitations of representing socio-economic influences within fire models using a simplified globally uniform formulation.
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Journal articleManolis AS, Manolis AA, Manolis TA, et al., 2026, , Curr Vasc Pharmacol
Work is a social determinant of Cardiovascular (CV) and general health and can both influence and be influenced by health. The type of work, working conditions, and work environment are fundamental social determinants of CV and general health status. Climate change presents an urgent and increasing threat to workers' health, via both direct exposure to environmental risks and the indirect worsening of social and health inequalities. Occupational health, which focuses on the promotion of mental and physical health and well-being of workers, and the avoidance of occupationrelated health risks, is a crucial but less discussed concern and component of human health. Relevant research at the intersection of climate change and occupational health remains scarce. Additionally, mitigation of climate change and adaptation efforts are driving forces for rapid transformations in the workplace, including shifts towards sustainability and circular economy models. These transitions are creating new occupational hazards, including those concerning renewable energy and the circular economy sectors. Investment in occupational health research and surveillance should be increased to address the evolving influences of both climate change and the green transition, to enhance and protect workers' CV and general health. Among the work-related factors that play an important role in patients with CVD, the following seem crucial: work participation, physical and mental work capability, appropriate work, support from and flexibility of the work environment, inter-personal communication, person-centered milieu, and interdisciplinary communication. A moderate leisure-time physical activity combined with moderate occupational physical activity may be a more plausible way to combine these two activities to sustain and/or improve CV health. Such an approach may be able to ameliorate workrelated outcomes in patients with CVD. Finally, lifestyle interventions targeting multiple behaviors are also mos
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Journal articleDong Y, Lu K, Hwang Y-T, et al., 2026, , Sci Adv, Vol: 12
Observed sea-surface temperature (SST) trends over recent decades feature cooling in the tropical eastern Pacific and the Southern Ocean (SO). Growing evidence suggests that tropical cooling may partly stem from remote impacts of the SO. Using a hierarchy of multimodel simulations, we demonstrate that these teleconnections are robustly modulated by the mean-state intertropical convergence zone (ITCZ): Models with a more realistic ITCZ simulate a stronger tropical SST response to SO forcing via stronger wind-evaporation-SST feedback. When realistic Antarctic meltwater forcing is included, correcting a model's tropical mean-state bias yields a stronger tropical cooling response to meltwater-driven SO cooling, improving the agreement between simulated and observed SST trends. Our results suggest that the SO's contribution to tropical warming patterns is systematically underestimated due to model mean-state biases. Improving representations of the mean-state climate is therefore critical for accurately assessing large-scale climate responses associated with historical and future warming patterns.
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Journal articleWyper PF, Squire J, Pariat E, et al., 2026, , Space Science Reviews, Vol: 222, ISSN: 0038-6308
Magnetic switchbacks are large amplitude deflections of the magnetic field within the solar wind. They are Alfvénic in character and so are associated with a spike in velocity and a generally small variation in local plasma density. Early orbits of Parker Solar Probe revealed that the solar wind near the Sun is dominated by these structures, and therefore, they may be playing an important role in the energy budget and acceleration of the young solar wind. In this review, we present an overview of different mechanisms that have been proposed for how switchbacks could be formed. We group the mechanisms by whether they predominantly act in the low solar atmosphere or within the solar wind (in situ). We focus on mechanisms that can create reversals of the ambient magnetic field direction and, thus, account for the most extreme perturbations. The general consensus is that mechanisms in the lower solar atmosphere do not form such reversals on their own but provide the seed perturbations, flows, or particle beams necessary for in situ mechanisms to create switchbacks within the solar wind. Switchback observations thus likely contain an imprint of the coronal source of the seed perturbation or flow, which is evolved further locally by one of several plausible in situ mechanisms. We discuss the strengths and weaknesses of each mechanism and outline future observational and theoretical tests that could help differentiate between them.
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Journal articleAlconcel L, Brown P, Oddy T, et al., 2026, , Journal of Geophysical Research: Space Physics, Vol: 131, ISSN: 2169-9380
The calibration parameters of the Cluster mission's fluxgate magnetometer instruments have beendetermined and updated on a perorbit basis throughout the 24 years of the mission. Since there is no absolute field reference for vector measurements inflight, various spacecrafttospacecraft and instrumenttoinstrument comparisons have been used to assess the accuracy of the measurements. Relative accuracy—consistency of the FGM measurements between spacecraft—is typically1%forfields up to 4,000nT,whichcoversmostof the key scientific regions visited by the Cluster spacecraft. Absolute accuracy is harder to quantify but may be as good as 2% over the same range. An analysis of longterm trends in the calibration parameters shows variations on annual and missionlength timescales, particularly for sensor offsets, while sensor gains and angles are remarkably stable. Offset variations are correlated with sensor temperature—for the Cluster 1 instrument in particular—and to a lesser extent with electronics temperature; coefficients are of the order 0.1 and 0.01 nT/ºC respectively. After correction for temperature effects, there is no clearly measurable offset drift over the mission lifetime. Statistics for all four spacecraft are presented. These data could be used to inform the design andimplementation of future missions employing fluxgate magnetometers. The spacecraft are found to bemagnetically “clean,” which allows inflight calibration techniques to be applied with confidence and precision,leading to consistently highquality magneticfield data sets available through the Cluster Science Archive.
