Geophysical Research Letters最新文献

{"title":"East Pacific Easterly Wave Representation in CMIP6 Models","authors":"Rosa M. Vargas Martes,&nbsp;Ángel F. Adames Corraliza,&nbsp;Víctor C. Mayta,&nbsp;Qiao-Jun Lin","doi":"10.1029/2024GL113233","DOIUrl":"https://doi.org/10.1029/2024GL113233","url":null,"abstract":"<p>The representation of easterly waves (EWs) over the east Pacific Ocean (PEWs) in Coupled Model Intercomparison Project phase 6 (CMIP6) simulations is examined. Models are assessed based on their ability of reproducing PEW-related precipitation and its evolution. The leading patterns reveal a large spread in the representation of PEW structure and amplitude. A comparison of the models with the most realistic PEWs with those with unrealistically weak PEW skill showed that the more accurate simulations more effectively capture the mean state and EW thermodynamic structures over the northeast Pacific. Particularly, good models exhibit realistic PEW precipitation, weaker meridional mean state humidity gradients, larger mean state precipitation over the Panama Bight, and realistic convective moisture adjustment timescales. These results underscore the importance of accurately representing the sensitivity of PEW convection to anomalous moisture for the realistic representation of the waves.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113233","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880114","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":"The Role of Wind Speed in Prolonging Large Fire Durations in the Western US","authors":"Sally S.-C. Wang,&nbsp;L. Ruby Leung,&nbsp;Yun Qian","doi":"10.1029/2024GL112539","DOIUrl":"https://doi.org/10.1029/2024GL112539","url":null,"abstract":"<p>The duration of large wildfires in the western US has increased significantly from 1992 to 2020 in the two fire seasons, by 0.76 days yr⁻¹ in summer and 0.55 days yr⁻¹ in fall. The factors driving the trend and variability were analyzed using multiple linear regression models. Our analysis identified the maximum daily wind speed during large fires, which has also increased during the study period, as the primary predictor for the large fire duration. Despite the observed rise in maximum wind speed specifically during large fires, there are no corresponding trends in the average daily mean wind speed throughout the fire seasons. The mechanisms underlying the increase in maximum wind speed during large fires remain unclear and warrant further investigation, as they may pose growing challenges for fire control.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL112539","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880102","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":"Can Large-Scale Satellite Products Track the Effects of Atmospheric Dryness and Soil Water Deficit on Ecosystem Productivity Under Droughts?","authors":"Xiaorong Wang,&nbsp;Zhengfei Guo,&nbsp;Kun Zhang,&nbsp;Zheng Fu,&nbsp;Calvin K. F. Lee,&nbsp;Dedi Yang,&nbsp;Matteo Detto,&nbsp;Yongguang Zhang,&nbsp;Jin Wu","doi":"10.1029/2024GL110785","DOIUrl":"https://doi.org/10.1029/2024GL110785","url":null,"abstract":"<p>Drought stress, characterized by increased vapor pressure deficit (VPD) and soil water content (SWC) deficit, significantly impacts ecosystem productivity (GPP). Accurately assessing these factors in satellite remote sensing (RS) GPP products is crucial for understanding the large-scale ecological consequences of drought. However, the accuracy of RS GPP in capturing the effects of VPD and SWC deficit, compared to EC flux data, remains under-investigated. Here we evaluated 10 RS GPP products and their mean (RSmean) concerning VPD and SWC deficit across diverse ecosystems along a dryness gradient. Our results revealed that RSmean and individual products generally capture the GPP response direction (VPD: mainly negative, SWC deficit: mixed positive/negative) but consistently misestimate the absolute GPP changes. This discrepancy is ecosystem-specific and consistent across all RS products, underscoring the need to enhance RS products to better account for ecosystem-specific VPD effects and non-linear SWC deficit responses, thereby improving RS GPP accuracy under drought.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL110785","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879970","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":"Internal Structure of the Mantle Transition Zone Beneath the Contiguous U.S.: Insights From the 520-km Discontinuity Revealed by Ambient Noise Correlations","authors":"Y. A. Aiman,&nbsp;Y. Lu,&nbsp;C. Esteve,&nbsp;G. Bokelmann","doi":"10.1029/2025GL115453","DOIUrl":"https://doi.org/10.1029/2025GL115453","url":null,"abstract":"<p>We investigate the internal structure of the Mantle Transition Zone (MTZ) beneath the contiguous U.S. by mapping the depth of the 520-km discontinuity (d520) and the relative amplitude of seismic phases associated with the 520-, 410-, and 660-km discontinuities. Specifically, we analyze short-period reflected waves between 3 and 10 s from the MTZ discontinuities extracted from seismic noise correlations. Our results show lateral d520 depth variations, deeper in the western U.S., likely indicating a warmer upper MTZ. Analysis of relative phase amplitude between the MTZ interfaces highlights a strong d520 reflection phase across the central U.S., supporting previous studies that report high seismic velocity contrasts and elevated olivine content. In contrast, the eastern U.S. shows a weaker d520 reflection phase, which may be attributed to a gradual seismic velocity transition and lower water content. The MTZ composition also likely varies across the U.S., with potential basalt accumulation in the southwest due to past subduction events.