Geophysical Research Letters最新文献

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Observations and Modeling of the Longest-Recorded Delayed Sprite 记录时间最长的延迟精灵的观察和建模

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl119602

Y. Yair, C. Haspel, M. Korzets, E. Di-Gangi, J. Lapierre, O. Chanrion, Y. Hobara, T. Bozóki, J. Mlynarczyk, M. Korman, M. López-Alegría

Transient luminous events (TLEs), such as sprites, have been investigated via observations and simulations for decades. Recent TLE research has focused on effects leading to the delay of a sprite from its parent lightning flash. Here we investigate a sprite with by far the longest recorded delay to date, a delay of almost a full second (916.6 ± 16.6 ms) from the onset of the parent flash, as observed from the ISS during the ILAN-ES campaign on 6 February 2024. Based on meteorological, satellite, and ground-based ELF data, we reconstruct a realistic charge configuration for the parent thunderstorm. We input this reconstructed charge configuration to a 3D quasi-electrostatic model in order to simulate regions of possible sprite inception as a function of time corresponding to this sprite event following the lightning. We demonstrate how the observed delayed sprite could have been incepted by a prolonged piecewise pattern of the current in the parent flash.

瞬态发光事件（TLEs），如精灵，已经通过观测和模拟研究了几十年。最近的TLE研究集中在导致精灵从母体闪电中延迟的效应上。在这里，我们研究了迄今为止记录的最长延迟的精灵，从母闪光开始延迟几乎整整一秒（916.6±16.6毫秒），这是在2024年2月6日的ILAN-ES活动期间从国际空间站观察到的。基于气象、卫星和地面的极低频数据，我们重建了母雷暴的真实电荷配置。我们将这种重构的电荷配置输入到三维准静电模型中，以模拟闪电后精灵事件对应的精灵可能开始的区域作为时间函数。我们演示了观察到的延迟精灵是如何被父闪中电流的一个延长的分段模式所接收的。

引用次数: 0

Quantifying High-Frequency Migrating Tides in the Atmosphere of Mars With Observations From EMIRS, Curiosity and Perseverance 通过EMIRS，好奇号和毅力号的观测，量化火星大气中的高频迁移潮汐

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl118933

Aishwarya Kumar, Scott L. England, R. John Wilson, Amanda S. Brecht

Thermal tides are global oscillations driven by periodic solar heating that strongly influence circulation and vertical coupling in the Martian atmosphere. Previous studies have focused on the first and second migrating harmonics, while recent work has revealed higher-frequency harmonics in surface pressure records. However, these detections are limited to single locations, and spacecraft observations have only confirmed global structure up to the third harmonic. Here, we present the first planetary-scale characterization of migrating thermal tides up to the eighth harmonic as observed in remotely sensed temperature observations from the Emirates Mars Mission, sampling the lower atmosphere, and surface pressure measurements from the Curiosity and Perseverance landers. We examine the latitudinal and seasonal structure and show that high-frequency migrating tides have deep vertical structure with little phase variation with height, suggestive of near-resonant Lamb wave structure. Nearly identical seasonal amplitude-phase evolution across the longitudinally separated landers, indicate dominance of migrating tides.

热潮汐是由周期性太阳加热驱动的全球振荡，强烈影响火星大气中的环流和垂直耦合。以前的研究主要集中在第一次和第二次迁移谐波上，而最近的工作揭示了地表压力记录中的高频谐波。然而，这些探测仅限于单个地点，航天器观测只能确认三次谐波的全球结构。在这里，我们展示了第一个行星尺度的迁移热潮汐特征，该特征是在阿联酋火星任务的遥感温度观测中观测到的，采样低层大气，以及好奇号和毅力号着陆器的表面压力测量。通过对纬度和季节结构的分析，发现高频迁移潮具有较深的垂直结构，且随高度的相位变化较小，提示近共振兰姆波结构。在纵向分离的着陆器上，几乎相同的季节性振幅-相位演变表明，迁徙潮占主导地位。