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Journal articleSun W, Phan T, Huang J, et al., 2026, , Astrophysical Journal Letters, Vol: 1003, ISSN: 2041-8205
Magnetic reconnection is a fundamental physical process that can drive rapid conversion of magnetic energy into plasma bulk flows, thermal heating, and particle acceleration in space and astrophysical plasmas. Classical reconnection theory predicts that the Alfvénic reconnection exhausts are bounded by pairs of slow-mode shocks. However, identifying and characterizing these shocks through in situ spacecraft observations remains a challenge. Here, we report Parker Solar Probe observations of a reconnection exhaust embedded in the heliospheric current sheet at a heliocentric distance of 12.2 (Formula presented) R漼. The reconnection exhaust is bounded on both boundaries by compound magnetic structures rather than a pair of pure slow shocks. Each boundary consists of a rapidly evolving, steep, inner slow shock, whose Mach numbers and shock-normal angles change significantly within several minutes, and an outer, gradual compound structure that comprises a slow shock and a rotational discontinuity. These slow shocks are quasi-perpendicular and are accompanied by enhanced proton perpendicular heating. Deep within the reconnection exhaust, high perpendicular temperature together with large plasma (Formula presented) β trigger mirror instability and generate mirror-mode structures. These observations provide new insights into the structure of reconnection exhaust boundaries and their role in energy conversion in the near-Sun plasma.
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Journal articleCanu P, Bouzid V, Piberne R, et al., 2026, , Journal of Geophysical Research: Space Physics, Vol: 131, ISSN: 2169-9380
The Spatio-Temporal Analysis of Field Fluctuations(STAFF) instruments onboard the Cluster satellites were designed to measure magnetic fluctuations in the 0.2–12 Hz and 0.2–180 Hz frequency ranges from the Search-Coil Magnetometer (SCM), as well as electromagnetic spectra from the Spectrum Analyzer (SA) in the 8–4000 Hz range. They provided a considerable amount of data throughout the 24-year mission. The production and calibration of these datasets were detailed in Robert et al. (2014), which demonstrated its excellent quality and good agreement with the FluxGate Magnetometer (FGM) measurements over their commonfrequency range. The Cluster's 24 years of operation, which far exceed the nominal two-year mission, represent the longest flight of search coil magnetometers and offer a unique opportunity to evaluate their performance over such a long period, as well as to compare the results of four initially identical instruments. The present work, based on data now archived at the Cluster Scientific Archive (CSA), examines the evolution of these products after the first 11 years in space, and until the end of the Cluster operations in September 2024. The quality of the measurements, calibration, sensitivities, and their agreement between spacecraft proved to be excellent and remained stable throughout the mission. Comparison of spectra derived from the calibrated waveforms of STAFF (CWF) and FGM shows a very good agreement until the end of operations, a further proof of the high quality of their respective calibrations.
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Journal articleSvenningsson I, Yordanova E, Khotyaintsev YV, et al., 2026, , Phys Rev E, Vol: 113
Despite heat flux's role in regulating energy conversion in collisionless plasmas, its properties and evolution in the magnetosheath downstream of the Earth's bow shock are scarcely explored. We use Magnetospheric Multiscale in situ measurements to quantify and characterize the electron heat flux in the magnetosheath. We find that the heat flux is shaped by the magnetosheath magnetic field as it drapes around the magnetosphere. While it is affected by solar wind upstream conditions and increases with magnetic field strength, it is not substantially changed by local magnetosheath processes. Also, the heat flux is limited by whistler instability thresholds.
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Journal articleKelly H, Archer M, Eastwood J, et al., 2026, , Geophysical Research Letters, Vol: 53, ISSN: 0094-8276
The Kelvin-Helmholtz instability (KHI) mediates the viscous-like solar-terrestrial interaction by generating magnetopause surface waves that quickly become non-linear. Basic theory predicts the locally most-unstable linear wave dominates. However, Kelvin-Helmholtz is a broad, convective instability that also amplifies waves originating upstream. We address this conundrum by applying dynamic mode decomposition to a Gorgon global magnetohydrodynamic simulation of the KHI. While distinct modes quickly grow at points along the magnetopause, signaling local generation, their energy continues to slowly grow downtail. Thus, a superposition is present along the magnetopause, where the dominant mode is not always the locally fastest-growing. Each mode's wavelength elongates downtail, correlating with the boundary layer flow speed due to the accelerating advective flow around the magnetosphere Doppler shifting the fixed-frequency waves. This may explain why longer wavelengths are observed in the tail than theory predicts and motivates further exploration of tangential inhomogeneities in basic Kelvin-Helmholtz theory.
