Journal of Geophysical Research: Atmospheres最新文献_第10页

A Single Compartment Relaxed Eddy Accumulation Method 单室松弛涡积法

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-08 DOI: 10.1029/2024JD040811

T. Banerjee, G. G. Katul, E. Zahn, N. L. Dias, E. Bou-Zeid

{"title":"A Single Compartment Relaxed Eddy Accumulation Method","authors":"T. Banerjee, G. G. Katul, E. Zahn, N. L. Dias, E. Bou-Zeid","doi":"10.1029/2024JD040811","DOIUrl":"https://doi.org/10.1029/2024JD040811","url":null,"abstract":"The relaxed eddy accumulation (REA) method is a widely-known technique that measures turbulent fluxes of scalar quantities. The REA technique has been used to measure turbulent fluxes of various compounds, such as methane, ethene, propene, butene, isoprene, nitrous oxides, ozone, and others. The REA method requires the accumulation of scalar concentrations in two separate compartments that conditionally sample updrafts and downdraft events. It is demonstrated here that the assumptions behind the conventional or two-compartment REA approach allow for one-compartment sampling, therefore called a one compartment or 1-C-REA approach, thereby expanding its operational utility. The one-compartment sampling method is tested across various land cover types and atmospheric stability conditions, and it is found that the one-compartment REA can provide results comparable to those determined from conventional two-compartment REA. This finding enables rapid expansion and practical utility of REA in studies of surface-atmosphere exchanges, interactions, and feedbacks.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD040811","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404599","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}

引用次数: 0

A Forensic Investigation of Climate Model Biases in Teleconnections: The Case of the Relationship Between ENSO and the Northern Stratospheric Polar Vortex 远距离联系中气候模式偏差的鉴证调查：厄尔尼诺/南方涛动与北部平流层极地涡旋之间的关系案例

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-08 DOI: 10.1029/2024JD041252

Xiaocen Shen, Marlene Kretschmer, Theodore G. Shepherd

{"title":"A Forensic Investigation of Climate Model Biases in Teleconnections: The Case of the Relationship Between ENSO and the Northern Stratospheric Polar Vortex","authors":"Xiaocen Shen, Marlene Kretschmer, Theodore G. Shepherd","doi":"10.1029/2024JD041252","DOIUrl":"https://doi.org/10.1029/2024JD041252","url":null,"abstract":"Teleconnections are crucial in shaping climate variability and regional climate change. The fidelity of teleconnections in climate models is important for reliable climate projections. As the observed sample size is limited, scientific judgment is required when models disagree with observed teleconnections. We illustrate this using the example of the relationship between El Niño-Southern Oscillation (ENSO) and the northern stratospheric polar vortex (SPV), where the MIROC6 large ensemble exhibits an ENSO-SPV correlation opposite in sign to observations. Yet the model well captures the upward planetary-wave propagation pathway through which ENSO is known to affect the SPV. We show that the discrepancy arises from the model showing an additional linkage related to horizontal stratospheric wave propagation. Observations do not provide strong statistical evidence for or against the existence of this linkage. Thus, depending on the research purpose, a choice has to be made in how to use the model simulations. Under the assumption that the additional linkage is spurious, a physically-based bias adjustment is applied to the SPV, which effectively aligns the modeled ENSO-SPV relationship with the observations, and thereby removes the model-observations discrepancy in the surface air temperature response. However, if one believed that the additional linkage was genuine and was undersampled in the observations, a different approach could be taken. Our study emphasizes that caution is needed when concluding that a model is not suitable for studying teleconnections. We propose a forensic approach and argue that it helps to better understand model performance and utilize climate model data more effectively.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD041252","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404600","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}

引用次数: 0

Attribution of Excess Methane Emissions Over Marine Environments of the Mediterranean and Arabian Peninsula 地中海和阿拉伯半岛海洋环境中过量甲烷排放的归因

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-08 DOI: 10.1029/2024JD041621

E. Bourtsoukidis, E. Germain-Piaulenne, V. Gros, P.-Y. Quéhé, M. Pikridas, J. Byron, J. Williams, D. Gliddon, R. Mohamed, R. Ekaabi, J. Lelieveld, J. Sciare, O. Teixidó, J.-D. Paris

