Electrons of several hundred keV in Saturn's ring current are important seed components of the radiation belt. In this study, we have statistically analyzed the spatial distribution of energetic electrons on the equatorial plane of the inner magnetosphere based on the Cassini in situ observations. We found for all energy channels, the peak position of energetic electron flux shifts from the midnight sector to the afternoon sector as L shell increases. At specific L shells, the transitional energy (Et), which separates the peaks of energetic electron flux in azimuthal direction, decreases as L shell increases and is consistent with the theoretical prediction of corotation drift resonant energy (ECDR). Further analysis indicates that the day-night asymmetry of energetic electron flux is caused by the noon-to-midnight electric field, with its direction deviates from the noon-midnight line. These findings advance our understanding of the energization mechanism of inward radial transport.
{"title":"Local Time Asymmetry in Energetic Electron Distribution Within Saturn's Inner Magnetosphere","authors":"Yimeng Li, Chao Yue, Yixin Sun, Yixin Hao, Qiugang Zong, Xuzhi Zhou","doi":"10.1029/2025gl119935","DOIUrl":"https://doi.org/10.1029/2025gl119935","url":null,"abstract":"Electrons of several hundred keV in Saturn's ring current are important seed components of the radiation belt. In this study, we have statistically analyzed the spatial distribution of energetic electrons on the equatorial plane of the inner magnetosphere based on the Cassini in situ observations. We found for all energy channels, the peak position of energetic electron flux shifts from the midnight sector to the afternoon sector as L shell increases. At specific L shells, the transitional energy (<i>E</i><sub><i>t</i></sub>), which separates the peaks of energetic electron flux in azimuthal direction, decreases as L shell increases and is consistent with the theoretical prediction of corotation drift resonant energy (<i>E</i><sub>CDR</sub>). Further analysis indicates that the day-night asymmetry of energetic electron flux is caused by the noon-to-midnight electric field, with its direction deviates from the noon-midnight line. These findings advance our understanding of the energization mechanism of inward radial transport.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"15 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440204","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}
Estelle Allan, Yunfeng Wang, Anne de Vernal, Yves Gélinas, Alfonso O. Mucci, Marit-Solveig Seidenkrantz, Peter M. J. Douglas
Organic carbon (OC) burial in sediments is partly controlled by catabolic biodegradation and remineralization by heterotrophic bacteria, but long-term records of these bacterially-mediated processes have not been available. Here, we use stable hydrogen isotope ratio of the saturated C16 fatty acid (δ2HC16:0) as a proxy of the prevalence of heterotrophic bacterial activity to reconstruct the history of Holocene OC biodegradation and remineralization from a sediment core recovered on the southwest Greenland Shelf. A positive shift in the δ2HC16:0 during the Holocene Thermal Maximum indicates increased inputs of heterotrophic bacterial biomass to sediments. This implies efficient biodegradation and remineralization of OC during this warm period that are linked to low sediment accumulation rates (SARs) and elevated primary productivity. We propose that enhanced bacterial catabolism of OC in the absence of increased SARs will reduce OC burial efficiency in warmer, high-latitude oceans, thereby providing positive feedback to climate warming.
