Pub Date : 2025-02-15DOI: 10.1016/j.atmosres.2025.107992
Chao Peng , Mi Tian , Guangming Shi , Shumin Zhang , Xin Long , Hanxiong Che , Jie Zhong , Xiangyu You , Zhier Bao , Fumo Yang , Xin Qi , Chongzhi Zhai , Yang Chen
The optical properties of brown carbon (BrC) and their correlation with chemical characteristics remained inadequately understood in different regions worldwide. This study investigated the correlations and estimated the subsequent radiative effects using real-time measurements during wintertime in the Sichuan Basin, China. The average light absorption of BrC (AbsBrC) at 370 nm constituted 35.5 ± 8.2 % of total absorption, significantly higher than those at 470 nm (20.9 ± 4.3 %), 590 nm (14.0 ± 2.5 %), and 660 nm (7.7 ± 2.1 %) (p < 0.001). The contributions of various organic aerosol (OA) sources to AbsBrC varied by wavelength, with biomass-burning OA (BBOA) and semi-volatile oxygenated OA (SVOOA) exhibiting the higher Abs (14.4 Mm−1 and 13.5 Mm−1), absorption Ångström exponents (AAE) (4.81 and 4.35), and contributions to AbsBrC (24.4 % and 22.8 %). Additionally, secondary BrC likely formed from BBOA through aqueous-phase reactions during winter. The transport of BBOA and SVOOA from northern regions (i.e., Guang'an in Sichuan and Hechuan in Chongqing) significantly contributed to elevated Abs370,BrC levels. The mean simple forcing efficiency for BrC (SFEBrC) was 60.5 W g−1, accounting for 14 % of SFEBC in the 370–880 nm range during winter. Overall, this study enhanced the understanding of AbsBrC and its evolution with sources, providing a more accurate assessment of its radiative effects, and emphasized the importance of biomass burning emissions.
{"title":"Sources and light absorption of brown carbon in urban areas of the Sichuan Basin, China: Contribution from biomass burning and secondary formation","authors":"Chao Peng , Mi Tian , Guangming Shi , Shumin Zhang , Xin Long , Hanxiong Che , Jie Zhong , Xiangyu You , Zhier Bao , Fumo Yang , Xin Qi , Chongzhi Zhai , Yang Chen","doi":"10.1016/j.atmosres.2025.107992","DOIUrl":"10.1016/j.atmosres.2025.107992","url":null,"abstract":"<div><div>The optical properties of brown carbon (BrC) and their correlation with chemical characteristics remained inadequately understood in different regions worldwide. This study investigated the correlations and estimated the subsequent radiative effects using real-time measurements during wintertime in the Sichuan Basin, China. The average light absorption of BrC (Abs<sub>BrC</sub>) at 370 nm constituted 35.5 ± 8.2 % of total absorption, significantly higher than those at 470 nm (20.9 ± 4.3 %), 590 nm (14.0 ± 2.5 %), and 660 nm (7.7 ± 2.1 %) (<em>p</em> < 0.001). The contributions of various organic aerosol (OA) sources to Abs<sub>BrC</sub> varied by wavelength, with biomass-burning OA (BBOA) and semi-volatile oxygenated OA (SVOOA) exhibiting the higher Abs (14.4 Mm<sup>−1</sup> and 13.5 Mm<sup>−1</sup>), absorption Ångström exponents (AAE) (4.81 and 4.35), and contributions to Abs<sub>BrC</sub> (24.4 % and 22.8 %). Additionally, secondary BrC likely formed from BBOA through aqueous-phase reactions during winter. The transport of BBOA and SVOOA from northern regions (i.e., Guang'an in Sichuan and Hechuan in Chongqing) significantly contributed to elevated Abs<sub>370,BrC</sub> levels. The mean simple forcing efficiency for BrC (SFE<sub>BrC</sub>) was 60.5 W g<sup>−1</sup>, accounting for 14 % of SFE<sub>BC</sub> in the 370–880 nm range during winter. Overall, this study enhanced the understanding of Abs<sub>BrC</sub> and its evolution with sources, providing a more accurate assessment of its radiative effects, and emphasized the importance of biomass burning emissions.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"318 ","pages":"Article 107992"},"PeriodicalIF":4.5,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437585","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}
Pub Date : 2025-02-14DOI: 10.1016/j.atmosres.2025.107987
Konstantinos Dimitriou
The main objective of this research, was to incorporate Mixed Layer Depth (MLD) estimations across backward air mass trajectories to the broadly used Trajectory Sector Analysis (TSA) and Concentration Weighted Trajectory (CWT) methods, in order to attain a three-dimensional (3D) identification of aerosol transport pathways and to reveal the role of the Mixed Layer (ML) on the transferring of particulates. The developed 3D-TSA and 3D-CWT tools, were combined with daily concentrations of PM10-bound , , , , and measured at three rural sampling sites in Spain during the years 2019–2020. Vertically extended Saharan dust intrusions from North Africa were associated with air masses travelling both inside and outside the ML and were related to increases of PM10-bound and at all stations, attributed to the reactions of mineral dust with gaseous precursors of such as SO2. The advection of sea salt particles, marked by high levels of and , was associated with marine air masses from the Mediterranean and Atlantic Ocean, moving mainly within the ML. Enhanced levels of PM10 constituents emitted by anthropogenic sources, such as (traffic and industrial emissions) and (biomass burning), were clearly related to air masses originating from Iberian Peninsula, Central Europe and North African coastline, whilst in most cases the strongest contributions were transferred by air masses moving above the ML. Therefore, the implemented 3D version of TSA and CWT methods, revealed new information regarding the altitudinal characteristics of air masses affecting PM10 levels in Spain.