{"title":"Attribution of Excess Methane Emissions Over Marine Environments of the Mediterranean and Arabian Peninsula","authors":"E. Bourtsoukidis, E. Germain-Piaulenne, V. Gros, P.-Y. Quéhé, M. Pikridas, J. Byron, J. Williams, D. Gliddon, R. Mohamed, R. Ekaabi, J. Lelieveld, J. Sciare, O. Teixidó, J.-D. Paris","doi":"10.1029/2024JD041621","DOIUrl":"https://doi.org/10.1029/2024JD041621","url":null,"abstract":"To accurately assess the current atmospheric methane budget and its future trends, it is essential to apportion and quantify the anthropogenic methane emissions to specific sources. This poses a significant challenge in the under-sampled Middle East, where estimates predominantly depend on remote sensing observations and bottom-up reporting of national emissions. Here, we present in situ shipborne observations of greenhouse gases (GHGs) and non-methane hydrocarbons (NMHCs) collected along a >10,000-km route from Vigo, Spain, to Abu Dhabi, UAE. By comparing our observations with Lagrangian dispersion model simulations, coupled with two methane emission inventories, we identify periods of considerable mismatch and apportion the responsible sources. Employing interspecies relationships with NMHCs has enabled the characterization of methane emissions from oil and gas (O&G) operations, urban centers, Red Sea deep water, enteric fermentation, and agriculture across diverse atmospheric environments. Our analysis reveals that the Suez area is a regional emission hotspot, where simulations consistently underestimate the methane emission sources. Importantly, the Middle Eastern O&G sector has been identified as an additional source of considerable uncertainty. Here, methane emissions were alternately underestimated and overestimated by the two inventories, exposing significant gaps in our understanding of fuel exploitation-related emissions in the Middle East. This underscores the need for further targeted field campaigns and long-term observations to improve the accuracy of emission data in the inventories.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD041621","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404601","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}

引用次数: 0

The Roles of Moat Width and Outer Eyewall Contraction in Affecting the Timescale of Eyewall Replacement Cycle 护壕宽度和外眼墙收缩在影响眼墙更换周期中的作用

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-07 DOI: 10.1029/2024JD041488

Jie Jiang, Yuqing Wang

{"title":"The Roles of Moat Width and Outer Eyewall Contraction in Affecting the Timescale of Eyewall Replacement Cycle","authors":"Jie Jiang, Yuqing Wang","doi":"10.1029/2024JD041488","DOIUrl":"https://doi.org/10.1029/2024JD041488","url":null,"abstract":"The timescale of eyewall replacement cycle (ERC) is critical for the prediction of intensity and structure changes of tropical cyclones (TCs) with concentric eyewall (CE) structures. Previous studies have indicated that the moat width can regulate the interaction between the inner and outer eyewalls and has a salient relationship with the ERC timescale. In this study, a series of sensitivity experiments are carried out to investigate the essential mechanisms resulting in the diversity of the duration of CEs using both simple and full-physics models. Results reveal that a larger moat can induce stronger inflow under the same inner eyewall intensity by providing a longer distance for air parcels to accelerate in the boundary layer. Thus, there is greater inward absolute vorticity flux to sustain the inner eyewall. Besides, the equivalent potential temperature (θe) budget indicates that the vertical advection and surface flux of moist entropy can overbalance the negative contribution from the horizontal advection and lead to an increasing trend of θe in the inner eyewall. This suggests that the thermodynamic process in the boundary layer is not indispensable to the inner eyewall weakening. It is also found that the contraction rate of the secondary eyewall, which directly influences the moat width, is subject to the activity of outer spiral rainbands. By directly introducing positive wind tendency outside the eyewall and indirectly promoting a vertically tilted eyewall structure, active convection in the outer region will impede or even suspend the contraction of the outer eyewall and hence extend the ERC timescale.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404335","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}

引用次数: 0

Extreme Precipitation Over the Southern Slope of the Tibetan Plateau and the Associated Atmospheric Circulation Anomalies 青藏高原南坡的极端降水及其相关的大气环流异常

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-07 DOI: 10.1029/2024JD040872

