Journal of Geophysical Research: Atmospheres最新文献

{"title":"Climate Variations of Autumn Tropical Cyclone Genesis in the Western North Pacific: Roles of Tropical and Midlatitude SST Anomalies","authors":"Lingfeng Tao,&nbsp;Lilan Chen,&nbsp;Wei Mei,&nbsp;Xiu-Qun Yang,&nbsp;Jianyun Gao,&nbsp;Tonghua Su","doi":"10.1029/2026JD046688","DOIUrl":"https://doi.org/10.1029/2026JD046688","url":null,"abstract":"<p>Tropical cyclones (TCs) in the western North Pacific (WNP) pose significant threats to socio-economic systems, yet their variability during the autumn season remains relatively understudied compared to summer. This study examines the interannual and decadal variations of WNP TC genesis in autumn using reanalysis data sets and atmospheric general circulation model (AGCM) simulations. It is shown that sea surface temperature anomalies (SSTAs) in the tropical Pacific and Indian Oceans, as well as in the midlatitude North Pacific, are the primary drivers. On interannual timescales, SSTAs in the tropical Pacific and Indian Oceans—resembling El Niño conditions—suppress convection and induce anomalous subsidence over the WNP via atmospheric wave responses, and thereby inhibit TC formation. On decadal timescales, warm SSTAs in the midlatitude North Pacific play a dominant role. These anomalies induce anomalous upward surface turbulent heat flux, leading to increased diabatic heating and weakened atmospheric baroclinicity and transient eddy activity. The resulting anomalous atmospheric circulation is characterized by a positive geopotential height anomaly over the midlatitude North Pacific. Anomalous southward energy propagation and meridional overturning circulation further modify the upper-tropospheric flow in the subtropics, leading to strengthened subtropical westerlies and enhanced vertical wind shear over the WNP, which are unfavorable for TC genesis. AGCM experiments forced with historical SSTAs reproduce these observed patterns well, supporting the proposed mechanisms. These findings underscore the distinct roles of tropical and midlatitude SSTAs in modulating autumn WNP TC activity on interannual and decadal timescales, with important implications for the prediction of TC genesis.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wind-Driven Circulation Feedbacks Offset Tropical Geoengineered Sea Salt Emissions","authors":"Cindy Wang,&nbsp;Leo J. Donner,&nbsp;Naser G. A. Mahfouz","doi":"10.1029/2026JD047411","DOIUrl":"https://doi.org/10.1029/2026JD047411","url":null,"abstract":"<p>Using a NOAA Geophysical Fluid Dynamics Laboratory coupled atmosphere–ocean (CM4) comprehensive model, we employ simulations of enhanced, geoengineered sea salt aerosol (SSA) emissions in the tropics to examine the circulation response to idealized marine cloud brightening. Increased tropical SSA emissions cool the deployment region and weaken the Equator-to-midlatitude temperature gradient, triggering circulation feedbacks that include weaker Southern Ocean westerlies. These circulation feedbacks suppress natural SSA emissions in both tropical and extratropical regions, offsetting about 23% of the imposed geoengineered SSA mass flux. In the offline sensitivity calculations, circulation feedbacks exert a weaker influence on aerosol number than on emitted mass (1% vs. 10%). Furthermore, wind speed is the primary driver of circulation-induced changes in SSA mass emissions, with sea surface temperature (SST) playing a secondary role. For number flux, SST has a larger influence in some regions due to the predominance of smaller particles. These findings demonstrate that aerosol injections can alter both circulation and aerosol distribution, potentially attenuating their intended climate effect.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JD047411","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Observations of Atmospheric Helium and Oxygen With SPHEREx","authors":"Howard Hui,&nbsp;Chi H. Nguyen,&nbsp;Ryan Wills,&nbsp;Katrina Bossert,&nbsp;Sean A. Bryan,&nbsp;Kazuma Noda,&nbsp;Jessica Norrell,&nbsp;Yoonsoo P. Bach,&nbsp;James J. Bock,&nbsp;Tzu-Ching Chang,&nbsp;Shuang-Shuang Chen,&nbsp;Asantha Cooray,&nbsp;Brendan P. Crill,&nbsp;Olivier Doré,&nbsp;C. Darren Dowell,&nbsp;Andreas L. Faisst,&nbsp;Jae Hwan Kang,&nbsp;Phil M. Korngut,&nbsp;Carey M. Lisse,&nbsp;Daniel C. Masters,&nbsp;Roberta Paladini,&nbsp;Volker Tolls,&nbsp;Michael W. Werner,&nbsp;Yujin Yang,&nbsp;Michael Zemcov","doi":"10.1029/2026JD047242","DOIUrl":"https://doi.org/10.1029/2026JD047242","url":null,"abstract":"<p>We present measurements of near-infrared (NIR) terrestrial airglow produced by helium and oxygen in the exosphere as observed by the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and ices Explorer (SPHEREx). Using 8 months of survey data obtained from a 680-km low-Earth orbit, emission from He<span>i</span> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>λ</mi>\u0000 <mn>10830</mn>\u0000 </mrow>\u0000 <annotation> $lambda 10830$</annotation>\u0000 </semantics></math>, O<span>i</span> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>λ</mi>\u0000 <mn>8446</mn>\u0000 </mrow>\u0000 <annotation> $lambda 