Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleHorner G, Gryspeerdt E, 2025,
How does the lifetime of detrained cirrus impact the high-cloud radiative effect in the tropics?
, Atmospheric Chemistry and Physics, Vol: 25, Pages: 5617-5631, ISSN: 1680-7316The lifetime of cirrus clouds from deep convection plays an important role in determining their overall cloud radiative effect (CRE). The net CRE of cirrus clouds from deep convection is close to zero over their whole lifetime. This CRE is the result of a near-cancellation of a large shortwave (SW) cooling and large longwave (LW) warming, such that small changes in cirrus properties have the potential to produce a significant net radiative effect. Changes in the atmospheric and sea surface temperature structure, along with changes in anthropogenic aerosol, have been hypothesised to impact the lifetime of detrained cirrus clouds, altering this radiative balance. Constraining the potential CRE response to changes in cirrus lifetime is therefore vital to understand the strength of these proposed climate forcings and feedbacks.This paper tracks the evolution of detrained cirrus clouds along trajectories from deep convection. The total cirrus CRE in the tropics is found to be warming, at 11.2 ± 0.4 W m−2. It is found that cirrus clouds along trajectories from oceanic origin convection have a warming CRE of 10.0 ± 0.4 W m−2. In contrast, cirrus clouds along trajectories from land convection have a warming of 15.9 ± 0.7 W m−2 throughout their lifetime. This contrast is predominantly due to differences in the diurnal cycle of the initial convection over land and ocean.A proposed extension to the lifetime of the detrained cirrus leads to changes in the total cirrus CRE in the tropics. In all cases, doubling the lifetime of the detrained cirrus leads to an increase in the total cirrus CRE of 0.6 ± 0.1 W m−2. Whilst there is uncertainty in the strength of mechanisms responsible for a change in cirrus lifetime, this work provides an important constraint on the impact that any potential lifetime extension may have.
-
Journal articleHamilton CW, Mcewen AS, Keszthelyi L, et al., 2025,
Comparing NASA Discovery and New Frontiers Class Mission Concepts for the Io Volcano Observer
, PLANETARY SCIENCE JOURNAL, Vol: 6- Cite
- Citations: 1
-
Journal articleDesai MI, Drake JF, Phan T, et al., 2025,
Magnetic Reconnection-driven Energization of Protons up to ∼400 keV at the Near-Sun Heliospheric Current Sheet
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 985, ISSN: 2041-8205- Cite
- Citations: 2
-
Journal articleLozinski AR, Kellerman AC, Bortnik J, et al., 2025,
Modeling the Internal Redistribution of Earth's Proton Radiation Belt by Interplanetary Shocks
, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 130, ISSN: 2169-9380 -
Journal articleMauritsen T, Tsushima Y, Meyssignac B, et al., 2025,
Earth's Energy Imbalance More Than Doubled in Recent Decades
, AGU ADVANCES, Vol: 6- Cite
- Citations: 3
-
Journal articleKim K, Edberg NJT, Modolo R, et al., 2025,
Electron Structures in Titan's Induced Magnetosphere and Low-Frequency Wave Activity
, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 130, ISSN: 2169-9097 -
Journal articleColomban L, Agapitov OV, Krasnoselskikh V, et al., 2025,
Polarization Properties of Whistler Waves From the First 17 Parker Solar Probe Encounters
, GEOPHYSICAL RESEARCH LETTERS, Vol: 52, ISSN: 0094-8276 -
Journal articleBowen TA, Dunn CI, Mallet A, et al., 2025,
Nonlinear Interactions in Spherically Polarized Alfvénic Turbulence
, ASTROPHYSICAL JOURNAL, Vol: 985, ISSN: 0004-637X- Cite
- Citations: 1
-
Journal articleAlnussirat ST, Larson DE, Livi R, et al., 2025,
Impulsive Solar Flares in the Parker Solar Probe Era. I. Low-energy Electron, Proton, and Alpha Beams
, ASTROPHYSICAL JOURNAL, Vol: 985, ISSN: 0004-637X -
Journal articleCuesta ME, Livadiotis G, Mccomas DJ, et al., 2025,
Transfer of Entropy between the Magnetic Field and Solar Energetic Particles during an Interplanetary Coronal Mass Ejection
, ASTROPHYSICAL JOURNAL LETTERS, Vol: 984, ISSN: 2041-8205- Cite
- Citations: 2
-
Journal articleShen MM, Szalay JR, Pokorny P, et al., 2025,
Diverse Dust Populations in the Near-Sun Environment Characterized by PSP/IS⊙IS
, ASTROPHYSICAL JOURNAL, Vol: 984, ISSN: 0004-637X- Cite
- Citations: 1
-
Journal articleVallim D, Grillakis M, Manoudakis S, et al., 2025,
Stakeholder Engagement Drivers: Insights from an Information System Innovation Project Supporting Wildfire Evacuation in Greece
, Proceedings of the International Iscram ConferenceThe Samaria Gorge, a tourist destination in Crete, faces wildfire risk due to its dense forest, topography, number of visitors, and climate. As part of a H2020 project, the Gorge serves as a testing pilot for a new wildfire management platform that integrates technologies to improve fire detection, risk assessment, and resource allocation during a wildfire evacuation. A central component of the project is a multi-stakeholder network, which supports both governance and acceptance of solutions. To understand the drivers of network formation, we used a Social Network Analysis and Exponential Random Graphs Model approaches to identify the drivers of stakeholder collaboration. Our findings indicate that sectoral and wildfire management focus phase are factors driving connections, while the working in intersecting jurisdictions is not. The results highlight the challenges of multi-stakeholder collaboration, suggesting that policy frameworks and information systems need to develop specific mechanisms to encourage stakeholders to bridge collaborative gaps.