{"title":"Trophic Changes off Southwest Greenland During the Holocene and Their Influence on Carbon Burial","authors":"Estelle Allan, Yunfeng Wang, Anne de Vernal, Yves Gélinas, Alfonso O. Mucci, Marit-Solveig Seidenkrantz, Peter M. J. Douglas","doi":"10.1029/2025gl120012","DOIUrl":"https://doi.org/10.1029/2025gl120012","url":null,"abstract":"Organic carbon (OC) burial in sediments is partly controlled by catabolic biodegradation and remineralization by heterotrophic bacteria, but long-term records of these bacterially-mediated processes have not been available. Here, we use stable hydrogen isotope ratio of the saturated C<sub>16</sub> fatty acid (δ<sup>2</sup>H<sub>C16:0</sub>) as a proxy of the prevalence of heterotrophic bacterial activity to reconstruct the history of Holocene OC biodegradation and remineralization from a sediment core recovered on the southwest Greenland Shelf. A positive shift in the δ<sup>2</sup>H<sub>C16:0</sub> during the Holocene Thermal Maximum indicates increased inputs of heterotrophic bacterial biomass to sediments. This implies efficient biodegradation and remineralization of OC during this warm period that are linked to low sediment accumulation rates (SARs) and elevated primary productivity. We propose that enhanced bacterial catabolism of OC in the absence of increased SARs will reduce OC burial efficiency in warmer, high-latitude oceans, thereby providing positive feedback to climate warming.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"84 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440200","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}
D. Griffin, X. Zhao, C. McLinden, N. Yazdani, C. R. Nowlan, G. González Abad, V. Fioletov, Elisabeth Galarneau, Cris Mihele, Sumi Wren, Yushan Su, Lukas Fehr, Adam Bourassa
The Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite provides hourly air quality measurements over North America. This study evaluates TEMPO <span data-altimg="/cms/asset/9fad4b6d-bcda-431b-bf24-bb5b2839a216/grl72001-math-0001.png"></span><mjx-container ctxtmenu_counter="117" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/grl72001-math-0001.png"><mjx-semantics><mjx-mrow><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-role="unknown" data-semantic-speech="NO Subscript 2" data-semantic-type="subscript"><mjx-mtext data-semantic-annotation="clearspeak:unit" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="text"><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mtext><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c></mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display="inline" unselectable="on"><math altimg="urn:x-wiley:00948276:media:grl72001:grl72001-math-0001" display="inline" location="graphic/grl72001-math-0001.png" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msub data-semantic-="" data-semantic-children="0,1" data-semantic-role="unknown" data-semantic-speech="NO Subscript 2" data-semantic-type="subscript"><mtext data-semantic-="" data-semantic-annotation="clearspeak:unit" data-semantic-font="normal" data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="text">NO</mtext><mn data-semantic-="" data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number">2</mn></msub></mrow>${text{NO}}_{2}$</annotation></semantics></math></mjx-assistive-mml></mjx-container> observations over snow-covered surfaces, highlighting its ability to capture sharp spatial and temporal gradients in <span data-altimg="/cms/asset/d0177287-f184-43c0-a40e-8341a32e06f2/grl72001-math-0002.png"></span><mjx-container ctxtmenu_counter="118" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/grl72001-math-0002.png"><mjx-semantics><mjx-mrow><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-role="unknown" data-semantic-speech="NO Subscript 2" data-semantic-type="subscript"><mjx-mtext data-semantic-annotation="clearspeak:unit" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="text"><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mtext><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clea
W. C. Zhou, D. K. Xue, Y. C. Zhang, H. S. Chen, W. J. Hua, X. Y. Kuang, Y. Yao, D. Q. Huang
Heat extremes occurring synchronously in multiple regions often result in more severe impacts than isolated heat events. Here we analyze observational and reanalysis data to objectively detect and examine the synchronization of heat extremes in the Northern Hemisphere and identify the regions that have remote linkages, particularly in western Europe (WEU), western North America (WNA) and the Yangtze-Huai River Basin (YHRB). The results indicate that the intensity and frequency of synchronized heat extremes show increasing trends during 1979–2023 summer, with most events occurring in the past 20 years. The synchronized heat extremes are triggered by a quasi-stationary Rossby wave with wavenumber 6, resembling a circum-global teleconnection (CGT)-like pattern along the subtropical jet. While large-scale atmospheric circulation provides a common dynamical background, the sustaining mechanisms differ across regions. Land-atmosphere interactions and surface processes jointly reinforce the persistence of synchronized heat extremes, providing new insights on compound event analysis.