{"title":"The influence of mixed layer depth along the course of incoming air masses to the transport of PM10 components at three rural sampling sites in Spain","authors":"Konstantinos Dimitriou","doi":"10.1016/j.atmosres.2025.107987","DOIUrl":"10.1016/j.atmosres.2025.107987","url":null,"abstract":"<div><div>The main objective of this research, was to incorporate Mixed Layer Depth (MLD) estimations across backward air mass trajectories to the broadly used Trajectory Sector Analysis (TSA) and Concentration Weighted Trajectory (CWT) methods, in order to attain a three-dimensional (3D) identification of aerosol transport pathways and to reveal the role of the Mixed Layer (ML) on the transferring of particulates. The developed 3D-TSA and 3D-CWT tools, were combined with daily concentrations of PM<sub>10</sub>-bound <span><math><msubsup><mi>SO</mi><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></math></span>, <span><math><msubsup><mi>NO</mi><mn>3</mn><mo>−</mo></msubsup></math></span>, <span><math><msup><mi>Na</mi><mo>+</mo></msup></math></span>, <span><math><msup><mi>Mg</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>, <span><math><msup><mi>Ca</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> and <span><math><msup><mi>K</mi><mo>+</mo></msup></math></span> measured at three rural sampling sites in Spain during the years 2019–2020. Vertically extended Saharan dust intrusions from North Africa were associated with air masses travelling both inside and outside the ML and were related to increases of PM<sub>10</sub>-bound <span><math><msubsup><mi>SO</mi><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></math></span> and <span><math><msup><mi>Ca</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> at all stations, attributed to the reactions of mineral dust with gaseous precursors of <span><math><msubsup><mi>SO</mi><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></math></span> such as SO<sub>2</sub>. The advection of sea salt particles, marked by high levels of <span><math><msup><mi>Na</mi><mo>+</mo></msup></math></span> and <span><math><msup><mi>Mg</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>, was associated with marine air masses from the Mediterranean and Atlantic Ocean, moving mainly within the ML. Enhanced levels of PM<sub>10</sub> constituents emitted by anthropogenic sources, such as <span><math><msubsup><mi>NO</mi><mn>3</mn><mo>−</mo></msubsup></math></span> (traffic and industrial emissions) and <span><math><msup><mi>K</mi><mo>+</mo></msup></math></span> (biomass burning), were clearly related to air masses originating from Iberian Peninsula, Central Europe and North African coastline, whilst in most cases the strongest contributions were transferred by air masses moving above the ML. Therefore, the implemented 3D version of TSA and CWT methods, revealed new information regarding the altitudinal characteristics of air masses affecting PM<sub>10</sub> levels in Spain.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107987"},"PeriodicalIF":4.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428010","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}
Pub Date : 2025-02-14DOI: 10.1016/j.atmosres.2025.107991
Peilan Huang , Qilin Wan , Lifang Li , Sheng Hu
Numerical models frequently cannot accurately predict warm-sector heavy rainfall (WSHR) in South China, which presents a challenge in forecasting severe weather events in the region. Considering the substantial impact of complex orography on the forecasting of WSHR in South China, to improve the accuracy of numerical models in predicting WSHR, this study utilized the non-hydrostatic mesoscale numerical model Weather Research Forecast (WRF) to simulate a WSHR event in the Pearl River Delta from 12:00 UTC on May 9, 2022, to 12:00 UTC on May 11, 2022. The modulation effect of Turbulent Orographic Form Drag (TOFD) on the prediction accuracy of the WSHR was investigated through sensitivity tests. The simulations suggest that TOFD improved the forecasting accuracy for WSHR in South China. TOFD significantly impacted the intensity and location of WSHR in the Pearl River Delta region. After incorporating TOFD, the forecast accuracy of WSHR improved in some regions (such as Guangzhou). Specifically, in the Pearl River Delta region, the TS score for 6-h heavy precipitation (>100 mm) increases by 91.12 %. The precipitation center shifts eastward, and the area affected by WSHR expands. Furthermore, the incorporation of TOFD in the simulations resulted in a delay of the WSHR onset time by 1–2 h and an extension of its duration by 1 h. Both these improvements brought the model results closer to actual observations. Additionally, with the inclusion of TOFD, the weakening of southerly winds has led to enhanced wind field convergence and stronger moisture convergence, resulting in increased moisture. In warm and moist atmospheric environments, there was an extended period of energy accumulation, resulting in a thicker mixed layer, increased negative buoyancy, and intensified upward airflow. As the system continued to move eastward, incorporating TOFD resulted in a further eastward positioning of the WSHR. Additionally, the intensity of the WSHR was stronger and the duration of intense precipitation was longer. The study highlights the critical role of TOFD in the realistic representation of WSHR by numerical models for South China.