8446$</annotation>\u0000 </semantics></math>, and O<span>i</span> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>λ</mi>\u0000 <mn>11287</mn>\u0000 </mrow>\u0000 <annotation> $lambda 11287$</annotation>\u0000 </semantics></math> is mapped with both global spatial and multiseason temporal coverage. These measurements are obtained along upward looking lines of sight as part of the astrophysical survey, in contrast to conventional nadir-viewing Earth remote sensing, which probes the behavior of low-density material in the thermo- and exosphere. We describe an analytical framework to extract atmospheric emission lines in the presence of astrophysical backgrounds including stars, resolved galaxies, and the diffuse zodiacal light. The resulting global measurements reveal temporal variability over the survey period and systematic dependencies on geographic locations. We interpret these variations in the context of the variable solar illumination and seasonal effects. SPHEREx, an astrophysical space observatory, is demonstrated to be a promising new platform for monitoring NIR airglow and investigating its coupling to solar activity and global geophysical processes.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clustering of Right-Moving Tornadic Supercell Proximity Sounding Profiles Using an Explainable Framework","authors":"Zhanxiang Hua,&nbsp;Alexandra Anderson-Frey,&nbsp;Qin Jiang,&nbsp;Matthew C. Brown","doi":"10.1029/2026JD046496","DOIUrl":"https://doi.org/10.1029/2026JD046496","url":null,"abstract":"<p>This study demonstrates an explainable machine learning framework for explicitly selecting important environmental features that determine clusters of right-moving tornadic supercells. Although previous studies have clustered and analyzed proximity sounding profiles associated with tornadic right-moving supercells, few have identified key features driving cluster assignments. Using self-organizing maps, we group soundings based on virtual buoyancy and wind profiles. Recursive feature elimination reveals that virtual buoyancy at heights of approximately 3 and 10.6 km (near the equilibrium level) are the most significant features in this clustering, with both acting as a proxy for the potential magnitude of Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN). Mid-level wind vectors (around 5 km) and low-level (below 3 km) meridional winds also play major roles in determining cluster assignments. Using these features at their identified key levels achieves skill comparable to traditional composite parameters in distinguishing between significant and non-significant tornado environments associated with right-moving supercells. We interpret these features as drivers of SOM node classification and as useful low-dimensional descriptors of already tornadic environments, not as independent evidence that each feature controls tornado intensity.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JD046496","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Cosmic Radiation Dose-Rates for Civil Aviation in the Middle East: Vertical Structure, Solar Modulation, and Comparison With Models","authors":"Roy Yaniv,&nbsp;Yoav Yair,&nbsp;Colin Price","doi":"10.1029/2026JD047316","DOIUrl":"https://doi.org/10.1029/2026JD047316","url":null,"abstract":"<p>High-altitude balloon measurements were conducted over southern Israel (30°35′N, 34°45′E; 850 m a.s.l., geomagnetic rigidity cutoff 10.3 GV) to characterize the vertical profiles of atmospheric ionization and radiation up to ∼35 km. Six balloon launches between October 2014 and August 2016 recorded the variability of atmospheric ionization during the declining phase of Solar Cycle 24. The Regener–Pfotzer maximum was observed at ∼17–20 km, consistent with mid-latitude conditions. The gamma-equivalent dose-rate proxy, derived from calibrated Geiger–Müller tube measurements, increased with altitude to a maximum near the Regener–Pfotzer altitudes and decreased sharply above it. At civil aviation altitudes (∼10 km), the measured dose rates were in the range ∼0.9–1.3 μSv hr⁻¹ and exhibited an inverse relationship with solar activity (<i>r</i> = −0.71). A strong linear dependence on heliospheric modulation potential was observed, with extrapolated values indicating a 40%–60% increase in dose rates under solar minimum conditions. Comparison with the EXPACS/PARMA atmospheric radiation model shows that the measurements closely match the electromagnetic component (photons and electrons/positrons) of the radiation field, typically within ∼10%–15%, while the total ambient dose equivalent H*(10) was dominated by neutrons. These results demonstrate that balloon-borne measurements can provide a robust characterization of the vertical radiation structure and its solar modulation, while highlighting the distinction between electromagnetic dose proxies and total radiation exposure.