Geophysical Research Letters

Abstract The large‐scale traveling ionospheric disturbances (LSTIDs) over the Asian‐Pacific sector during the 10–11 May 2024 superstorm are investigated using ionosonde observation and simulation from a whole geospace model—Multiscale Atmosphere Geospace Environment (MAGE), which fully couples multiple magnetosphere, ionosphere and thermosphere models. The ionosonde‐observed ionospheric hmF2 and …

Abstract The South Pole‐Aitken (SPA) Basin, the Moon's largest impact structure, holds key insights into lunar evolution, prompting the Chang'e‐6 mission to return first samples for ground‐truth verification. Analysis of over 6,000 grains from the Chang'e‐6 soil returned from the SPA Basin reveals a composition dominated by clinopyroxene (26.5–32.9 vol.%), plagioclase (29.9–33.2 vol.%) and glass …

Abstract Recent decades have seen persistent sea surface temperature (SST) cooling in the Southeast Pacific (SEP) and Southern Ocean (SO), contrasting with broad ocean warming expected under anthropogenic forcing. Using an interpretable machine‐learning attribution framework applied to multi‐source observations and reanalyses, we focus on monthly SST variations beyond intrinsic oceanic persistenc…

Abstract The Arabian Peninsula encompasses one of the world's most extensive aeolian systems, yet the provenance and transport history of its dune sediments are not well understood. Using hyperspectral data from NASA's Earth Surface Mineral Dust Source Investigation (EMIT), we mapped mineral compositions and abundance patterns across dune fields and adjacent source regions by analyzing diagnostic…

Abstract Despite decades of research, hundreds of peer‐reviewed papers, and considerable relevance to Earth's future, the rapid global warming and tremendous CO 2 input at the start of the Paleocene‐Eocene Thermal Maximum (PETM) remain highly debated. Cael and Foster (2026, https://doi.org/10.1029/2025gl120456 ) present a statistical treatment of Cenozoic benthic foraminifera (BF) stable isotope …

Abstract Plagioclase records characteristic shock features that constrain meteorite impact conditions, but its phase evolution along the Hugoniot remains unresolved. We investigated shock‐induced phase transition in albite using in situ X‐ray diffraction during laser‐driven shock at 14–66 GPa. Albite retained its crystal structure up to at least 14 GPa and underwent complete amorphization above 2…

Abstract Equation discovery methods, such as symbolic regression, show great promise to generate parameterizations of biogeochemical processes in an objective data‐driven manner, yet remain untested in ocean biogeochemistry. Here, we apply symbolic regression to a state‐of‐the‐art ocean biogeochemical model, using it as a surrogate data set to rediscover an empirical equation used to calculate co…

Abstract Mercury experiences the most intense and variable solar wind (SW) conditions in the solar system due to its close, eccentric orbit about the Sun. In addition to variation driven by coronal source and solar cycle, the SW arriving at Mercury varies periodically as the planet's heliocentric distance changes by over 50% per orbit. We use 30 years of SW measurements near Earth and scale them …

Abstract The surface energy budget governs Arctic sea‐ice growth/melt, yet observations are sparse, and reanalysis data sets suffer from systematic biases. Here, we train a neural network with observational data to bias‐correct hourly ERA5 fluxes over Arctic ice‐covered regions (≥70°N; sea‐ice concentration >80%) for 1994–2024. Training data cover two full seasonal cycles and different sea‐ice…

Abstract A southward shift of the Intertropical Convergence Zone (ITCZ) during the latter half of the 20th century has been primarily attributed to interhemispheric differences in anthropogenic aerosol forcing. However, in recent decades anthropogenic aerosol emissions have declined, particularly over Northern Hemisphere (NH). Here, we explore the response of the ITCZ to changes in anthropogenic …

Abstract Compound drought and heatwave (CDHW) events pose a major threat to agricultural sectors worldwide. This study quantifies projected changes in the frequency, duration, and intensity of CDHW events across major breadbasket regions. Historical CDHW occurrences (1982–2019) are compared with future projections (2020–2095) derived from eight CMIP6 climate models under three Shared Socioeconomi…

Abstract This paper examines discrepancies between cloud optical thickness (COT) retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud product, and cloud opacity measurements from the Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) lidar. The statistical analysis of a yearlong data set of collocated MODIS‐CALIOP retrievals reveals a striking discrepancy: many s…

Abstract Machine learning (ML) applications in hydrological forecasting are increasingly prevalent and show great potential. However, many previous studies have only evaluated performance through reanalysis or retrospective simulations compared to simplified baselines. This study provides the first assessment of ML performance against actual operational forecasting systems operated by the Califor…

Abstract Atmospheric rivers (ARs) can rapidly alter regional hydrothermal conditions and directly affect lake ice. This study presents the first assessment of AR impacts on lake ice phenology across the Northern Hemisphere. AR events were associated with positive anomalies in temperature, rainfall, and snowfall, as well as negative anomalies in solar radiation. These climate anomalies showed sign…

Abstract Frictional slip behavior in fault zones can be analyzed with friction laws using 1 or 2 state variables, but the physical meaning and applicability of the 2‐state variable form of the law remain unclear. Here, we re‐analyze friction experiments by Roesner et al. (2022, https://doi.org/10.1186/s40623‐022‐01728‐w ) using a natural sample from the megasplay fault in the Nankai subduction zo…

Abstract Sea‐level rise (SLR) alters nearshore hydrodynamics, yet its influence on coral reef thermal regimes under climate‐driven ocean warming remains poorly quantified. Using a fully coupled hydrodynamic–wave model validated at Palmyra Atoll, we isolate how SLR modifies temperature variability during a projected 2050 marine heatwave. Results show that while basin‐scale warming raises reef bott…

Abstract The direct effective radiative forcing (ERF) of long‐lived ozone‐depleting substances (ODS) is around 15%–20% of the pre‐industrial to present‐day ERF of , but their net ERF, including indirect chemical adjustments, remains poorly constrained. We use an adapted simple climate model, trained on bulk indirect ODS forcing from complex climate models, to quantify uncertainty in net ERF over …

Abstract A nonlinear gyrokinetic simulation is applied to the magnetosphere‐ionosphere (M‐I) coupling system to investigate spontaneous growth of auroral structures and electron acceleration self‐consistently. Perturbations of electron density, potential and field‐aligned current in the auroral ionosphere develop through the feedback instability, resulting in nonlinear deformations of the auroral…

Abstract Seismological estimates of the 400‐km and 670‐km mantle discontinuities (d400 and d670) are crucial for understanding the thermochemical structure and dynamics of the mantle transition zone (MTZ). However, artifacts from using ray theory and uncertainties in mantle velocity structure can affect topographic mapping of these boundaries. The artifacts are expected but have not been thorough…

Abstract The evolution of moist static energy (MSE) is widely used to understand the organization and propagation of the Madden‐Julian Oscillation (MJO). Past studies, largely based on reanalysis or short‐term observations, have highlighted humidity as the dominant driver of MJO evolution. Using 14 years of bias‐corrected radiosonde observations from the Department of Energy—Atmospheric Radiation…