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The LCROSS Impact Crater as Seen by ShadowCam and Mini-RF: Size, Context, and Excavation of Copernican Volatiles Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-17 C. I. Fassett, M. S. Robinson, G. W. Patterson, B. W. Denevi, P. Mahanti, E. Mazarico, E. G. Rivera-Valentín, F. S. Turner, M. R. Manheim, A. Colaprete
The Lunar CRater Observations and Sensing Satellite (LCROSS) impacted a Centaur rocket stage into a permanently shadowed region (PSR) in Cabeus crater, excavating water ice and other volatiles. We used the Miniature Radio Frequency (Mini-RF) instrument on the Lunar Reconnaissance Orbiter and the ShadowCam instrument on the Korean Pathfinder Lunar Orbiter to detect the probable 22-m diameter crater
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Looking for Subsurface Oceans Within the Moons of Uranus Using Librations and Gravity Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-15 D. J. Hemingway, F. Nimmo
Several of the icy moons in the Jupiter and Saturn systems appear to possess internal liquid water oceans. Our knowledge of the Uranian moons is more limited but a future tour of the system has the potential to detect subsurface oceans. Planning for this requires an understanding of how the moons' internal structures—with and without oceans—relate to observable quantities. Here, we show that the amplitude
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Humid, Warm and Treed Ecosystems Show Longer Time-Lag of Vegetation Response to Climate Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-17 Xinran Gao, Wen Zhuo, Alemu Gonsamo
Climate-vegetation interaction assessments often focus on vegetation response to concurrent climatic perturbations, seldom on the time-lag effect of climate. Here we employ global satellite observations, climate data records and CO2 flux measurements to calculate the time-lag of vegetation response to climate. We analyze the time-lags of various climate variables under distinct environmental conditions
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Permafrost Hydrogeology of Taylor Valley, Antarctica: Insights From Deep Electrical Resistivity Tomography Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-16 Valentina Romano, Federico Fischanger, Gary Wilson, Alessandra Sciarra, Adriano Mazzini, Claudio Mazzoli, Fabio Florindo, Maria Chiara Tartarello, Massimiliano Ascani, Jacob Anderson, Rachel Worthington, Richard Hardie, Bob Dagg, Livio Ruggiero
Global warming has prompted globally widespread permafrost thawing, resulting in enhanced greenhouse gas release into the atmosphere. Studies conducted in the Northern Hemisphere reveal an alarming increase in permafrost thawing. However, similar data from Antarctica are scarce. We conducted a 2-D Deep Electrical Resistivity Tomography (DERT) survey in Taylor Valley, Antarctica, to image the distribution
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Inland Summer Speedup at Zachariæ Isstrøm, Northeast Greenland, Driven by Subglacial Hydrology Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-15 Shfaqat A. Khan, Mathieu Morlighem, Shivani Ehrenfeucht, Helene Seroussi, Youngmin Choi, Eric Rignot, Angelika Humbert, Derek Pickell, Javed Hassan
The Northeast Greenland Ice Stream (NEGIS) has experienced substantial dynamic thinning in recent years. Here, we examine the evolving behavior of NEGIS, with focus on summer speedup at Zachariae Isstrøm, one of the NEGIS outlet glaciers, which has exhibited rapid retreat and acceleration, indicative of its vulnerability to changing climate conditions. Through a combination of Sentinel-1 data, in-situ
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Large-Scale Climate Features Control Fire Emissions and Transport in Africa Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-15 Amin Dezfuli, Charles M. Ichoku, Michael G. Bosilovich
Recent increase in extreme wildfire events has led to major health and environmental consequences across the globe. These adverse impacts underlined the need for better understanding of this phenomenon and to formulate mitigating actions. While previous research has focused on local weather drivers of wildfires, our knowledge about their large-scale climatic controls remains limited, especially in
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Variation of Molecular Ions in the Inner Magnetosphere Observed by the Arase Satellite Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-16 A. Nagatani, Y. Miyoshi, K. Asamura, L. M. Kistler, S. Nakamura, K. Seki, Y. Ogawa, I. Shinohara
We analyzed time-of-flight (TOF) data from the Arase satellite to investigate temporal variations of the molecular ion group (O2+, NO+, and N2+) at 19.2 keV/q in the inner magnetosphere for 6 years from the solar declining to rising phase. The molecular ions counts were estimated by subtracting the background contamination of oxygen counts. While the number of clear molecular ion events was small,
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Changes in Four Decades of Near-CONUS Tropical Cyclones in an Ensemble of 12 km Thermodynamic Global Warming Simulations Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-15 Colin M. Zarzycki, Tyrone Zhang, Andrew D. Jones, Deeksha Rastogi, Pouya Vahmani, Paul A. Ullrich
