Pub Date : 2024-11-13DOI: 10.1016/j.atmosres.2024.107776
Enda Zhu , Yaqiang Wang , Yan Zhao , Xing Yuan
Accurate climate prediction is crucial for terrestrial water storage (TWS) decadal prediction, which contributes to the sustainable development of hydrological infrastructure. Although the initial memories from atmosphere, ocean and land surface are important sources of climate predictability, their impacts on the decadal hydrological prediction still remain unknown. Here, climate predictions with different initialization strategies from the sixth Coupled Model Intercomparison Project (CMIP6) are incorporated into the hydrological predictions over global major river basins through the elasticity framework. Integrations of the climate initialization and external forcings can improve the TWS prediction skill (Nash-Sutcliffe efficiency) by 0.14–0.24 over 69 % basins against a reference forecast without any climate prediction information, especially over high-latitudes at long lead time. Specifically, climate initialization results in a higher skill for TWS prediction over 62.5 % of basins, while considering the Atlantic or Pacific sea surface temperature information is benefit to the hydrological prediction over 38 %–90 % of basins at different lead times. Our findings imply that reliable hydrological decadal prediction can be achieved if skillful climate prediction that originates from initial conditions, external forcings and specific climate variability has been utilized appropriately.
{"title":"Improving long-term prediction of terrestrial water storage through integration with CMIP6 decadal prediction","authors":"Enda Zhu , Yaqiang Wang , Yan Zhao , Xing Yuan","doi":"10.1016/j.atmosres.2024.107776","DOIUrl":"10.1016/j.atmosres.2024.107776","url":null,"abstract":"<div><div>Accurate climate prediction is crucial for terrestrial water storage (TWS) decadal prediction, which contributes to the sustainable development of hydrological infrastructure. Although the initial memories from atmosphere, ocean and land surface are important sources of climate predictability, their impacts on the decadal hydrological prediction still remain unknown. Here, climate predictions with different initialization strategies from the sixth Coupled Model Intercomparison Project (CMIP6) are incorporated into the hydrological predictions over global major river basins through the elasticity framework. Integrations of the climate initialization and external forcings can improve the TWS prediction skill (Nash-Sutcliffe efficiency) by 0.14–0.24 over 69 % basins against a reference forecast without any climate prediction information, especially over high-latitudes at long lead time. Specifically, climate initialization results in a higher skill for TWS prediction over 62.5 % of basins, while considering the Atlantic or Pacific sea surface temperature information is benefit to the hydrological prediction over 38 %–90 % of basins at different lead times. Our findings imply that reliable hydrological decadal prediction can be achieved if skillful climate prediction that originates from initial conditions, external forcings and specific climate variability has been utilized appropriately.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107776"},"PeriodicalIF":4.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663435","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 : 2024-11-09DOI: 10.1016/j.atmosres.2024.107778
Jie Jiang , Shengping He , Ke Fan
It has been a challenge to identify the impact of Arctic sea-ice loss on the intensity and position of the winter North Atlantic jet stream (NAJS) and the related mechanisms due to the uncertain effects of atmospheric internal variability. This study investigates the response of the winter NAJS to Arctic sea-ice loss and roughly estimates the contribution of internal variability in Arctic sea ice (ArcSIC) after the pre-industrial period, based on reanalysis dataset (referred to as observation here), the Coupled Model Inter-comparison Project phase 6 (CMIP6) and the Polar Amplification Model Inter-comparison Project (PAMIP). The results indicate that the majority of PAMIP models display robust but weak equatorward shift of the NAJS response to Arctic sea-ice loss, as well as robust NAJS-related circulation anomalies. Further analysis shows that the ability of models to reproduce observed NAJS response is primarily associated with tropospheric baroclinic wave activity and the troposphere–stratosphere coupling. Based on 20th-Century reanalysis data and CMIP6 historical simulations, we further estimate the relative contributions of external forcing and internal variability (including reduced ArcSIC) to NAJS latitude and speed variability. Compared to the pre-industrial period, the recent winter NAJS at 850 hPa has accelerated and shifted poleward. By calculating the ratio of the difference in NAJS speed (latitude) between the present-day and pre-industrial in CMIP6 multi-model ensemble mean to the difference in observation, this study approximately estimates that the external forcing contributes about 40 % of NAJS acceleration with minimal influence on its shift. The remaining acceleration and poleward shift are mainly attributed to internal variability. The difference between the present-day and pre-industrial PAMIP ensemble mean is considered as the “pure” forcing of Arctic sea-ice loss. Most models indicate that reduced ArcSIC tends to slow down the acceleration and poleward shift of winter NAJS, but show quantitively a wide range of uncertainty.