-
Journal articleBeggan CD, Eastwood JP, Eggington JWB, et al., 2025,
Implementing an operational cloud‐based now‐ and forecasting system for space weather ground effects in the UK
, Space Weather, Vol: 23, ISSN: 1539-4956The enhanced variation of the magnetic field during severe to extreme geomagnetic storms induces a large geoelectric field in the subsurface. Grounded infrastructure can be susceptible to geomagnetically induced currents (GICs) during these events. Modeling the effect in real-time and forecasting the magnitude of GICs are important for allowing operators of critical infrastructure to make informed decisions on potential impacts. As part of the UK-funded Space Weather Innovation, Measurement, Modeling and Risk (SWIMMR) program, we implemented nine research-level models into operational codes capable of running consistently and robustly to produce estimates of GICs in the Great Britain high voltage power transmission network, the high pressure gas pipeline network and the railway network. To improve magnetic coverage and geoelectric field modeling accuracy, three new variometer sites were installed in the UK and a 3 year campaign of magnetotelluric measurements at 53 sites was undertaken. The models rely on real-time ground observatory data and solar wind data from satellites at the L1 Lagrange point. A mixture of empirical machine learning and numerical magnetohydrodynamic models are used for forecasting. In addition to nowcast capabilities, contextual information on the likelihood of substorms, sudden commencements and large rates of change of the magnetic field were developed. The final nowcast and forecast codes were implemented in a cloud-based environment using modern software tools and practices. We describe the process to move from research to operations (R2O).
-
Journal articleNair R, Halekas JS, Cattell C, et al., 2025,
Suprathermal Electron Scattering by Narrowband Whistler Waves and Broadband Electrostatic Waves: Parker Solar Probe Observations
, ASTROPHYSICAL JOURNAL, Vol: 984, ISSN: 0004-637X -
Journal articlePerkins O, Kasoar M, Voulgarakis A, et al., 2025,
The spatial distribution and temporal drivers of changing global fire regimes: a coupled socio-ecological modeling approach
, Earth's Future, Vol: 13, ISSN: 2328-4277The limited capacity of fire-enabled vegetation models to represent human influences on fire regimes is a fundamental challenge in fire science. This limitation places a major constraint on our capacity to understand how vegetation fire may change under future scenarios of climate change and socio-economic development. Here, we address this challenge by presenting a novel integration of two process-based models. The first is the Wildfire Human Agency Model (WHAM!), which draws on agent-based approaches to represent anthropogenic fire use and management. The second is JULES-INFERNO, a fire-enabled dynamic global vegetation model, which takes a physically grounded approach to the representation of vegetation-fire dynamics. The combined model enables a coupled socio-ecological simulation of historical burned area. We calibrate the combined model using GFED5 burned area data and perform an independent evaluation using MODIS-based fire radiative power observations. Results suggest that as much as half of all global burned area is generated by managed anthropogenic fires—typically small fires that are lit for, and then spread according to, land user objectives. Furthermore, we demonstrate that including representation of managed anthropogenic fires in a coupled socio-ecological simulation improves understanding of the drivers of unmanaged wildfires. For example, we show how vegetation flammability and landscape fragmentation control inter-annual variability and longer-term change in unmanaged fires. Overall, findings presented here indicate that both socio-economic and climate change will be vital in determining the future trajectory of fire on Earth.