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Journal articleLewis H, Eastwood J, Phan T, et al., 2026, , The Astrophysical Journal (ApJ), Vol: 1002, Pages: 1-12, ISSN: 0004-637X
In situ observations by Parker Solar Probe (PSP) suggest that the heliospheric current sheet (HCS) undergoes near-continuous magnetic reconnection close to the Sun, in stark contrast to scarce observations of this phenomenon in the HCS at 1 AU. Situated at the boundary between sectors of opposite interplanetary magnetic field (IMF) polarity, reconnection in the HCS has important consequences for magnetic topology and plasma dynamics in the slow solar wind. We report observations of a reconnection outflow in theHCS near the Alfv´en transition region in PSP’s 17th solar encounter, featuring plasma jetting, proton temperature enhancement, and electron heat flux dropout. Embedded within the exhaust is a non-force-free flux rope plasmoid exhibiting counterstreaming strahl electrons, indicating connection at both ends to the Sun in an otherwise disconnected region of magnetic field. The flux rope features diminished isotropic protontemperature and lower bulk speed compared to the remainder of the HCS exhaust. Its oblique orientation and different plasma properties imply the flux rope originates from a different reconnection site to the HCS exhaust, suggesting PSP has intercepteda flux-rope-like streamer blob produced at the helmet streamer. Remote observations show several comparable blobs travelling in a distant coronal ray, demonstrating the possibility that the in situ flux rope is a streamer blob. The combination of in situ andremote observations demonstrate the role of magnetic reconnection in HCS dynamics, contributing to a growing understanding of this fundamental mechanism and its impact on the young solar wind.
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Journal articleWilson LB, Bale SD, Stevens ML, et al., 2026, , Astrophysical Journal, Vol: 1002, ISSN: 0004-637X
Between 2005 January 1 and 2017 November 25, the Wind spacecraft measured 3,996,051 electron velocity distribution functions (VDFs) in the near-Earth solar wind. The instrument was calibrated, and velocity moments were calculated up to the third moment (i.e., electron heat flux). The magnetic field and ion velocity moments have been interpolated to the midpoint time of the VDFs, where we have 3,947,607 finite electron velocity moments (most prior studies used <300,000 moments). The median values for the velocity moments are as follows: n<inf>e,int</inf> ∼ 5.43 cm<sup>−3</sup>, Τ<inf>oe</inf> ∼ 421 km s<sup>−1</sup>, T<inf>e,tot</inf> ∼ 12.7 eV, and χ<inf>e,</inf> ∼4.92 μW m<sup>−2</sup>. The median values for the electron-to-proton temperature ratio is (Formula presented) Te,tot/Tp,tot ∼2.55, the electron temperature anisotropy A<inf>e</inf> = (Formula presented) Te,⊥/Te, ∼ 0.89, total electron beta β<inf>e,tot</inf> ∼ 1.27, electron–electron collision frequency ν<inf>ee</inf> ∼ 0.18 day<sup>−1</sup>, and electron–electron Knudsen number K<inf>n,ee</inf> ∼ 2.57. The results are mostly consistent with previous studies except that K<inf>n,ee</inf> is significantly larger than some other works, which implies that the near-Earth solar wind is less collisional than may have been inferred.
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Journal articleHorbury T, OBrien HL, Greenaway C, et al., 2026,
The IMAP magnetometer
, Space Science Reviews, Vol: 222, ISSN: 0038-6308The magnetometer (MAG) is one of the ten scientific instruments on the Interstellar Mapping and Acceleration Probe (IMAP), which will take in situ and remote measurements from a Sun- Earth L1 halo orbit. MAG contributes to IMAP science goals of investigating the acceleration and propagation of energetic particles, as well as providing real-time space weather monitoringdata. The magnetometer is a conventional dual sensor fluxgate instrument with a noise floor under 10 pT at 1 Hz, taking science measurements continuously at 2 vectors/s as well as a burst mode of 64 vectors/s for at least 8 hours per day. It also provides a real-time space weathermonitoring product at 4 second cadence. We describe the requirements, design and performance of the instrument, including a novel lossless compression algorithm. Data products, processing and calibration plans are presented.
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Journal articleEdberg NJT, Boldu J, Eriksson AI, et al., 2026, , Journal of Geophysical Research (JGR): Space Physics, Vol: 131, ISSN: 2169-9380
Solar Orbiter entered the topside ionosphere of Venus for the first time when performing its 4th flyby of the planet, reaching an altitude of 378 km on 18 Feb 2025. High-cadence electron density measurements showed previously unresolved fine-structuring within plasma regions and boundaries, particularly at the ionopause. During the rapid flyby, a rare snapshot of the entire induced magnetosphere was captured during calm solar wind conditions around solar maximum. A well-structured and a relatively steady plasma environment was observed. Assuming an electron temperature of 0.5 eV, pressure balance was found across the ionopause, while at the same time quasi-periodic density and magnetic field variations suggest boundary oscillations. Near closest approach, non-force free magnetic flux ropes were observed. Small-scale perturbations in both magnetic field strength and density across them indicate them being dynamically evolving, rather than in a stationary state.