{"title":"Recent impact of reduced arctic sea-ice on the winter North Atlantic jet stream and its quantitative contributions compared to pre-industrial level","authors":"Jie Jiang , Shengping He , Ke Fan","doi":"10.1016/j.atmosres.2024.107778","DOIUrl":"10.1016/j.atmosres.2024.107778","url":null,"abstract":"<div><div>It has been a challenge to identify the impact of Arctic sea-ice loss on the intensity and position of the winter North Atlantic jet stream (NAJS) and the related mechanisms due to the uncertain effects of atmospheric internal variability. This study investigates the response of the winter NAJS to Arctic sea-ice loss and roughly estimates the contribution of internal variability in Arctic sea ice (ArcSIC) after the pre-industrial period, based on reanalysis dataset (referred to as observation here), the Coupled Model Inter-comparison Project phase 6 (CMIP6) and the Polar Amplification Model Inter-comparison Project (PAMIP). The results indicate that the majority of PAMIP models display robust but weak equatorward shift of the NAJS response to Arctic sea-ice loss, as well as robust NAJS-related circulation anomalies. Further analysis shows that the ability of models to reproduce observed NAJS response is primarily associated with tropospheric baroclinic wave activity and the troposphere–stratosphere coupling. Based on 20th-Century reanalysis data and CMIP6 historical simulations, we further estimate the relative contributions of external forcing and internal variability (including reduced ArcSIC) to NAJS latitude and speed variability. Compared to the pre-industrial period, the recent winter NAJS at 850 hPa has accelerated and shifted poleward. By calculating the ratio of the difference in NAJS speed (latitude) between the present-day and pre-industrial in CMIP6 multi-model ensemble mean to the difference in observation, this study approximately estimates that the external forcing contributes about 40 % of NAJS acceleration with minimal influence on its shift. The remaining acceleration and poleward shift are mainly attributed to internal variability. The difference between the present-day and pre-industrial PAMIP ensemble mean is considered as the “pure” forcing of Arctic sea-ice loss. Most models indicate that reduced ArcSIC tends to slow down the acceleration and poleward shift of winter NAJS, but show quantitively a wide range of uncertainty.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107778"},"PeriodicalIF":4.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663436","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 : 2024-11-09DOI: 10.1016/j.atmosres.2024.107777
Ajay Bankar , V. Rakesh , Smrati Purwar
This study explores the impact of assimilating diverse observational data on forecasting extreme rainfall events (EREs) using a three dimensional variational (3D-Var) assimilation approach. It focuses on 38 EREs across three meteorological divisions in Karnataka, India, using a high-resolution (03-km) Weather Research and Forecasting (WRF) model with three nested domains. Five distinct experiments were conducted, including a Control experiment without assimilation, and subsequent experiments integrating observations from various sources like atmospheric profiles from Atmospheric InfraRed Sounder (AIRS) and Moderate resolution Imaging Spectroradiometer (MODIS) satellites and radiosondes, ocean surface wind observations from Advanced Scatterometer (ASCAT), Special Sensor Microwave Imager (SSMI), and WindSAT satellites and buoys, ground observations from Karnataka State Natural Disaster Monitoring Centre (KSNDMC), as well as a combined assimilation experiment with all available observations. The accuracy of rainfall forecasts is evaluated by comparing model outputs with high-resolution telemetric rain-gauge (TRG; 6480 stations) data and other meteorological parameters against telemetric weather station (TWS; 860 stations) data from KSNDMC. Assimilation experiments show positive improvements over control experiment in predicting rainfall. Results consistently indicate underprediction of rainfall in the intricate topographical region of the Western Ghats (WG) across all experiments, contrasting with overprediction along the coastal areas of Karnataka. The experiment involving Ocean Winds showcased a substantial 40 % reduction in rainfall overprediction (above 2 mm threshold). Both Ocean Winds and Station Data assimilation notably enhanced rainfall prediction accuracy over most of the regions in Karnataka, with Ocean Winds exhibiting the highest improvement (53 %), closely followed by Station Data (50 %). Importantly, assimilating Ocean Winds and Station Data aided in reducing overprediction, while assimilating Satellite Profiles reduced underprediction in the interior part of Karnataka but increased overprediction over the coastal region compared to the control experiment. Frequency of occurrence of rainfall is considerably enhanced along the coastline in all 3D-Var experiments. Bias score indicates maximum improvement in assimilation using Ocean Winds and Station Data. Simulation of basic meteorological parameters also improved with assimilation particularly during the day hours. The results underscore the crucial role of assimilation of satellite and in-situ observations in improving forecast accuracy of EREs during the monsoon season.