{"title":"Numerical simulation and analysis of the modulation effect of sub-grid turbulent orographic form drag on warm-sector heavy rainfall in South China","authors":"Peilan Huang , Qilin Wan , Lifang Li , Sheng Hu","doi":"10.1016/j.atmosres.2025.107991","DOIUrl":"10.1016/j.atmosres.2025.107991","url":null,"abstract":"<div><div>Numerical models frequently cannot accurately predict warm-sector heavy rainfall (WSHR) in South China, which presents a challenge in forecasting severe weather events in the region. Considering the substantial impact of complex orography on the forecasting of WSHR in South China, to improve the accuracy of numerical models in predicting WSHR, this study utilized the non-hydrostatic mesoscale numerical model Weather Research Forecast (WRF) to simulate a WSHR event in the Pearl River Delta from 12:00 UTC on May 9, 2022, to 12:00 UTC on May 11, 2022. The modulation effect of Turbulent Orographic Form Drag (TOFD) on the prediction accuracy of the WSHR was investigated through sensitivity tests. The simulations suggest that TOFD improved the forecasting accuracy for WSHR in South China. TOFD significantly impacted the intensity and location of WSHR in the Pearl River Delta region. After incorporating TOFD, the forecast accuracy of WSHR improved in some regions (such as Guangzhou). Specifically, in the Pearl River Delta region, the TS score for 6-h heavy precipitation (>100 mm) increases by 91.12 %. The precipitation center shifts eastward, and the area affected by WSHR expands. Furthermore, the incorporation of TOFD in the simulations resulted in a delay of the WSHR onset time by 1–2 h and an extension of its duration by 1 h. Both these improvements brought the model results closer to actual observations. Additionally, with the inclusion of TOFD, the weakening of southerly winds has led to enhanced wind field convergence and stronger moisture convergence, resulting in increased moisture. In warm and moist atmospheric environments, there was an extended period of energy accumulation, resulting in a thicker mixed layer, increased negative buoyancy, and intensified upward airflow. As the system continued to move eastward, incorporating TOFD resulted in a further eastward positioning of the WSHR. Additionally, the intensity of the WSHR was stronger and the duration of intense precipitation was longer. The study highlights the critical role of TOFD in the realistic representation of WSHR by numerical models for South China.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"318 ","pages":"Article 107991"},"PeriodicalIF":4.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437604","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}
Pub Date : 2025-02-14DOI: 10.1016/j.atmosres.2025.107990
Ji-Young Han
This study aims to evaluate and improve the performance of the scale-aware cumulus parameterization scheme (CPS) in the Korean Integrated Model (KIM), referred to as KSAS. The performance of the KSAS for simulating precipitation over Korea is first evaluated in comparison with other scale-aware CPSs available in the Weather Research and Forecasting (WRF) model by conducting a series of experiments at multiple horizontal resolutions, including the gray zone. The results show that the KSAS significantly improves precipitation forecast skill compared to its original version. However, its performance is lower than that of the other scale-aware CPSs at 27-km and 9-km spatial resolutions due to the substantial contribution of cumulus parameterization. To address issues in the scale-aware parameterization of KSAS, the method for defining the convective updraft fraction is revised to adopt a more physically based approach. The WRF simulation results demonstrate improved precipitation forecast skill with the revised scale-aware parameterization at the gray-zone resolution, where the contribution of cumulus parameterization is significantly reduced. Further evaluation of the revised scheme in KIM also reveals enhanced medium-range forecast skill for both large-scale fields and precipitation at horizontal resolutions of NE360NP3 (∼12 km) and NE576NP3 (∼8 km). The warm bias in the mid-latitudes of the Northern Hemisphere is alleviated by reduced convective heating. Notably, the revised scheme exhibits a pronounced improvement in the skill for forecasting precipitation over the Korean Peninsula, better capturing the pattern and intensity of the precipitation core for heavy rainfall events, as confirmed by higher skill scores.