-
Journal articleEastwood J, Brown P, Oddy T, et al., 2025,
In flight performance of the MAGIC magnetoresistive magnetometer on the RadCube CubeSat
, Space Science Reviews, Vol: 221, ISSN: 0038-6308In studying space physics, planetary science, and space weather, space-based in situ measurements of the magnetic field are fundamental to understanding underlying physical processes, as well as providing context for other observations. Whilst in many cases instrument design is not severely constrained by the available resource envelope, there are many applications, particularly when using new generations of spacecraft platforms such as CubeSats, that require very low resource sensors. In this context we review the design, development, construction, and flight of the highly miniaturised MAGIC (MAGnetometer from Imperial College) instrument on the RadCube Technology Demonstration CubeSat. MAGIC consists of a boom-mounted (outboard) Anisotropic Magneto-Resistive (AMR) vector sensor connected by harness to a single electronics card inside RadCube. A second inboard AMR vector sensor is mounted on the electronics card. RadCube launched on 17 August 2021 to a sun-synchronous low-Earth polar orbit, with the main mission lasting until April 2022. Routine operations were subsequently extended to the end of 2022, with further special operations in 2023 and 2024 before re-entry on 20 August 2024. Here we review RadCube observations made over more than two years in orbit. Key results from MAGIC on RadCube include meeting ESA space weather magnetic field measurement requirements with both the outboard and inboard sensor, as well as detection of field aligned current signatures at high latitude.
-
Journal articleMackie A, Byrne MP, Van de Koot EK, et al., 2025,
Circulation and Cloud Responses to Patterned SST Warming
, Geophysical Research Letters, Vol: 52, ISSN: 0094-8276<jats:title>Abstract</jats:title><jats:p>The climatological atmospheric circulation is key to establishing the tropical “pattern effect”, whereby cloud feedbacks induced by sea surface temperature (SST) warming depend on the spatial structure of that warming. But how patterned warming‐induced circulation changes affect cloud responses is less clear. Here we use idealized simulations with prescribed SST perturbations to understand the contributions to changes in tropical‐mean cloud radiative effects (CRE) from different circulation regimes. We develop a novel framework based on moist static energy to understand the circulation response, targeting in particular the bulk circulation metric of ascent fraction. Warming concentrated in regions of ascent leads to a strong “upped‐ante” effect and spatial contraction of the ascending region. Our framework reveals substantial contributions to tropical‐mean CRE changes not only from traditional “pattern effect” regimes, but also from the intensification of convection in ascent regions as well as a smaller contribution from cloud changes in convective margins.</jats:p>
-
Journal articleWilson Kemsley S, Nowack P, Ceppi P, 2025,
Climate models underestimate global decreases in high‐cloud amount with warming
, Geophysical Research Letters, Vol: 52, ISSN: 0094-8276Cloud feedback has prevailed as a leading source of uncertainty in climate model projections under increasing atmospheric carbon dioxide. Cloud-controlling factor (CCF) analysis is an approach used to observationally constrain cloud feedback, and subsequently the climate sensitivity. Although high clouds contribute significantly toward uncertainty, they have received comparatively little attention in CCF and other observational analyses. Here we use CCF analysis for the first time to constrain the high-cloud radiative feedback, focusing on the cloud amount component owing to its dominant contribution to uncertainty in high-cloud feedback. Globally, observations indicate larger decreases in high cloudiness than state-of-the-art climate models suggest. In fact, half of the 16 models considered here predict radiative feedbacks inconsistent with observations, likely due to misrepresenting the stability iris mechanism. Despite the suggested strong high-cloud amount decreases with warming, observations point toward a near-neutral net high-cloud amount radiative feedback, owing to almost canceling longwave and shortwave contributions.
-
Journal articleDing M, 2025,
Challenges in Atomic Spectroscopy of Low-Ionisation-Stage Heavy Elements for Astrophysics
, ATOMS, Vol: 13 -
Conference paperBeth A, Galand M, Modolo R, et al., 2025,
Ionospheric environment of Ganymede during the Galileo flybys
, EGU General Assembly, Publisher: EGUThe 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.