{"title":"Relative Impact of Assimilation of Multi-Source Observations using 3D-Var on Simulation of Extreme Rainfall Events over Karnataka, India","authors":"Ajay Bankar , V. Rakesh , Smrati Purwar","doi":"10.1016/j.atmosres.2024.107777","DOIUrl":"10.1016/j.atmosres.2024.107777","url":null,"abstract":"<div><div>This study explores the impact of assimilating diverse observational data on forecasting extreme rainfall events (EREs) using a three dimensional variational (3D-Var) assimilation approach. It focuses on 38 EREs across three meteorological divisions in Karnataka, India, using a high-resolution (03-km) Weather Research and Forecasting (WRF) model with three nested domains. Five distinct experiments were conducted, including a Control experiment without assimilation, and subsequent experiments integrating observations from various sources like atmospheric profiles from Atmospheric InfraRed Sounder (AIRS) and Moderate resolution Imaging Spectroradiometer (MODIS) satellites and radiosondes, ocean surface wind observations from Advanced Scatterometer (ASCAT), Special Sensor Microwave Imager (SSMI), and WindSAT satellites and buoys, ground observations from Karnataka State Natural Disaster Monitoring Centre (KSNDMC), as well as a combined assimilation experiment with all available observations. The accuracy of rainfall forecasts is evaluated by comparing model outputs with high-resolution telemetric rain-gauge (TRG; 6480 stations) data and other meteorological parameters against telemetric weather station (TWS; 860 stations) data from KSNDMC. Assimilation experiments show positive improvements over control experiment in predicting rainfall. Results consistently indicate underprediction of rainfall in the intricate topographical region of the Western Ghats (WG) across all experiments, contrasting with overprediction along the coastal areas of Karnataka. The experiment involving Ocean Winds showcased a substantial 40 % reduction in rainfall overprediction (above 2 mm threshold). Both Ocean Winds and Station Data assimilation notably enhanced rainfall prediction accuracy over most of the regions in Karnataka, with Ocean Winds exhibiting the highest improvement (53 %), closely followed by Station Data (50 %). Importantly, assimilating Ocean Winds and Station Data aided in reducing overprediction, while assimilating Satellite Profiles reduced underprediction in the interior part of Karnataka but increased overprediction over the coastal region compared to the control experiment. Frequency of occurrence of rainfall is considerably enhanced along the coastline in all 3D-Var experiments. Bias score indicates maximum improvement in assimilation using Ocean Winds and Station Data. Simulation of basic meteorological parameters also improved with assimilation particularly during the day hours. The results underscore the crucial role of assimilation of satellite and in-situ observations in improving forecast accuracy of EREs during the monsoon season.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107777"},"PeriodicalIF":4.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637407","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 : 2024-11-08DOI: 10.1016/j.atmosres.2024.107774
Pierre Grzegorczyk , Wolfram Wobrock , Antoine Canzi , Laurence Niquet , Frédéric Tridon , Céline Planche
Secondary ice production (SIP) is a crucial phenomenon for explaining the formation of ice crystal clouds, especially when addressing the discrepancies between observed ice crystal number concentrations and ice nucleating particles (INPs). In this study, we investigate parameterizations of three SIP processes (Hallett-Mossop, fragmentation of freezing drops, and fragmentation due to ice–ice collision) by simulating a deep convective cloud observed during the HAIC/HIWC campaign with the 3D bin microphysics scheme DESCAM (DEtailed SCAvening and Microphysics model). The simulated mean cloud properties, including particle size distributions and ice crystal number concentration are compared with in situ probe observations obtained during the campaign. Simulation excluding SIP shows a large underestimation of small ice crystals ( 1 mm diameter) for temperatures warmer than . In our results, incorporating Hallett-Mossop and fragmentation due to ice–ice collision processes leads to ice crystal number concentrations close to observed values, thereby reducing discrepancies by two orders of magnitude. Our simulations also indicates that fragmentation of freezing drops affect minimally the properties of the cloud at its mature stage. Furthermore, we investigate the impact of fragments sizes resulting from SIP processes and show that the size of fragments generated from fragmentation due to ice–ice collision significantly influences the shape of ice particle size distribution. Employing various parameterizations of the ice crystal sticking efficiency reveals a notable impact on cloud properties. This study shows that SIP mechanisms are important and have to be considered for cold and mixed-phase clouds. However their parameterization lack reliability, highlighting the need for better quantifying these mechanisms. The companion paper, investigates the effects of SIP processes on the formation and the evolution of the deep convective system.