We evaluate tropical cyclones (TCs) in a set of thermodynamic global warming (TGW) simulations over the continental United States (CONUS). A 12 km simulation forced by ERA5 provides a 40-year historical (1980–2019) control. Four complimentary future scenarios are generated using thermodynamic deltas applied to lateral boundary, interior, and surface forcing. We curate a data set of 4,498 6-hourly TC
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A Model-Based Investigation of the Recent Rebound of Shelf Water Salinity in the Ross Sea Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-16 Jingwei Zhang, Xuebin Zhang, Matt A. King, Kewei Lyu
Intense atmosphere-ocean-ice interactions in the Ross Sea play a vital role in global overturning circulation by supplying saline and dense shelf waters. Since the 1960s, freshening of the Ross Sea shelf water has led to a decline in Antarctic Bottom Water formation. However, during 2012–2018, salinity of the western Ross Sea has rebounded. This study adopts a global ocean-sea ice model to investigate
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Fluid Drainage Leads to Thermal Decomposition of Wet Gouge During Experimental Seismic Slip Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Thi Trinh Nguyen, Li-Wei Kuo, Qing-En Kong, Chia-Wei Kuo, Jia-Jyun Dong, Dennis Brown, Huan Wang, Szu-Ting Kuo, Haibing Li, Jialiang Si
Several borehole cores intersecting faults related to coseismic slip display high-temperature features, including thermal decomposition of fault gouge. We present evidence that these features may be related to fluid drainage of the slip zone during seismic slip. We sheared water-saturated kaolinite powders under both fluid drained and undrained conditions, expected for seismic slip at shallow crustal
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Plasma Structure Decay Rates in the Equatorial Ionosphere Are Strongly Coupled by Turbulence Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 M. F. Ivarsen, J.-P. St-Maurice, J. Park, J. Klenzing, Y. Jin, W. Lee
Equatorial plasma irregularities in the ionospheric F-region proliferate after sunset, causing the most apparent radio scintillation “hot-spot” in geospace. These irregularities are caused by plasma instabilities, and appear mostly in the form of under-densities that rise up from the F-region's bottomside. After an irregularity production peak at sunset, the amplitude of the resulting turbulence decays
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Delayed Summer Monsoon Onset in Response to the Cold Tongue in the South China Sea Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Xiaorong Fang, Weidong Yu
The interannual variation of the South China Sea (SCS) summer monsoon onset (SMO) may bring extreme weather and climate disasters in East Asia. However, its skillful forecast still remains challenging. This study investigates the intraseasonal ocean-atmosphere interaction that affects the SCSSMO through diagnostic analysis and numerical experiments. It reveals that the cold sea surface temperature
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Using Random Forests to Compare the Sensitivity of Observed Particulate Inorganic and Particulate Organic Carbon to Environmental Conditions Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Rui Jin, Anand Gnanadesikan, Christopher Holder
The balance between particulate inorganic carbon (PIC) and particulate organic carbon (POC) holds significant importance in carbon storage within the ocean. A recent investigation delved into the spatial distribution of phytoplankton and the physiological mechanisms governing their growth. Employing random forests, a machine learning technique, this study unveiled apparent relationships between POC
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Plasma Sheet Magnetic Flux Transport During Geomagnetic Storms Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Savvas Raptis, Viacheslav Merkin, Shinichi Ohtani, Matina Gkioulidou, Leonardo H. Regoli
Plasma sheet convection is a key element of storm-time plasma dynamics in the magnetosphere. While decades of observations have advanced our understanding of convection in general, specifically storm-time convection remains poorly understood. Using data from ISAS/NASA's Geotail and NASA's MMS, this study characterizes plasma sheet magnetic flux transport across the magnetotail during numerous storms
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The Shortwave Cloud-SST Feedback Amplifies Multi-Decadal Pacific Sea Surface Temperature Trends: Implications for Observed Cooling Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Zachary I. Espinosa, Mark D. Zelinka
Climate models struggle to produce sea surface temperature (SST) gradient trends in the tropical Pacific comparable to those seen recently in nature. Here, we find that the magnitude of the cloud-SST feedback in the subtropical Southeast Pacific is correlated across models with the magnitude of Eastern Pacific multi-decadal SST variability. A heat-budget analysis reveals coupling between cloud-radiative
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Orbital Tuning of Short Reversed Geomagnetic Polarity Intervals in the Cretaceous Normal Polarity Superchron Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 J. M. F. Ramos, J. F. Savian, D. R. Franco, M. F. Figueiredo, C. G. Leandro, F. Frontalini
