Geophysical Research Letters

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…

Abstract Topographic highlands commonly develop along convergent plate boundaries through long‐term processes such as subduction and continental collision. However, the pre‐Cenozoic mountain‐building history of deep‐time orogenic systems in northeastern Pangaea remains poorly constrained due to later tectonic overprinting and denudation. Here we present detrital zircon U–Pb–Hf data to reconstruct…

Abstract Extreme rainfall events over Central India have increased, reflecting intensified monsoon precipitation driven by factors like urbanization and land use change. With projections indicating further intensification and flood vulnerability, better prediction is critical. We present a physically grounded, operationally actionable framework using network divergence on directed networks from n…

Abstract As the most recent interglacial period and the timeframe for the development of human civilization, the Holocene provides a critical perspective for understanding future climate under continued global warming. This special collection focuses on Holocene climate changes and features 14 interdisciplinary studies. It addresses three core themes: reconstructing climate variability and extrem…

Abstract Laboratory experiments measured velocity and bedload transport in vegetated channels under current‐dominated, combined wave‐current conditions. Waves and vegetation, respectively, introduced temporal and spatial heterogeneity in the velocity, which significantly impacted sediment transport rate. Compared to pure‐current, the addition of waves only moderately increased (<40%) the time‐…

Abstract Our understanding of raindrop size distributions (DSDs) aloft is largely limited, owing to a scarcity of effective measurements. In this study, a two‐step optimal estimation technique is developed for retrieving binned DSDs based on a newly developed vertically‐pointing triple‐frequency radar system. In the first step, we employ the Tridon and Battaglia (2015, https://doi.org/10.1002/201…

Abstract It is known that solar flares generate instantaneous ionization enhancement, referred to as sudden ionospheric disturbance (SID), that occurs simultaneously across the entire dayside. In this work, we use high‐rate 1‐s data of total electron content (TEC) to analyse ionospheric response to 13 solar flares that occurred in 2003–2023. For the first time, we demonstrate that the SID first a…

Abstract Climate change impacts include contributions from both anthropogenic forcing and internal (natural) climate variability. Large ensembles of Earth System Model (ESM) simulations have been used to quantify the influence of natural variability in climate change impact projections. However, such ensembles have high computational costs. Future climate scenarios can be simulated at much lower …

Abstract The threefold daytime electron density increases, along with strong poleward meridional winds exceeding 200 m/s were captured by Sanya Incoherent Scatter Radar (SYISR) during the geomagnetic storm of 12 November 2025. The great ionospheric enhancements were extending to mid‐latitudes over 40° observed by total electron content (TEC) from Beidou geostationary satellites. Thermosphere‐Iono…

Abstract We use novel, fast 4D Synchrotron X‐ray imaging with large field‐of‐view to reveal pore‐ and macro‐scale drainage dynamics during gas–brine flow through a layered sandstone rock sample. We show that a single centimeter‐scale layer, similar in pore size distribution to the surrounding rock but with reduced connectivity, temporarily inhibits, and redirects gas flow, acting as a capillary b…

Abstract The Atlantic Niño/Niña is a leading mode of tropical climate variability with profound global environmental and socioeconomic impacts. Conventionally, its variability is projected to weaken under greenhouse warming, primarily attributed to suppressed basin‐scale air–sea interactions. However, the modulating role of sub‐basin‐scale ocean dynamical processes remains largely unexplored. Her…