Franck Latallerie, Paula Koelemeijer, Andrew Walker, Alessia Maggi, Sophie Lambotte, Christophe Zaroli
How oceanic plates cool and thicken with age remains a subject to debate, with several thermal models supported by apparently contradictory data. Combining a novel imaging technique that balances resolution and uncertainty with finite-frequency surface-wave measurements, we build tomographic model SS3DPacific to revisit the cooling style of the oceanic lithosphere beneath the Pacific ocean. Resolution analysis indicates a strong vertical smearing that biases estimates of the apparent lithospheric thickness, limiting the ability to discriminate between the half space and plate cooling models. Laterally, a pattern of anomalous bands in seismic velocity aligned with fracture zones points to additional lateral complexities in the lithosphere, complicating simple age-trend analyses.
{"title":"New Insights Into the Cooling of the Oceanic Lithosphere From Surface-Wave Tomographic Inferences","authors":"Franck Latallerie, Paula Koelemeijer, Andrew Walker, Alessia Maggi, Sophie Lambotte, Christophe Zaroli","doi":"10.1029/2025gl119309","DOIUrl":"https://doi.org/10.1029/2025gl119309","url":null,"abstract":"How oceanic plates cool and thicken with age remains a subject to debate, with several thermal models supported by apparently contradictory data. Combining a novel imaging technique that balances resolution and uncertainty with finite-frequency surface-wave measurements, we build tomographic model SS3DPacific to revisit the cooling style of the oceanic lithosphere beneath the Pacific ocean. Resolution analysis indicates a strong vertical smearing that biases estimates of the apparent lithospheric thickness, limiting the ability to discriminate between the half space and plate cooling models. Laterally, a pattern of anomalous bands in seismic velocity aligned with fracture zones points to additional lateral complexities in the lithosphere, complicating simple age-trend analyses.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"37 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
10Be deposition in ice cores is widely used for solar reconstructions, but its interpretation is complicated by volcanic influences. Using the state-of-the-art aerosol-climate model ECHAM6.3-HAM2.3-SALSA2.0: 10Be, we assess the impacts of three major volcanic eruptions: Agung (1963), El Chichón (1982) and Pinatubo (1991). All eruptions enhance stratospheric 10Be sedimentation, increasing atmospheric 10Be below the injection altitude for several months, followed by stratospheric 10Be depletion that takes years to recover. Increases in tropospheric 10Be and deposition coincide with periods of strong stratosphere–troposphere exchange. Aerosol-induced sedimentation significantly enhances polar 10Be deposition subsequent to the Pinatubo and El Chichón eruptions but plays a limited role after the Agung eruption. Sensitivity experiments reveal that higher SO2 injections generally lead to nonlinear increases in global 10Be deposition. These results underscore the need to account for volcanic influences when interpreting and modeling polar 10Be records following major eruptions.
冰芯中的be沉积被广泛用于太阳重建，但其解释由于火山的影响而变得复杂。利用最先进的气溶胶-气候模式ECHAM6.3-HAM2.3-SALSA2.0: 10Be，我们评估了三个主要火山喷发的影响：Agung (1963), El Chichón（1982）和Pinatubo（1991）。所有的火山喷发都增强了平流层的10Be沉积，使注入高度以下的大气10Be增加数月，随后平流层的10Be耗尽，需要数年才能恢复。对流层10Be和沉积的增加与平流层-对流层强烈交换的时期一致。在Pinatubo和El Chichón火山喷发后，气溶胶诱导的沉积显著增强了极地10Be沉积，但在Agung火山喷发后作用有限。灵敏度实验表明，较高的SO2注入通常会导致整体10Be沉积的非线性增加。这些结果强调了在解释和模拟大喷发后的极地10Be记录时考虑火山影响的必要性。
{"title":"Atmospheric and Deposition Responses of 10Be to Volcanic Eruptions Inferred From the Aerosol-Climate Model ECHAM6.3-HAM2.3-SALSA2.0: 10Be","authors":"Minjie Zheng, Raimund Muscheler, Anton Laakso, Florian Adolphi, Zhengyao Lu, Mousong Wu, Peng Chen, Qin Tao, Ulrike Lohmann","doi":"10.1029/2025gl117481","DOIUrl":"https://doi.org/10.1029/2025gl117481","url":null,"abstract":"<sup>10</sup>Be deposition in ice cores is widely used for solar reconstructions, but its interpretation is complicated by volcanic influences. Using the state-of-the-art aerosol-climate model ECHAM6.3-HAM2.3-SALSA2.0: <sup>10</sup>Be, we assess the impacts of three major volcanic eruptions: Agung (1963), El Chichón (1982) and Pinatubo (1991). All eruptions enhance stratospheric <sup>10</sup>Be sedimentation, increasing atmospheric <sup>10</sup>Be below the injection altitude for several months, followed by stratospheric <sup>10</sup>Be depletion that takes years to recover. Increases in tropospheric <sup>10</sup>Be and deposition coincide with periods of strong stratosphere–troposphere exchange. Aerosol-induced sedimentation significantly enhances polar <sup>10</sup>Be deposition subsequent to the Pinatubo and El Chichón eruptions but plays a limited role after the Agung eruption. Sensitivity experiments reveal that higher SO<sub>2</sub> injections generally lead to nonlinear increases in global <sup>10</sup>Be deposition. These results underscore the need to account for volcanic influences when interpreting and modeling polar <sup>10</sup>Be records following major eruptions.