Ying Na, Riyu Lu, Qiang Fu, L. Ruby Leung

{"title":"Extreme Precipitation Over the Southern Slope of the Tibetan Plateau and the Associated Atmospheric Circulation Anomalies","authors":"Ying Na, Riyu Lu, Qiang Fu, L. Ruby Leung","doi":"10.1029/2024JD040872","DOIUrl":"https://doi.org/10.1029/2024JD040872","url":null,"abstract":"The southern slope of the Tibetan Plateau (SSTP) is one of the rainiest regions in the world where geological hazards caused by extreme precipitation often occur. This study investigates the characteristics and mechanisms of extreme precipitation over SSTP from June to September during 2001–2020 using Global Precipitation Measurement satellite observation. The extreme precipitation days are defined as the days with top 5% of regional-mean daily precipitation over SSTP in this period, which has an average precipitation of 27.2 mm/d. Averaging over the extreme precipitation days, precipitation peaks at an altitude of about 300 m, coinciding with the climatological maximum precipitation, but with a much larger value of 37.2 mm/d than the climatology of 11.9 mm/d. Composite analysis of circulations on extreme days reveals significant circulation anomalies in both the lower and upper troposphere. Specifically, the lower-tropospheric circulations are characterized by significant westerly anomalies over northern India, and the upper-tropospheric circulations are characterized by northerly anomalies over the central Tibetan Plateau, which are statistically independent. The lower-tropospheric westerly anomalies blowing toward SSTP are blocked by the topography, favoring extreme precipitation over SSTP. The upper-tropospheric northerly anomalies, on the other hand, correspond to anomalous northeasterlies north of SSTP in the middle troposphere and southeasterlies to the south in the lower troposphere, and the convergence of these circulation anomalies favors extreme precipitation over SSTP. Lastly, the lower-tropospheric westerly and upper-tropospheric northerly anomalies, respectively, correspond to less precipitation over the South Asian monsoon region and the Tibetan Plateau.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404336","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}

引用次数: 0

The Cumulative Effect of Wintertime Weather Systems on the Ocean Mixed-Layer Stable Isotope Composition in the Iceland and Greenland Seas 冬季天气系统对冰岛海和格陵兰海海洋混合层稳定同位素组成的累积效应

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-05 DOI: 10.1029/2024JD041138

Harald Sodemann, Yongbiao Weng, Alexandra Touzeau, Emil Jeansson, Iris Thurnherr, Chris Barrell, Ian A. Renfrew, Stefanie Semper, Kjetil Våge, Martin Werner

{"title":"The Cumulative Effect of Wintertime Weather Systems on the Ocean Mixed-Layer Stable Isotope Composition in the Iceland and Greenland Seas","authors":"Harald Sodemann, Yongbiao Weng, Alexandra Touzeau, Emil Jeansson, Iris Thurnherr, Chris Barrell, Ian A. Renfrew, Stefanie Semper, Kjetil Våge, Martin Werner","doi":"10.1029/2024JD041138","DOIUrl":"https://doi.org/10.1029/2024JD041138","url":null,"abstract":"The Iceland and Greenland Seas are characterized by strong heat fluxes from the ocean to the atmosphere during wintertime. Here we characterize the atmospheric signal of this strong evaporation in terms of water vapor isotopes and investigate if such a signal can have a cumulative imprint on the ocean mixed-layer. Observations include continuous water vapor isotope measurements, event-based precipitation samples, and sea-water samples taken at various depths from the research vessel Alliance during the Iceland-Greenland Seas Project cruise in February and March 2018. In conjunction with a simulation from a regional, isotope-enabled atmospheric model, we find that the predominant atmospheric isotope signature during predominant marine cold-air outbreak conditions is −129.8 ± 16.6‰ for δ2H and −18.10 ± 2.87‰ for δ18O, with a d-excess of 15.1 ± 7.9‰, indicating enhanced non-equilibrium fractionation compared to the global average. During events of warm-air intrusion from mid-latitudes, near-surface vapor becomes saturated and the vapor d-excess approaches equilibrium or becomes negative. Similarly, precipitation d-excess is lower and thus closer to equilibrium conditions during warm-air intrusions. There are indications that an evaporation signal of waters exiting the Nordic Seas through Denmark Strait could be locally enhanced over seasons to years, as supported by simple model calculations. Our findings thus suggest that evaporation signals could be transferred into the ocean isotope composition in this region, potentially enabling mass-balance constraints in isotope-enabled coupled ocean-atmosphere models.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD041138","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404145","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}

引用次数: 0

Effect of Soil Moisture on Future Heatwaves Over Eastern China: Convection-Permitting Regional Climate Simulations 土壤水分对未来中国东部热浪的影响：对流允许的区域气候模拟

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-05 DOI: 10.1029/2024JD041654

