Luoyao Guan, Jason Blake Cohen, Shuo Wang, Pravash Tiwari, Zhewen Liu, Kai Qin
Accurate aerosol particle size distribution is essential for estimating radiative forcing but is often hindered by assumptions that oversimplify more physical approximations of aerosol mixing state and size. This work performs a single-site observational-closure study that combines AERONET multi-wavelength extinction and absorption retrievals, in situ observations of particle size, and Mie modeling over multi-waveband, while treating the BC-sulfate core-shell scheme as a mass- and number-conserved, radiatively-closed set of probabilistically possible solutions and quantifying the resulting mixing, number concentration, and radiative forcing solution space. Results show conventional retrievals overestimate coarse-mode particles and internal mixing, leading to higher single scattering albedo and broader asymmetry coefficient. Ground-based constraints yield more physically consistent PSDs and systematically modifies aerosol optical properties, especially for smaller particles within sub-2.5 micron range. Radiative transfer simulations using these constrained properties reveal enhanced atmospheric heating alongside reduced top-of-atmosphere cooling, underscoring the sensitivity of forcing to size-resolved multi-waveband constraints.
{"title":"Improving Aerosol Absorption Estimates Via Size-Resolved Constraints Based on AERONET and In Situ Measurements","authors":"Luoyao Guan, Jason Blake Cohen, Shuo Wang, Pravash Tiwari, Zhewen Liu, Kai Qin","doi":"10.1029/2025gl117418","DOIUrl":"https://doi.org/10.1029/2025gl117418","url":null,"abstract":"Accurate aerosol particle size distribution is essential for estimating radiative forcing but is often hindered by assumptions that oversimplify more physical approximations of aerosol mixing state and size. This work performs a single-site observational-closure study that combines AERONET multi-wavelength extinction and absorption retrievals, in situ observations of particle size, and Mie modeling over multi-waveband, while treating the BC-sulfate core-shell scheme as a mass- and number-conserved, radiatively-closed set of probabilistically possible solutions and quantifying the resulting mixing, number concentration, and radiative forcing solution space. Results show conventional retrievals overestimate coarse-mode particles and internal mixing, leading to higher single scattering albedo and broader asymmetry coefficient. Ground-based constraints yield more physically consistent PSDs and systematically modifies aerosol optical properties, especially for smaller particles within sub-2.5 micron range. Radiative transfer simulations using these constrained properties reveal enhanced atmospheric heating alongside reduced top-of-atmosphere cooling, underscoring the sensitivity of forcing to size-resolved multi-waveband constraints.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"22 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319722","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}
Fulin Shi, Li Zeng, Yuhui Fu, Jinbin Cao, Zhima Zeren, Dapeng Liu, Dehe Yang
Resolving the mixture of natural plasma waves and persistent spacecraft interference is a fundamental challenge in space physics, as it obstructs the analysis of wave-particle interactions and energy transport processes. Traditional signal decomposition methods often fail to adequately separate these components due to their time-varying frequencies and overlapping spectra. We propose the instantaneous bandwidth Vold-Kalman Filtering (IB-VKF), which first defines the component-specific bandwidth weighting functions <span data-altimg="/cms/asset/75d03afa-aba2-4d0e-9914-f8b878ce198a/grl72092-math-0001.png"></span><mjx-container ctxtmenu_counter="66" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/grl72092-math-0001.png"><mjx-semantics><mjx-mrow data-semantic-annotation="clearspeak:simple" data-semantic-children="5,9" data-semantic-content="10,0" data-semantic- data-semantic-role="simple function" data-semantic-speech="r Subscript i comma IB Baseline left parenthesis n right parenthesis" data-semantic-type="appl"><mjx-msub data-semantic-children="0,4" data-semantic- data-semantic-parent="11" data-semantic-role="simple function" data-semantic-type="subscript"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-operator="appl" data-semantic-parent="5" data-semantic-role="simple function" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mrow data-semantic-children="1,2,3" data-semantic-content="2" data-semantic- data-semantic-parent="5" data-semantic-role="sequence" data-semantic-type="punctuated" size="s"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="4" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator="punctuated" data-semantic-parent="4" data-semantic-role="comma" data-semantic-type="punctuation" rspace="1"><mjx-c></mjx-c></mjx-mo><mjx-mtext