{"title":"Impact of different scale-aware cumulus parameterizations on precipitation forecasts over Korea","authors":"Ji-Young Han","doi":"10.1016/j.atmosres.2025.107990","DOIUrl":"10.1016/j.atmosres.2025.107990","url":null,"abstract":"<div><div>This study aims to evaluate and improve the performance of the scale-aware cumulus parameterization scheme (CPS) in the Korean Integrated Model (KIM), referred to as KSAS. The performance of the KSAS for simulating precipitation over Korea is first evaluated in comparison with other scale-aware CPSs available in the Weather Research and Forecasting (WRF) model by conducting a series of experiments at multiple horizontal resolutions, including the gray zone. The results show that the KSAS significantly improves precipitation forecast skill compared to its original version. However, its performance is lower than that of the other scale-aware CPSs at 27-km and 9-km spatial resolutions due to the substantial contribution of cumulus parameterization. To address issues in the scale-aware parameterization of KSAS, the method for defining the convective updraft fraction is revised to adopt a more physically based approach. The WRF simulation results demonstrate improved precipitation forecast skill with the revised scale-aware parameterization at the gray-zone resolution, where the contribution of cumulus parameterization is significantly reduced. Further evaluation of the revised scheme in KIM also reveals enhanced medium-range forecast skill for both large-scale fields and precipitation at horizontal resolutions of NE360NP3 (∼12 km) and NE576NP3 (∼8 km). The warm bias in the mid-latitudes of the Northern Hemisphere is alleviated by reduced convective heating. Notably, the revised scheme exhibits a pronounced improvement in the skill for forecasting precipitation over the Korean Peninsula, better capturing the pattern and intensity of the precipitation core for heavy rainfall events, as confirmed by higher skill scores.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107990"},"PeriodicalIF":4.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428011","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}
Pub Date : 2025-02-13DOI: 10.1016/j.atmosres.2025.107982
Pin Lv , Wangsheng Wang , Ping Yuan , Yingying An , Tingting An , Hong Deng , Lizhen Yuan
The study on transmission characteristics of lightning return-stroke currents along the channel is of great significance for deeply understanding the microphysical mechanisms of lightning discharge processes, improving theoretical models, and optimizing lightning protection systems. Based on the spectra obtained from three lightning processes and the waveforms of ground electric field changes caused by the lightning, the characteristic parameters such as channel temperature, linear charge density, and radius are calculated. Combined with the electrodynamics model of lightning, the propagation process of electromagnetic waves in the lightning channel and the surrounding corona sheath is simulated, and the dispersion curves, as well as the intensity changes of radial and axial electric fields are obtained under two conditions: with and without considering the electrical conductivity in the corona sheath. The impact of the actual electrical conductivity distribution in the corona sheath on the transmission characteristic of electromagnetic waves is analyzed for the first time. On this basis, the transmission law of current along the channel height at different moments for the three return-strokes is simulated. The results show that compared with the case that only the electrical conductivity of the current-carrying core channel is considered, the radial distribution of electrical conductivity in the outer corona sheath will slow down the decay rate of current transmission along the channel. The larger the radius of the high electrical conductivity channel, the smaller the decay rate of the return-stroke current along the channel. In the early stage of the return-stroke, the current intensity decays rapidly along the channel height, decaying in an exponential form. As time goes on, the current decay slows down and gradually transitions to a linear decay or a uniform distribution form. It further confirms that the decay of the return-stroke current along the channel height is mainly manifested in the early stage of the return-stroke. The radius of the current-carrying channel and the distribution of conductivity in the corona sheath are key factors affecting the transmission decay of current along the channel.
{"title":"The influence of corona sheath conductivity distribution on the transmission characteristics of return-stroke currents","authors":"Pin Lv , Wangsheng Wang , Ping Yuan , Yingying An , Tingting An , Hong Deng , Lizhen Yuan","doi":"10.1016/j.atmosres.2025.107982","DOIUrl":"10.1016/j.atmosres.2025.107982","url":null,"abstract":"<div><div>The study on transmission characteristics of lightning return-stroke currents along the channel is of great significance for deeply understanding the microphysical mechanisms of lightning discharge processes, improving theoretical models, and optimizing lightning protection systems. Based on the spectra obtained from three lightning processes and the waveforms of ground electric field changes caused by the lightning, the characteristic parameters such as channel temperature, linear charge density, and radius are calculated. Combined with the electrodynamics model of lightning, the propagation process of electromagnetic waves in the lightning channel and the surrounding corona sheath is simulated, and the dispersion curves, as well as the intensity changes of radial and axial electric fields are obtained under two conditions: with and without considering the electrical conductivity in the corona sheath. The impact of the actual electrical conductivity distribution in the corona sheath on the transmission characteristic of electromagnetic waves is analyzed for the first time. On this basis, the transmission law of current along the channel height at different moments for the three return-strokes is simulated. The results show that compared with the case that only the electrical conductivity of the current-carrying core channel is considered, the radial distribution of electrical conductivity in the outer corona sheath will slow down the decay rate of current transmission along the channel. The larger the radius of the high electrical conductivity channel, the smaller the decay rate of the return-stroke current along the channel. In the early stage of the return-stroke, the current intensity decays rapidly along the channel height, decaying in an exponential form. As time goes on, the current decay slows down and gradually transitions to a linear decay or a uniform distribution form. It further confirms that the decay of the return-stroke current along the channel height is mainly manifested in the early stage of the return-stroke. The radius of the current-carrying channel and the distribution of conductivity in the corona sheath are key factors affecting the transmission decay of current along the channel.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107982"},"PeriodicalIF":4.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428007","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}
Pub Date : 2025-02-12DOI: 10.1016/j.atmosres.2025.107984
Yihong Su , Qiming Cheng , Yang He , Fei Liu , Jun Liu , Jiayue Zhu , Ye Rao , Yunsong Chao , Zhen Liu , Yao Chen
Accurate short-term convective weather prediction is crucial for mitigating the impact of natural disasters. Although radar echo extrapolation is a commonly employed forecasting method, traditional optical flow-based approaches face computational accuracy challenges when dealing with rapidly changing weather systems. Additionally, some deep learning models experience degradation in prediction accuracy due to blurring effects over extended forecast periods. In this study, we proposed Evolution-Unet-ConvNeXt, a novel deep learning model that effectively addresses these limitations by incorporating feature fusion of latent physical information. The experiments conducted on MeteoNet dataset have demonstrated a significant enhancement in prediction accuracy and reduction of blurring effects when dealing with complex convective phenomena using this model. The Evolution module successfully extracted both motion and intensity fields from radar images, while the recently developed Unet-ConvNeXt network enhanced the efficiency of feature extraction and processing workflow. Quantitative evaluations indicated that our model achieved substantial improvements in meteorological metrics, such as Critical Success Index (CSI) and Probability of Detection (POD), as well as in image clarity and spatial structure metrics like Tenengrad (TEN) and Structure Similarity Index Measure (SSIM), compared to existing baseline model architectures. Furthermore, qualitative analysis of specific rainfall events demonstrated that the robust predictive capability of this model for the intricated nonlinear dynamics of intense echo weather systems.
