Geophysical Research Letters最新文献

{"title":"Validation of a Global Geospace Model With a Systems Science Approach Based on Canonical Correlation Analysis","authors":"Gian Luca Delzanno,&nbsp;Brianna Isola,&nbsp;Christian Lao,&nbsp;Joseph E. Borovsky,&nbsp;Kareem Sorathia,&nbsp;Viacheslav G. Merkin,&nbsp;Oleksandr Koshkarov,&nbsp;Andrew McCubbin,&nbsp;Jeff Garretson,&nbsp;Harry Arnold,&nbsp;Dong Lin","doi":"10.1029/2025GL115589","DOIUrl":"10.1029/2025GL115589","url":null,"abstract":"<p>A systems science approach based on canonical correlation analysis (CCA) is applied as a new, behavioral way to validate global geospace models. The biggest novelty of the technique is that it validates models at a system level, whereby a side-by-side comparison is performed of CCA applied to a 30-day observational and the corresponding simulation data sets comprising quiet, moderate and active times. The simulation used the Multiscale Atmosphere-Geospace Environment (MAGE) model. It is shown that (a) CCA must be combined with sensitivity analysis to be effective, (b) the MAGE model generally reproduces the observed behavior (more so for quieter time intervals), quantified by the intercorrelations between different variables and (c) the technique identifies the SuperMAG SML index as a quantity for which refinements of the model are needed.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115589","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comprehensive Crustal Coda Attenuation Map of Continental China","authors":"Fan Yang,&nbsp;Wei Wang,&nbsp;Yutong Liang,&nbsp;Sidan Chen,&nbsp;Li Sun,&nbsp;Wenze Deng,&nbsp;Nozomu Takeuchi,&nbsp;Juan Li","doi":"10.1029/2025GL117317","DOIUrl":"10.1029/2025GL117317","url":null,"abstract":"<p>Seismic coda wave attenuation (<i>Q</i>_C) reflects both intrinsic inelasticity and small-scale heterogeneities in the Earth's crust, offering insights into its thermal state and structural complexity. Continental China, characterized by widespread plate boundary deformation, is among the most tectonically active regions globally. Using over a decade of data from the China National Seismic Network, we apply the Multiple Station and Multiple Event Method to estimate station-side <i>Q</i>_C across 1–14 Hz, yielding high-resolution maps that reveal block-scale patterns aligned with tectonic boundaries. The Northeast, South, and North China blocks show consistently high <i>Q</i>_C values, while significantly lower values are observed in Xinjiang, Tibetan Plateau, and North–South Seismic Belt, consistent with theoretical expectations that low values are observed in active regions. Furthermore, we identify a negative correlation between <i>Q</i>_C and shear strain rate at higher frequencies, suggesting a fundamental link between attenuation and crustal stress heterogeneity.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL117317","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Carbon Losses From Burned Permafrost Peatlands During Post-Fire Succession","authors":"Christopher Schulze,&nbsp;Oliver Sonnentag,&nbsp;Craig A. Emmerton,&nbsp;Lorna Harris,&nbsp;Haley Alcock,&nbsp;Kate Marouelli,&nbsp;Gabriel Hould Gosselin,&nbsp;Sara H. Knox,&nbsp;Rosie Howard,&nbsp;June Skeeter,&nbsp;Paul Moore,&nbsp;Zoran Nesic,&nbsp;David Olefeldt","doi":"10.1029/2025GL118344","DOIUrl":"10.1029/2025GL118344","url":null,"abstract":"<p>The carbon (C) storage of boreal peatlands is threatened by an intensifying wildfire regime. Between 2019 and 2023 we used eddy covariance and surface closed chambers to monitor two permafrost peatlands in boreal western Canada that burned in 2019 and 2007. Deeper thaw, warmer soils, and slow vegetation recovery caused the 2019 Burn to be a net carbon dioxide (CO₂) source (+130 g C m⁻² yr⁻¹) for four years post-fire, despite reduced soil respiration. The 2007 Burn was a sink (−11 g C m⁻² yr⁻¹) 13–15 years post-fire, similar to undisturbed peatlands. We estimate that wildfire caused a loss (∼2.9 kg C m⁻²) from permafrost peatlands, with ∼1.7 kg C m⁻² due to combustion and ∼1.2 kg C m⁻² due to net CO₂ losses during post-fire succession. This highlights the importance of the post-fire CO₂ losses and emphasizes the vulnerability of permafrost peatland soil C to fire.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL118344","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the Connection Between Subsurface Stress and Geomorphic Features","authors":"B. Kuhasubpasin,&nbsp;S. Moon,&nbsp;C. Lithgow-Bertelloni","doi":"10.1029/2025GL116798","DOIUrl":"10.1029/2025GL116798","url":null,"abstract":"<p>The tectonic stress field induces surface deformation. At long wavelengths, both lithospheric heterogeneity (changes in the thickness and density of crust and lithospheric mantle) and basal tractions from mantle convection contribute to the stress field. Here, we analyze the global alignment of principal horizontal tectonic stresses, fault traces, and river flow directions to infer whether and how deep subsurface stresses control geomorphic features. We find that fault trace orientations are consistent with predictions from Anderson's fault theory. River directions largely align with fault traces and partly with stresses. The degree of alignment depends on fault regime, the source of stress, and river order. Extensional faulting is best predicted by stresses from lithospheric structure variations, while compressive faulting is best predicted by stresses from mantle flow. We propose a metric to quantify the relative influence of mantle flow or lithospheric heterogeneity on surface features, which provides a proxy for lithospheric strength.