{"title":"Synchronized Heat Extremes in the Northern Hemisphere Based on a Complex Network","authors":"W. C. Zhou, D. K. Xue, Y. C. Zhang, H. S. Chen, W. J. Hua, X. Y. Kuang, Y. Yao, D. Q. Huang","doi":"10.1029/2025gl120839","DOIUrl":"https://doi.org/10.1029/2025gl120839","url":null,"abstract":"Heat extremes occurring synchronously in multiple regions often result in more severe impacts than isolated heat events. Here we analyze observational and reanalysis data to objectively detect and examine the synchronization of heat extremes in the Northern Hemisphere and identify the regions that have remote linkages, particularly in western Europe (WEU), western North America (WNA) and the Yangtze-Huai River Basin (YHRB). The results indicate that the intensity and frequency of synchronized heat extremes show increasing trends during 1979–2023 summer, with most events occurring in the past 20 years. The synchronized heat extremes are triggered by a quasi-stationary Rossby wave with wavenumber 6, resembling a circum-global teleconnection (CGT)-like pattern along the subtropical jet. While large-scale atmospheric circulation provides a common dynamical background, the sustaining mechanisms differ across regions. Land-atmosphere interactions and surface processes jointly reinforce the persistence of synchronized heat extremes, providing new insights on compound event analysis.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"16 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147447898","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}
Haonan Wu, Wenbin Wang, Xueling Shi, Dong Lin, Michael D. Hartinger, Joseph B. H. Baker, Shibaji Chakraborty
Ultra-low-frequency (ULF) waves cause local Thermosphere-Ionosphere (T-I) perturbations, but their impacts on the global T-I system including the generation of Traveling Atmospheric Disturbances (TADs) have never been evaluated. The mechanisms responsible for the TAD generation and propagation, whether through dynamic or thermal process, are not clear either. We present a model study of ULF wave impacts on the thermosphere using the Thermosphere-Ionosphere-Electrodynamics General Circulation Model. The model results indicate that ULF waves can trigger globally propagating TADs at ∼810 m/s. Thermal processes are the main driver for the TAD generation and propagation, with Joule heating and adiabatic processes taking effects inside the TAD source region, and adiabatic processes and heat conduction being the dominant processes outside. Model results also show that TAD propagation is almost independent of seasonal effects. This study reveals the physical connections between magnetospheric ULF waves and thermospheric disturbances for the first time.
{"title":"Global Impacts of Ultra-Low-Frequency Waves: 1. Thermospheric Responses and Traveling Atmospheric Disturbances","authors":"Haonan Wu, Wenbin Wang, Xueling Shi, Dong Lin, Michael D. Hartinger, Joseph B. H. Baker, Shibaji Chakraborty","doi":"10.1029/2025gl119835","DOIUrl":"https://doi.org/10.1029/2025gl119835","url":null,"abstract":"Ultra-low-frequency (ULF) waves cause local Thermosphere-Ionosphere (T-I) perturbations, but their impacts on the global T-I system including the generation of Traveling Atmospheric Disturbances (TADs) have never been evaluated. The mechanisms responsible for the TAD generation and propagation, whether through dynamic or thermal process, are not clear either. We present a model study of ULF wave impacts on the thermosphere using the Thermosphere-Ionosphere-Electrodynamics General Circulation Model. The model results indicate that ULF waves can trigger globally propagating TADs at ∼810 m/s. Thermal processes are the main driver for the TAD generation and propagation, with Joule heating and adiabatic processes taking effects inside the TAD source region, and adiabatic processes and heat conduction being the dominant processes outside. Model results also show that TAD propagation is almost independent of seasonal effects. This study reveals the physical connections between magnetospheric ULF waves and thermospheric disturbances for the first time.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"97 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147447899","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}
Full-depth (Surface-to-bottom) turbulent kinetic energy dissipation (TKED) observed with fast-response thermistors across the Antarctic Circumpolar Current (ACC) at 50E is compared with the energy flux of bottom-generated internal waves estimated with high-resolution multibeam bathymetry. Turbulent kinetic energy dissipation is here found to be locally balanced with the energy flux of internal lee waves generated through the interactions between quasi-steady deep currents and small horizontal-scale bottom topography, except in the region where the energy flux of internal tides over relatively large topographic roughness is dominant. The suppression of the lee-wave energy flux due to the co-existence with tides is not large. The agreement is different from previous observations across the ACC performed in Drake Passage and Kerguelen Plateau, where the energy flux overestimated TKED. Linearity with relatively low steepness in the present observation is suggested to be the cause of the balance.