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115453","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880103","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":"River Avulsion Precursors Encoded in Alluvial Ridge Geometry","authors":"J. H. Gearon,&nbsp;D. A. Edmonds","doi":"10.1029/2024GL114047","DOIUrl":"https://doi.org/10.1029/2024GL114047","url":null,"abstract":"&lt;p&gt;River avulsions generate catastrophic floods that threaten communities, ecosystems, and infrastructure worldwide. Alluvial ridges—elevated regions of near-channel topography—are thought to precede avulsions, yet their spatial patterns and relationship to avulsion impact remain poorly understood. We analyzed pre-event topographic cross-sections from 14 rivers to quantify avulsion potential &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;Λ&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $({Lambda })$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, a metric combining ridge height and slope relative to the channel. Our analysis reveals that &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;Λ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Lambda }$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; varies downstream and defines distinct alluvial ridge segments. We identify two characteristic length scales: a longer-wavelength complex (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mover&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;L&lt;/mi&gt;\u0000 &lt;mi&gt;λ&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;‾&lt;/mo&gt;\u0000 &lt;/mover&gt;\u0000 &lt;mo&gt;≈&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $overline{{L}_{lambda }}approx $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 30 km) composed of shorter ridge segments (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mover&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;L&lt;/mi&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;‾&lt;/mo&gt;\u0000 &lt;/mover&gt;\u0000 &lt;mo&gt;≈&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $overline{{L}_{C}}approx $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 8 km). Segments with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;Λ&lt;/mi&gt;\u0000 &lt;mo&gt;≥&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${Lambda }ge $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 2 correspond to 73% of observed avulsion activity locations (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $n$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 37). Avulsion activity length &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;L&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879974","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":"Infrasound Unmasks Flow Turbulence as an Additional Seismic Source in Debris Flows","authors":"Giacomo Belli,&nbsp;Emanuele Marchetti,&nbsp;Fabian Walter,&nbsp;Duccio Gheri","doi":"10.1029/2025GL116107","DOIUrl":"https://doi.org/10.1029/2025GL116107","url":null,"abstract":"<p>Debris flows radiate both seismic and infrasonic waves. According to previous studies, seismic energy is generated by the solid particle collisions with the riverbed and is dominated by the boulder-rich front, while infrasound is produced by turbulence-induced waves at the flow surface. To further investigate this complex radiation processes, we present the seismo-acoustic analysis of a debris-flow event at Illgraben (Switzerland). Array processing shows that infrasound is preferentially radiated at channel irregularities, acting as predominant acoustic sources because of the intense flow turbulence. The high crosscorrelation observed between the recorded infrasonic and seismic signals suggests that, in addition to the dominant source related to particle impacts, a minor seismic component is produced by the flow waves developing at topographic steps.