{"title":"Investigating secondary ice production in a deep convective cloud with a 3D bin microphysics model: Part I - Sensitivity study of microphysical processes representations","authors":"Pierre Grzegorczyk , Wolfram Wobrock , Antoine Canzi , Laurence Niquet , Frédéric Tridon , Céline Planche","doi":"10.1016/j.atmosres.2024.107774","DOIUrl":"10.1016/j.atmosres.2024.107774","url":null,"abstract":"<div><div>Secondary ice production (SIP) is a crucial phenomenon for explaining the formation of ice crystal clouds, especially when addressing the discrepancies between observed ice crystal number concentrations and ice nucleating particles (INPs). In this study, we investigate parameterizations of three SIP processes (Hallett-Mossop, fragmentation of freezing drops, and fragmentation due to ice–ice collision) by simulating a deep convective cloud observed during the HAIC/HIWC campaign with the 3D bin microphysics scheme DESCAM (DEtailed SCAvening and Microphysics model). The simulated mean cloud properties, including particle size distributions and ice crystal number concentration are compared with in situ probe observations obtained during the campaign. Simulation excluding SIP shows a large underestimation of small ice crystals (<span><math><mo><</mo></math></span> 1 mm diameter) for temperatures warmer than <span><math><mo>‐</mo><msup><mn>30</mn><mo>∘</mo></msup><mi>C</mi></math></span>. In our results, incorporating Hallett-Mossop and fragmentation due to ice–ice collision processes leads to ice crystal number concentrations close to observed values, thereby reducing discrepancies by two orders of magnitude. Our simulations also indicates that fragmentation of freezing drops affect minimally the properties of the cloud at its mature stage. Furthermore, we investigate the impact of fragments sizes resulting from SIP processes and show that the size of fragments generated from fragmentation due to ice–ice collision significantly influences the shape of ice particle size distribution. Employing various parameterizations of the ice crystal sticking efficiency reveals a notable impact on cloud properties. This study shows that SIP mechanisms are important and have to be considered for cold and mixed-phase clouds. However their parameterization lack reliability, highlighting the need for better quantifying these mechanisms. The companion paper, investigates the effects of SIP processes on the formation and the evolution of the deep convective system.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107774"},"PeriodicalIF":4.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637410","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 : 2024-11-07DOI: 10.1016/j.atmosres.2024.107752
Qilei Huang, Ning Shi, Botao Zhou
This study employs the ERA5 and JRA-55 monthly reanalysis datasets to examine the monthly impact of the Scandinavian (SCA) teleconnection pattern on the surface air temperature (SAT) over Asia in boreal winters from 1958 to 2021. We demonstrate that the monthly impacts of the SCA vary by month and region. Notably, the accumulated SAT anomalies over the region to the north of Tibetan Plateau (NP) due to the SCA tend to propagate southward to the eastern China (EC) during late winter, which is associated with the gradually intensifying westward gradient of the air temperature over the EC. Furthermore, both the November and January SCA patterns can significantly cause one-month-lagged SAT anomalies over the NP, albeit through different mechanisms. For the November SCA pattern, it induces significant snowfall anomalies over the NP and the associated snow cover anomalies can persist until December, facilitating the formation of local significant SAT anomalies via anomalous sensible heat flux. In contrast, from January to February, the background states for the air temperature in the lower troposphere and absolute vorticity in the upper troposphere change in such a way that creates a more favorable condition for the vertical coupling between the upper and lower circulation anomalies associated with the SCA pattern. Consequently, the SCA pattern tends to persist from January to February, leading to significant SAT anomalies over both the NP and EC in February.