While the Cretaceous Normal Polarity Superchron has documented instances of brief reversed polarity intervals, the absence of accurate age determinations for such abrupt shifts poses a challenge in leveraging them as reliable reference tiepoints. This study presents a cyclostratigraphic analysis of gamma-ray data from the DSDP Site 402A. The identification of Milankovitch cycles allowed us to construct
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South Pacific Water Intrusion Into the Sub-Thermocline Makassar Strait in the Winter of 2016–2017 Following a Super El Niño Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Mingting Li, Dongliang Yuan, Arnold L. Gordon, Laura K. Gruenburg, Dongxiao Wang
The Makassar Strait throughflow (MST) is the major component of the Indonesian Throughflow (ITF), transferring Pacific water into the Indian Ocean. In our previous study, we identified a new zonal pathway, a. k.a. the North Equatorial Subsurface Current (NESC), which carried equatorial water into the MST sub-thermocline (>300 m) in the summer 2016 following the 2015/16 El Niño. We now show continued
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Mapping Los Angeles Basin Depth With Sp Converted Phases Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-13 Yan Yang, Robert W. Clayton
The depth of the Los Angeles (LA) basin is a critical factor for seismic hazard assessment and active tectonic studies. By analyzing S-waves generated by earthquakes below the basin that convert to P-waves at the sediment-bedrock interface, we estimate the maximum depth of the LA basin to be 9 km. This estimate depends on the velocities within and below the basin, and the depth presented here is based
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Strong Energy Conversion at Magnetotail Plasma Sheet Boundary Layer Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-12 C. X. Du, H. S. Fu, J. B. Cao, Z. Wang, Y. Yu, W. D. Fu, W. Z. Zhang
The magnetotail plasma sheet boundary layer (PSBL) is a dynamic boundary layer between the hot-denser plasma sheet and the cold-tenuous tail lobes. It plays an important role in exchanging mass and energy in the magnetotail. In previous studies, the local current carried by the electron beams has been well understood. The strong energy conversion (E ⋅ J, E is electric field and J is current density)
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First Altitude-Triggered Lightning Experiment Associated With an Elevated Wind Turbine Blade on the Ground Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 Jinliang He, Guohua Yang, Quanxin Li, Jianpei Zhang, Yang Zhang, Weitao Lyu, Lei Fu, Chijie Zhuang, Bo Zhang
Lightning is the severest threaten to safe operation of wind turbines. In this letter, the authors present the first altitude-triggered lightning experiment involving an elevated 12 m-long wind turbine blade placed on the ground. A total of 50 precursors with amplitude over 62.9 A were observed through measurements of channel-base current, fast electric field, and optical data. The air gap with around
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Three Atmospheric Patterns Dominate Decadal North Atlantic Overturning Variability Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 Dafydd Stephenson, Daniel E. Amrhein, LuAnne Thompson
Atlantic Meridional Overturning Circulation (AMOC) variability originates from a large number of interacting processes with multiple time scales, with dominant processes dependent on both the latitude and timescale of interest. Here, we isolate the optimal atmospheric modes driving climate-relevant decadal AMOC variability using a novel approach combining dynamical and statistical attribution (dynamics-weighted
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Modeling the Impact of Seasonal Water Table Fluctuations on Ambient Noise Interferometry Using Acousto-Elastic Effect Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-12 Y. Wang, J. Schmittbuhl, J. Azzola, F. Mattern, D. Zigone, O. Lengliné, V. Magnenet, J. Vergne
Ambient noise interferometry has become a common technique for monitoring slight changes in seismic velocity in a variety of contexts. However, the physical origin of the resolved small velocity fluctuations is not well established for long-term seasonal effects. Here we propose a physical forward model of scattered waves in a deformable medium that includes acousto-elastic effect, which refers to
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Separating Injection-Driven and Earthquake-Driven Induced Seismicity by Combining a Fully Coupled Poroelastic Model With Interpretable Machine Learning Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 R. G. Hill, D. T. Trugman, M. Weingarten
In areas of induced seismicity, earthquakes can be triggered by stress changes due to fluid injection and static deformation from fault slip. Here we present a method to distinguish between injection-driven and earthquake-driven triggering of induced seismicity by combining a calibrated, fully coupled, poroelastic stress model of wastewater injection with interpretation of a machine learning algorithm
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Mid-Latitude Auroras and Energetic Particle Precipitation Occurred Unusually in a Moderate Magnetic Storm on 1 December 2023 Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 Longxing Ma, Yiqun Yu, Xiaoqi Ding, Xiyu Liu, Depeng An, Chenlong Zhou, Jinbin Cao, Kazuo Shiokawa