Yi Xu, Juan Fang, Pinya Wang, Xuexing Qiu, Jianping Tang

{"title":"Effect of Soil Moisture on Future Heatwaves Over Eastern China: Convection-Permitting Regional Climate Simulations","authors":"Yi Xu, Juan Fang, Pinya Wang, Xuexing Qiu, Jianping Tang","doi":"10.1029/2024JD041654","DOIUrl":"https://doi.org/10.1029/2024JD041654","url":null,"abstract":"Soil moisture deficiencies exacerbate heatwaves through soil moisture-temperature feedback, an effect that is expected to intensify with climate change, resulting in critical impacts on society and ecosystems. This study aims to investigate the evolving soil moisture-heatwave relationship over eastern China in the future, using a convection-permitting (CP, ∼4 km) regional climate model (RCM). The CP-RCM model simulates historical (1998–2007) and future (2070–2099) climates over eastern China, with three pseudo-global warming (PGW) experiments conducted under the RCP2.6, RCP4.5, and RCP8.5 scenarios. Results indicate a substantial increase in heatwave frequency (HWF) and magnitude (HWM) over eastern China, particularly under the RCP8.5 scenario. The largest HWF (up to 23 days) is expected in South China (SC), and the largest HWM (up to 3.25°C) is expected in Loess Plateau (LP) and North China Plain (NCP), indicating a pronounced future risk of heatwave in the region. Antecedent soil moisture exhibits a negative correlation with heatwave indices (HWM and HWF) in most areas of eastern China, suggesting its role in mitigating heatwaves. Quantile regression analysis shows that antecedent soil moisture exerts a stronger effect on the upper quantile of the HWF/HWM than on the lower quantile. With global warming, the amplifying effect due to soil moisture deficiency on future heatwaves is expected to expand spatially and become more pronounced. Increased soil moisture control on heatwaves can be attributed to reduced energy limitation and intensified water limitation. A comprehensive investigation across five sub-regions reveals the role of various soil moisture regimes in modulating heatwaves over eastern China.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404291","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}

引用次数: 0

Climatological Tracking and Lifecycle Characteristics of Mesoscale Convective Systems in Northwestern South America 南美洲西北部中尺度对流系统的气候学跟踪和生命周期特征

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-05 DOI: 10.1029/2024JD041159

Vanessa Robledo, Juan J. Henao, John F. Mejía, Álvaro Ramírez-Cardona, K. Santiago Hernández, Sebastián Gómez-Ríos, Ángela M. Rendón

{"title":"Climatological Tracking and Lifecycle Characteristics of Mesoscale Convective Systems in Northwestern South America","authors":"Vanessa Robledo, Juan J. Henao, John F. Mejía, Álvaro Ramírez-Cardona, K. Santiago Hernández, Sebastián Gómez-Ríos, Ángela M. Rendón","doi":"10.1029/2024JD041159","DOIUrl":"https://doi.org/10.1029/2024JD041159","url":null,"abstract":"Mesoscale convective systems (MCSs) are crucial in shaping large-scale tropical circulation and the hydrological cycle, particularly in Northwestern South America (NwSA), a region marked by complex terrain and significant MCS activity. Understanding MCSs in NwSA is vital due to their impact on precipitation patterns and potential for severe weather events. To enhance this understanding, the ATRACKCS algorithm was developed for tracking convective systems, utilizing precipitation and brightness temperature data sets. This research focuses on documenting the spatiotemporal variability of MCS occurrence, life cycle, and movement. Notably, MCS hotspots were identified to the west of the major orographic features in the region, with maximum occurrences at night, contrasting with the region's typical afternoon peak in land convection. MCS movement is also heavily influenced by topography, with higher velocities on the eastern (windward) side of the Andes compared to velocities on the western (leeward) side. MCSs generally move westward, driven by easterly winds, but this pattern is not consistent throughout the year or region. Northward movement is predominant to the west of the Andes, while southward movement is observed to the east. These seasonal and regional movement variations are linked to factors such as the intertropical convergence zone position, moisture availability, topography, and low-level jets. This research underscores the complexity of MCSs in NwSA and emphasizes the need for detailed studies on the atmospheric environment shaping these systems. Additionally, it provides a robust 21-year MCS database for NwSA and an advanced tracking tool for research in various geographic contexts and impact areas.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD041159","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404143","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}