{"title":"An Evolution-Unet-ConvNeXt approach based on feature fusion for enhancing the accuracy of short-term precipitation forecasting","authors":"Yihong Su , Qiming Cheng , Yang He , Fei Liu , Jun Liu , Jiayue Zhu , Ye Rao , Yunsong Chao , Zhen Liu , Yao Chen","doi":"10.1016/j.atmosres.2025.107984","DOIUrl":"10.1016/j.atmosres.2025.107984","url":null,"abstract":"<div><div>Accurate short-term convective weather prediction is crucial for mitigating the impact of natural disasters. Although radar echo extrapolation is a commonly employed forecasting method, traditional optical flow-based approaches face computational accuracy challenges when dealing with rapidly changing weather systems. Additionally, some deep learning models experience degradation in prediction accuracy due to blurring effects over extended forecast periods. In this study, we proposed Evolution-Unet-ConvNeXt, a novel deep learning model that effectively addresses these limitations by incorporating feature fusion of latent physical information. The experiments conducted on MeteoNet dataset have demonstrated a significant enhancement in prediction accuracy and reduction of blurring effects when dealing with complex convective phenomena using this model. The Evolution module successfully extracted both motion and intensity fields from radar images, while the recently developed Unet-ConvNeXt network enhanced the efficiency of feature extraction and processing workflow. Quantitative evaluations indicated that our model achieved substantial improvements in meteorological metrics, such as Critical Success Index (CSI) and Probability of Detection (POD), as well as in image clarity and spatial structure metrics like Tenengrad (TEN) and Structure Similarity Index Measure (SSIM), compared to existing baseline model architectures. Furthermore, qualitative analysis of specific rainfall events demonstrated that the robust predictive capability of this model for the intricated nonlinear dynamics of intense echo weather systems.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107984"},"PeriodicalIF":4.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418584","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}
Pub Date : 2025-02-12DOI: 10.1016/j.atmosres.2025.107980
Zachary Medley, Sandip Pal
An accurate numerical weather prediction (NWP) model for the atmospheric boundary layer (ABL) has remained a demand of society, agriculture, energy sectors, policy makers, and urban planners. Even miniscule inaccuracies in initial and boundary conditions and associated parameterizations can cause errors in NWP forecasts. The combination of factors such as synoptic scale airmass exchange, convergence, lifting, subsidence, convection initiation, and cloud formation cause frontal systems to be particularly complex with respect to ABL kinematics and thermodynamics. Though previous studies provided extensive information on surface fronts, empirical evidence of the horizontal and vertical variability in front-relative daytime ABL thermodynamic features remained underexplored. We investigated the impacts of frontal passages on daytime ABL thermodynamics during summer and winter across three regions of the continental US using in-situ aircraft measurements of state variables. Results revealed that ABL moisture heterogeneity during frontal passages may occur due to terrain heterogeneity, front-induced precipitation and subsequent soil moisture impacts, and synoptic scale mixing near frontal boundaries. The vertical contrasts in moisture between the ABL and overlying free troposphere were larger in the warm sectors than the cold sectors for most cases due to cold air advection and enhanced turbulent mixing near the front. The vertical contrasts in moisture did not yield a clear pattern based on sector, meaning that the vertical moisture structures in our cases depended on the properties of the individual airmasses. Our findings on front-relative ABL thermodynamic features provide unprecedented information which could help improve parameterizations for more accurate NWP for frontal ABL regimes.