{"title":"Internal Lee Waves Control Deep Ocean Turbulent Mixing in the Antarctic Circumpolar Current at 50°E","authors":"Yusuke Sasaki, Ichiro Yasuda","doi":"10.1029/2025gl117002","DOIUrl":"https://doi.org/10.1029/2025gl117002","url":null,"abstract":"Full-depth (Surface-to-bottom) turbulent kinetic energy dissipation (TKED) observed with fast-response thermistors across the Antarctic Circumpolar Current (ACC) at 50<span data-altimg=\"/cms/asset/0ce2a555-9f3d-4feb-a73a-30cfa98663c4/grl72176-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"193\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/grl72176-math-0001.png\"><mjx-semantics><mjx-mrow><mjx-mo data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"degree\" data-semantic-speech=\"italic degree\" data-semantic-type=\"punctuation\"><mjx-c></mjx-c></mjx-mo></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display=\"inline\" unselectable=\"on\"><math altimg=\"urn:x-wiley:00948276:media:grl72176:grl72176-math-0001\" display=\"inline\" location=\"graphic/grl72176-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mo data-mjx-pseudoscript=\"true\" data-semantic-=\"\" data-semantic-font=\"italic\" data-semantic-role=\"degree\" data-semantic-speech=\"italic degree\" data-semantic-type=\"punctuation\" mathvariant=\"italic\">°</mo></mrow>$mathit{{}^{circ}}$</annotation></semantics></math></mjx-assistive-mml></mjx-container>E is compared with the energy flux of bottom-generated internal waves estimated with high-resolution multibeam bathymetry. Turbulent kinetic energy dissipation is here found to be locally balanced with the energy flux of internal lee waves generated through the interactions between quasi-steady deep currents and small horizontal-scale bottom topography, except in the region where the energy flux of internal tides over relatively large topographic roughness is dominant. The suppression of the lee-wave energy flux due to the co-existence with tides is not large. The agreement is different from previous observations across the ACC performed in Drake Passage and Kerguelen Plateau, where the energy flux overestimated TKED. Linearity with relatively low steepness in the present observation is suggested to be the cause of the balance.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"74 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440202","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}
Cara Remai, Daniel Zawada, Adam Bourassa, Kimberlee Dubé, Alexandre Baron, Kate Smith, Landon Rieger, Douglas Degenstein
The 2022 Hunga eruption significantly perturbed the stratosphere by injecting substantial water vapor and <span data-altimg="/cms/asset/3a0761b5-7590-477c-85ea-188e831d7b27/grl72203-math-0001.png"></span><mjx-container ctxtmenu_counter="34" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/grl72203-math-0001.png"><mjx-semantics><mjx-mrow><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-role="unknown" data-semantic-speech="SO Subscript 2" data-semantic-type="subscript"><mjx-mtext data-semantic-annotation="clearspeak:unit" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="text"><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mtext><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c></mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display="inline" unselectable="on"><math altimg="urn:x-wiley:00948276:media:grl72203:grl72203-math-0001" display="inline" location="graphic/grl72203-math-0001.png" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msub data-semantic-="" data-semantic-children="0,1" data-semantic-role="unknown" data-semantic-speech="SO Subscript 2" data-semantic-type="subscript"><mtext data-semantic-="" data-semantic-annotation="clearspeak:unit" data-semantic-font="normal" data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="text">SO</mtext><mn data-semantic-="" data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number">2</mn></msub></mrow>${text{SO}}_{2}$</annotation></semantics></math></mjx-assistive-mml></mjx-container>, drastically changing the Aerosol Optical Depth (AOD) and particle size. Post-eruption, satellite limb-scattering retrievals of aerosol extinction from Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) and Optical Spectrograph and InfraRed Imager System (OSIRIS) diverged from Stratospheric Aerosol and Gas Experiment (SAGE) on the International Space Station (SAGE III/ISS) solar occultation measurements. We demonstrate that this discrepancy stems from the fixed aerosol particle size assumptions inherent to the limb sensor's retrieval algorithms, which are different than the large particle sizes observed following the eruption. Using particle size distribution parameters derived from SAGE III/ISS measurements as input to the OMPS-LP and OSIRIS retrievals, we effectively eliminated the bias in retrieved extinction and AOD compared to SAGE III/ISS. This consistency across the three data sets provides an improved understanding of aerosol distributions in the highly pe