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL116798","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Global Lagrangian Analysis of Near-Surface Temperature Extremes","authors":"Amelie Mayer","doi":"10.1029/2025GL116696","DOIUrl":"10.1029/2025GL116696","url":null,"abstract":"<p>Temperature extremes strongly affect the society and the environment, yet a complete physical understanding of their formation mechanisms is still lacking. Specifically, the relative importance of the three key processes—horizontal advection, subsidence accompanied by adiabatic warming, and diabatic heating—remains controversial. This paper presents a global quantification of the contributions from these processes to near-surface temperature extremes using the Lagrangian framework. Two Lagrangian potential temperature anomaly decompositions are applied: one based on the full fields of the respective terms, and the other one based on the anomaly fields of the respective terms (i.e., deviations from their corresponding climatologies). The results from the decomposition based on full fields mostly align with those of a previous study, while the decomposition based on anomaly fields offers a different assessment of the roles of the different processes. Most importantly, horizontal transport is attributed the primary role for both extremes globally.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL116696","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calving as a Source of Acute and Persistent Kinetic Energy to Enhance Submarine Melting of Tidewater Glaciers","authors":"M. F. Shaya,&nbsp;J. D. Nash,&nbsp;E. C. Pettit,&nbsp;J. M. Amundson,&nbsp;R. H. Jackson,&nbsp;D. A. Sutherland,&nbsp;D. Winters","doi":"10.1029/2025GL117900","DOIUrl":"10.1029/2025GL117900","url":null,"abstract":"<p>Calving icebergs at tidewater glaciers release large amounts of potential energy. This energy—in principle—could be a source for submarine melting, which scales with near-terminus water temperature and velocity. Because near-terminus currents are challenging to observe or predict, submarine melt remains a key uncertainty in projecting tidewater glacier retreat and sea level rise. Here, we study one submarine calving event at Xeitl Sít’ (LeConte Glacier), Alaska, to explore the effect of calving on ice melt, using a suite of autonomously deployed instruments beneath, around, and downstream of the calving iceberg. Our measurements captured flows exceeding 5 m/s and demonstrate how potential energy converts to kinetic energy <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mfenced>\u0000 <msub>\u0000 <mi>E</mi>\u0000 <mi>K</mi>\u0000 </msub>\u0000 </mfenced>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $left({E}_{K}right)$</annotation>\u0000 </semantics></math>. While most energy decays quickly (through turbulence, mixing, and radiated waves), near-terminus <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mi>E</mi>\u0000 <mi>K</mi>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${E}_{K}$</annotation>\u0000 </semantics></math> remains elevated, nearly doubling predicted melt rates for hours after the event. Calving-induced currents could thus be an important overlooked energy source for submarine melt and glacier retreat.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL117900","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reducing Uncertainty in Climate Projections for the Mid and High Latitudes of the Northern Hemisphere","authors":"Yongxiao Liang,&nbsp;Nathan P. Gillett","doi":"10.1029/2025GL117477","DOIUrl":"10.1029/2025GL117477","url":null,"abstract":"<p>The mid latitudes and high latitudes of the Northern Hemisphere are warming faster than the global average, particularly over land. Model uncertainty in the forced response is the largest contributor to the total uncertainty in climate projections for these regions. Beyond climate sensitivity differences, regional climate feedbacks—like Arctic sea-ice loss—drive model uncertainty of the climate response. By applying emergent constraints based on the observed global warming trend and a metric related to Arctic sea ice loss, we reduce uncertainty in projected air temperature and precipitation changes over high-latitude land areas. Based on an imperfect model test, such projections outperform projections constrained using only the global warming trend or unconstrained projections. Compared to unconstrained projections, our approach reduces uncertainty by 22%–47% for temperature changes and 10%–51% for precipitation changes across different IPCC regions in the mid to high latitudes of the Northern Hemisphere by the end of the century under a middle-of-the-road scenario.