{"title":"Exploration of daytime atmospheric boundary layer thermodynamics across fronts over land using in-situ airborne measurements","authors":"Zachary Medley, Sandip Pal","doi":"10.1016/j.atmosres.2025.107980","DOIUrl":"10.1016/j.atmosres.2025.107980","url":null,"abstract":"<div><div>An accurate numerical weather prediction (NWP) model for the atmospheric boundary layer (ABL) has remained a demand of society, agriculture, energy sectors, policy makers, and urban planners. Even miniscule inaccuracies in initial and boundary conditions and associated parameterizations can cause errors in NWP forecasts. The combination of factors such as synoptic scale airmass exchange, convergence, lifting, subsidence, convection initiation, and cloud formation cause frontal systems to be particularly complex with respect to ABL kinematics and thermodynamics. Though previous studies provided extensive information on surface fronts, empirical evidence of the horizontal and vertical variability in front-relative daytime ABL thermodynamic features remained underexplored. We investigated the impacts of frontal passages on daytime ABL thermodynamics during summer and winter across three regions of the continental US using in-situ aircraft measurements of state variables. Results revealed that ABL moisture heterogeneity during frontal passages may occur due to terrain heterogeneity, front-induced precipitation and subsequent soil moisture impacts, and synoptic scale mixing near frontal boundaries. The vertical contrasts in moisture between the ABL and overlying free troposphere were larger in the warm sectors than the cold sectors for most cases due to cold air advection and enhanced turbulent mixing near the front. The vertical contrasts in moisture did not yield a clear pattern based on sector, meaning that the vertical moisture structures in our cases depended on the properties of the individual airmasses. Our findings on front-relative ABL thermodynamic features provide unprecedented information which could help improve parameterizations for more accurate NWP for frontal ABL regimes.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107980"},"PeriodicalIF":4.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436934","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}
Pub Date : 2025-02-11DOI: 10.1016/j.atmosres.2025.107974
Bo Zhang , Guitao Shi , Chuanjin Li , Su Jiang , Yilan Li , Guangmei Wu , Hongmei Ma , Imali Kaushalya Herath , Danhe Wang
Sulfate (SO42−) is an essential constituent of aerosols that play an important role in regulating global climate. Over the past decades, polar sea-ice cover changed significantly, potentially influencing the atmospheric budget of SO42−. However, limited research has been conducted to quantify the effects of sea ice on atmospheric SO42− over different times and regions. Here, we report the SO42−/Na+ mass ratios of aerosols and precipitation samples collected in coastal East Antarctica and the Antarctic Peninsula during 2016–2022. The SO42−/Na+ mass ratios at both sites show similar seasonal trends; aerosols display higher ratios than precipitation in summer, with no significant difference in winter, possibly due to precipitation preferentially removing coarse-mode aerosols. The percentage of air mass travelling time over sea ice (P-Time) is positively correlated with SO42−/Na+ mass ratio (or nss-SO42− concentrations) in summer, suggesting the enhanced atmospheric SO42− production over sea ice due to higher dimethyl sulfide (DMS) emissions and/or enhanced oxidation chemistry of DMS. But this relationship becomes negative during winter, suggesting the predominant influence of sea salt aerosols (SSA) from the sea ice surface on atmospheric SO42− levels. In winter, the SO42−/Na+ mass ratio appears to be relatively invariable when the P-Time exceeds ∼40–60 %, ranging from ∼0.08 to 0.18. The lower limit of the mass ratio, ∼0.08, likely representing the influence of sea ice SSA on the mass ratio. Based on this value, it is estimated that approximately half of the atmospheric SO42− in winter originates from sea ice SSA. These findings highlight the importance of sea ice on aerosol budgets and atmospheric chemistry in polar regions.
{"title":"Influence of sea ice on sulfate aerosol budgets in Antarctic Regions with distinct climate conditions","authors":"Bo Zhang , Guitao Shi , Chuanjin Li , Su Jiang , Yilan Li , Guangmei Wu , Hongmei Ma , Imali Kaushalya Herath , Danhe Wang","doi":"10.1016/j.atmosres.2025.107974","DOIUrl":"10.1016/j.atmosres.2025.107974","url":null,"abstract":"<div><div>Sulfate (SO<sub>4</sub><sup>2−</sup>) is an essential constituent of aerosols that play an important role in regulating global climate. Over the past decades, polar sea-ice cover changed significantly, potentially influencing the atmospheric budget of SO<sub>4</sub><sup>2−</sup>. However, limited research has been conducted to quantify the effects of sea ice on atmospheric SO<sub>4</sub><sup>2−</sup> over different times and regions. Here, we report the SO<sub>4</sub><sup>2−</sup>/Na<sup>+</sup> mass ratios of aerosols and precipitation samples collected in coastal East Antarctica and the Antarctic Peninsula during 2016–2022. The SO<sub>4</sub><sup>2−</sup>/Na<sup>+</sup> mass ratios at both sites show similar seasonal trends; aerosols display higher ratios than precipitation in summer, with no significant difference in winter, possibly due to precipitation preferentially removing coarse-mode aerosols. The percentage of air mass travelling time over sea ice (P-Time) is positively correlated with SO<sub>4</sub><sup>2−</sup>/Na<sup>+</sup> mass ratio (or nss-SO<sub>4</sub><sup>2−</sup> concentrations) in summer, suggesting