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JD047316","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Fast All-Sky Hyperspectral Infrared Radiative Transfer With Physically Recursive Cloud Treatment","authors":"Yuxiang Ling,&nbsp;Chao Liu,&nbsp;Junyu Yan,&nbsp;Bin Yao,&nbsp;Dong Liu,&nbsp;Na Xu,&nbsp;Byung-Ju Sohn,&nbsp;Peng Zhang","doi":"10.1029/2026JD047590","DOIUrl":"https://doi.org/10.1029/2026JD047590","url":null,"abstract":"<p>Clouds strongly modify thermal infrared radiances through absorption, emission, and multiple scattering, yet rigorous line-by-line (LBL) gas absorption coupled with multi-stream scattering remains too expensive for large ensembles of all-sky hyperspectral simulations. We present a fast monochromatic radiative transfer (RT) model for the thermal infrared spectrum that retains the physical structure and vertical flexibility of the layered RT problem while embedding type-wise trained radiative response models for the computationally dominant cloud-layer scattering and emission calculations. The model combines accelerated LBL gas absorption, analytic thermal-source integration, and an extended Adding-Doubling framework that recursively couples clear and cloudy layers within a physically recursive framework. Cloud-layer reflectance, transmittance, and emission responses are learned from DISORT solutions using single-scattering optical properties, cloud optical thickness, spectral position, and angular coordinates as predictors, with radiance-level constraints imposed during scattering training. Against LBL + DISORT references, the model reproduces clear-sky brightness temperatures with an RMSE of 0.006 K and cloudy single-layer, multilayer, mixed-phase, and vertically extended cases with RMSEs below 0.05 K. A vertically distributed cirrus layer produces a maximum error of 0.55 K and RMSE of 0.28 K when compressed into one layer, whereas the proposed recursive treatment reduces the RMSE to 0.03 K. A full cloudy-sky spectrum is computed approximately three orders of magnitude faster than the conventional LBL + DISORT pipeline. Application to FY-4B/AGRI observations gives channel-wise <i>R</i>² values of up to 0.96 after spectral convolution, indicating that the model can function as a physically constrained forward model for satellite radiance simulation.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Causes of the Delayed Seasonality of Northern Hemisphere Tropical Cyclones in CMIP6 Models","authors":"Jiawei Feng,&nbsp;Jian Cao,&nbsp;Boyang Wang,&nbsp;Haikun Zhao,&nbsp;Chao Wang","doi":"10.1029/2026JD046965","DOIUrl":"https://doi.org/10.1029/2026JD046965","url":null,"abstract":"<p>Observed tropical cyclone genesis frequency (TCGF) over the Northern Hemisphere (NH) exhibits a clear seasonal transition from the peak season (July-September) to the late season (October-December). Correct simulation of TCGF seasonality has profound impacts on TC activity and disaster predictions. This study finds slower seasonal transitions of NH TCGF in both uncoupled and coupled CMIP6 models, revealing that the atmospheric model is the source of this bias. Atmospheric models are biased in surface wind speed over the tropical oceans, which decreases (increases) the latent heat flux in July-September (October-December). The latent heat flux bias dominates the slower seasonal transition of the net atmospheric energy from July-September to October-December, resulting in a delayed southward movement of the Hadley circulation and TC-related environmental fields in both coupled and uncoupled models. Thus, models simulate a slower seasonal transition of TCGF over the NH oceans. Our findings provide an energetic perspective on TCGF seasonality and aid in improving models' lower-boundary physics.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two Modes of Self-Organizing Development of Extreme Rainfall-Producing Storms in South China","authors":"Zhenghui Li,&nbsp;Yali Luo,&nbsp;Jiwen Fan,&nbsp;Yuwei Zhang,&nbsp;Ruoyun Ma,&nbsp;Fei Chen","doi":"10.1029/2026JD046438","DOIUrl":"https://doi.org/10.1029/2026JD046438","url":null,"abstract":"<p>The convective-scale dynamics of extreme rainstorms on monsoon coasts (South China) remain poorly understood. This study uses the advanced coupled model WRF-Chem-MOSAIC for a 90-hr, 3-km simulation, reasonably capturing the thermodynamic conditions, inhomogeneous near-surface PM2.5, and the dynamical and microphysical features of two storms with contrasted convective intensities during the Guangzhou “May 7” record-breaking rainfall event. Two modes of the storms' rapid self-organizing development are unraveled via the vertical momentum equation. Storm1 (strong convective intensity) develops in an “effective buoyancy dominantly driving mode,” where a deep inflow layer with high convective available potential energy (CAPE) from the South China Sea is lifted by a convectively-generated shallow cold pool. Strong effective buoyancy accelerates ascent, generating intense updrafts that advect upward above the melting level, with minor aid from dynamic vertical pressure perturbation forcing below 3 km. Under reduced boundary-layer CAPE due to nocturnal cooling, Storm2 forms when a convective region merges with a northward-moving convective cell and follows a “dynamic-buoyancy jointly driving mode.” Strengthened southerly inflows below 3 km interact with the overturning outflow from lower-topped Storm2, lifting inflow air via vertical twisting acceleration. Rear low-level downdrafts enhance the cold pool and near-surface northerlies, which converge with strengthened southerlies to form a strong horizontal convergence zone centered at 300 m. The sharp vertical decrease in convergence above this level forces the near-surface moist air upward via vertical extension acceleration, intensifying sub-4 km updrafts, boosting southerly moisture transport and in-cloud latent heating, and thus elevating effective buoyancy up to ∼7 km.