Mid-latitude auroras are conventionally generated during intense magnetic storms. However, mid-latitude auroras were observed by naked eyes at Beijing China (39°N, 116°E) unusually during a moderate storm event on 1 December 2023 with the minimum Sym-H index only ∼${\sim} $ −120 nT. This study combines conjugative in-site and ground-based observations to analyze the auroras and underlying physical
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Contrasting Chlorine Chemistry on Volcanic and Wildfire Aerosols in the Southern Mid-Latitude Lower Stratosphere Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 Peidong Wang, Susan Solomon
Volcanic eruptions and wildfires can impact stratospheric chemistry. We apply tracer-tracer correlations to satellite data from Atmospheric Chemistry Experiment—Fourier Transform Spectrometer and the Halogen Occultation Experiment at 68 hPa to consistently compare the chemical impact on HCl after multiple wildfires and volcanic eruptions of different magnitudes. The 2020 Australian New Year (ANY) fire
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Unraveling the Extensive Impact of Subthermocline Eddies on the Western Pacific Undercurrent System Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 Fuad Azminuddin, Chan Joo Jang, Raden Dwi Susanto, Saat Mubarrok
Subthermocline eddies (SEs) influencing ocean circulation are progressively known, yet their extensive impact on the western Pacific undercurrent system remains largely unexplored and, in some regions, often underestimated. Okubo-Weiss parameter analysis reveals a distinctive meridional pattern of cyclonic and anticyclonic SE distribution in the interior western Pacific basin that aligns with zonally
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Seamounts Enhance the Local Emission of CO2 in the Northern South China Sea Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-11 Gong Zhang, Bo Han, Qinghua Yang, Xueming Zhu, Xiaojing Wang, Honge He, Hongliang Li, Xinyang Wang, Wei Xie, Dake Chen
The South China Sea is a typical marginal sea characterized by the presence of numerous seamounts. However, the effect of seamounts on the air-sea CO2 flux has not yet been well studied. In September 2021, the air-sea CO2 flux was measured directly using eddy covariance (EC), and discrete waterside sampling was conducted. The results indicate that the northern South China Sea is a source of atmospheric
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A Mid-Crustal Channel of Positive Radial Anisotropy Beneath the Eastern South China Block From F-J Multimodal Ambient Noise Tomography Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-10 Juqing Chen, Zhengbo Li, Xiaofei Chen
We investigated the crustal radial anisotropy in the eastern South China Block (ESCB) with the F-J multimodal ambient noise tomography. Well corresponding to widespread mid-crustal low-velocity zones in the VSV${V}_{SV}$ model, a pronounced mid-crustal channel of positive radial anisotropy is revealed. In the Cathaysia Block, it may origin from sub-horizontally aligned quartz induced by extension
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The Influence of Large-Scale Spatial Warming on Jet Stream Extreme Waviness on an Aquaplanet Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-10 T. J. Batelaan, C. Weijenborg, G. J. Steeneveld, C. C. van Heerwaarden, V. A. Sinclair
The effect of modified equator-to-pole temperature gradients on the jet stream by low-level polar warming and upper-level tropical warming is not fully understood. We perform aquaplanet simulations to quantify the impact of different sea surface temperature distributions on jet stream strength, large wave amplitudes and extreme waviness. The responses to warming in the waviness metrics Sinuosity Index
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Inferring the Speed of Sound and Wind in the Nighttime Martian Boundary Layer From Impact-Generated Infrasound Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-10 Marouchka Froment, Zongbo Xu, Philippe H. Lognonné, Carène Larmat, Raphael F. Garcia, Mélanie Drilleau, Brent G. Delbridge, Aymeric Spiga, Taichi Kawamura, Éric Beucler
The properties of the first kilometers of the Martian atmospheric Planetary Boundary Layer have until now been measured by only a few instruments and probes. InSight offers an opportunity to investigate this region through seismoacoustics. On six occasions, its seismometers recorded short low-frequency waveforms, with clear dispersion between 0.4 and 4 Hz. These signals are the air-to-ground coupling
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The Effect of Nitrogen on the Dihedral Angle Between Fe−Ni Melt and Ringwoodite: Implications for the Nitrogen Deficit in the Bulk Silicate Earth Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-10 Kyusei Tsuno, Damanveer S. Grewal, Virginia Xu, Logan Leinbach, Kurt Leinenweber, Axel Wittmann, Sang-Heon Shim
Nitrogen (N) is extremely depleted in the bulk silicate Earth (BSE). However, whether the silicate magma ocean was as N-poor as the present-day BSE is unknown. We performed multi-anvil experiments at 20 GPa and 1,673−2,073 K to determine the dihedral angle of Fe−Ni−N alloy melt in ringwoodite matrix to investigate whether percolation of Fe-rich alloy melt in the solid mantle can explain N depletion
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Issue Information Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-10
No abstract is available for this article.