引用次数: 0

Generation of the Quasi-Biweekly Oscillation in the Surface Potential Vorticity Over the Tibetan Plateau During Boreal Summer: A Case Study of 2014 北半球夏季青藏高原表面位势涡度准双周涛动的产生：2014 年案例研究

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-05 DOI: 10.1029/2024JD041161

Danni Guo, Yimin Liu, Guoxiong Wu, Jiangyu Mao, Jilan Jiang, Yaoxian Yang

{"title":"Generation of the Quasi-Biweekly Oscillation in the Surface Potential Vorticity Over the Tibetan Plateau During Boreal Summer: A Case Study of 2014","authors":"Danni Guo, Yimin Liu, Guoxiong Wu, Jiangyu Mao, Jilan Jiang, Yaoxian Yang","doi":"10.1029/2024JD041161","DOIUrl":"https://doi.org/10.1029/2024JD041161","url":null,"abstract":"The atmospheric circulation around the Tibetan Plateau (TP) exhibits a substantial 10–20-day quasi–biweekly oscillation (QBWO), profoundly impacting weather and climate locally and remotely. Understanding the factors influencing the generation of QBWO over the TP (QBWOTP) and its physical mechanism is crucial. This study has investigated the influence of multi–timescale and land–atmosphere interactions on the generation of the QBWOTP in surface potential vorticity (SPV), a valuable tool for characterizing the mechanical and thermal variabilities in mountain forcing, based on a 2014 case study. Results indicate that in the free atmosphere, the summer monsoon onset over the Bay of Bengal induces a northward shift in the westerly jet toward the TP, manifested as an increase in low-frequency zonal winds. This shift facilitates the propagation of wave trains, leading to atmospheric quasi–biweekly potential temperature anomalies (θa) over the TP through a multi-timescale interaction. Additionally, the TP's surface thermal forcing and arrival of wave trains trigger anomalous upward motion and increase cloud cover. The resultant decrease in net short-wave radiations and increase in net long-wave radiations contribute to variations in surface potential temperature (θs) over the TP. As θa and θs evolve, the difference between them enlarges, resulting in the generation of the SPV QBWOTP. Given the relationship between the QBWOTP and downstream rainfall, this study could provide novel insights into understanding and predicting downstream rainfall QBWO.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JD041161","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404144","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}

引用次数: 0

Backscattering Linear Depolarization Ratio of Smoke Aerosols From Biomass Burning 生物质燃烧产生的烟雾气溶胶的反向散射线性去极化率

IF 3.8 2区地球科学

Journal of Geophysical Research: Atmospheres Pub Date : 2024-10-03 DOI: 10.1029/2024JD041276

Zhenhai Qin, Haihui Wang, Aonan He, Yuping Sun, Jingan Li, Yongming Zhang, Qixing Zhang

{"title":"Backscattering Linear Depolarization Ratio of Smoke Aerosols From Biomass Burning","authors":"Zhenhai Qin, Haihui Wang, Aonan He, Yuping Sun, Jingan Li, Yongming Zhang, Qixing Zhang","doi":"10.1029/2024JD041276","DOIUrl":"https://doi.org/10.1029/2024JD041276","url":null,"abstract":"The linear depolarization ratio (LDR) of backscattering is a key parameter for distinguishing particle types. The measured LDRs of smoke in previous studies are highly variable and different from each other. Existing research on smoke aerosols considers only the internal mixing state of the black carbon (BC) particle population either by ignoring the externally mixed organic carbon (OC) particle population or by evaluating the LDR of smoke aerosols using the results of individual particles rather than the particle population. The field-measured LDR of smoke then becomes difficult to interpret properly. The recent prescribed forest burning experiment in China showed that the LDR of freshly emitted smoke varies between 0.0% and 20.1% in wavelength (λ) of 532 nm. Electron microscopy images also showed that coated BC and pure OC exist simultaneously in biomass burning aerosols. Therefore, this study evaluates the influence of various parameters on the LDR of smoke by considering the internal and external mixing states. The calculated LDRs of the smoke aerosols were found to vary between 0.0% and 28.2% when λ is equal to 532 nm. The calculation results indicate that the LDR of smoke is slightly influenced by BC, considerably affected by the externally mixed OC, and is essentially dominated by the latter's morphology and particle size distribution. High levels and rapid changes of LDR of smoke can be well explained by nonsphericity and particle size distribution of externally mixed OC. This study advances the research on the measurement and evaluation of the LDR of smoke aerosols.","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"129 19","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404464","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}

引用次数: 0