-
Journal articleKim H, Kang SM, Pendergrass AG, et al., 2025,
Higher precipitation in East Asia and western United States expected with future Southern Ocean warming
, Nature Geoscience, Vol: 18, Pages: 313-321, ISSN: 1752-0894Precipitation over East Asia and the western United States is projected to increase as a result of global warming, although substantial uncertainties persist regarding the magnitude. A key factor driving these uncertainties is the tropical surface warming pattern, yet the mechanisms behind both this warming pattern and the resulting regional precipitation changes remain elusive. Here we use a set of climate model experiments to argue that these changes are partly driven by global teleconnection from the Southern Ocean, which rapidly absorbs anthropogenic heat but releases it with a delay of decades to a century. We show that the delayed Southern Ocean warming contributes to broad tropical ocean warming with an El Niño-like pattern, enhancing precipitation during summer in East Asia and winter in the western United States. The atmospheric teleconnections from the tropical ocean link the Southern Ocean warming to the Northern Hemisphere regional wetting. Southern Hemisphere low clouds are a key regulator of this teleconnection, partly explaining the projected uncertainty of regional precipitation. The documented teleconnection has practical implications: even if climate mitigation reduces carbon dioxide levels, the delayed Southern Ocean warming will sustain a wetter East Asia and western United States for decades to centuries.
-
Journal articleMooney MK, Milan SE, Lester M, et al., 2025,
Cluster observations of plasma in the high latitude magnetotail associated with cusp‐aligned arcs
, Journal of Geophysical Research: Space Physics, Vol: 130, ISSN: 2169-9380During periods of northward interplanetary magnetic field (IMF), the magnetospheric structureand dynamics are dramatically different compared to the southward IMF case. Previous studies using bothobservations and simulations have shown that under northward IMF the magnetotail becomes dominated byclosed magnetic flux and associated trapped particle populations. In this study, we analyze three intervals ofplasma observed in the high latitude magnetotail during a period of prolonged northward IMF, coinciding withobservations of cusp‐aligned arcs in the polar region. We observe that the plasma is typically observed by all 4Cluster spacecraft near simultaneously and has some substructure observed on length scales of 0.5–1.5 RE. Theplasma characteristics in each of the three intervals studied are similar. The ion and electron densities are on theorder of 10− 1–100 cm− 3. The electron energies typically vary between 102 and 103 eV. The ion energies arehigher compared to the electron energies and range between 102 and 104 eV. The ion temperatures are on theorder of 5–18 MK. The speed of the plasma crossing the Cluster spacecraft is between 1 and 10 kms− 1. In oneinterval Cluster observes distinctly different but adjacent plasma populations. We suggest these plasmapopulations are on interleaving flux tubes and may present supporting evidence for dual lobe reconnectionacting to trap plasma within the magnetosphere and resulting cusp‐aligned arc formation
-
Journal articleBeth A, Galand M, Modolo R, et al., 2025,
Ionosphere of Ganymede: Galileo observations versus test particle simulation
, Monthly Notices of the Royal Astronomical Society, Vol: 538, Pages: 2483-2507, ISSN: 0035-8711In this paper, we model the plasma environment of Ganymede by means of a collisionless test particle simulation. By couplingthe outputs from a Direct Simulation Monte Carlo (DSMC) simulation of Ganymede’s exosphere (i.e. number density profiles ofneutral species such as H, H2, O, HO, H2O, O2 for which we provide parametrization) with those of a MagnetoHydroDynamicsimulation of the interaction between Ganymede and the Jovian plasma (i.e. electric and magnetic fields), we perform acomparison between simulated ion plasma densities and ion energy spectra with those observed in situ during six close flybys ofGanymede by the Galileo spacecraft. We find that not only our test particle simulation sometimes can well reproduce the in situion number density measurement, but also the dominant ion species during these flybys are H+2 , O+2 , and occasionally H2O+.Although the observed ion energy spectra cannot be reproduced exactly, the simulated ion energy spectra exhibit similar trendsto those observed near the closest approach and near the magnetopause crossings but at lower energies. We show that the neutralexosphere plays an important role in supplying plasma to Ganymede’s magnetized environment and that additional mechanismsmay be at play to energize/accelerate newborn ions from the neutral exosphere.
-
Journal articleDeca J, Divin A, Stephenson P, et al., 2025,
A fully kinetic perspective on weakly active comets: asymmetric outgassing
, Planetary and Space Science, Vol: 258, ISSN: 0032-0633The European Space Agency’s Rosetta mission measured the complex plasma environment surrounding comet 67P/Churyumov-Gerasimenko for more than two years. In this work, the collisionless dynamics of the plasma interaction during the comet’s weakly outgassing phases is investigated through a fully kinetic semi-implicit particle-in-cell approach. The effects of an asymmetric outgassing profile with respect to the upstream plasma conditions are compared with a spherically symmetric Haser model. The three-dimensional shape of the plasma density and the parallel acceleration potential are used as primary measures. It is found that the four-fluid coupled system is not majorly distorted. The different components of the potential structure can be associated with the large-scale behavior and density profiles of the four simulated plasma species. The implications for the acceleration and cooling of electrons within the cometary plasma environment are identified by contrasting the differences in the shape of the acceleration potential between the distinct asymmetric outgassing models. The analysis provides a detailed overview that can help interpret past Rosetta plasma measurements and could be key to help disentangle the physical drivers active in the plasma environment of comets visited by future exploration missions.