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引用次数: 0

Future Weakening of the Kuroshio Extension Decadal Variability Revealed by an Eddy-Resolving Global Climate Model 涡旋解析全球气候模式揭示的未来黑潮扩展年代际变率的减弱

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl118480

Xin Wang, Bolan Gan, Lixin Wu, Hong Wang

The Kuroshio Extension (KE) exhibits pronounced decadal variability, influencing marine ecosystems, fisheries, and regional climate. However, how anthropogenic warming affects this variability remains uncertain due to limited satellite records and model resolution constraints. Based on an eddy-resolving historical-and-future transient climate simulation, we find that the KE decadal variability weakens significantly under a high-emissions scenario. This weakening likely results from a disruption of the coupled ocean-atmosphere delayed oscillation, which involves basin-scale atmospheric circulation both forcing and responding to KE variations. Specifically, warming-induced strengthening of atmospheric stratification likely suppresses the thermodynamic adjustment, including the deep-reaching updraft and associated mid-to-upper tropospheric responses, typically triggered by oceanic mesoscale warming during the KE stable state. Such suppression disrupts the coupled ocean-atmosphere delayed oscillation, contributing to the weakened KE decadal variability. Our findings imply that the KE system might be less predictable under future warming.

黑潮延伸（Kuroshio Extension， KE）表现出明显的年代际变化，影响海洋生态系统、渔业和区域气候。然而，由于有限的卫星记录和模式分辨率的限制，人为变暖如何影响这种变率仍然不确定。基于涡旋解析的历史和未来瞬态气候模拟，我们发现在高排放情景下，KE年代际变率显著减弱。这种减弱可能是由于耦合的海洋-大气延迟振荡的中断，这涉及到盆地尺度的大气环流强迫和响应KE变化。具体而言，变暖引起的大气分层强化可能抑制热力学调整，包括深层上升气流和相关的对流层中高层响应，这些响应通常是在KE稳定状态期间由海洋中尺度变暖触发的。这种抑制破坏了耦合的海洋-大气延迟振荡，导致KE年代际变率减弱。我们的研究结果表明，在未来变暖的情况下，KE系统可能难以预测。

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引用次数: 0

Subtropical Atmospheric Response to Extratropical SST Warming in the Western North Pacific Under Atmospheric Internal Variability 大气内部变率下北太平洋西部副热带大气对温带海温变暖的响应

IF 4.6 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025GL118296

Itsuki Miura, Youichi Tanimoto

Sea surface temperature (SST) anomalies in the Kuroshio Extension (KE) region have been increasingly recognized as playing a key role in shaping the extratropical air–sea interactions. However, the extent to which such extratropical SST forcing can influence large-scale atmospheric circulation and surrounding SST remains uncertain, particularly given strong atmospheric internal variability. Here, we investigate the atmospheric response to idealized positive SST anomalies in the KE region using large-ensemble atmospheric general circulation model experiments. The imposed forcing generates a robust sea-level pressure anomaly over and downstream of the KE, leading to surface westerly wind anomalies extending into the subtropical North Pacific. Despite substantial atmospheric internal variability over the Aleutian Low region, these subtropical wind anomalies consistently emerge across the ensemble. Our results suggest that SST forcing in the KE region can modulate air–sea interactions not only locally but also across a broader region extending equatorward.

黑潮伸展区海温异常在温带海气相互作用中起着重要作用。然而，这种温带海温强迫对大尺度大气环流和周围海温的影响程度仍不确定，特别是考虑到强烈的大气内部变率。本文利用大集合大气环流模式试验研究了KE地区大气对理想海温正异常的响应。施加的强迫在东太平洋上空和下游产生强烈的海平面气压异常，导致地面西风异常延伸到副热带北太平洋。尽管在阿留申低地地区有大量的大气内部变化，但这些副热带风异常始终出现在整个集合中。我们的研究结果表明，KE区域的海温强迫不仅可以局部调节海气相互作用，而且可以在更广泛的区域向赤道延伸。