data-semantic-annotation="clearspeak:unit" data-semantic-font="normal" data-semantic- data-semantic-parent="4" data-semantic-role="unknown" data-semantic-type="text"><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mtext></mjx-mrow></mjx-script></mjx-msub><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="appl" data-semantic-parent="11" data-semantic-role="application" data-semantic-type="punctuation" style="margin-left: 0.056em; margin-right: 0.056em;"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-children="7" data-semantic-content="6,8" data-semantic- data-semantic-parent="11" data-semantic-role="leftright" data-semantic-type="fenced"><mjx-mo data-semantic- data-semantic-operator="fenced" data-semantic-parent="9" data-semantic-role="open" data-semantic-type="fence" style="margin-left: 0.056em; margin-right:
{"title":"Enabling High-Fidelity Wave-Particle Interaction Studies: A Novel Filtering for Isolating Whistlers From Spacecraft Noise","authors":"Fulin Shi, Li Zeng, Yuhui Fu, Jinbin Cao, Zhima Zeren, Dapeng Liu, Dehe Yang","doi":"10.1029/2025gl120170","DOIUrl":"https://doi.org/10.1029/2025gl120170","url":null,"abstract":"Resolving the mixture of natural plasma waves and persistent spacecraft interference is a fundamental challenge in space physics, as it obstructs the analysis of wave-particle interactions and energy transport processes. Traditional signal decomposition methods often fail to adequately separate these components due to their time-varying frequencies and overlapping spectra. We propose the instantaneous bandwidth Vold-Kalman Filtering (IB-VKF), which first defines the component-specific bandwidth weighting functions <span data-altimg=\"/cms/asset/75d03afa-aba2-4d0e-9914-f8b878ce198a/grl72092-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"66\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/grl72092-math-0001.png\"><mjx-semantics><mjx-mrow data-semantic-annotation=\"clearspeak:simple\" data-semantic-children=\"5,9\" data-semantic-content=\"10,0\" data-semantic- data-semantic-role=\"simple function\" data-semantic-speech=\"r Subscript i comma IB Baseline left parenthesis n right parenthesis\" data-semantic-type=\"appl\"><mjx-msub data-semantic-children=\"0,4\" data-semantic- data-semantic-parent=\"11\" data-semantic-role=\"simple function\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-operator=\"appl\" data-semantic-parent=\"5\" data-semantic-role=\"simple function\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mrow data-semantic-children=\"1,2,3\" data-semantic-content=\"2\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"sequence\" data-semantic-type=\"punctuated\" size=\"s\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"4\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator=\"punctuated\" data-semantic-parent=\"4\" data-semantic-role=\"comma\" data-semantic-type=\"punctuation\" rspace=\"1\"><mjx-c></mjx-c></mjx-mo><mjx-mtext data-semantic-annotation=\"clearspeak:unit\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"4\" data-semantic-role=\"unknown\" data-semantic-type=\"text\"><mjx-c></mjx-c><mjx-c></mjx-c></mjx-mtext></mjx-mrow></mjx-script></mjx-msub><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"appl\" data-semantic-parent=\"11\" data-semantic-role=\"application\" data-semantic-type=\"punctuation\" style=\"margin-left: 0.056em; margin-right: 0.056em;\"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-children=\"7\" data-semantic-content=\"6,8\" data-semantic- data-semantic-parent=\"11\" data-semantic-role=\"leftright\" data-semantic-type=\"fenced\"><mjx-mo data-semantic- data-semantic-operator=\"fenced\" data-semantic-parent=\"9\" data-semantic-role=\"open\" data-semantic-type=\"fence\" style=\"margin-left: 0.056em; margin-right: ","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"25 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319717","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}
Atmospheric rivers (ARs) constitute a global, interconnected highway network rather than isolated regional events. In boreal summer, cross-Pacific ARs originate over Southeast Asia, are fueled by subtropical outflows from the Asian monsoon plume, transport warm, moist air across the North Pacific, and make landfall in North America (NA). Our results show that diabatic heating anomalies over the Indian summer monsoon region and the Philippine Sea–Western North Pacific area jointly modulate AR pathways and landfalls. Numerical experiments verify that distinct heating archetypes generate diverse downstream triple-pressure circulation structures, steering ARs toward different landfall locations. Cross-Pacific AR activity is also modulated by climate oscillations; different phases preferentially induce distinct Indo-Pacific heating patterns and thus redirect AR pathways. Therefore, tropical heating anomalies in Indo-Western Pacific are valuable predictors of boreal-summer AR activity. The interconnected “AR highways” linking Asian climate to NA and extend the predictability beyond Asia to the broader Pacific Rim.
