Journal of Geophysical Research: Atmospheres最新文献

{"title":"Regional Gross Primary Productivity Estimation Using Passive Microwave Observations From China's Fengyun-3B Satellite","authors":"Binbin Song,&nbsp;Jiheng Hu,&nbsp;Yipu Wang,&nbsp;Dong Li,&nbsp;Peng Zhang,&nbsp;Yu Wang,&nbsp;Lei Zhong,&nbsp;Rui Li","doi":"10.1029/2024JD041425","DOIUrl":"https://doi.org/10.1029/2024JD041425","url":null,"abstract":"<p>In this study, we present the development and validation of a microwave-based regional gross primary productivity (GPP) estimation method, EDVI-GPP, using the Emissivity Difference Vegetation Index (EDVI) retrieved from the China's Fengyun-3B satellite over East Asia for the period 2016–2018. Given the common issue of cloud cover contamination in optical remote sensing, microwave remote sensing is explored as a viable alternative due to its ability to penetrate clouds. Our approach is substantiated with in situ GPP measurements from 18 eddy covariance flux sites and comparative analysis against four satellite-derived GPP products. At a daily scale, EDVI-GPP demonstrated proficiency in capturing day-to-day variations of GPP on a regional scale, exhibiting a strong correlation with in situ measurements. When extended to an 8-day temporal resolution, EDVI-GPP correlations (<i>R</i>² = 0.51) are comparable to MODIS-GPP (<i>R</i>² = 0.59), FLUXCOM-GPP (<i>R</i>² = 0.66), GLASS-GPP (<i>R</i>² = 0.53), and VODCA2-GPP (<i>R</i>² = 0.13), with a reduced bias of −0.84 gC/m²/day. Notably, under moderate to heavy cloud cover, the method maintained superior performance, suggesting resilience to cloud interference. On a regional scale, EDVI-GPP exhibited spatial consistency and high spatiotemporal correlation with the compared GPP products (<i>R</i> = 0.69–0.83). Such robust correlations lay the groundwork for the method's application across broader geographical extents. The annual averaged EDVI-GPP of China was 6.00 Pg C yr⁻¹, which was in close agreement with other published estimates and thereby supported China's carbon peak and carbon neutrality objectives. This research marks a pioneering effort to incorporate microwave-derived variables into daily GPP estimation on a regional scale, with potential for global application, providing a less cloud-affected and reliable measurement.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818352","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":"Validation of Aerosol Optical Depth Retrieved From CALIPSO Lidar Ocean Surface Backscatter","authors":"Tyler J. Thorsen,&nbsp;Robert A. Ryan,&nbsp;Mark A. Vaughan","doi":"10.1029/2024JD042416","DOIUrl":"https://doi.org/10.1029/2024JD042416","url":null,"abstract":"<p>Aerosol optical depth (AOD) from the new Ocean Derived Column Optical Depth (ODCOD) data product derived from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) spacecraft is validated using the ground-based Aerosol Robotic Network (AERONET). Relative to AERONET, ODCOD is shown to provide an unbiased AOD and a root mean squared error (RMSE) of 60%. This is in contrast to the performance of the “standard” CALIPSO AOD retrievals (which first detect/identify aerosol layers, retrieve their extinction profile, and then integrate to obtain AOD) that show a larger RMSE (93%) and a significant negative bias (−20%). ODCOD is also shown to provide a higher-fidelity uncertainty estimate than the standard retrievals with the estimated uncertainties providing a good prediction of the true errors as diagnosed with AERONET. A perturbation analysis is performed to assess ODCOD as a retrieval constraint to improve the profiling capability of CALIOP. This analysis indicates that ODCOD has the potential to improve up to 40% of CALIOP retrievals globally.