the enhanced atmospheric SO<sub>4</sub><sup>2−</sup> production over sea ice due to higher dimethyl sulfide (DMS) emissions and/or enhanced oxidation chemistry of DMS. But this relationship becomes negative during winter, suggesting the predominant influence of sea salt aerosols (SSA) from the sea ice surface on atmospheric SO<sub>4</sub><sup>2−</sup> levels. In winter, the SO<sub>4</sub><sup>2−</sup>/Na<sup>+</sup> mass ratio appears to be relatively invariable when the P-Time exceeds ∼40–60 %, ranging from ∼0.08 to 0.18. The lower limit of the mass ratio, ∼0.08, likely representing the influence of sea ice SSA on the mass ratio. Based on this value, it is estimated that approximately half of the atmospheric SO<sub>4</sub><sup>2−</sup> in winter originates from sea ice SSA. These findings highlight the importance of sea ice on aerosol budgets and atmospheric chemistry in polar regions.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107974"},"PeriodicalIF":4.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420055","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}
Pub Date : 2025-02-10DOI: 10.1016/j.atmosres.2025.107979
Xingnuo Ren , Fengwen Wang , Xiaochen Wang , Mulan Chen , Weikai Fang , Xu Deng , Peili Lu , Zhenliang Li , Hai Guo , Neil L. Rose
Volatile organic compounds (VOCs) are key precursors in ozone formation, and their photochemical losses during atmospheric transport critically influence pollution characterization and source apportionment. The Chengdu-Chongqing region experiences heightened ozone pollution during the summer months. In light of this, we conducted an in-depth analysis of the atmospheric concentrations and photochemical losses of 56 VOC species in Rongchang of Chongqing, a representative city within the Chengdu-Chongqing Economic Circle from June to September 2023. We employed a combination of Positive matrix factorization and backward trajectory analysis to comprehensively resolve emission sources. The results indicate that not considering photochemical losses could lead to substantial underestimations in VOC concentrations (TVOC, 20.87 %), ozone formation potential (OFP, 27.40 %) and hydroxyl radical loss (LOH, 56.20 %). Positive matrix factorization (PMF) analysis, based on the initial and observed concentrations, revealed that the motor vehicle emissions are overestimated by 7.95 % if neglecting the photochemical losses. Conversely, the industrial emissions, natural emissions, fossil fuel combustion, and solvent use sources are underestimated by 70.49 %, 44.24 %, 13.02 %, and 25.07 %, respectively. Backward trajectory analysis identified that industrial emissions predominantly originated from southeastern Sichuan and southwestern Chongqing, while solvent use emissions were concentrated in the main urban area of Chongqing. This study quantifies the impact of photochemical reactions on the characterization of atmospheric VOCs and source apportionment in Chongqing. The results provide critical insights to inform more effective control strategies for VOC pollution in the Chengdu-Chongqing metropolitan area.
{"title":"Photochemical loss and source apportionment of atmospheric volatile organic compounds in a typical basin city of the Chengdu-Chongqing Economic Circle","authors":"Xingnuo Ren , Fengwen Wang , Xiaochen Wang , Mulan Chen , Weikai Fang , Xu Deng , Peili Lu , Zhenliang Li , Hai Guo , Neil L. Rose","doi":"10.1016/j.atmosres.2025.107979","DOIUrl":"10.1016/j.atmosres.2025.107979","url":null,"abstract":"<div><div>Volatile organic compounds (VOCs) are key precursors in ozone formation, and their photochemical losses during atmospheric transport critically influence pollution characterization and source apportionment. The Chengdu-Chongqing region experiences heightened ozone pollution during the summer months. In light of this, we conducted an in-depth analysis of the atmospheric concentrations and photochemical losses of 56 VOC species in Rongchang of Chongqing, a representative city within the Chengdu-Chongqing Economic Circle from June to September 2023. We employed a combination of Positive matrix factorization and backward trajectory analysis to comprehensively resolve emission sources. The results indicate that not considering photochemical losses could lead to substantial underestimations in VOC concentrations (TVOC, 20.87 %), ozone formation potential (OFP, 27.40 %) and hydroxyl radical loss (L<sub>OH</sub>, 56.20 %). Positive matrix factorization (PMF) analysis, based on the initial and observed concentrations, revealed that the motor vehicle emissions are overestimated by 7.95 % if neglecting the photochemical losses. Conversely, the industrial emissions, natural emissions, fossil fuel combustion, and solvent use sources are underestimated by 70.49 %, 44.24 %, 13.02 %, and 25.07 %, respectively. Backward trajectory analysis identified that industrial emissions predominantly originated from southeastern Sichuan and southwestern Chongqing, while solvent use emissions were concentrated in the main urban area of Chongqing. This study quantifies the impact of photochemical reactions on the characterization of atmospheric VOCs and source apportionment in Chongqing. The results provide critical insights to inform more effective control strategies for VOC pollution in the Chengdu-Chongqing metropolitan area.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107979"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396191","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}