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Deep Learning Improves Global Satellite Observations of Ocean Eddy Dynamics Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 Scott A. Martin, Georgy E. Manucharyan, Patrice Klein
Ocean eddies affect large-scale circulation and induce a kinetic energy cascade through their non-linear interactions. However, since global observations of eddy dynamics come from satellite altimetry maps that smooth eddies and distort their geometry, the strength of this cascade is underestimated. Here, we use deep learning to improve observational estimates of global surface geostrophic currents
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Earth's Mesosphere During Possible Encounters With Massive Interstellar Clouds 2 and 7 Million Years Ago Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 Jesse A. Miller, Merav Opher, Maria Hatzaki, Kyriakoula Papachristopoulou, Brian C. Thomas
Our solar system's path has recently been shown to potentially intersect dense interstellar clouds 2 and 7 million years ago: the Local Lynx of Cold Cloud and the edge of the Local Bubble. These clouds compressed the heliosphere, directly exposing Earth to the interstellar medium. Previous studies that examined climate effects of these encounters argued for an induced ice age due to the formation of
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Evidence of Groundwater Seepage and Mixing at the Vicinity of a Knickpoint in a Mountain Stream Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-08 Marius G. Floriancic, Ronan Abhervé, Camille Bouchez, Joaquin Jimenez-Martinez, Clément Roques
Streamflow generation and biochemical hotspots are significantly influenced by groundwater contributions distributed along the drainage network. However, identifying the geomorphic landscape features that drive groundwater-surface water interactions remains challenging. In this study, we investigate the role of knickpoints in controlling these interactions in a mountainous stream in Switzerland. We
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Rapid Downwelling of Tracer Particles Across the Boundary Layer and Into the Pycnocline at Submesoscale Ocean Fronts Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 Hieu T. Pham, Vicky Verma, Sutanu Sarkar, Andrey Y. Shcherbina, Eric A. D’Asaro
A neutrally buoyant float deployed in an atmospherically driven turbulent ocean boundary layer on the dense side of a submesoscale front was repeatedly carried across the boundary layer by the turbulence and then trapped beneath the slumping front. Lagrangian particles in a large-eddy simulation of a similar baroclinically unstable front forced by surface cooling move along convergent surface filaments
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The Principal Role of Chorus Ducting for Night-Side Relativistic Electron Precipitation Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-08 Ning Kang, Anton V. Artemyev, Jacob Bortnik, Xiao-Jia Zhang, Vassilis Angelopoulos
Night-side chorus waves are often observed during plasma sheet injections, typically confined around the equator and thus potentially responsible for precipitation of ≲100 keV electrons. However, recent low-altitude observations have revealed the critical role of chorus waves in scattering relativistic electrons on the night-side. This study presents a night-side relativistic electron precipitation
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Low-Viscosity Zones Beneath the Coso Volcanic Field Revealed by Postseismic Deformations Following the 2019 Ridgecrest Earthquake Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 Fei Chen, Faqi Diao, Yuhao Xu, Xiong Xiong
The rheology of materials near fault zones controls the deformation of the fault, thus playing an important role in the rupture propagation of large earthquakes. Here, we model the postseismic deformation in the first 4 years following the 2019 Ridgecrest earthquake, and probe the laterally variable lower-crustal viscosity and fault afterslip, using a combined model incorporating afterslip and viscoelastic
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Dust Accelerates the Life Cycle of High Clouds Unveiled Through Strongly-Constrained Meteorology Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-06 Jinming Ge, Wenxue Li, Jianping Huang, Qinyu Mu, Qinghao Li, Qingyun Zhao, Jing Su, Yongkun Xie, Khan Alam, Zeen Zhu, Xiaoyu Hu