-
Journal articleLittle K, Vitali R, Belcher CM, et al., 2025,
Priority research directions for wildfire science: views from a historically fire-prone and an emerging fire-prone country
, Philosophical Transactions of the Royal Society B: Biological Sciences, Vol: 380, ISSN: 0962-8436Fire regimes are changing across the globe, with new wildfire behaviour phenomena and increasing impacts felt, especially in ecosystems without clear adaptations to wildfire. These trends pose significant challenges to the scientific community in understanding and communicating these changes and their implications, particularly where we lack underlying scientific evidence to inform decision-making. Here, we present a perspective on priority directions for wildfire science research—through the lens of academic and government wildfire scientists from a historically wildfire-prone (USA) and emerging wildfire-prone (UK) country. Key topic areas outlined during a series of workshops in 2023 were as follows: (A) understanding and predicting fire occurrence, fire behaviour and fire impacts; (B) increasing human and ecosystem resilience to fire; and (C) understanding the atmospheric and climate impacts of fire. Participants agreed on focused research questions that were seen as priority scientific research gaps. Fire behaviour was identified as a central connecting theme that would allow critical advances to be made across all topic areas. These findings provide one group of perspectives to feed into a more transdisciplinary outline of wildfire research priorities across the diversity of knowledge bases and perspectives that are critical in addressing wildfire research challenges under changing fire regimes.
-
Conference paperLee D, Ceppi P, 2025,
Hydrological sensitivity affected by tropical tropospheric stability
<jats:p>Climate forcers perturb the energy amount inside the Earth, and atmospheric interactions in the troposphere sequentially vary to pursue the new stable state in the given energy budget. The varied energy amount of longwave, shortwave, and sensible heat flux in the atmosphere is balanced with latent heat flux, equivalent to the changes in precipitation in the global mean sense. For example, rising temperature emits more longwave radiation from the atmosphere (longwave cooling, LWC), and it allows more energy budget room for latent heat flux (LHF) heating, which explains enhanced precipitation.Although previous studies argued hydrological sensitivity as the linearized scale of precipitation change per the global mean temperature change, this study confirms that tropical tropospheric stability has additionally affected hydrological sensitivity over the decades. Our results reveal that tropical ocean temperature patterns correlate statistically with the stability index. The numerically simplified term of this stability effect improves the prediction skills of the theoretical equation for the global mean precipitation change under scenarios with various forcing conditions.&#160; Lastly, we discuss the possible impacts of recent ocean patterns and the tropical tropospheric stability phase on precipitation by comparing the observed data and climate models&#8217; simulations, which are forced by the observed sea surface temperature.</jats:p>
-
Journal articleFujita R, Graven H, Zazzeri G, et al., 2025,
Global Fossil Methane Emissions Constrained by Multi-Isotopic Atmospheric Methane Histories
, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, Vol: 130, ISSN: 2169-897X- Cite
- Citations: 2
-
Conference paperTarasi D, Kasoar M, Mulyasih H, et al., 2025,
An improved approach for simulating peat ignition probability using experimental data
, AGU General Assembly -
Journal articleSimpson IR, Shaw TA, Ceppi P, et al., 2025,
Confronting Earth System Model trends with observations
, Science Advances, Vol: 11, ISSN: 2375-2548Anthropogenically forced climate change signals are emerging from the noise of internal variability in observations, and the impacts on society are growing. For decades, Climate or Earth System Models have been predicting how these climate change signals will unfold. While challenges remain, given the growing forced trends and the lengthening observational record, the climate science community is now in a position to confront the signals, as represented by historical trends, in models with observations. This review covers the state of the science on the ability of models to represent historical trends in the climate system. It also outlines robust procedures that should be used when comparing modeled and observed trends and how to move beyond quantification into understanding. Finally, this review discusses cutting-edge methods for identifying sources of discrepancies and the importance of future confrontations.
-
Journal articleDriver O, Stettler MEJ, Gryspeerdt E, 2025,
Factors limiting contrail detection in satellite imagery
, Atmospheric Measurement Techniques, ISSN: 1867-1381
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.