Accurate knowledge of cloud properties is essential for reducing uncertainties in weather forecasts and improving climate prediction models. This study investigates the characteristics of cloud base height (CBH) using high-resolution ceilometer data collected at Kototabang, West Sumatra, Indonesia (0.202°S, 100.317°E), situated at 864.5 m above sea level. Analyzing data recorded over 18 years (April 2002 – December 2021), we found that clouds in Kototabang are predominantly characterized by low CBH (below 2 km), which accounts for 71.3 % of total cloud occurrences, followed by medium CBH (2–6 km) at 25.4 %. Most clouds in Kototabang consist of single-layer clouds (57.78 %), while two-layer and three-layer clouds are observed at 8.41 % and 0.56 %, respectively. Furthermore, CBH tends to decrease as the number of cloud layers increases, with the distance between cloud layers being relatively small, typically less than 0.5 km. The dominance of low CBH in Kototabang is consistent with the frequent occurrence of intense convective clouds in this region, as reported in previous studies. This pattern is also evident from cloud cover data derived from the fifth-generation ECMWF reanalysis (ERA5), which shows high cloud cover (HCC) during the wet season and low HCC during the dry season. Additionally, the mean CBH of the lowest cloud layer varies with weather conditions, reaching 1.80 km during non-rainy condition and decreasing to 1.3 km during rainfall events. CBH in Kototabang exhibits distinct seasonal and diurnal variations. The monthly cloud occurrence follows a bimodal pattern, closely aligning with the monthly average rainfall recorded by an optical rain gauge, which peaks in November and April. During the wet season (April and November), low-CBH clouds (<2 km) are more dominant, whereas clouds with medium and high CBH (2–6 km) are more frequently observed during the dry season (May–July). The prevalence of low CBH in the wet season indicates the presence of thick convective clouds that develop rapidly, as corroborated by ERA5 cloud cover data. A clear diurnal pattern of CBH is also observed. In the morning (06:00–12:00 LST), when rainfall occurrence is minimal, CBH is generally higher. However, a noticeable decline in CBH is observed after 13:00 LST, coinciding with the increasing dominance of convective clouds over the Sumatran landmass. ERA5 data also support this diurnal variation. The observed CBH variations in Kototabang are a genuine atmospheric phenomenon rather than an artefact of ceilometer measurement limitations. Separating CBH data between rainy and non-rainy periods confirms the persistence of these seasonal and diurnal variations.
{"title":"Behavior of Cloud Base Height over Sumatra Mountains Region from Ceilometer Observations","authors":"Helmi Yusnaini , Marzuki Marzuki , Hiroyuki Hashiguchi , Ravidho Ramadhan , Elfira Saufina","doi":"10.1016/j.atmosres.2025.107978","DOIUrl":"10.1016/j.atmosres.2025.107978","url":null,"abstract":"<div><div>Accurate knowledge of cloud properties is essential for reducing uncertainties in weather forecasts and improving climate prediction models. This study investigates the characteristics of cloud base height (CBH) using high-resolution ceilometer data collected at Kototabang, West Sumatra, Indonesia (0.202°S, 100.317°E), situated at 864.5 m above sea level. Analyzing data recorded over 18 years (April 2002 – December 2021), we found that clouds in Kototabang are predominantly characterized by low CBH (below 2 km), which accounts for 71.3 % of total cloud occurrences, followed by medium CBH (2–6 km) at 25.4 %. Most clouds in Kototabang consist of single-layer clouds (57.78 %), while two-layer and three-layer clouds are observed at 8.41 % and 0.56 %, respectively. Furthermore, CBH tends to decrease as the number of cloud layers increases, with the distance between cloud layers being relatively small, typically less than 0.5 km. The dominance of low CBH in Kototabang is consistent with the frequent occurrence of intense convective clouds in this region, as reported in previous studies. This pattern is also evident from cloud cover data derived from the fifth-generation ECMWF reanalysis (ERA5), which shows high cloud cover (HCC) during the wet season and low HCC during the dry season. Additionally, the mean CBH of the lowest cloud layer varies with weather conditions, reaching 1.80 km during non-rainy condition and decreasing to 1.3 km during rainfall events. CBH in Kototabang exhibits distinct seasonal and diurnal variations. The monthly cloud occurrence follows a bimodal pattern, closely aligning with the monthly average rainfall recorded by an optical rain gauge, which peaks in November and April. During the wet season (April and November), low-CBH clouds (<2 km) are more dominant, whereas clouds with medium and high CBH (2–6 km) are more frequently observed during the dry season (May–July). The prevalence of low CBH in the wet season indicates the presence of thick convective clouds that develop rapidly, as corroborated by ERA5 cloud cover data. A clear diurnal pattern of CBH is also observed. In the morning (06:00–12:00 LST), when rainfall occurrence is minimal, CBH is generally higher. However, a noticeable decline in CBH is observed after 13:00 LST, coinciding with the increasing dominance of convective clouds over the Sumatran landmass. ERA5 data also support this diurnal variation. The observed CBH variations in Kototabang are a genuine atmospheric phenomenon rather than an artefact of ceilometer measurement limitations. Separating CBH data between rainy and non-rainy periods confirms the persistence of these seasonal and diurnal variations.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107978"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402930","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}
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