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042416","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809519","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":"Millennial Cycles in Greenland and Antarctic Ice Core Records: Evidence of Astronomical Influence on Global Climate","authors":"Vadim A. Kravchinsky,&nbsp;Rui Zhang,&nbsp;Ryan Borowiecki,&nbsp;Avto Goguitchaichvili,&nbsp;Jan Czarnecki,&nbsp;Andrzej Czarnecki,&nbsp;Niklas Boers,&nbsp;André Berger,&nbsp;Mirko van der Baan","doi":"10.1029/2024JD042810","DOIUrl":"https://doi.org/10.1029/2024JD042810","url":null,"abstract":"<p>Multimillennial-scale climate events are well-documented in ice-core records from both Greenland and Antarctica, yet the role of orbital and solar input oscillations in shaping these events remains unresolved. In this study, we analyze two high-resolution oxygen isotope records from Greenland and Antarctica to assess the influence of orbital cycles on global climate variability. Using two techniques, synchrosqueezing transform (SST) and Bayesian statistical analysis (BSA), we identify prominent climatic periodicities at ∼11, ∼5.5, and ∼2.75 kyr. The duration and amplitude of these oscillations correspond to bi-hemispherical (BHI) and equatorial insolation (EI) cycles and their harmonic emphasizing their role in shaping climate transitions during glacial and interglacial periods. We suggest that the shorter ∼2.75 kyr cycle may match the Hallstatt cycle, which is currently interpreted as a hypothetical solar cycle but could appear to be an EI harmonic. Further comparison with high-resolution BHI and EI records from other geographic zones confirms the presence of these cycles across multiple regions. The use of both SST and BSA techniques increases the robustness of our analysis by ensuring that potential signal artifacts are minimized and that weaker ∼5.5 and ∼2.75 kyr cycles are accurately detected. This study provides new insights into the drivers of major climate variability over the past 150,000 years, demonstrating the significant influence of BHI and EI cycles on Earth's climate system in the past and offering new perspectives on how these orbital cycles may continue to impact Earth's climate in the future.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042810","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809518","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":"Dynamics and Energetics Associated With Two East Pacific Easterly Waves During the OTREC Campaign in August 2019","authors":"Yihao Zhou,&nbsp;Eric D. Maloney","doi":"10.1029/2024JD042266","DOIUrl":"https://doi.org/10.1029/2024JD042266","url":null,"abstract":"<p>This study investigates the vertical structure and related dynamical and energy conversion processes that aided the development of two east Pacific easterly waves (EWs) during the 2019 OTREC (Organization of Tropical East Pacific Convection) campaign period. The initial mesoscale convective systems (MCSs) that seeded both disturbances formed near the Panama Bight and developed into EWs near the Papagayo jet exit region. In the MCS stage, both disturbances were characterized by top-heavy vertical motions and midlevel vorticity near the maximum vorticity center. The deep convection caused strong latent heating and eddy available potential energy (EAPE) generation and conversion to eddy kinetic energy (EKE) in the upper levels. When the disturbances moved to the south of the Papagayo jet, they interacted with the low-level shear vorticity there, enhancing low-level stretching and vorticity. Subsequently, the top-heavy upward motion intensified and led to enhanced stretching and vorticity intensification at midlevels. The enhanced stretching on the southwest side also favored the formation of southwest-northeast tilted vorticity at midlevels that characterizes EWs. After the EWs formed near the jet exit, the vertical motion weakened and became more bottom-heavy, with the maximum vorticity shifting to lower levels. This change in the vertical motion profile near the jet exit region is likely modulated by the lower sea surface temperature, reduced moisture, and weaker convective instability. While EAPE-to-EKE conversion weakened during this period, the low-level barotropic conversion of EKE in the jet exit served as the primary energy source for the EWs.