{"title":"Indo–Western Pacific Tropical Heating Anomalies Regulate the Cross-Pacific Atmospheric River Highways During Boreal Summer","authors":"Yurong Song, Mengqian Lu, Yang Zhao","doi":"10.1029/2025gl120489","DOIUrl":"https://doi.org/10.1029/2025gl120489","url":null,"abstract":"Atmospheric rivers (ARs) constitute a global, interconnected highway network rather than isolated regional events. In boreal summer, cross-Pacific ARs originate over Southeast Asia, are fueled by subtropical outflows from the Asian monsoon plume, transport warm, moist air across the North Pacific, and make landfall in North America (NA). Our results show that diabatic heating anomalies over the Indian summer monsoon region and the Philippine Sea–Western North Pacific area jointly modulate AR pathways and landfalls. Numerical experiments verify that distinct heating archetypes generate diverse downstream triple-pressure circulation structures, steering ARs toward different landfall locations. Cross-Pacific AR activity is also modulated by climate oscillations; different phases preferentially induce distinct Indo-Pacific heating patterns and thus redirect AR pathways. Therefore, tropical heating anomalies in Indo-Western Pacific are valuable predictors of boreal-summer AR activity. The interconnected “AR highways” linking Asian climate to NA and extend the predictability beyond Asia to the broader Pacific Rim.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"13 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319716","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}
A. H. Cheng, D. M. Schroeder, N. S. Wolfenbarger, R. Shaper, C. Seltzer, B. Hills
Ice-penetrating radar is a powerful geophysical tool for understanding the subsurfaces of Earth, Mars, and icy moons. Radar reflectivity, attenuation, and birefringence are used to infer subsurface hydrology, englacial temperature, water content, and crystal orientation fabric. However, conventional radar sounding analyses either ignore melt or use classical mixing models which assume spherical melt inclusions, obscuring anisotropic contributions of melt. Here, we use geometric mixing models to calculate the reflectivity, attenuation, and birefringence of temperate ice containing anisotropic melt. We find that anisotropic melt can introduce significant deviations in radar measurements. For instance, melt anisotropy may impact reflectivity-based estimates of water content by up to 30% volume fraction, while attenuation-based estimates may vary by up to 43%. Critically, a melt volume fraction of just <span data-altimg="/cms/asset/f3e438ac-93f6-4268-a177-ac7ea2bb7f69/grl72146-math-0001.png"></span><mjx-container ctxtmenu_counter="221" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/grl72146-math-0001.png"><mjx-semantics><mjx-mrow data-semantic-children="0,9" data-semantic-content="1" data-semantic- data-semantic-role="equality" data-semantic-speech="f tilde 1 0 Superscript negative 5" data-semantic-type="relseq"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="10" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator="relseq,∼" data-semantic-parent="10" data-semantic-role="equality" data-semantic-type="relation" rspace="5" space="5"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-annotation="clearspeak:unit" data-semantic-children="2,7" data-semantic-content="8" data-semantic- data-semantic-parent="10" data-semantic-role="implicit" data-semantic-type="infixop"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="9" data-semantic-role="integer" data-semantic-type="number"><mjx-c></mjx-c></mjx-mn><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="infixop," data-semantic-parent="9" data-semantic-role="multiplication" data-semantic-type="operator" style="margin-left: 0.056em; margin-right: 0.056em;"><mjx-c></mjx-c></mjx-mo><mjx-msup data-semantic-children="3,6" data-semantic- data-semantic-parent="9" data-semantic-role="integer" data-semantic-type="superscript"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="7" data-semantic-role="integer" data-semantic-type="number"><mjx-c></mjx-c></mjx-mn><mjx-script style="vertical-align: 0.363em;"><mjx-mrow data-semantic-annotation="clearspeak:simple" data-semantic-children="5" data-seman
{"title":"Anisotropic Melt Inclusions as a Confounding Signal for Ice-Penetrating Radar Observations","authors":"A. H. Cheng, D. M. Schroeder, N. S. Wolfenbarger, R. Shaper, C. Seltzer, B. Hills","doi":"10.1029/2025gl120182","DOIUrl":"https://doi.org/10.1029/2025gl120182","url":null,"abstract":"Ice-penetrating radar is a powerful geophysical tool for understanding the subsurfaces of Earth, Mars, and icy moons. Radar reflectivity, attenuation, and birefringence are used to infer subsurface hydrology, englacial temperature, water content, and crystal orientation fabric. However, conventional radar sounding analyses either ignore melt or use classical mixing models which assume spherical melt inclusions, obscuring anisotropic contributions of melt. Here, we use geometric mixing models to calculate the reflectivity, attenuation, and birefringence of temperate ice containing anisotropic melt. We find that anisotropic melt can introduce significant deviations in radar measurements. For instance, melt anisotropy may impact reflectivity-based estimates of water content by up to 30% volume fraction, while attenuation-based estimates may vary by up to 43%. Critically, a melt volume