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引用次数: 0

Frequency-Dependent Seismic Velocity Variations Reveal Layered Aquifer Behavior Under Groundwater Fluctuations 频率相关的地震速度变化揭示了地下水波动下的层状含水层行为

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl118568

C. Rattanavetchasit, H.-H. Huang, H. Sone, Y.-M. Wu

Frequency-dependent seismic velocity variations (dv/v) provide depth-resolved constraints on aquifer behavior under groundwater fluctuations. We analyze 17 years of dv/v time series from ambient noise interferometry in the Chiang Mai Basin, Thailand, and observe contrasting dv/v behavior below and above 1 Hz. By integrating GPS, meteorological, and GWL data with poroelastic stress modeling, we disentangle the contemporaneous effects of pore saturation, pore pressure change, and mass loading. Our results show that the pore saturation and pore pressure change jointly influence shallow aquifer layers, while mass loading governs deeper responses. This depth-dependent interplay highlights the importance of effective stress modeling in interpreting dv/v patterns and the potential of passive seismic techniques to monitor layered hydromechanical processes in aquifer systems.

频率相关的地震速度变化（dv/v）为地下水波动下的含水层行为提供了深度分辨约束。我们分析了泰国清迈盆地17年的环境噪声干涉测量dv/v时间序列，并观察了低于和高于1 Hz的dv/v行为的对比。通过将GPS、气象和GWL数据与孔隙弹性应力建模相结合，我们解开了孔隙饱和度、孔隙压力变化和质量载荷的同时影响。研究结果表明，孔隙饱和度和孔隙压力变化共同影响浅层含水层，而质量荷载影响深层含水层的响应。这种依赖深度的相互作用凸显了有效应力建模在解释dv/v模式中的重要性，以及被动地震技术在监测含水层系统分层流体力学过程中的潜力。

引用次数: 0

On the Beam Characteristics of X-Ray Bursts Observed in Rocket-Triggered Lightning 火箭触发闪电中观测到的x射线爆发的光束特性

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl120120

Yuan Wang, Peng Li, Yang Zhang, Heting Hong, Xiao Li, Yanfeng Fan, Baofeng Cao, Weiqun Xu, Zongxiang Li, Weitao Lyu, Gaopeng Lu, Xiong Zhang, Xiaoqiang Li

Employing the multi-station Thunderstorm Energetic Radiation Observation System, we detected X-ray bursts during two rocket-triggered lightning events in 2024. By innovatively integrating optical imaging with three-dimensional lightning channel reconstruction based on Distributed Acoustic Sensing (DAS), we analyzed the X-ray emission characteristics from these events. During the Tl_20240812 event, lateral deflection of a descending negative leader resulted in X-rays being detected exclusively by a distal sensor. This clear spatial correlation provides direct and conclusive geometric evidence that the radiation is emitted in a beam-like pattern along the leader propagation path. Furthermore, based on the Tl_20240801 event, this study achieved the first quantitative estimation of the X-ray photon beam half-angle width, determined to be between 40° and 46°. This angular range aligns with the predicted structure of the leader tip electric field, thereby providing robust support for the hypothesis that X-rays originate from the leader tip high-field runaway electron mechanism.

利用多站雷暴高能辐射观测系统，我们在2024年探测到两次火箭触发闪电事件中的x射线爆发。通过创新地将光学成像与基于分布式声传感（DAS）的三维闪电通道重建相结合，我们分析了这些事件的x射线发射特征。在Tl_20240812事件中，下行负导联的横向偏转导致x射线仅被远端传感器检测到。这种清晰的空间相关性提供了直接和确凿的几何证据，表明辐射沿着引线传播路径以束状模式发射。此外，基于Tl_20240801事件，本研究首次实现了x射线光子束半角宽度的定量估计，确定在40°~ 46°之间。该角度范围与前导尖端电场的预测结构一致，从而为x射线起源于前导尖端高场失控电子机制的假设提供了强有力的支持。