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manisha Mehra, Yang Wang, Chanakya Bagya Ramesh, Ruoyu Zhang, Jiaoshi Zhang, Scott E. Giangrande, Jian Wang
Deep convective clouds regulate Earth's energy and moisture budgets, yet their impact on the atmospheric boundary layer (BL) composition remains underexplored. Using long-term observations from three mid-latitude sites, we show that deep convection (DC) consistently enhances nighttime surface ozone and is often accompanied by modest increases in ultrafine particle concentrations. Within the BL, the condensational growth of these transported ultrafine particles may contribute up to 60% of total cloud condensation nuclei (CCN). Mass flux calculations suggest that short-lived convective cores (∼30 min) account for ∼2% of total vertical air mass transport relative to steady entrainment, increasing to ∼13% when the trailing stratiform regions are included. These results show that DC provides an episodic but efficient pathway linking the free troposphere and BL, influencing oxidant budgets, CCN variability, and climate forcing. Accurately representing this process in climate models may help reduce uncertainties in climate projections, under both preindustrial and present-day conditions.
{"title":"Deep Convection-Driven Downward Transport of Trace Gases and Aerosols From the Free Troposphere to the Boundary Layer","authors":"Manisha Mehra, Yang Wang, Chanakya Bagya Ramesh, Ruoyu Zhang, Jiaoshi Zhang, Scott E. Giangrande, Jian Wang","doi":"10.1029/2025gl119490","DOIUrl":"https://doi.org/10.1029/2025gl119490","url":null,"abstract":"Deep convective clouds regulate Earth's energy and moisture budgets, yet their impact on the atmospheric boundary layer (BL) composition remains underexplored. Using long-term observations from three mid-latitude sites, we show that deep convection (DC) consistently enhances nighttime surface ozone and is often accompanied by modest increases in ultrafine particle concentrations. Within the BL, the condensational growth of these transported ultrafine particles may contribute up to 60% of total cloud condensation nuclei (CCN). Mass flux calculations suggest that short-lived convective cores (∼30 min) account for ∼2% of total vertical air mass transport relative to steady entrainment, increasing to ∼13% when the trailing stratiform regions are included. These results show that DC provides an episodic but efficient pathway linking the free troposphere and BL, influencing oxidant budgets, CCN variability, and climate forcing. Accurately representing this process in climate models may help reduce uncertainties in climate projections, under both preindustrial and present-day conditions.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"11 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gloria M. S. Reithmaier, Ariel K. Pezner, Adam Ulfsbo, Frank Melzner, Isaac R. Santos
Mangroves host many marine species and support fisheries in developing (sub)tropical countries. The suitability of mangrove habitats depends strongly thier the water chemistry. Here, we show how global warming and rising atmospheric CO2 will reduce dissolved oxygen and increase CO2 in mangrove waters. Observations from 23 mangrove-lined estuaries worldwide revealed that most sites already experience mild (34%–43% of the time) or severe (6%–32%) hypercapnic hypoxia, that is, high CO2 and low oxygen conditions. Hypercapnic hypoxia mostly occurs during low tide, at low-salinity sites, and in warm tropical regions. Climate change will decrease oxygen concentrations by 5%–35% and increase CO2 concentrations by 8%–60% in mangrove waters by 2100. Overall, hypercapnic hypoxia events will occur more frequently, last longer, and become more severe. These shifts will reduce mangrove biodiversity and deteriorate habitat quality for commercially valuable fish. The strongest impact is expected in tropical developing countries.