fraction of just <span data-altimg=\"/cms/asset/f3e438ac-93f6-4268-a177-ac7ea2bb7f69/grl72146-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"221\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/grl72146-math-0001.png\"><mjx-semantics><mjx-mrow data-semantic-children=\"0,9\" data-semantic-content=\"1\" data-semantic- data-semantic-role=\"equality\" data-semantic-speech=\"f tilde 1 0 Superscript negative 5\" data-semantic-type=\"relseq\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"10\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator=\"relseq,∼\" data-semantic-parent=\"10\" data-semantic-role=\"equality\" data-semantic-type=\"relation\" rspace=\"5\" space=\"5\"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-annotation=\"clearspeak:unit\" data-semantic-children=\"2,7\" data-semantic-content=\"8\" data-semantic- data-semantic-parent=\"10\" data-semantic-role=\"implicit\" data-semantic-type=\"infixop\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"9\" data-semantic-role=\"integer\" data-semantic-type=\"number\"><mjx-c></mjx-c></mjx-mn><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"9\" data-semantic-role=\"multiplication\" data-semantic-type=\"operator\" style=\"margin-left: 0.056em; margin-right: 0.056em;\"><mjx-c></mjx-c></mjx-mo><mjx-msup data-semantic-children=\"3,6\" data-semantic- data-semantic-parent=\"9\" data-semantic-role=\"integer\" data-semantic-type=\"superscript\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"7\" data-semantic-role=\"integer\" data-semantic-type=\"number\"><mjx-c></mjx-c></mjx-mn><mjx-script style=\"vertical-align: 0.363em;\"><mjx-mrow data-semantic-annotation=\"clearspeak:simple\" data-semantic-children=\"5\" data-seman","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"14 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147320175","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}
Lake ice impacts seismic noise on nearby seismometers, and therefore seismic observations can be used to monitor ice changes. However, the transfer function describing how lake-microseism noise covaries with ice cover has not been quantified. We use seismic data from a long-operating station near Lake Superior and satellite-derived lake ice cover from 2009 to 2024 to determine their covariance. A linear model calibrated using annual ice cover averaged during the coldest months (15 February–9 March) explains ∼87% of the variance in 0.5–2 Hz seismic noise averaged during the same period. This 15-year-calibrated model is used to predict daily ice cover during the 2014 Polar Vortex with reasonable accuracy, explaining ∼58% variance in the daily 0.5–2 Hz noise. One season of daily lake ice cover data is sufficient to calibrate the model. During unfrozen periods, 0.25–0.5 Hz lake-wave power explains ∼75% of the variance in the daily averaged 0.5–1 Hz seismic noise, consistent with the secondary microseism mechanism.
{"title":"Estimating Ice Cover on the Great Lakes Using Seismic Ambient Noise","authors":"Joshua B. Russell, Christopher J. W. Carchedi","doi":"10.1029/2025gl120498","DOIUrl":"https://doi.org/10.1029/2025gl120498","url":null,"abstract":"Lake ice impacts seismic noise on nearby seismometers, and therefore seismic observations can be used to monitor ice changes. However, the transfer function describing how lake-microseism noise covaries with ice cover has not been quantified. We use seismic data from a long-operating station near Lake Superior and satellite-derived lake ice cover from 2009 to 2024 to determine their covariance. A linear model calibrated using annual ice cover averaged during the coldest months (15 February–9 March) explains ∼87% of the variance in 0.5–2 Hz seismic noise averaged during the same period. This 15-year-calibrated model is used to predict daily ice cover during the 2014 Polar Vortex with reasonable accuracy, explaining ∼58% variance in the daily 0.5–2 Hz noise. One season of daily lake ice cover data is sufficient to calibrate the model. During unfrozen periods, 0.25–0.5 Hz lake-wave power explains ∼75% of the variance in the daily averaged 0.5–1 Hz seismic noise, consistent with the secondary microseism mechanism.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"20 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319721","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}
Lionel Renault, Carlos Conejero, Fabien Desbiolles
Using an ocean-atmosphere coupled simulation, we investigate the seasonal variability of the low-level wind response to submesoscale (O(1–10 km)) sea surface temperature (SST) anomalies over the Gulf Stream, focusing on the respective roles of the downwind momentum mixing (DMM) and pressure adjustment (PA) mechanisms. The wind response to submesoscale SST anomalies exhibits a strong seasonal cycle, with larger coupling in summer and pronounced spatial heterogeneity—significant north of the Gulf Stream but weak to the south. We furthermore show that the DMM dominates the coupling. Background atmospheric stability and wind speed control the seasonal modulation by driving the sensitivity of winds to SST perturbations. The spatial heterogeneity arises from the weak SST gradients south of the Gulf Stream. Two distinct regimes are found: (a) unstable conditions and weak winds, favoring a primarily divergent response, and (b) near-stable conditions with moderate to strong winds, yielding both divergent and rotational response.