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL117477","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cutoff and Emergence of Dart Leaders in an Unbranched Positive Leader Simulation","authors":"J. G. Pantuso,&nbsp;C. L. da Silva,&nbsp;D. P. Jensen,&nbsp;M. Stock,&nbsp;J. Wemhoner,&nbsp;S. Heckman,&nbsp;B. M. Hare,&nbsp;A. F. R. Leal,&nbsp;R. G. Sonnenfeld,&nbsp;O. Scholten,&nbsp;X.-M. Shao","doi":"10.1029/2025GL117337","DOIUrl":"10.1029/2025GL117337","url":null,"abstract":"<p>Channel cutoff is the process by which an active lightning channel cools down, goes dark, and loses its ability to effectively conduct electricity. Current cutoff precedes several lightning phenomena, notably dart leaders and return strokes, but the process by which a hot, highly-conducting leader channel can undergo current cutoff is poorly understood. In this work, we present self-consistent simulations of positive leader propagation, which include coupled treatment of electrodynamics and plasma physics. The unstable positive leader spontaneously undergoes channel cutoff and creates the conditions for the emission of dart leaders, that is, it accumulates a packet of negative charge at the intersection between cutoff and conducting channel segments. A residual conductivity in the cutoff section facilitates the conversion of the electric field enhancement into a traveling wave, which retraces and reionizes the channel. This is critical for allowing the frail positive leader to keep propagating.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL117337","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spontaneous Transient Summit Uplift at Taftan Volcano (Makran Subduction Arc) Imaged Using an InSAR Common-Mode Filtering Method","authors":"Mohammadhossein Mohammadnia,&nbsp;Man Wai Yip,&nbsp;A. Alexander G. Webb,&nbsp;Pablo J. González","doi":"10.1029/2025GL114853","DOIUrl":"10.1029/2025GL114853","url":null,"abstract":"<p>We unambiguously document unrest at Taftan volcano. Summit uplift was detected using Interferometric Synthetic Aperture Radar time series and its timing tightly constrained applying a new common mode filtering method. Uplift started and ended gradually lasting 10 months (July 2023 to May 2024). Uplift peaked at 11 cm/year rates, and during slowing-down several gas emission events occurred. Unrest was triggerless, uncorrelated with rainfall or seismic events. We favor internal driving processes with two possible scenarios: (a) dynamic hydrothermal alteration leading to permeability changes, shallow gas storage and pressurization, followed by opening of degassing pathways; or (b) a minor, undetected deep magmatic intrusion causing volatile exsolution and pore pressure increases within the hydrothermal system. Lack of post-unrest subsidence suggests persistence of hydrothermal high-pressure conditions at the summit and associated hazards. Our study shows how satellite imagery reveals hidden volcanic hazards at Taftan, and the need to implement a holistic volcano risk reduction strategy.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL114853","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145241160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermohaline Preconditioning for Sea Ice Formation in the Beaufort Sea","authors":"O. J. Houndegnonto,&nbsp;I. G. Fenty,&nbsp;S. Fournier,&nbsp;M. Steele,&nbsp;M. J. Zahn,&nbsp;P. Gaube","doi":"10.1029/2025GL115023","DOIUrl":"10.1029/2025GL115023","url":null,"abstract":"<p>The influence of ocean stratification and heat content on the timing of sea ice formation and its subsequent growth remains an open question. Here we investigate the thermohaline conditions prior to fall sea ice formation as well as the roles of stratification and heat content on sea ice growth rates through the analysis of in situ observations and numerical simulations from a one-dimensional ocean-ice-column model. We find that the simulated time series of sea ice concentration are highly correlated with observations. We identify two clusters of sea ice concentration growth rate, which we name Early Slow and Late-Fast. We find that cold, shallow mixed layers promote early sea ice freeze-up. Salinity stratification within the upper pycnocline slows the release of heat into the deepening mixed layer, leading to slower ice growth. However, where salinity stratification above the upper pycnocline is absent, sea ice growth occurs later and, once started, progresses faster.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 19","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145235235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}