{"title":"Climate Change Will Enhance Hypercapnic Hypoxia Threatening Mangrove Habitats","authors":"Gloria M. S. Reithmaier, Ariel K. Pezner, Adam Ulfsbo, Frank Melzner, Isaac R. Santos","doi":"10.1029/2025gl119355","DOIUrl":"https://doi.org/10.1029/2025gl119355","url":null,"abstract":"Mangroves host many marine species and support fisheries in developing (sub)tropical countries. The suitability of mangrove habitats depends strongly thier the water chemistry. Here, we show how global warming and rising atmospheric CO<sub>2</sub> will reduce dissolved oxygen and increase CO<sub>2</sub> in mangrove waters. Observations from 23 mangrove-lined estuaries worldwide revealed that most sites already experience mild (34%–43% of the time) or severe (6%–32%) hypercapnic hypoxia, that is, high CO<sub>2</sub> and low oxygen conditions. Hypercapnic hypoxia mostly occurs during low tide, at low-salinity sites, and in warm tropical regions. Climate change will decrease oxygen concentrations by 5%–35% and increase CO<sub>2</sub> concentrations by 8%–60% in mangrove waters by 2100. Overall, hypercapnic hypoxia events will occur more frequently, last longer, and become more severe. These shifts will reduce mangrove biodiversity and deteriorate habitat quality for commercially valuable fish. The strongest impact is expected in tropical developing countries.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"173 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sporadic E (Es) layer is a prominent ionospheric irregularity mainly driven by vertical wind shear at mid-latitudes. Hereby we statistically investigate for the first time Es responses to variations of the northern polar vortex (represented by NAM index) using long-term ionosonde observations over Japan (44 years) and Australia (34 years). The analysis reveals clear polar vortex modulation of Es, with increasing/decreasing foEs on low/high NAM days over Japan and decreasing foEs over Australia on low NAM days with a time lag of 5–7 days. This hemispheric asymmetry is largely attributed to nearly anti-phase wind shear responses in two hemispheres. Our results demonstrate the modulation of deep connection between stratosphere dynamics and ionospheric irregularities, emphasizing the importance atmosphere-ionosphere coupling. It suggests that the NAM index could be used to increase the accuracy of Es layer prediction and serve as indicator for assessing the risk of Es layer occurrence in advance. This has practical implications for fields such as radiocommunications and over-the-horizon radar.