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Journal articleVecchio A, Maksimovic M, Galand MIF, et al., 2026, , Astronomy and Astrophysics (A & A), Vol: 709, ISSN: 0004-6361
Context. On February 18, 2025, Solar Orbiter (SO) completed its fourth gravity assist maneuver of Venus (VGAM4) and reached an unprecedented proximity coming within 378 km of the planet. This flyby was necessary to steer the spacecraft into an orbit outside the plane of the ecliptic. Near the closest approach, only the Radio and Plasma Wave (RPW) and Magnetometer (MAG) instruments were operational; this enabled high-cadence measurements to be taken to investigate the plasma properties of the Venusian ionosphere.Aims. The main goal of this study is to derive the electron density and temperature in the ionosphere of Venus using electric potential measurements from RPW, and to characterize them.Methods. During approximately five minutes around the closest approach, the High Frequency Receiver of RPW detected radio emissions of a type naturally generated by planetary ionospheres whose frequency can be related to the electron density. Using quasithermal noise spectroscopy, we inferred the electron temperature at discrete altitudes and solar zenith angles.Results. Solar Orbiter measured an average density and electron temperature in the ionosphere of Venus of 12 385 ± 148 cm−3 and 0.43 ± 0.05 eV, respectively. These values are in agreement with in-situ measurements by Pioneer Venus Orbiter (PVO) obtained at the solar maximum. Binned magnetic fields and temperatures are anticorrelated, which suggests that the magnetic flux ropes, observed in the Venus ionosphere, are more likely non-force-free structures.Conclusions. The findings presented in this paper, together with the measurement from the Parker Solar Probe (PSP) during the third gravity assist, support the conclusion that the plasma density in the Venusian ionosphere above 350 km varies with solar activity, whereas the electron temperature shows a much weaker dependence. Notably, the electron temperature remains consistent across the three missions (SO, PSP, and PVO), despite varying levels of sola
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Journal articleWilson LB, Bale SD, Stevens ML, et al., 2026, , Astrophysical Journal Supplement Series, Vol: 284, ISSN: 0067-0049
Calibrated measurements of electron velocity distribution functions (VDFs) are necessary to characterize fluid and kinetic processes in weakly collisional and nearly collisionless plasmas such as the solar wind. Therefore, we analyzed 3,996,051 electron VDFs observed by the Wind 3DP thermal electron detector near 1 au between 2005 January 1 and 2017 November 25. The data were calibrated for each electron VDF to produce accurate velocity moments in the solar wind. This is the first full solar cycle coverage electron velocity moment dataset in the near-Earth solar wind. Herein (Paper I) we discuss the calibration process/algorithms and the velocity moment constraints, uncertainties, and resulting public dataset. In the second paper (Paper II), we statistically analyze the electron velocity moment dataset.
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Journal articleLau KH, Czernichow S, Sparks N, et al., 2026, , Natural Hazards, Vol: 122, ISSN: 0921-030X
Rainfall associated with tropical cyclones (TCs) is a crucial driver of TC hazards, yet estimating TC rain risk from observations is hindered by their relative infrequency. Parametric TC rain models coupled with stochastic TC risk models provide an efficient mean for quantifying such risk. This study introduces a new parametric rain model for landfalling TCs, integrated into the 勛圖窪蹋 College Storm Model (IRIS), a statistical-thermodynamic global TC hazard model. Using a 10,000-year simulation, IRIS reproduces observed global return periods of landfall rain rate, storm-total rain volume, and lifetime rain production over land. Over the United States, the model captures observed rainfall climatology and event accumulations with skill comparable to or slightly exceeding existing parametric models. The capability of the model for climate projection is demonstrated through a United States case study using a storyline approach that isolates thermodynamic effects, specifically increases in potential intensity and total column water, under a +2 °C global warming scenario. The pre-landfall maximum azimuthal mean rain rate of United States hurricanes increases by 20.1%, while contraction of the rain field limits the storm-total rain volume increase to 3.9%. Across their lifetimes over land, hurricanes produce 14.6% more rainfall. Spatially, warming enhances rain rates and accumulations across the eastern and southern United States, with the largest absolute increases in the southeast but the strongest relative increases inland and in the northeast, indicating greater inland and poleward penetration of hurricane rainfall under warming.