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引用次数: 0

Corona Discharges Glow on Trees Under Thunderstorms 电晕在雷暴下在树上发光

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl119591

P. J. McFarland, W. H. Brune, D. O. Miller, J. M. Jenkins

Coronae, which are weak electrical discharges, have long been hypothesized to form on trees under thunderstorms, though never directly observed, characterized, or quantified. Using a newly developed instrument that measures ultraviolet emissions from coronae, the first direct observations and quantifications of coronae are presented for two trees under a thunderstorm in North Carolina. Coronae moved sporadically among leaves on every tree branch in a narrow field of view while the thunderstorm was directly overhead. Coronae emitted ∼10¹¹ photons at 260 nm, corresponding to electrical currents of ∼1 μA, derived from unique measurements relating corona intensity to tree electrical current. Similar results across four additional storm intercepts from Florida to Pennsylvania give rise to a vision of swaths of scintillating corona glow as thunderstorms pass over forests. Such widespread coronae have implications for the removal of hydrocarbons emitted by trees, subtle tree leaf damage, and limited thunderstorm electrification.

日冕是一种微弱的放电，长期以来一直被假设在雷暴天气下在树上形成，尽管从未直接观察到，表征或量化。利用一种新开发的测量日冕紫外线辐射的仪器，对北卡罗来纳州雷暴下的两棵树的日冕进行了首次直接观测和量化。在一片狭窄的视野中，每根树枝上的树叶上都有日冕零星地移动，而雷暴正好在头顶上。日冕在260 nm处发射约1011个光子，对应于约1 μA的电流，这是由日冕强度与树电流的独特测量得出的。从佛罗里达州到宾夕法尼亚州的另外四个风暴拦截点也得到了类似的结果，这些结果产生了雷暴经过森林时闪烁的日冕光带的景象。如此广泛的日冕对树木排放的碳氢化合物的去除、轻微的树叶损伤和有限的雷暴电气化都有影响。

引用次数: 0

The Impact of OCO-2 Seasonally Dependent Sampling on Carbon Flux Estimation in the Northern Tropical Africa OCO-2季节性采样对北热带非洲碳通量估算的影响

IF 4.6 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025GL119838

Junjie Liu, Sourish Basu, Brendan Byrne, Jeongmin Yun, Chris O’Dell

The large annual carbon source over northern tropical Africa (NTA), inferred from satellite CO₂, remains highly debated. Using observing system simulation experiments with Orbiting Carbon Observatory-2 (OCO-2) sampling, we show that seasonally dependent sampling can lead to overestimated annual fluxes. These biases arise when prior flux seasonal cycle differs from the assumed truth. Since OCO-2 provides more observations during the non-growing season, posterior fluxes are more constrained in that period. When prior fluxes underestimate the seasonal amplitude, the posterior carbon sink during the growing season is underestimated, leading to a net positive bias. This effect is supported by real OCO-2 data, where we hypothesize that underestimating fire emissions during non-growing season and weaker seasonality of prior fluxes may contribute to overestimated annual fluxes. Our results highlight the need to improve prior flux estimates and expand observational coverage during the growing season to reduce biases in regional carbon budget assessments over NTA.

从卫星二氧化碳推断出的热带非洲北部（NTA）巨大的年碳源仍存在高度争议。利用轨道碳观测站-2 （OCO-2）采样的观测系统模拟实验，我们发现季节依赖的采样可能导致高估年通量。当先前的通量季节周期与假定的事实不同时，就会产生这些偏差。由于OCO-2在非生长期提供了更多的观测数据，因此该时期的后通量更受限制。当先验通量低估季节振幅时，生长季节的后向碳汇被低估，导致净正偏差。实际OCO-2数据支持这一效应，其中我们假设低估非生长期的火排放和先前通量的季节性较弱可能导致高估年通量。我们的研究结果强调需要改进先前的通量估算并扩大生长季节的观测覆盖范围，以减少NTA区域碳预算评估的偏差。

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引用次数: 0

Irreversible Transitions of the Ocean Circulation in Antarctic Ice-Shelf Cavities 南极冰架空腔中海洋环流的不可逆转变