{"title":"Environmental Controls on the Seasonal and Spatial Variability of Submesoscale Thermal Air–Sea Coupling Over the Gulf Stream","authors":"Lionel Renault, Carlos Conejero, Fabien Desbiolles","doi":"10.1029/2025gl120700","DOIUrl":"https://doi.org/10.1029/2025gl120700","url":null,"abstract":"Using an ocean-atmosphere coupled simulation, we investigate the seasonal variability of the low-level wind response to submesoscale (O(1–10 km)) sea surface temperature (SST) anomalies over the Gulf Stream, focusing on the respective roles of the downwind momentum mixing (DMM) and pressure adjustment (PA) mechanisms. The wind response to submesoscale SST anomalies exhibits a strong seasonal cycle, with larger coupling in summer and pronounced spatial heterogeneity—significant north of the Gulf Stream but weak to the south. We furthermore show that the DMM dominates the coupling. Background atmospheric stability and wind speed control the seasonal modulation by driving the sensitivity of winds to SST perturbations. The spatial heterogeneity arises from the weak SST gradients south of the Gulf Stream. Two distinct regimes are found: (a) unstable conditions and weak winds, favoring a primarily divergent response, and (b) near-stable conditions with moderate to strong winds, yielding both divergent and rotational response.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319718","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}
Bolei Yang, Ji Nie, Zhe-Min Tan, Juan Fang, William R. Boos
The formation of tropical cyclones (TCs) remains a significant scientific challenge. Here, we demonstrate that robust quasi-periodic behavior (QPB) emerges during TC genesis with idealized numerical simulations. The QPB is an internal mode of the TC precursor, whose underlying mechanism is a convectively coupled inertia-gravity oscillation. With typical environmental parameters and the spatial scale of TC precursors, the period of oscillation is around daily timescale. When the phase of the QPB and the solar diurnal cycle match, the coupling between the two oscillations accelerates TC genesis due to the state-dependent responses of precursors to diurnal radiation. This research unveils a potentially important mechanism for TC genesis in the real world: the diurnal cycle partially strengthens the TC seeds with matched phases among those from natural variability. Thus, our results have significant implications for understanding TC dynamics and improving predictions.
{"title":"Quasi-Periodic Behavior of Tropical Cyclone Precursors and Its Phase Matching With the Insolation Diurnal Cycle","authors":"Bolei Yang, Ji Nie, Zhe-Min Tan, Juan Fang, William R. Boos","doi":"10.1029/2025gl121568","DOIUrl":"https://doi.org/10.1029/2025gl121568","url":null,"abstract":"The formation of tropical cyclones (TCs) remains a significant scientific challenge. Here, we demonstrate that robust quasi-periodic behavior (QPB) emerges during TC genesis with idealized numerical simulations. The QPB is an internal mode of the TC precursor, whose underlying mechanism is a convectively coupled inertia-gravity oscillation. With typical environmental parameters and the spatial scale of TC precursors, the period of oscillation is around daily timescale. When the phase of the QPB and the solar diurnal cycle match, the coupling between the two oscillations accelerates TC genesis due to the state-dependent responses of precursors to diurnal radiation. This research unveils a potentially important mechanism for TC genesis in the real world: the diurnal cycle partially strengthens the TC seeds with matched phases among those from natural variability. Thus, our results have significant implications for understanding TC dynamics and improving predictions.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319720","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}
Wenchang Ge, Han-Ching Chen, Wenjun Zhang, Yu-Heng Tseng, Fei-Fei Jin
Accurately predicting the El Niño–Southern Oscillation (ENSO) remains a key challenge in climate science. An evaluation of the International Research Institute for Climate and Society (IRI) real-time ENSO forecast system reveals an asymmetry in prediction skill linked to consecutive La Niña events. ENSO forecasts show consistently high skill for El Niño events, whereas La Niña forecasts exhibit greater uncertainty. Specifically, first-year La Niña events demonstrate prediction skill comparable to that of El Niño events; however, most consecutive La Niña events display much lower predictability. This asymmetry is related to differences in ENSO dynamics. El Niño and first-year La Niña events typically follow the linear recharge–discharge oscillator framework, supporting their high predictability. In contrast, consecutive La Niña events tend to deviate from this framework, likely due to enhanced nonlinear processes that constrain their forecast skill. Improved representation of these nonlinear processes may help enhance prediction skill for consecutive La Niña events.