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Journal articleHorne RB, Angling MJ, Attrill GDR, et al., 2026, , Royal Society Open Science, Vol: 13, ISSN: 2054-5703
The May 2024 geomagnetic storm was the largest for over 20 years. The storm was categorized as a ‘low-level’ G5, where G5 is the highest on the National Oceanic and Atmospheric Administration (NOAA) scale for geomagnetic storms, yet the individual solar eruptive events were not particularly severe, and the observed impacts were relatively minor. The impacts that were observed were due to the combined and sustained effect of five successive earthward-directed coronal mass ejections (CMEs) which drove the storm. The event exposed the weakness of the current storm classification system which does not discriminate between low impact and high impact G5 events; it exercised the UK Met Office forecasting system, communications and UK preparedness; and it highlighted key areas that need to be addressed, particularly relating to national power supplies, space traffic management, aviation, forecasting and data gaps. Here, we set out what happened, record some of the key impacts, discuss what went well and what needs to be improved. We make 14 recommendations relevant to four government departments, so that the UK can be better prepared for a low-probability, high-impact space weather event described in the reasonable worst-case scenario that informs the national risk register.
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Journal articleFiedler S, O'Connor FM, Watson-Parris D, et al., 2026, , Geoscientific Model Development, Vol: 19, Pages: 3477-3508, ISSN: 1991-959X
Phase 2 of the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP2) is a registered model intercomparison project (MIP) of the Coupled Model Intercomparison Project phase 7 (CMIP7). The focus of AerChemMIP2 is the quantification of the atmospheric composition, biogeochemical feedbacks, air quality and climate responses to changes in emissions of chemically reactive gases, aerosol particles, and land use. AerChemMIP2 aims to facilitate a better understanding of their relative contributions to changes in atmospheric composition, radiative forcing, and the climate response and feedbacks from the pre-industrial period to the present day and for projected future emission pathways. Some experiments from the first phase of AerChemMIP are requested in the second phase to track changes in the results of CMIP7 compared to phase six of CMIP. New experiments in AerChemMIP2 open scientific opportunities to address knowledge gaps and persistent uncertainties. Specifically, AerChemMIP2 requests experiments (1) to assess the dependence of effective radiative forcing for aerosols on the fidelity of resolved processes and the simulated base climate, (2) to provide first estimates of forcing for hydrogen and individual volatile organic compounds in the context of CMIP, (3) to enable studies on non-linearity in the Earth system response, (4) to understand the response of wild fires to historical forcings, and (5) to quantify the influence of desert dust increases on climate change. AerChemMIP2 further requests variants of the ScenarioMIP-CMIP7 high-end and overshoot scenarios to quantify future responses to policy implementations for air quality management. Diagnostic requests of AerChemMIP2 are made from CMIP7 core experiments to facilitate offline experiments for chemistry and aerosols. The experimental protocol of AerChemMIP2 presented here closely aligns with the CMIP7 core experimental design, and its other registered MIPs. Selected AerChemMIP2 experiments are perform
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Journal articleErgun RE, Vo T, Qi Y, et al., 2026, , Astrophysical Journal, Vol: 1001, ISSN: 0004-637X
We investigate the magnetic (B) and electric (E) field spectra in the dissipation range of strong turbulence of a collisionless plasma. This investigation, which is relevant to turbulence studies in many astrophysical settings, is enabled by high-resolution measurements from the four-spacecraft Magnetospheric Multiscale (MMS) mission in the Earth’s magnetotail. B and E spectra are derived as a function of the product of the wave number and electron skin depth (|k| d<inf>e</inf>) using a novel technique that employs time-delay analysis on multiple intervals of B and E. Using the MMS tetrahedral formation with close (several d<inf>e </inf>) spacing, velocities of B and E signals can be derived so that native frequency-based spectra can be accurately translated to k spectra. The most important finding is a mathematically significant break in the B spectral index that appears at |k| d<inf>e</inf> ≈ 1. In the subion range, which spans from the ion inertial length (d<inf>ι </inf>) to d<inf>e </inf>, the B spectral index is −2.35, then steepens to − 3.13 at sub-d<inf>e </inf> scales. As expected from previously derived frequency spectra, E has a particularly shallow spectral index (−0.67) in the subion range. At scales smaller than d<inf>e </inf> and/or the electron thermal gyroradius (ρ<inf>e </inf>), the E spectral index steepens to −2.73. Spectral breaks in both B and E in the dissipation range indicate a change in the physical dissipation processes from ion to electron domination at |k| d<inf>e</inf> ≈ 1. We also confirm that at |k| ρ<inf>e</inf> > ~ 2, the energy density of B and E approaches equipartition, suggesting that energy transfer is near complete.