{"title":"Modulation of the Mid-Latitude Ionospheric Sporadic E Layer by the Northern Polar Vortex","authors":"Tomoki Maeda, Huixin Liu, Yosuke Yamazaki, Lihui Qiu","doi":"10.1029/2025gl119055","DOIUrl":"https://doi.org/10.1029/2025gl119055","url":null,"abstract":"The sporadic E (Es) layer is a prominent ionospheric irregularity mainly driven by vertical wind shear at mid-latitudes. Hereby we statistically investigate for the first time Es responses to variations of the northern polar vortex (represented by NAM index) using long-term ionosonde observations over Japan (44 years) and Australia (34 years). The analysis reveals clear polar vortex modulation of Es, with increasing/decreasing foEs on low/high NAM days over Japan and decreasing foEs over Australia on low NAM days with a time lag of 5–7 days. This hemispheric asymmetry is largely attributed to nearly anti-phase wind shear responses in two hemispheres. Our results demonstrate the modulation of deep connection between stratosphere dynamics and ionospheric irregularities, emphasizing the importance atmosphere-ionosphere coupling. It suggests that the NAM index could be used to increase the accuracy of Es layer prediction and serve as indicator for assessing the risk of Es layer occurrence in advance. This has practical implications for fields such as radiocommunications and over-the-horizon radar.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"102 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yong Ren, Minghui Zhu, Lei Dai, Walter Gonzalez, Shan Wang, Chi Wang, C. Philippe Escoubet, Jiaojiao Zhang, Qiugang Zong
Substorms are often described by a loading-unloading cycle, where onset follows gradual accumulation of solar wind magnetic flux in the magnetosphere. Yet observations indicate that intense substorms can also be directly driven, though the underlying mechanism remains unresolved. For the first time, global observations strongly indicate that substorm triggering is linked to enhanced dayside-driven convection and Region 1 FAC, supported by simulations. At 17:17UT during the May 2024 superstorm, a shock-compressed southward interplanetary magnetic field enhanced sunward convection and auroral currents. These rapidly extended to the nightside, initiating substorm expansion within 6 min. Simulations reproduce this response, revealing that dayside-driven convection of closed field lines depleted nightside flux and thinned the current sheet. This lowered onset threshold and triggered substorm expansion with negligible flux loading. Following onset, nightside flux loading became significant as a reconnection X-line formed near 10 Earth radii, extended azimuthally, and supported a global substorm current wedge.
{"title":"Solar-Wind Triggering of Substorm Onset During the May 2024 Superstorm: Coordinated Global Observations and Simulations","authors":"Yong Ren, Minghui Zhu, Lei Dai, Walter Gonzalez, Shan Wang, Chi Wang, C. Philippe Escoubet, Jiaojiao Zhang, Qiugang Zong","doi":"10.1029/2025gl119629","DOIUrl":"https://doi.org/10.1029/2025gl119629","url":null,"abstract":"Substorms are often described by a loading-unloading cycle, where onset follows gradual accumulation of solar wind magnetic flux in the magnetosphere. Yet observations indicate that intense substorms can also be directly driven, though the underlying mechanism remains unresolved. For the first time, global observations strongly indicate that substorm triggering is linked to enhanced dayside-driven convection and Region 1 FAC, supported by simulations. At 17:17UT during the May 2024 superstorm, a shock-compressed southward interplanetary magnetic field enhanced sunward convection and auroral currents. These rapidly extended to the nightside, initiating substorm expansion within 6 min. Simulations reproduce this response, revealing that dayside-driven convection of closed field lines depleted nightside flux and thinned the current sheet. This lowered onset threshold and triggered substorm expansion with negligible flux loading. Following onset, nightside flux loading became significant as a reconnection X-line formed near 10 Earth radii, extended azimuthally, and supported a global substorm current wedge.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"15 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaomi Teng, Liang Xu, Fan Zhang, Yihan Cheng, Min Gao, Xiyao Chen, Jiefeng Li, Shengzhen Zhou, Shoujuan Shu, Shupeng Zhu, Dantong Liu, Chuanfeng Zhao, Joseph Ching, Weijun Li
Aerosol–cloud interactions (ACI) are a major source of uncertainty in anthropogenic climate forcing. Anthropogenic aerosols modulate the cloud albedo by impacting the relative dispersion (ε) of cloud droplet size distributions (CDSDs), known as the dispersion effect. This effect can be either suppressive or enhancing, introducing considerable uncertainties in polluted continental clouds. Here, we developed in situ measurements in polluted East China and simultaneously measured the CDSDs and aerosol properties. A wide range of ε from 0.20 to 0.78 with a mean value of 0.43 was observed. Machine learning analysis shows that aerosol number concentration and hygroscopicity dominate the changes of ε in polluted continental stratiform clouds under weak vertical velocities (<0.5 m s−1) and low liquid water content (∼0.1 g m−3) conditions. Overall, the dispersion effect enhances the aerosol indirect effect by ∼11%. These results highlight the importance of aerosol properties in evaluating ACI in polluted environments.