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using Tower-Based Observational Networks to Assess the Impact of COVID-19 Lockdowns on Greenhouse Gas Emissions in Six North American Cities","authors":"Z. R. Barkley,&nbsp;K. J. Davis,&nbsp;N. L. Miles,&nbsp;S. Baray,&nbsp;F. Vogel,&nbsp;J. Kim,&nbsp;R. F. Weiss,&nbsp;J. C. Lin,&nbsp;K. R. Gurney,&nbsp;J. C. Turnbull,&nbsp;H. A. Young","doi":"10.1029/2025JD045115","DOIUrl":"https://doi.org/10.1029/2025JD045115","url":null,"abstract":"<p>The onset of the COVID-19 pandemic in North America and the lockdowns that followed in March 2020 brought forth a rapid change to societal functions disrupting many aspects of normal life, including the greenhouse gas emissions associated with them. In this work, we examine the capabilities of tower networks established in six North American cities in quantifying the change in these emissions. Influence functions, which relate tower-based observational sites to their upwind source regions, were created for sites in Los Angeles, the D.C./Baltimore urban corridor, Indianapolis, Salt Lake City, Boston, and Toronto for the months of February–April of 2017–2020, and model CO₂ enhancements were generated by multiplying the influence functions by regional inventories. Scaling factors are assigned to the city emissions to minimize the difference between observed and modeled afternoon CO₂ enhancements in 15 days intervals. Scaling factors from the 2020 period are then compared directly to those from the 2017 to 2019 timeframe to calculate a relative change in the emissions during the COVID-lockdown timeframe. Results across all six cities show a consistent message; by the end of March 2020, CO₂ emissions decreased by an average of 34% relative to the same 2017–2019 timeframe. This decrease matches values observed from bottom-up inventories during the same period. A similar technique is performed for methane across four cities with more variable trends across cities. The results of this paper demonstrate the ability to utilize simple approaches to detect and quantify temporal changes in emissions using a tower network.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD045115","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Sources of Potential Predictability for July–August 2025 Extreme Precipitation Anomalies Over Northern China: Roles of the Western Pacific and North Atlantic–Barents–Kara Sea Sectors","authors":"Xinyu He,&nbsp;Bian He,&nbsp;Yimin Liu,&nbsp;Guoxiong Wu,&nbsp;Chen Sheng,&nbsp;Bin Tang,&nbsp;Natalia Victorovna Vazaeva","doi":"10.1029/2026JD047254","DOIUrl":"https://doi.org/10.1029/2026JD047254","url":null,"abstract":"<p>Accurately predicting persistent extreme precipitation remains a major challenge for subseasonal-to-seasonal (S2S) prediction models. This study identifies two distinct sources of predictability for the July and August 2025 extreme precipitation anomalies over northern China (NC) and reveals how these remote signals improved the prediction. By separating S2S models into high-skill and low-skill groups, we show that the July predictability was mainly linked to tropical forcing over the western Pacific (WP), whereas the August predictability was primarily associated with midlatitude wave-train activity from the North Atlantic (NA) and Barents–Kara Seas (BKS). In July, high-skill models better captured typhoon-induced convection over the subtropical WP and the associated northward-propagating Pacific–Japan wave train. This circulation response favored westward moisture transport from the warm WP along the edge of the northward-extended western Pacific subtropical high, thereby improving the prediction of NC precipitation. In August, high-skill models more realistically represented eastward-propagating midlatitude wave trains from the NA and BKS. These wave trains enhanced energy conversion over NC and contributed to a more accurate prediction of the August extreme precipitation anomaly. Although the S2S models showed clear indications of predictability, most models underestimated the precipitation intensity, highlighting persistent model deficiencies in representing the amplitude of extreme rainfall. Nudging experiments further quantified the contribution of these remote predictable signals. Correcting WP circulation and convection-related anomalies explained approximately 78% of the July intensity improvement, while correcting NA and BKS wave-train anomalies explained approximately 46% and 66% of the August improvement, respectively.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 17","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}