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl118278

Louis Saddier, Corentin Herbert, Christopher Y. S. Bull, Louis-Alexandre Couston

Ice shelves fringing the Antarctic continent experience low or high basal melt rates depending on local shelf conditions, ocean circulation and intensity of ice-sea-air exchanges. Recent studies have uncovered potential cold-to-warm transitions in specific ice-shelf cavities, which could lead to a dramatic increase in sea-level rise. Here we demonstrate that brine rejection in coastal polynyas promotes bistable dynamics in ice-shelf cavities, which would be otherwise monostable, for a broad diversity of Circumpolar Deep Water temperatures. We develop a generic low-dimensional box model featuring warm and cold circulation modes and apply it to nine ice-shelf cavities. We find that most ice-shelf cavities are in a bistable regime and are therefore susceptible to irreversible abrupt transitions for a realistic range of sea-ice formation rates. Bistability is robust to changes in cavity parameterization. However, the vertical mixing scheme at the ice-shelf front can be tuned to make the transitions reversible.

南极大陆边缘的冰架根据当地的冰架条件、海洋环流和冰-海-气交换的强度，经历着低或高的基础融化速率。最近的研究发现，在特定的冰架空洞中，可能会发生从冷到暖的转变，这可能会导致海平面上升的急剧增加。在这里，我们证明了沿海多冰湖的盐水排斥促进了冰架空洞的双稳态动力学，否则，对于环极深水温度的广泛多样性来说，这将是单稳态的。我们开发了一个具有冷热循环模式的通用低维盒模型，并将其应用于9个冰架空洞。我们发现大多数冰架空洞处于双稳态状态，因此在海冰形成速率的实际范围内容易发生不可逆的突变。双稳定性对空腔参数化的变化具有鲁棒性。然而，可以调整冰架前缘的垂直混合方案，使这种转变可逆。

引用次数: 0

Leveraging Laboratory Experiments of Shoreline Response to Sea-Level Rise: A Beach Disequilibrium Perspective 利用海岸线对海平面上升响应的实验室实验：海滩不平衡的视角

IF 5.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters

Pub Date : 2026-02-12 DOI: 10.1029/2025gl120802

M. D’Anna, F. Ribas, G. Coco, P. M. Bayle, D. Calvete, A. Falqués, T. E. Baldock, A. L. Atkinson, T. Beuzen

This study analyzes laboratory data of beach response to sea-level rise (SLR), isolating shoreline changes driven by passive flooding (PF) of the beach and consequent wave-driven processes. The disequilibrium concept relates shoreline change to instantaneous and equilibrium beach states. While PF shifts the shoreline geometrically, SLR induces disequilibrium that produces wave-driven changes due to apparent profile changes. For the first time, 24 experiments from wave flumes of different scale (including new high-low energy cyclic waves experiments) are gathered into a dimensionless data set through a scaling technique to investigate SLR-induced processes. The data indicate trends (possibly linear) between relative wave power and wave-driven shoreline changes for a given SLR, highlighting the effects of changing background wave energy. Cyclic wave experiments best represent Bruun model's behavior. Wave-energy dissipation emerges as a key variable for quantifying SLR-induced disequilibrium, offering new pathways for future improvements of equilibrium shoreline models under SLR and wave-climate change.

本研究分析了海滩对海平面上升（SLR）响应的实验室数据，分离了海滩被动洪水（PF）和随之而来的波浪驱动过程驱动的海岸线变化。不平衡概念将海岸线变化与瞬时和平衡海滩状态联系起来。当PF使海岸线发生几何位移时，SLR引起不平衡，由于明显的剖面变化而产生波浪驱动的变化。采用标度技术，首次将不同尺度的24个波槽实验（包括新型高低能循环波实验）集合成一个无量纲数据集，研究slr诱导过程。数据显示了给定单反相对波浪能和波浪驱动的海岸线变化之间的趋势（可能是线性的），突出了背景波能变化的影响。循环波实验最能反映布鲁恩模型的特性。波浪能量耗散成为量化SLR引起的不平衡的关键变量，为SLR和波浪气候变化下平衡海岸线模型的未来改进提供了新的途径。

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