{"title":"Stratospheric Aerosol Particle Size Explains Divergent Limb and Solar Occultation Measurements After the Hunga Eruption","authors":"Cara Remai, Daniel Zawada, Adam Bourassa, Kimberlee Dubé, Alexandre Baron, Kate Smith, Landon Rieger, Douglas Degenstein","doi":"10.1029/2025gl120243","DOIUrl":"https://doi.org/10.1029/2025gl120243","url":null,"abstract":"The 2022 Hunga eruption significantly perturbed the stratosphere by injecting substantial water vapor and <span data-altimg=\"/cms/asset/3a0761b5-7590-477c-85ea-188e831d7b27/grl72203-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"34\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/grl72203-math-0001.png\"><mjx-semantics><mjx-mrow><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-role=\"unknown\" data-semantic-speech=\"SO Subscript 2\" data-semantic-type=\"subscript\"><mjx-mtext data-semantic-annotation=\"clearspeak:unit\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"text\"><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mtext><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c></mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display=\"inline\" unselectable=\"on\"><math altimg=\"urn:x-wiley:00948276:media:grl72203:grl72203-math-0001\" display=\"inline\" location=\"graphic/grl72203-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><msub data-semantic-=\"\" data-semantic-children=\"0,1\" data-semantic-role=\"unknown\" data-semantic-speech=\"SO Subscript 2\" data-semantic-type=\"subscript\"><mtext data-semantic-=\"\" data-semantic-annotation=\"clearspeak:unit\" data-semantic-font=\"normal\" data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"text\">SO</mtext><mn data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\">2</mn></msub></mrow>${text{SO}}_{2}$</annotation></semantics></math></mjx-assistive-mml></mjx-container>, drastically changing the Aerosol Optical Depth (AOD) and particle size. Post-eruption, satellite limb-scattering retrievals of aerosol extinction from Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) and Optical Spectrograph and InfraRed Imager System (OSIRIS) diverged from Stratospheric Aerosol and Gas Experiment (SAGE) on the International Space Station (SAGE III/ISS) solar occultation measurements. We demonstrate that this discrepancy stems from the fixed aerosol particle size assumptions inherent to the limb sensor's retrieval algorithms, which are different than the large particle sizes observed following the eruption. Using particle size distribution parameters derived from SAGE III/ISS measurements as input to the OMPS-LP and OSIRIS retrievals, we effectively eliminated the bias in retrieved extinction and AOD compared to SAGE III/ISS. This consistency across the three data sets provides an improved understanding of aerosol distributions in the highly pe","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"7 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440243","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}
Latitudinal variations in heat transport shape the thermal and magnetic evolution of rapidly rotating planets, stars, and icy moons. Although global simulations have revealed strong equatorial–polar contrasts, a predictive scaling theory has been lacking. Here we use rotating Rayleigh-Bénard convection with tilted rotation and gravity axes to model dynamics at different latitudes in the geostrophic regime. We derive scaling relations for convective length scales and the Nusselt number that explain the latitude dependence of heat transfer. At high latitudes, <span data-altimg="/cms/asset/7855c314-081f-4505-b86b-8740f93dbb60/grl72211-math-0001.png"></span><mjx-container ctxtmenu_counter="165" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/grl72211-math-0001.png"><mjx-semantics><mjx-mrow data-semantic-children="16,14" data-semantic-content="2" data-semantic- data-semantic-role="equality" data-semantic-speech="upper N u tilde sine Superscript negative 4 divided by 3 Baseline phi" data-semantic-type="relseq"><mjx-mrow data-semantic-annotation="clearspeak:simple;clearspeak:unit" data-semantic-children="0,1" data-semantic-content="15" data-semantic- data-semantic-parent="17" data-semantic-role="implicit" data-semantic-type="infixop"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="16" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="infixop," data-semantic-parent="16" data-semantic-role="multiplication" data-semantic-type="operator" style="margin-left: 0.056em; margin-right: 0.056em;"><mjx-c></mjx-c></mjx-mo><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="16" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi></mjx-mrow><mjx-mo data-semantic- data-semantic-operator="relseq,∼" data-semantic-parent="17" data-semantic-role="equality" data-semantic-type="relation" rspace="5" space="5"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-annotation="clearspeak:simple" data-semantic-children="10,12" data-semantic-content="13,3" data-semantic- data-semantic-parent="17" data-semantic-role="prefix function" data-semantic-type="appl"><mjx-msup data-semantic-children="3,9" data-semantic- data-semantic-parent="14" data-semantic-role="prefix function" data-semantic-type="superscript"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-operator="appl" data-semantic-parent="10" data-semantic-role="prefix function" data-semantic-type="function"><mjx-c></mjx-c><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mi><mjx-script style="vertical-align: 0.396em;"><mjx-mrow data-semantic-children="8,7" data-semantic-content="6" data-semantic- data-semantic-parent="10" dat