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL116107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880099","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":"The Negative Elevation-Dependent Pattern of Non-Growing Season CO2 Loss From Alpine Frozen Ground","authors":"Zhaoheng Deng,&nbsp;Jiabin Fan,&nbsp;Da Wei,&nbsp;Yahui Qi,&nbsp;Jing Tao,&nbsp;Zhuangzhuang Wang,&nbsp;Liqin Hua,&nbsp;Xiaodan Wang","doi":"10.1029/2024GL113490","DOIUrl":"https://doi.org/10.1029/2024GL113490","url":null,"abstract":"<p>Substantial organic carbon stores in the soil of high-elevation regions are vulnerable to rapid warming. The “Third Pole”, encompassing the Tibetan Plateau and adjacent regions, is home to the largest alpine permafrost on the Earth. Through analysis of 118 eddy covariance and chamber observations in the non-growing season—a unique time window for examining soil CO₂ loss, we report a negative elevation-dependent pattern. More importantly, there is a negative elevation-dependent pattern regarding the temperature sensitivities of CO₂ loss, determined by the soil carbon content. We project that, compared to low elevations, future increases in CO₂ loss will be lower at high elevations (&gt;4,000 m) with lower soil organic carbon. The pattern of alpine soil CO₂ loss, in which the higher the elevation and the colder it is, the less sensitive the loss is to warming, implies limited CO₂ will be lost in the future from high-elevation permafrost regions.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL113490","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880100","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":"Local Finite-Amplitude Wave Activity of Water Vapor as a Diagnostic of Atmospheric River Events","authors":"Rui Zhang,&nbsp;Edmund K. M. Chang","doi":"10.1029/2024GL114314","DOIUrl":"https://doi.org/10.1029/2024GL114314","url":null,"abstract":"<p>We generalize the formalism of local wave activity of quasi-geostrophic potential vorticity to water vapor, defined as LWA-V, and derive the LWA-V budget equation. LWA-V measures the waviness of moisture contours from the zonal symmetry in the eddy-free atmosphere. It delineates well the northward moisture intrusion and the filamentary feature of AR events. Compared with the traditional moisture budget, the climatological LWA-V and LWA-V budget terms are more consistent in structure and are able to delineate the climatological AR. Moisture flux convergence is the dominant process for the intensification and movement of the LWA-V center associated with the AR event while the combined effect of evaporation and precipitation is mainly a sink of LWA-V, which is consistent with traditional moisture budget analysis. Furthermore, utilizing the Lagrangian aspect of LWA-V, we demonstrate quantitatively that the original latitudes of the largest precipitable water of the AR event are in the tropical region.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114314","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880104","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":"Analytical Solution for the Frictional Anisotropy of a Corrugated Fault","authors":"Martin P. J. Schöpfer,&nbsp;Conrad Childs","doi":"10.1029/2024GL114281","DOIUrl":"https://doi.org/10.1029/2024GL114281","url":null,"abstract":"<p>Fault surfaces exhibit anisotropic roughness, with elongate ridges and grooves aligned in the slip direction. When inactive faults are reactivated under a new stress regime, induced by natural processes or human activities, the maximum resolved shear stress is likely to act obliquely to inherited surface corrugations increasing the fault shear strength. Analytical solutions for the shear strength of a corrugated fault, idealized as a frictional serrated surface of infinite extent separating rigid blocks under any shear stress direction, have been derived. The solutions show that the shear strength increases with increasing angle between the corrugation axes and the shear stress direction, and with fault roughness. Further, the fault slip direction may deviate significantly from the maximum resolved shear stress direction toward the corrugation axes. Finally, the reactivation potential does not only depend on stress state, fault orientation and friction, but also on surface roughness and the orientation of the corrugations.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL114281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880105","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":"Detection of Low-Altitude Cislunar Dust With the Lunar Occultation Archive","authors":"M. L. Khodachenko,&nbsp;O. V. Arkypov","doi":"10.1029/2024GL111606","DOIUrl":"https://doi.org/10.1029/2024GL111606","url":null,"abstract":"<p>It is believed that dust formations above the lunar surface, manifested via sunlight scattering and detected in-situ, are of too low density to pose threats to lunar missions. However, occasionally prolonged fading/kindling of the immersing/emerging stars near the lunar limb indicates much denser low-altitude dust clouds. We performed statistical analysis of such abnormal stellar occultation events (ASOEs), found in the Lunar Occultation Archive. Specific dependence of their duration on selenographic position reveals an impact-plume like shape of dust clouds and excludes visual illusions, terrestrial cloudiness, and double stars as causes of the observed starlight extinction. The probability of the long-lasting ASOEs peaks during the Perseid meteor shower in August, confirming the impact-related nature of most of the related dust clouds. At the same time, additional semi-monthly periodicity of ASOEs points to a complementary mechanism of dust lifting due to, for example, lunar outgassing triggered by solar tides.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880113","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}