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Journal articleGuo J, Xie X, Myhre G, et al., 2026, , Atmospheric Chemistry and Physics, Vol: 26, Pages: 5169-5184, ISSN: 1680-7316
Observational evidence reveals a pronounced wetting trend over Central Asia in recent decades, with the most substantial increases occurring during winter and summer. Yet the extent to which the drivers of these changes differ seasonally remains unknown. Here, we use single-forcing experiments from the Precipitation Driver and Response Model Intercomparison Project (PDRMIP) to examine the effects of various external forcings on winter and summer precipitation across Central Asia and to explore the physical mechanisms underlying seasonal precipitation changes. We find that greenhouse gas (GHG) forcing mainly increases winter precipitation by enhancing atmospheric moisture content through warming. In contrast, in summer, Asian sulfate aerosols enhance precipitation by modulating the westerly jet, which strengthens atmospheric moisture transport into the region. Asian black carbon exerts an opposing influence that partially offsets the sulfate-induced effect. Further attribution analysis based on CMIP6 simulations reinforces these sensitivity results and shows that GHG forcing is the primary driver of winter precipitation increases whereas anthropogenic aerosols dominate summer trends. Future CMIP6 projections suggest that under moderate- to high-emission scenarios, winter precipitation will continue to rise due to increasing GHG concentrations, while summer precipitation may decline across much of Central Asia as a result of reduced aerosol emissions following Asian clean air policies. These findings highlight a distinct seasonality in the drivers of recent precipitation increase and suggest a plausible divergence in future winter and summer precipitation trends.
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Journal articleM繹stl C, Davies EE, Weiler E, et al., 2026, , Astrophysical Journal, Vol: 1001, ISSN: 0004-637X
A central question for understanding interplanetary coronal mass ejection (ICME) physics and improving space weather forecasting is how ICMEs evolve in interplanetary space. We have updated one of the most comprehensive in situ ICME catalogs to date, which now includes 1976 events from 11 space missions covering over 34 yr, from 1990 December to 2025 August. We have combined existing catalogs including magnetic obstacles (MOs) and identified and added boundaries of an additional 807 (40.8%) events. With this catalog, we demonstrate the most extensive analysis to date of total ICME magnetic field values as a function of heliocentric distance. Parker Solar Probe has observed six ICMEs at <0.23 au (until 2025 April), and Solar Orbiter and BepiColombo have added more events near 0.3 au, bridging the major observational gap towards the solar corona. Our main result is that a single power law can describe the evolution of the mean total magnetic field (exponent value of k = −1.57) and maximum field (k = −1.53) for ICMEs with MOs, from 0.07 to 5.4 au. Extending the power law to the solar photosphere reveals a strong inconsistency with magnetic field magnitudes observed in the quiet Sun and active regions by 2 and 4 orders of magnitude, respectively. We introduce a multipole-type power law with two exponents, k <inf>1</inf> = −1.57, and k <inf>2</inf> = −6, relating the ICME magnetic field magnitude to an average solar active region field strength. These results present important observational constraints for the evolution of ICMEs from the Sun to the heliosphere.
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Journal articleKretzschmar M, Vecchio A, Krasnoselskikh V, et al., 2026, , Astrophysical Journal Letters, Vol: 1001, ISSN: 2041-8205
Solar radio bursts, and astrophysical radio emissions in general, are observed either in space or on the ground by measuring their fluctuating electric field. Here, we report the first measurement of the magnetic component of a solar radio wave, observed simultaneously by the Solar Orbiter and Parker Solar Probe missions. The observations were made during the type III radio burst on 2021 October 28. The analysis of the wave polarization and magnetic and electric field amplitudes allows us to estimate the refractive index and put constraints on the direction of the wave. The wave is found to be consistent with an ordinary-mode wave and with a source near the southeast limb of the Sun. These results pave the way for future observations and analyses of the magnetic field of radio waves, in particular, for solar radio bursts.
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Journal articleWojciechowska I, Gryspeerdt E, 2026, , Atmospheric Chemistry and Physics, Vol: 26, Pages: 4571-4582, ISSN: 1680-7316
Liquid marine clouds exert a substantial control on the Earth-atmosphere energy system through their large global coverage and high reflectivity of shortwave radiation, resulting in overall negative radiative impact. Previous studies showed that the two dominant factors determining their albedo are cloud fraction (CF) and liquid water path (LWP), but this relationship varies in regions of high aerosol loading. In this work, a simplified kernel was built to assess how well the top of atmosphere (TOA) all-sky albedo (α) can be estimated from the given properties of marine liquid clouds: CF, LWP and cloud droplet number concentration (<inf>Nd</inf>), and to what extent this approach applies globally. The study uses data retrieved from MODIS and CERES instruments for a near-global ocean domain (60° S–60° N) covering the period 2003–2021. The results showed that the albedo is only reconstructed to within 10 % in less than 40 % of cases. Several modifications of investigated method were tested for the improvement in albedo reconstructions. It was found that the number of biases decreases when the maximum solar zenith angle is considered, as well as if the CF–LWP–<inf>Nd</inf>–α kernel is calculated on a higher spatial resolution grid. The findings show that the relationship between the TOA albedo of a scene of clouds and the retrieved mean cloud properties is not universal and while accounting for regional variation is one way to address this, a better understanding of this effect is still needed to reduce uncertainty in aerosol-cloud interactions.