{"title":"Scaling of Latitude-Dependent Heat Transport in Geostrophic Convection","authors":"Veeraraghavan Kannan, Varghese Mathai, Xiaojue Zhu","doi":"10.1029/2025gl119650","DOIUrl":"https://doi.org/10.1029/2025gl119650","url":null,"abstract":"Latitudinal variations in heat transport shape the thermal and magnetic evolution of rapidly rotating planets, stars, and icy moons. Although global simulations have revealed strong equatorial–polar contrasts, a predictive scaling theory has been lacking. Here we use rotating Rayleigh-Bénard convection with tilted rotation and gravity axes to model dynamics at different latitudes in the geostrophic regime. We derive scaling relations for convective length scales and the Nusselt number that explain the latitude dependence of heat transfer. At high latitudes, <span data-altimg=\"/cms/asset/7855c314-081f-4505-b86b-8740f93dbb60/grl72211-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"165\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/grl72211-math-0001.png\"><mjx-semantics><mjx-mrow data-semantic-children=\"16,14\" data-semantic-content=\"2\" data-semantic- data-semantic-role=\"equality\" data-semantic-speech=\"upper N u tilde sine Superscript negative 4 divided by 3 Baseline phi\" data-semantic-type=\"relseq\"><mjx-mrow data-semantic-annotation=\"clearspeak:simple;clearspeak:unit\" data-semantic-children=\"0,1\" data-semantic-content=\"15\" data-semantic- data-semantic-parent=\"17\" data-semantic-role=\"implicit\" data-semantic-type=\"infixop\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"16\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"16\" data-semantic-role=\"multiplication\" data-semantic-type=\"operator\" style=\"margin-left: 0.056em; margin-right: 0.056em;\"><mjx-c></mjx-c></mjx-mo><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"16\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi></mjx-mrow><mjx-mo data-semantic- data-semantic-operator=\"relseq,∼\" data-semantic-parent=\"17\" data-semantic-role=\"equality\" data-semantic-type=\"relation\" rspace=\"5\" space=\"5\"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-annotation=\"clearspeak:simple\" data-semantic-children=\"10,12\" data-semantic-content=\"13,3\" data-semantic- data-semantic-parent=\"17\" data-semantic-role=\"prefix function\" data-semantic-type=\"appl\"><mjx-msup data-semantic-children=\"3,9\" data-semantic- data-semantic-parent=\"14\" data-semantic-role=\"prefix function\" data-semantic-type=\"superscript\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-operator=\"appl\" data-semantic-parent=\"10\" data-semantic-role=\"prefix function\" data-semantic-type=\"function\"><mjx-c></mjx-c><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mi><mjx-script style=\"vertical-align: 0.396em;\"><mjx-mrow data-semantic-children=\"8,7\" data-semantic-content=\"6\" data-semantic- data-semantic-parent=\"10\" dat","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"127 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147447908","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}
Yang Xu, Hui-Shuang Yuan, Zhi-Da Sun, Youli Chang, Cheng Shen
As near-surface wind speed (NSWS) largely controls wind power generation, robust projection is vital to wind energy planning and broader sustainability goals. However, the predictive skill of climate models for NSWS remains uncertain. Analysis of Coupled Model Intercomparison Project Phase 6 simulations shows that the models reproduce the mean NSWS over China reasonably well but substantially underestimate the observed long-term trend and variability. Given these large biases, bias correction is essential for obtaining more reliable NSWS projections. We correct this bias using an Empirical Orthogonal Function approach to isolate the dominant spatial modes of NSWS variability. The corrected projections exhibit amplified future trends and increased variability of NSWS over China compared with the original model output, with the strongest changes emerging under higher greenhouse gas emissions. Our results indicated that unadjusted models may understate the magnitude of future NSWS changes. This study provides a more reliable reference for future evolution of NSWS.