Dust and high cloud interactions are critical for climate change, primarily due to the dominant roles of high cloud in the greenhouse effect and the continental precipitation. Nonetheless, disentangling the specific impacts of dust from the overlying meteorology influence on high clouds presents great challenges. In this study, we construct a meteorological pattern that successfully reveal the intricate
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Evidence of a New Population of Weak Terrestrial Gamma-Ray Flashes Observed From Aircraft Altitude Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 I. Bjørge-Engeland, N. Østgaard, D. Sarria, M. Marisaldi, A. Mezentsev, A. Fuglestad, N. Lehtinen, J. E. Grove, D. Shy, T. Lang, M. Quick, H. Christian, C. Schultz, R. Blakeslee, I. Adams, R. Kroodsma, G. Heymsfield, K. Ullaland, S. Yang, B. Hasan Qureshi, J. Søndergaard, B. Husa, D. Walker, M. Bateman, D. Mach, P. Bitzer, M. Fullekrug, M. Cohen, M. Stanley, S. Cummer, J. Montanya, M. Pazos, C. Velosa
Terrestrial Gamma-ray Flashes (TGFs) are ten-to-hundreds of microsecond bursts of gamma-rays produced when electrons in strong electric fields in thunderclouds are accelerated to relativistic energies. Space instruments have observed TGFs with source photon brightness down to ∼1017–1016. Based on space and aircraft observations, TGFs have been considered rare phenomena produced in association with
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JIRAM Observations of Volcanic Flux on Io: Distribution and Comparison to Tidal Heat Flow Models Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 M. Pettine, S. Imbeah, J. Rathbun, A. Hayes, R. M. C. Lopes, A. Mura, F. Tosi, F. Zambon, S. Bertolino
Juno has allowed clear, high-resolution imaging of Io's polar volcanoes using the Jovian Infrared Auroral Mapper (JIRAM) instrument. We have used data from JIRAM's M-band (4.78 μm) imager from 11 Juno orbits to construct a global map of volcanic flux. This map provides short-term insight into the spatial distribution of volcanoes and the ways in which high- and low-latitude volcanoes differ. Using
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The Origin of the Lehmann Discontinuity Beneath the Ancient Craton: Insight From the High Pressure-Temperature Elasticity Measurements of Topaz Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 Yingxin Yu, Luo Li, Xinyue Zhang, Zhu Mao, Ningyu Sun, Jing Li, Xinyang Li, Wancai Li
In this study, we concentrate on the seismic signature of subducted sediments and suggest the formation of the L-discontinuity beneath the ancient craton related to migrated sediment dehydration. We first determined the single-crystal elasticity of topaz, the product of sediment dehydration, at high pressures and temperatures by Brillouin scattering. Using the derived elastic parameters, we establish
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Detectable Continental Crust in the Earth's Deep Interior Inferred From Thermodynamic Modeling Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-07 Yibing Li, Yi Chen, Richard M. Palin, Xiaobo Tian, Xiaofeng Liang, Lijun Liu
Compelling evidence indicates that continental crust can subduct to >300 km and even enter the mantle transition zone (MTZ). However, detecting continental materials within the deep Earth is challenging due to our incomplete knowledge about their physical properties at mantle conditions. We use a newly compiled mineral-physical database coupled with thermodynamic modeling to calculate seismic velocities
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Deciphering the Prevalence of Warm-Wet Extremes in Ice-Covered Zones Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-06 Xinlu Chen, Lianlian Xu, Ran Yang, Ming Cai, Yi Deng, Deliang Chen, Song Yang, Jiping Liu, Qinghua Yang, Xiaoming Hu
Compound warm extremes exert profound impacts on environment, health, and socioeconomics. Yang et al. (2024) indicated a shift or transition from warm-dry extremes (WDEs), common in non-ice-covered areas, to warm-wet extremes (WWEs) in ice-covered zones. Utilizing ERA5 reanalysis data, this study determined the duration and frequency of WDEs and WWEs across ice-covered and non-ice-covered regions.