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Journal articleKim K, Modolo R, Edberg NJT, et al., 2026, , Journal of Geophysical Research Space Physics, Vol: 131, ISSN: 2169-9380
In this study, we combine Cassini fields and particle observations to investigate Titan's induced magnetosphere from the TA to T82 flybys, including flybys from the Cassini prime, equinox, and part of the solstice mission, to investigate the average location and the shape of Titan's induced magnetosphere. Although earlier studies have provided valuable information on Titan's induced magnetosphere, they were largely based on separate analyses of fields and particle data. We provide an integrated map of electron density and temperature in Titan's near plasma environment to outline the external boundary of the induced magnetosphere. We identify a dense ionospheric region and an extended plasma wake with electron densities ranging between (Formula presented.) and (Formula presented.) c (Formula presented.). In addition, we systematize the spatial distribution of pick-up ions at Titan with respect to the background convective electric field. We indicate that pickup ions are found in the positive hemisphere of the Kronian plasma convective electric field. The mass of the observed pickup corresponds to methane group ions, (Formula presented.) ions as well as protons and molecular hydrogen ions. The Kronian background electric field progressively accelerates these ions, and we estimate its intensity by reconstructing the radial energy gain of this population in response to the convective electric field. We find the estimated from the pickup ions electric field values within 0.05 mV (Formula presented.) and 1.92 mV (Formula presented.) range, which is consistent with an estimate of 0.61 mV (Formula presented.) deduced from (Formula presented.) computation.
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Journal articleKim TK, Reisenfeld DB, Wilson RJ, et al., 2026, , Journal of Geophysical Research (JGR): Space Physics, Vol: 131, ISSN: 2169-9380
Saturn's magnetosphere is continuously supplied with neutrals from the Enceladus plume and the icy rings, which undergo ionization and charge-exchange to form a complex water-group plasma environment. While the Cassini Plasma Spectrometer (CAPS) instrument has provided extensive compositional information, detailed separation of individual water-group ion species in time-of-flight (TOF) data has not previously been achieved. In this study, we perform forward modeling of CAPS-IMS energy-per-charge (E/Q) and TOF spectra obtained between 2004 and 2012 to resolve O+, OH+, H2O+, and H3O+ and to characterize their plasma properties, including number density, temperature, and thermodynamic κ. Our results demonstrate that O+ is the dominant thermal ion species throughout Saturn's magnetosphere, comprising up to ∼70% of the total ion population beyond ∼5 Saturn radii (RS). In contrast, molecular ions such as OH+, H2O+, and H3O+ dominate closer to Enceladus but rapidly dissociate into atomic ions between ∼5 and 10 RS. This radial region is also characterized by the steepest increase in plasma flow speed, which rises from ∼40% to ∼80% of rigid corotation. Simultaneously, ion velocity distributions approach Maxwell–Boltzmann equilibrium, as indicated by high kappa values. These findings provide new constraints on the ion–neutral chemistry that regulates the balance between molecular and atomic ions in Saturn's magnetosphere. They also emphasize the critical role of the 5–10 RS region as a transition zone for both plasma composition and dynamics. Our results refine previous CAPS-based studies and underscore the need to incorporate seasonal variability and ionospheric coupling into future global models of Saturn's plasma environment.
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Journal articleDesai MI, Drake JF, Swisdak M, et al., 2026, , Astrophysical Journal, Vol: 1000, ISSN: 0004-637X
Magnetic reconnection at the near-Sun heliospheric current sheet (HCS) dissipates the Parker spiral and converts magnetic energy into plasma kinetic energy. During Encounter 14 at a radial distance of ∼16.25 R <inf></inf>, Parker Solar Probe observed an HCS crossing where reconnection-driven acceleration—likely facilitated by merging large-scale flux tubes—energized protons up to ∼400 keV. This energy gain is ≈1000 times greater than the available magnetic energy per particle. We present here a comprehensive analysis of pitch-angle distributions and differential energy spectra for protons and heavy ions (He, O, and Fe) in conjunction with local wave activity during this crossing. Our results provide the first direct in situ observations of simultaneous proton and heavy-ion energization during HCS reconnection. Crucially, we find that heavy-ion power-law spectral indices differ significantly from those of protons, contradicting previous simulations that predict species-independent slopes. We further demonstrate that ion beams and anisotropies produced during reconnection drive waves in the ion cyclotron range of frequencies. Finally, we show that proton pitch-angle scattering is stronger than that of heavy ions, which may account for the flatter spectra or harder spectral indices observed in the heavy-ion populations. These observations provide definitive evidence for in situ reconnection-driven acceleration at the near-Sun HCS and necessitate the inclusion of species-dependent transport and acceleration efficiencies in contemporary reconnection-based particle energization models.