{"title":"EOF-Based Bias Correction of Near-Surface Wind Speed Over China Reveals Stronger Future Trends and Variability","authors":"Yang Xu, Hui-Shuang Yuan, Zhi-Da Sun, Youli Chang, Cheng Shen","doi":"10.1029/2025gl120559","DOIUrl":"https://doi.org/10.1029/2025gl120559","url":null,"abstract":"As near-surface wind speed (NSWS) largely controls wind power generation, robust projection is vital to wind energy planning and broader sustainability goals. However, the predictive skill of climate models for NSWS remains uncertain. Analysis of Coupled Model Intercomparison Project Phase 6 simulations shows that the models reproduce the mean NSWS over China reasonably well but substantially underestimate the observed long-term trend and variability. Given these large biases, bias correction is essential for obtaining more reliable NSWS projections. We correct this bias using an Empirical Orthogonal Function approach to isolate the dominant spatial modes of NSWS variability. The corrected projections exhibit amplified future trends and increased variability of NSWS over China compared with the original model output, with the strongest changes emerging under higher greenhouse gas emissions. Our results indicated that unadjusted models may understate the magnitude of future NSWS changes. This study provides a more reliable reference for future evolution of NSWS.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"188 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440246","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}
Hongquan Song, Xueli Ni, Yujie Chang, Adrian Chappell, Zhuoli Zhou, Boyan Liu
Accurate simulation of near-surface wind speed is crucial for applications in renewable energy, dust emission, and air quality modeling. However, the Weather Research and Forecasting (WRF) model systematically over-estimates 10 m wind speed due to simplified representations of surface roughness and momentum exchange. Here we incorporate into WRF a physically based changing aerodynamic roughness (CAR) scheme using satellite albedo, to dynamically adjust near-surface wind friction and momentum exchange. Simulations during 2023 over China show that CAR substantially improves near-surface wind speed estimates, reducing the normalized mean bias from 14.6% to 2.2%. The improvements are pronounced over cropland, shrubland, grassland, and bare land. Limited improvements occur in closed canopies (forests and urban areas) because CAR poorly represents skimming flow. Nevertheless, bridging satellite observations with boundary-layer dynamics, the CAR scheme provides a more realistic representation of surface–atmosphere momentum exchange, offering enhanced reliability for climate, air-quality, and wind-resource studies.
{"title":"Changing Aerodynamic Roughness in WRF Reduces Bias and Improves Accuracy in Near-Surface Wind Simulations","authors":"Hongquan Song, Xueli Ni, Yujie Chang, Adrian Chappell, Zhuoli Zhou, Boyan Liu","doi":"10.1029/2025gl120811","DOIUrl":"https://doi.org/10.1029/2025gl120811","url":null,"abstract":"Accurate simulation of near-surface wind speed is crucial for applications in renewable energy, dust emission, and air quality modeling. However, the Weather Research and Forecasting (WRF) model systematically over-estimates 10 m wind speed due to simplified representations of surface roughness and momentum exchange. Here we incorporate into WRF a physically based changing aerodynamic roughness (CAR) scheme using satellite albedo, to dynamically adjust near-surface wind friction and momentum exchange. Simulations during 2023 over China show that CAR substantially improves near-surface wind speed estimates, reducing the normalized mean bias from 14.6% to 2.2%. The improvements are pronounced over cropland, shrubland, grassland, and bare land. Limited improvements occur in closed canopies (forests and urban areas) because CAR poorly represents skimming flow. Nevertheless, bridging satellite observations with boundary-layer dynamics, the CAR scheme provides a more realistic representation of surface–atmosphere momentum exchange, offering enhanced reliability for climate, air-quality, and wind-resource studies.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"18 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440245","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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