{"title":"Asymmetry in ENSO Prediction Skill Linked to Consecutive La Niña Events Within the IRI Real-Time Forecast System","authors":"Wenchang Ge, Han-Ching Chen, Wenjun Zhang, Yu-Heng Tseng, Fei-Fei Jin","doi":"10.1029/2025gl118767","DOIUrl":"https://doi.org/10.1029/2025gl118767","url":null,"abstract":"Accurately predicting the El Niño–Southern Oscillation (ENSO) remains a key challenge in climate science. An evaluation of the International Research Institute for Climate and Society (IRI) real-time ENSO forecast system reveals an asymmetry in prediction skill linked to consecutive La Niña events. ENSO forecasts show consistently high skill for El Niño events, whereas La Niña forecasts exhibit greater uncertainty. Specifically, first-year La Niña events demonstrate prediction skill comparable to that of El Niño events; however, most consecutive La Niña events display much lower predictability. This asymmetry is related to differences in ENSO dynamics. El Niño and first-year La Niña events typically follow the linear recharge–discharge oscillator framework, supporting their high predictability. In contrast, consecutive La Niña events tend to deviate from this framework, likely due to enhanced nonlinear processes that constrain their forecast skill. Improved representation of these nonlinear processes may help enhance prediction skill for consecutive La Niña events.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"32 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147292540","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}
Dani B. Jones, Hunter Y. Brown, Jacqueline M. Nugent, August Mikkelsen, Ci Song, Damao Zhang, Susannah M. Burrows, Hamish Gordon, Andrew Kirby, Daniel T. McCoy
Uncertainty in anthropogenic forcing driven by aerosol-cloud interactions (aci) limits our ability to infer the sensitivity of the Earth system to forcing from historical records. The driver of aci is the change in cloud droplet number concentration (Nd) due to changes in aerosol serving as cloud condensation nuclei (CCN). Here, we combine a perturbed parameter ensemble run in a global Earth system model with observations of CCN and single-layer-cloud Nd at surface sites in the Azores, the Southern Great Plains, and Ascension Island to provide a constraint on the anthropogenic contribution to present-day Nd. These observational lines of evidence constrain the preindustrial to present-day change in Nd to be between 11 and 43 cm−3. This is consistent with the upper end of some previous estimates but has a higher minimum perturbation, pointing to a stronger historical aerosol cooling.
{"title":"Surface Observations From Atmospheric Radiation Measurement Sites Constrain the Anthropogenic Contribution to Cloud Droplet Number","authors":"Dani B. Jones, Hunter Y. Brown, Jacqueline M. Nugent, August Mikkelsen, Ci Song, Damao Zhang, Susannah M. Burrows, Hamish Gordon, Andrew Kirby, Daniel T. McCoy","doi":"10.1029/2025gl121383","DOIUrl":"https://doi.org/10.1029/2025gl121383","url":null,"abstract":"Uncertainty in anthropogenic forcing driven by aerosol-cloud interactions (aci) limits our ability to infer the sensitivity of the Earth system to forcing from historical records. The driver of aci is the change in cloud droplet number concentration (<i>N</i><sub>d</sub>) due to changes in aerosol serving as cloud condensation nuclei (CCN). Here, we combine a perturbed parameter ensemble run in a global Earth system model with observations of CCN and single-layer-cloud <i>N</i><sub>d</sub> at surface sites in the Azores, the Southern Great Plains, and Ascension Island to provide a constraint on the anthropogenic contribution to present-day <i>N</i><sub>d</sub>. These observational lines of evidence constrain the preindustrial to present-day change in <i>N</i><sub>d</sub> to be between 11 and 43 cm<sup>−3</sup>. This is consistent with the upper end of some previous estimates but has a higher minimum perturbation, pointing to a stronger historical aerosol cooling.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"19 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319810","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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