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Elevated Tropospheric Iodine Over the Central Continental United States: Is Iodine a Major Oxidant of Atmospheric Mercury? Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 C. F. Lee, T. Elgiar, L. M. David, T. Y. Wilmot, M. Reza, N. Hirshorn, I. B. McCubbin, V. Shah, J. C. Lin, S. N. Lyman, A. G. Hallar, L. E. Gratz, R. Volkamer
Previous efforts to measure atmospheric iodine have focused on marine and coastal regions. We report the first ground-based tropospheric iodine monoxide (IO) radical observations over the central continental United States. Throughout April 2022, IO columns above Storm Peak Laboratory, Colorado (3,220 m.a.s.l.) ranged from 0.7 ± 0.5 to 3.6 ± 0.5 × 1012 (average: 1.9 × 1012 molec cm−2). IO was consistently
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Internal-Wave Dissipation Mechanisms and Vertical Structure in a High-Resolution Regional Ocean Model Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-06 Joseph Skitka, Brian K. Arbic, Yuchen Ma, Kayhan Momeni, Yulin Pan, William R. Peltier, Dimitris Menemenlis, Ritabrata Thakur
Motivated by the importance of mixing arising from dissipating internal waves (IWs), vertical profiles of internal-wave dissipation from a high-resolution regional ocean model are compared with finestructure estimates made from observations. A horizontal viscosity scheme restricted to only act on horizontally rotational modes (such as eddies) is introduced and tested. At lower resolutions with horizontal
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Centennial-Scale Intensification of Wet and Dry Extremes in North America Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-06 Kyungmin Sung, Gil Bohrer, James H. Stagge
Drought and pluvial extremes are defined as deviations from typical climatology; however, background climatology can shift over time in a non-stationary climate, impacting interpretations of extremes. This study evaluated trends in meteorological drought and pluvial extremes by merging tree-ring reconstructions, observations, and climate-model simulations spanning 850–2100 CE across North America to
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Automated Quality Control Scheme for GPM Satellite Precipitation Products Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 Jackson Tan, George J. Huffman, Yi Song
The constellation approach underpinning precipitation products such as the Integrated Multi-satellitE Retrievals for GPM (IMERG) is key to achieving high resolution, but the use of data from multiple sources can unintentionally incorporate instrumental artifacts. Here, we introduce a machine learning–based anomaly detection scheme called SPEEDe, which processes a two-dimensional precipitation field
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Short-Duration Extreme Rainfall Events in the Central and Eastern United States During the Summer: 2003–2023 Trends and Variability Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 Jason Chiappa, David B. Parsons, Jason C. Furtado, Alan Shapiro
Extreme rainfall events (EREs) caused by convection are a major prediction challenge and can lead to deadly flash flooding. This study investigates EREs from 2003 to 2023 over the central and eastern United States using high-resolution (4-km) Stage IV precipitation analyses. EREs were defined where 12-hr accumulations exceeded the 10-year average recurrence interval thresholds. Summertime (June–August)
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Why Is Decadal Climate Variability Predominantly Observed in the Niño4 Region? Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 Sieu-Cuong San, Yu-Heng Tseng, Ruiqiang Ding, Emanuele Di Lorenzo
This study investigates why observed decadal-scale climate variability is predominantly pronounced in the Niño4 region compared to other equatorial Pacific areas using both observation and model sensitivity experiments. The initial shift to the negative phase of Tropical Pacific Decadal Variability (TPDV) is primarily driven by the upward and eastward migration of isopycnal negative temperature anomalies
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Study of Heat Wave Using High-Resolution Real Time Meso-Scale Analysis Over India Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 Ch. Sridevi, Ashish Routray, M. V. S. Ramarao, Suryakanti Dutta, K. B. R. R. Hari Prasad, Edward Colón, Annette Gibbs, Manuel Pondeca, V. S. Prasad
The applicability and accuracy of high-resolution Real-Time Meso-scale Analysis (RTMA) system is assessed over India for the first time. The RTMA is a high-spatial (2.5 km) and temporal resolution analysis system for near-surface weather conditions. It is used to simulate near-surface air temperature over India during the Heatwave (HW) period 12th to 20th April 2023. The verification analysis of temperature
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Widespread and Rapid Activities of Retrogressive Thaw Slumps on the Qinghai-Tibet Plateau From 2016 to 2022 Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 Zhuoxuan Xia, Lin Liu, Cuicui Mu, Xiaoqing Peng, Zhuoyi Zhao, Lingcao Huang, Jing Luo, Chengyan Fan
Retrogressive thaw slumps (RTSs), formed by abrupt degradation of ice-rich permafrost, are widely distributed on the Qinghai-Tibet Plateau, causing infrastructure damage and enhancing soil carbon emissions. We compiled annual RTS inventories across the plateau from 2016 to 2022 using a deep-learning-aided method to quantify the spatial-temporal variations. We found that RTS-affected locations increased