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Journal articleOka M, Russell AJB, Harada Y, et al., 2026, , Astrophysical Journal, Vol: 1000, ISSN: 0004-637X
Particles are energized—heated and accelerated to nonthermal energies—in laboratory, space, solar, and astrophysical plasmas. In collisionless plasmas, ion and electron temperatures are often unequal and cannot be fully understood within the framework of magnetohydrodynamics (MHD). In this context, a relation, Δ炵<inf>s</inf> = q<inf>s</inf>VBL<inf>s</inf>, for each species can be useful, where Δ炵<inf>s</inf> is the energy gain for species s, measured in the plasma rest frame, relative to the upstream region of shocks and magnetic reconnection; q<inf>s</inf> is the charge; V is the plasma bulk flow speed; B is the magnetic field strength; and L<inf>s</inf> is a characteristic length scale of energization. From this relation, we recently derived semiempirical scalings for ion and electron temperature increases across shocks and magnetic reconnection in Earth’s plasma environment. However, it remains unclear how broadly these scalings apply. Here we show that the same scalings explain temperature increases in other plasma environments such as laboratory experiments, planetary magnetospheres, solar flares, and supernova remnant shocks. Combined with another recent report that the maximum energy of particles in various plasma environments follows the same relation when L<inf>s</inf> is taken as the system size, our results indicate that Δ炵<inf>s</inf> = q<inf>s</inf>VBL<inf>s</inf> provides a novel framework that universally captures particle energization—both heating and acceleration to nonthermal energies. Additionally, the scaling captures the essential MHD trends while revealing systematic deviations that point to kinetic effects beyond fluid models, highlighting promising directions for theoretical and simulation studies.
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Journal articleLopez-Marti F, Czaja A, Messori G, et al., 2026, , Quarterly Journal of the Royal Meteorological Society, Vol: 152, ISSN: 0035-9009
Extreme precipitation and wind events in Western Europe are often driven by atmospheric rivers (ARs) developing over the North Atlantic Ocean. Even though research has explored AR variability in relation to large-scale atmospheric dynamics and the North Atlantic Storm Track, gaps remain in understanding how oceanic variability influences AR activity, particularly within the eddy-rich environment of the Gulf Stream extension. The enhanced ocean heat transport and mesoscale eddy activity associated with this western boundary current can influence large-scale dynamics, modulate moisture availability in the lower atmosphere, and potentially control the AR activity downstream. In this study, we evaluated ocean mesoscale features, oceanic heat supply, and surface heat fluxes in the Gulf Stream extension region at monthly time-scales. We assessed their downstream impact on AR activity using state-of-the-art observational datasets. Our analysis identified winter and spring as the key seasons for interactions between Gulf Stream conditions and ARs. Higher ocean heat transport and mesoscale sea-surface height (SSH) meandering were associated with a northward shift in downstream AR activity and a positive North Atlantic Oscillation (NAO) pattern, although the atmospheric response is weaker in the latter case. In contrast, stronger than average surface heat fluxes in the Gulf Stream were linked to a southward shift of ARs and a strong negative NAO pattern, suggesting a dominant atmospheric influence that enhanced moisture availability and modulated North Atlantic dynamics. These results show that the Gulf Stream plays an important role in controlling the latitudinal variability of ARs over the Euro-Atlantic sector during winter and spring.
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Journal articleWang S, Yang P, Brindley HE, et al., 2026, , Geophysical Research Letters, Vol: 53, ISSN: 0094-8276
A new compilation of the complex refractive index of liquid water is presented, spanning temperatures from (Formula presented.) (near homogeneous freezing) to (Formula presented.) K and wavelengths from (Formula presented.) μm to 10 m. The real part of the refractive index is derived using the Kramers–Kronig relation, where the imaginary part is constrained by measurements reported in literature and validated through the f-sum rule. The result reveals a significant temperature dependence, especially at wavelengths beyond the near-infrared. Sensitivity analyses in the infrared split-window and microwave spectral regime demonstrate substantial differences in bulk optical properties between supercooled and ambient conditions. These findings manifest the importance of accounting for temperature-dependent refractive indices in optical radiative transfer and simulations.
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Journal articleCeppi P, Wilson Kemsley S, Andersen H, et al., 2026, , Atmospheric Chemistry and Physics (ACP), Vol: 26, Pages: 4153-4171, ISSN: 1680-7316
From mid-2003 to mid-2024, a global decrease in low-cloud amount enhanced the absorption ofsolar radiation by 0.22±0.07Wm−2 per decade (±1σ range), accelerating the energy imbalance trend duringthat period (0.44Wm−2 per decade). Through controlling factor analysis, here we show that the low-cloudtrend is due to a combination of cloud feedback and adjustments to greenhouse gases and aerosols (respectively 0.09±0.02, 0.05±0.03, and 0.03±0.03Wm−2 per decade), which jointly account for 74% of the trend. The contribution of natural climate variability is weak but uncertain (0.01±0.08Wm−2 per decade), owing to apoorly constrained trend in boundary-layer inversion strength. Importantly, the observed low-cloud radiativetrend lies well within the range of values simulated by contemporary global climate models under conditionsclose to present day. Any systematic model error in the representation of present-day global energy imbalancetrends is thus likely to originate in processes unrelated to low clouds.
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