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042266","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818732","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":"Thermodynamic and Dynamic Changes in the Japan Sea Polar Air Mass Convergence Zone and Its Associated Heavy Snowfall Under Warmer Climate","authors":"Ryota Nakamura,&nbsp;Sunao Matsunaga,&nbsp;Martin Mäll","doi":"10.1029/2024JD042369","DOIUrl":"https://doi.org/10.1029/2024JD042369","url":null,"abstract":"<p>The Japan Sea polar air mass convergence zone (JPCZ) has the potential to cause heavy snowfall events several times per year in the west side of the Japanese archipelago. The associated severe snowfall can cause adverse effects on the social, economic, and ecological well-being in the affected areas. Therefore, understanding the changes of JPCZ and its associated snowfall under warmer climate conditions is of high importance. In the present study, pseudo global warming (PGW) experiments, considering the 2050s under SSP5-8.5 scenario, were carried out to evaluate these thermodynamic and dynamic changes. The amount of PGW experiment-simulated snowfall in 13 historical cases during 2015–2024 were in good agreement with ground observations. Warmer climate conditions can potentially reduce the amount of heavy snowfall as statistically supported by the <i>t</i> test, though increase the rainfall mainly due to the shift in hydrometeors in the convective zone. On the other hand, total precipitation does not significantly change, likely due to almost no changes in the sum of latent and sensible heat fluxes. Further, dynamic changes are not significant as the position of the convergence zone seems not to be different between PGW and historical climate, though local shifts in the convergence zone were simulated probably due to the changes in the geopotential fields and perturbed wind velocity in the lateral boundary. Our study shows that thermodynamic changes of the JPCZ can be significant, and it has the potential to change the ratio of snowfall within the total precipitation from 57.7% under historical condition to 34.7% under warmer climates.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818351","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":"Efficient Forward Radar Operator Simulations in Melting Layer Scenarios and Evaluations of Melting Layer Scheme in ZJU-AERO Based on Ground-Based and Spaceborne Radar Observations","authors":"Hejun Xie,&nbsp;Lei Bi,&nbsp;Wei Han","doi":"10.1029/2024JD043140","DOIUrl":"https://doi.org/10.1029/2024JD043140","url":null,"abstract":"<p>In this study, we proposed a novel method for improving the computational efficiency of forward radar operator in melting layer (ML) scenarios for ground-based radar. This method is based on the insights that the vertical gradients of scattering properties of stratiform cloud/precipitation systems far outweigh their horizontal gradients. Based on this new volume-sampling approach, significant performance improvements (up to 85% savings in CPU core-time with minimal loss in simulation details) were observed when simulating low fixed-elevation-angle Plan Position Indicator scans in ZJU-AERO. This study also validates the capability of the forward radar operator ZJU-AERO (Accurate and Efficient Radar Operator designed by ZheJiang University) to simulate the ML through case studies and observation verifications using both ground-based and spaceborne radar observations. The ML polarimetric signatures (Z_H, Z_DR, K_DP, and ρ_hv) in volume scan observations of a ground-based radar (S-band) from CINRAD-98DP (China's new generation Doppler weather radars with polarimetric capacity) were compared with their counterparts simulated by ZJU-AERO. Path-integrated attenuation observations obtained from Dual-frequency Precipitation Radar on board the Global Precipitation Measurements satellite were used to verify the simulated ML attenuation effects in the Ku- and Ka-bands. Results showed that the polarimetric signatures and attenuation effects of the ML generally matched up well with measurements, except for the correlation coefficients ρ_hv. Overall, these findings demonstrate the effectiveness of ZJU-AERO in modeling the ML across different platforms and radar types.