气溶胶-云相互作用（ACI）是人为气候强迫的一个主要不确定性来源。人为气溶胶通过影响云滴大小分布（CDSDs）的相对色散（ε），即色散效应来调节云的反照率。这种影响可以抑制或增强，在受污染的大陆云中引入相当大的不确定性。为此，我们在华东污染地区开展了现场测量，同时测量了CDSDs和气溶胶特性。ε的变化范围为0.20 ~ 0.78，平均值为0.43。机器学习分析表明，在弱垂直速度（<0.5 m s−1）和低液态水含量（~ 0.1 g m−3）条件下，气溶胶数浓度和吸湿性主导了污染大陆层状云中ε的变化。总体而言，分散效应使气溶胶间接效应提高了约11%。这些结果突出了气溶胶特性在评价污染环境中ACI中的重要性。
{"title":"Low Cloud Dispersion Effects by Anthropogenic Aerosols in Polluted Air","authors":"Xiaomi Teng, Liang Xu, Fan Zhang, Yihan Cheng, Min Gao, Xiyao Chen, Jiefeng Li, Shengzhen Zhou, Shoujuan Shu, Shupeng Zhu, Dantong Liu, Chuanfeng Zhao, Joseph Ching, Weijun Li","doi":"10.1029/2025gl120887","DOIUrl":"https://doi.org/10.1029/2025gl120887","url":null,"abstract":"Aerosol–cloud interactions (ACI) are a major source of uncertainty in anthropogenic climate forcing. Anthropogenic aerosols modulate the cloud albedo by impacting the relative dispersion (<i>ε</i>) of cloud droplet size distributions (CDSDs), known as the dispersion effect. This effect can be either suppressive or enhancing, introducing considerable uncertainties in polluted continental clouds. Here, we developed in situ measurements in polluted East China and simultaneously measured the CDSDs and aerosol properties. A wide range of ε from 0.20 to 0.78 with a mean value of 0.43 was observed. Machine learning analysis shows that aerosol number concentration and hygroscopicity dominate the changes of ε in polluted continental stratiform clouds under weak vertical velocities (<0.5 m s<sup>−1</sup>) and low liquid water content (∼0.1 g m<sup>−3</sup>) conditions. Overall, the dispersion effect enhances the aerosol indirect effect by ∼11%. These results highlight the importance of aerosol properties in evaluating ACI in polluted environments.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"5 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quanjia Zhong, Wansuo Duan, Shifei Tu, Yongjie Huang, Johnny C. L. Chan, Ruiqiang Ding
Accurate forecasts of near-landfall TC characteristics (direction, translation speed, and intensity) are essential for timely disaster preparedness. Using best-track data (1951–2023), this study reveals a significant pre-landfall acceleration of TCs along the South China coast, with translation speed increasing by 35.5% and 16.4% during the 24 hr prior to landfall for eastbound and westbound cases, respectively. This acceleration is primarily contributed by the normal component of the translation vector. For westbound TCs, translation speed and its normal component increase with intensity, particularly at typhoon strength and above. Numerical simulations and diagnostic analyses attribute the acceleration to horizontal advection and diabatic heating, primarily driven by land-induced asymmetric flow and convection. These findings strengthen the current understanding of TC motion dynamics and support more effective disaster prevention and mitigation strategies as TCs approach coastal regions.
{"title":"Landward Acceleration of Tropical Cyclones Making Landfall Along the South China Coast","authors":"Quanjia Zhong, Wansuo Duan, Shifei Tu, Yongjie Huang, Johnny C. L. Chan, Ruiqiang Ding","doi":"10.1029/2025gl119733","DOIUrl":"https://doi.org/10.1029/2025gl119733","url":null,"abstract":"Accurate forecasts of near-landfall TC characteristics (direction, translation speed, and intensity) are essential for timely disaster preparedness. Using best-track data (1951–2023), this study reveals a significant pre-landfall acceleration of TCs along the South China coast, with translation speed increasing by 35.5% and 16.4% during the 24 hr prior to landfall for eastbound and westbound cases, respectively. This acceleration is primarily contributed by the normal component of the translation vector. For westbound TCs, translation speed and its normal component increase with intensity, particularly at typhoon strength and above. Numerical simulations and diagnostic analyses attribute the acceleration to horizontal advection and diabatic heating, primarily driven by land-induced asymmetric flow and convection. These findings strengthen the current understanding of TC motion dynamics and support more effective disaster prevention and mitigation strategies as TCs approach coastal regions.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"16 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dan Muramatsu, John J. Lyons, Hannah R. Dietterich, Mie Ichihara, Alexandra M. Iezzi
Pulse-like infrasound accompanying volcanic phenomena sometimes suggests interaction with water at the crater. We focus on pulse-like infrasound observed at Semisopochnoi Island in the Aleutian Arc, Alaska, during the phreatomagmatic activity on 13 July 2021. Overflight observations confirmed a small, ephemeral water lake on the crater floor in June 2021. We examined temporal variations in pulse-like infrasound activity, seismoacoustic amplitudes, and spectral characteristics. Pulse-like infrasound activity gradually became intermittent and waned at the end of the day. Seismic-infrasonic amplitude ratio decreased, while the infrasound frequency index increased with time. These results suggest less interaction with water due to drying out of the vent. Satellite observations also show increased ground surface temperatures inside the crater from 13 to 14 July. Numerical simulation suggests a significant topographic effect on the waveform and spectrum of the pulse-like infrasound, which should be considered before interpreting the source process.