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Electron Acceleration via Secondary Reconnection in the Separatrix Region of Magnetopause Reconnection Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-02 X. S. Fu, Z. H. Zhong, M. Zhou, W. Q. Ma, Y. Pang, L. J. Song, X. J. Ou, R. Q. Jin, X. H. Deng
Magnetic reconnection is a fundamental process known to play a crucial role in electron acceleration and heating, however, the mechanism of electron energization during reconnection is still not fully understood. This study introduces a novel electron acceleration mechanism in which electrons can be accelerated by secondary reconnection in the separatrix region. The secondary reconnection occurs in
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Opposing Changes in Indian Summer Monsoon Rainfall Variability Produced by Orbital and Anthropogenic Forcing Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-05 Jiazhi He, Weiyi Sun, Bin Wang, Jian Liu, Liang Ning, Mi Yan
Future projections indicate that Indian Summer Monsoon Rainfall (ISMR) faces a “wetter and more variable” climate. However, the reasons remain uncertain. The Last Interglacial (LIG) climate provides a potential analog for future warming. Investigating ISMR responses to these two warming scenarios could help understand the causes of ISMR changes. Using PMIP4 simulations, we find that ISMR became “wetter
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Intraseasonal Variations and Extreme Occurrence in the Local Sea Level Along the Western Coast of India Remotely Controlled by a Basin-Scale Climate Variability Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-03 Y. Yamagami, T. Suzuki, H. Tatebe
The equatorial Kelvin waves, remotely excited by basin-scale climate modes, and subsequent coastal trapped waves significantly influence the intraseasonal variations, their low-frequency modulations, and the frequency of extreme sea level events along the western coast of India. This study demonstrates that the frequency of extreme events are linked to the phase of the Indian Ocean Dipole mode. The
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A Predicted Pause in the Rapid Warming of the Northwest Atlantic Shelf in the Coming Decade Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-03 Vimal Koul, Andrew C. Ross, Charles Stock, Liping Zhang, Thomas Delworth, Andrew Wittenberg
The capability to anticipate the exceptionally rapid warming of the Northwest Atlantic Shelf and its evolution over the next decade could enable effective mitigation for coastal communities and marine resources. However, global climate models have struggled to accurately predict this warming due to limited resolution; and past regional downscaling efforts focused on multi-decadal projections, neglecting
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Observations and Simulations of a Double-Core Hot Flow Anomaly Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-01 Xi Lu, Antonius Otto, Hui Zhang, Terry Liu, Xingran Chen
Hot Flow anomalies (HFAs), one of the most well-analyzed transient phenomena in the Earth's foreshock, are known as kinetic structures driven by tangential discontinuities (TDs). Recently, a 2-dimensional (2D) magnetohydrodynamics (MHD) model reproduced HFAs with either a high- or low-density core. Further investigation of an HFA with two cores observed by the Magnetospheric Multiscale (MMS) mission
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Rapid Inundation Mapping Using the US National Water Model, Satellite Observations, and a Convolutional Neural Network Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-04 Jonathan M. Frame, Tanya Nair, Veda Sunkara, Philip Popien, Subit Chakrabarti, Tyler Anderson, Nicholas R. Leach, Colin Doyle, Mitchell Thomas, Beth Tellman
Rapid and accurate maps of floods across large domains, with high temporal resolution capturing event peaks, have applications for flood forecasting and resilience, damage assessment, and parametric insurance. Satellite imagery produces incomplete observations spatially and temporally, and hydrodynamic models require tradeoffs between computational efficiency and accuracy. We address these challenges
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Separation of Electron Flux in Pitch Angle Distribution During the Drift Echo Event and Shabansky Orbits Effect Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-03 Zhekai Luo, Lun Xie, Suiyan Fu, Zuyin Pu, Xuzhi Zhou, X. X. Zhao
The Shabansky orbit effect can exert a significant influence on the dynamics of particle motion. However, the north-south asymmetry of the Shabansky orbits has received relatively little attention in previous research. This study investigates this asymmetry to elucidate the recently observed phenomenon of flux separation in the pitch angle distribution during drift echo events. The asymmetry in Shabansky
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A Physics-Enhanced Neural Network for Estimating Longitudinal Dispersion Coefficient and Average Solute Transport Velocity in Porous Media Geophys. Res. Lett. (IF 4.6) Pub Date : 2024-09-04 Yinquan Meng, Jianguo Jiang, Jichun Wu, Dong Wang
Dispersion coefficients and the average solute transport velocity are pivotal for groundwater solute transport modeling. Accurately and efficiently determining these parameters is challenging due to difficulties in directly correlating them with pore-space structure. To address this issue, we introduced the Physics-enhanced Convolutional Neural Network-Transformer (PhysenCT-Net), an innovative model