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818414","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":"A Copula-Based Composite Drought Index for Enhanced Drought Monitoring and Analysis","authors":"Xiaohan Yu,&nbsp;Xiankui Zeng,&nbsp;Luca Brocca,&nbsp;Dongwei Gui,&nbsp;Dong Wang,&nbsp;Jichun Wu","doi":"10.1029/2024JD041867","DOIUrl":"https://doi.org/10.1029/2024JD041867","url":null,"abstract":"<p>This research developed a composite drought index based on the copula theory, standardized precipitation, evapotranspiration and groundwater Index (SPEGI). SPEGI innovatively integrated surface water variables, that is, precipitation and actual evapotranspiration, and groundwater variables, that is, groundwater water storage changes. Subsequently, it was compared with standardized precipitation evapotranspiration index (SPEI), standardized soil moisture index (SSMI), and standardized groundwater index (SGI), and cross-validated with observed crop yield to validate its applicability. The Tarim River, recognized as China's largest inland river, has its water resources primarily supplied by its headstream. The headstream of the Tarim River Basin (TRB) is increasingly subjected to intense and prolonged droughts under climate change, which serves as the study area. Finally, the study assessed drought characteristics in the headstream of TRB using SPEGI. The results demonstrated that Gaussian copula provided the best fit for constructing joint probability distributions at a 1-month scale, whereas the Gumbel copula was most suitable at the 3-, 6-, and 12-month scales. The SPEGI effectively identified both meteorological and groundwater drought features and demonstrated a better correlation with crop yields compared to SPEI, SSMI, and SGI. Additionally, the drought characteristics in mountainous regions exhibited high frequency, short duration, and low intensity, whereas the plains exhibited low frequency, long duration, and high intensity. This research provided an innovative perspective for drought research, considering both surface water and groundwater and focusing on improved regional drought assessment and strategic development.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818415","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":"Inferior Performance of the Generalized Complementary Relationship for Evaporation in the Mediterranean Climates","authors":"Liming Wang,&nbsp;Songjun Han,&nbsp;Fuqiang Tian,&nbsp;Baozhong Zhang,&nbsp;Yaqi Wang,&nbsp;Mahmut Tudaji,&nbsp;Yanzheng Yang","doi":"10.1029/2024JD042774","DOIUrl":"https://doi.org/10.1029/2024JD042774","url":null,"abstract":"<p>The complementary principle was widely used in evaporation (<i>E</i>) estimation. However, it has been found that the complementary principle has biases in estimating evaporation in the Mediterranean climates, which affects its application. In this study, a deep analysis by using the original sigmoid generalized complementary equation and its modified version by introducing soil moisture content were applied on 24 eddy flux sites located in the Mediterranean climates. We found that (a) the performance of the generalized complementary relationship is inferior at most of the sites in the Mediterranean climates, which results in low accuracy on <i>E</i> estimation with the mean absolute error (MAE) of 12.06 ± 5.62 W m⁻²; (b) rescaling the complementary function with surface moisture information can substantially reduce the simulation biases with MAE decreases by 26%; and (c) the modification works well in most of the ecosystem types with the MAE decreases from 24% to 48% except in the forests. The results indicate that when precipitation and heat conditions are not synchronized (i.e., in the Mediterranean climate), the original complementarity principle cannot provide a reasonable explanation for the real world. It is necessary to introduce certain surface information into the complementary framework reasonably to improve the accuracy of evaporation simulation.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818727","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":"Transport by Asian Summer Monsoon Convection to the Upper Troposphere and Lower Stratosphere During ACCLIP (2022)","authors":"Warren P. Smith,&nbsp;Laura L. Pan,&nbsp;Rei Ueyama,&nbsp;Shawn Honomichl,&nbsp;Teresa Campos,&nbsp;Silvia Viciani,&nbsp;Francesco D’Amato,&nbsp;Giovanni Bianchini,&nbsp;Marco Barruci,&nbsp;Rebecca S. Hornbrook,&nbsp;Eric C. Apel,&nbsp;Alan J. Hills,&nbsp;Barbara Barletta,&nbsp;Elliot Atlas,&nbsp;Sue Schauffler,&nbsp;Victoria Treadaway,&nbsp;Katie Smith,&nbsp;Rich Lueb,&nbsp;Roger Hendershot,&nbsp;Stephen Donnelly,&nbsp;Andrew Rollins,&nbsp;Eleanor Waxman,&nbsp;Gordon Novak,&nbsp;L. Gregory Huey,&nbsp;David Tanner,&nbsp;Young Ro Lee,&nbsp;Chelsea