{"title":"Seismoacoustic Analysis of Possible Vent-Drying Sequence During Phreatomagmatic Activity on 13 July 2021 at Semisopochnoi Island, Alaska","authors":"Dan Muramatsu, John J. Lyons, Hannah R. Dietterich, Mie Ichihara, Alexandra M. Iezzi","doi":"10.1029/2025gl119273","DOIUrl":"https://doi.org/10.1029/2025gl119273","url":null,"abstract":"Pulse-like infrasound accompanying volcanic phenomena sometimes suggests interaction with water at the crater. We focus on pulse-like infrasound observed at Semisopochnoi Island in the Aleutian Arc, Alaska, during the phreatomagmatic activity on 13 July 2021. Overflight observations confirmed a small, ephemeral water lake on the crater floor in June 2021. We examined temporal variations in pulse-like infrasound activity, seismoacoustic amplitudes, and spectral characteristics. Pulse-like infrasound activity gradually became intermittent and waned at the end of the day. Seismic-infrasonic amplitude ratio decreased, while the infrasound frequency index increased with time. These results suggest less interaction with water due to drying out of the vent. Satellite observations also show increased ground surface temperatures inside the crater from 13 to 14 July. Numerical simulation suggests a significant topographic effect on the waveform and spectrum of the pulse-like infrasound, which should be considered before interpreting the source process.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"99 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantifying how and where climate change will alter meteorological drought properties is a priority to inform adaptation policies. Here we use the standardized precipitation index to portray future changes in the climatological properties of moderate drought events projected by the latest generation of Earth system models. Beyond the assessment of their mean frequency and intensity, other metrics are explored including length of drought intervals, drought duration, starting date and severity. Two extended 6-month seasons are distinguished starting in October and April, respectively. Consistent changes in drought properties are projected across timescales and seasons. Regional “dry spots” are identified, such as northern South America and the Caribbean Islands, where the median model response shows the largest increase in drought severity, mostly as a result of prolonged duration. Yet, there are many regions where the inter-model spread remains substantial and cannot be reduced by the application of global and regional observational constraints.
{"title":"How Do Projections of Meteorological Droughts Vary Across Models and Regions?","authors":"H. Douville","doi":"10.1029/2025gl119644","DOIUrl":"https://doi.org/10.1029/2025gl119644","url":null,"abstract":"Quantifying how and where climate change will alter meteorological drought properties is a priority to inform adaptation policies. Here we use the standardized precipitation index to portray future changes in the climatological properties of moderate drought events projected by the latest generation of Earth system models. Beyond the assessment of their mean frequency and intensity, other metrics are explored including length of drought intervals, drought duration, starting date and severity. Two extended 6-month seasons are distinguished starting in October and April, respectively. Consistent changes in drought properties are projected across timescales and seasons. Regional “<i>dry spots</i>” are identified, such as northern South America and the Caribbean Islands, where the median model response shows the largest increase in drought severity, mostly as a result of prolonged duration. Yet, there are many regions where the inter-model spread remains substantial and cannot be reduced by the application of global and regional observational constraints.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"1 2 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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