Bekemeier,&nbsp;Kenneth P. Bowman","doi":"10.1029/2024JD042732","DOIUrl":"https://doi.org/10.1029/2024JD042732","url":null,"abstract":"<p>The Asian Summer Monsoon (ASM) has garnered attention in recent years for its impacts on the composition of the upper troposphere and lower stratosphere (UTLS) via deep convection. A recent observational effort into this mechanism, the Asian Summer Monsoon Chemical and CLimate Impact Project (ACCLIP), sampled the composition of the ASM UTLS over the northwestern Pacific region during boreal summer 2022 using two airborne platforms. In this work, we integrate Lagrangian trajectory modeling with convective cloud top observations to diagnose ASM convective transport which contributed to ACCLIP airborne observations. This diagnostic is applied to explore the properties of convective transport associated with prominent ASM sub-systems, revealing that for species ranging in lifetime from days to months, transport from convection along the East Asia Subtropical Front was generally associated with more UTLS pollutants than transport from convection over South Asia. The convective transport diagnostic is used to isolate three convective transport events over eastern Asia which had distinct chemical tracer relationship behaviors, indicating the different economical behaviors of the contributing source regions. One of these transport events is explored in greater detail, where a polluted air mass was sampled from convection over the Northeast China Plain which may have been high enough in altitude to impact the composition of the stratosphere. Overall, the presented diagnosis of convective transport contribution to ACCLIP airborne sampling indicates a key scientific success of the campaign and enables process studies of the climate interactions from the two ASM sub-systems.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD042732","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801871","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":"Reactive Oxidized Nitrogen at a High Mountain Site in the North China Plain: Chemical Speciation and Temporal Variations During 2007–2023","authors":"Likun Xue,&nbsp;Ying Jiang,&nbsp;Hongyong Li,&nbsp;Qingqing Liu,&nbsp;Ji Zhang,&nbsp;Hengqing Shen,&nbsp;Yong Zhao,&nbsp;Zhaoxin Guo,&nbsp;Tianshu Chen,&nbsp;Liang Wen,&nbsp;Yuhong Liu,&nbsp;Jiangshan Mu,&nbsp;Xinfeng Wang,&nbsp;Jian Gao,&nbsp;Tao Wang,&nbsp;Wenxing Wang","doi":"10.1029/2024JD042479","DOIUrl":"https://doi.org/10.1029/2024JD042479","url":null,"abstract":"<p>Total reactive oxidized nitrogen (NO_<i>y</i>) and its speciated compounds, such as nitric oxide (NO), nitrogen dioxide (NO₂), peroxyacetyl nitrate (PAN), and particulate nitrate (pNO₃⁻), play a major role in tropospheric chemistry, regional air quality, and climate change. However, little is known regarding the chemical speciation and long-term trends of NO_<i>y</i> in China. In this study, we analyzed the temporal variations in NO_<i>y</i> and speciated compounds during eight intensive field campaigns and 6 years of continuous measurements during 2007–2023 at Mount Tai in the North China Plain (NCP). The measured concentration levels of NO_<i>y</i> were significantly higher than those at other remote high-altitude sites globally. NO₂ was the most abundant species (24%–42%), followed by pNO₃⁻ (18%–34%) and PAN (7%–12%). Over the study period, the concentrations of NO_<i>x</i>, NO_<i>y</i>, and NO_<i>z</i> exhibited a significant downward trend, while pNO₃⁻ exhibited a significant upward trend. Vertical transport from the planetary boundary layer (PBL) substantially influences the atmosphere at Mount Tai, with air masses from both PBL and free troposphere containing different chemical compositions of NO_y. The lower free troposphere above the NCP contained relatively high abundances of PAN and pNO₃⁻. This study represents the first comprehensive analysis of decadal trends in NO_<i>y</i> and its chemical speciation in China's high-altitude atmosphere. Our findings underscore the necessity for additional efforts to mitigate photochemical and secondary aerosol pollution caused by nitrogen species at high altitudes in China.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801866","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}