{"title":"Monthly impact of the Scandinavian pattern on winter surface air temperature over Asia","authors":"Qilei Huang, Ning Shi, Botao Zhou","doi":"10.1016/j.atmosres.2024.107752","DOIUrl":"10.1016/j.atmosres.2024.107752","url":null,"abstract":"<div><div>This study employs the ERA5 and JRA-55 monthly reanalysis datasets to examine the monthly impact of the Scandinavian (SCA) teleconnection pattern on the surface air temperature (SAT) over Asia in boreal winters from 1958 to 2021. We demonstrate that the monthly impacts of the SCA vary by month and region. Notably, the accumulated SAT anomalies over the region to the north of Tibetan Plateau (NP) due to the SCA tend to propagate southward to the eastern China (EC) during late winter, which is associated with the gradually intensifying westward gradient of the air temperature over the EC. Furthermore, both the November and January SCA patterns can significantly cause one-month-lagged SAT anomalies over the NP, albeit through different mechanisms. For the November SCA pattern, it induces significant snowfall anomalies over the NP and the associated snow cover anomalies can persist until December, facilitating the formation of local significant SAT anomalies via anomalous sensible heat flux. In contrast, from January to February, the background states for the air temperature in the lower troposphere and absolute vorticity in the upper troposphere change in such a way that creates a more favorable condition for the vertical coupling between the upper and lower circulation anomalies associated with the SCA pattern. Consequently, the SCA pattern tends to persist from January to February, leading to significant SAT anomalies over both the NP and EC in February.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"312 ","pages":"Article 107752"},"PeriodicalIF":4.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637447","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 : 2024-11-06DOI: 10.1016/j.atmosres.2024.107757
Roy Yaniv , Yoav Yair , Assaf Hochman
Characterizing the interaction between meteorological variables such as humidity, wind speed, cloud cover, and precipitation with the atmospheric electric field is vital for improving the nowcast of extreme weather events such as heavy precipitation. With this aim, we provide minute-scale electric field observations in southern Israel. These were taken during low-pressure weather systems in winter, often termed ‘Cyprus Lows.’ We focus only on precipitating (‘wet’) events, where rain was measured at the surface during and after the cold front's passage. The mean |PG| values for ‘wet’ Cyprus Lows are higher (Hundreds to thousands V m−1) compared with the mean fair-weather values (∼100–200 V m−1, and exhibit a sharp and rapid increase of the |PG| of up to tens of V m−1 min−1 during the arrival of the cold front and hundreds of V m−1 min−1 during precipitation. Then, we analyzed selected case studies in detail. The response of the |PG| to thunderstorm clouds, i.e., Cumulonimbus, is an increase to values of thousands of V m−1. The temporal evolution of the |PG| allowed us to identify the type of cloud and its life cycle stage. We suggest that using state-of-the-art 1 Hz measurements of the |PG| and deducing cloud patterns at strategic locations, such as in arid regions like southern Israel, may improve the nowcasting capabilities of localized heavy precipitation events.
描述湿度、风速、云层和降水等气象变量与大气电场之间的相互作用对于改善强降水等极端天气事件的预报至关重要。为此，我们提供了以色列南部的分钟级电场观测数据。这些观测数据是在冬季低压天气系统期间拍摄的，通常被称为 "塞浦路斯低气压"。我们只关注降水（"湿"）事件，即在冷锋通过期间和之后在地表测得的降雨量。与晴天的平均值（100-200 V m-1）相比，"湿 "塞浦路斯低气压的平均|PG|值更高（数百至数千 V m-1），而且在冷锋到来时，|PG|值急剧快速上升，最高可达数十 V m-1 min-1，而在降水过程中则高达数百 V m-1 min-1。然后，我们详细分析了部分案例研究。雷暴云（即积雨云）的|PG|响应值增加到数千 V m-1。通过|PG|的时间演变，我们可以确定云的类型及其生命周期阶段。我们建议，使用最先进的 1 Hz |PG|测量方法并推断战略地点（如以色列南部干旱地区）的云模式，可提高局地强降水事件的预报能力。
{"title":"Understanding heavy precipitation events in southern Israel through atmospheric electric field observations","authors":"Roy Yaniv , Yoav Yair , Assaf Hochman","doi":"10.1016/j.atmosres.2024.107757","DOIUrl":"10.1016/j.atmosres.2024.107757","url":null,"abstract":"<div><div>Characterizing the interaction between meteorological variables such as humidity, wind speed, cloud cover, and precipitation with the atmospheric electric field is vital for improving the nowcast of extreme weather events such as heavy precipitation. With this aim, we provide minute-scale electric field observations in southern Israel. These were taken during low-pressure weather systems in winter, often termed ‘Cyprus Lows.’ We focus only on precipitating (‘wet’) events, where rain was measured at the surface during and after the cold front's passage. The mean |PG| values for ‘wet’ Cyprus Lows are higher (Hundreds to thousands V m<sup>−1</sup>) compared with the mean fair-weather values (∼100–200 V m<sup>−1</sup>, and exhibit a sharp and rapid increase of the |PG| of up to tens of V m<sup>−1</sup> min<sup>−1</sup> during the arrival of the cold front and hundreds of V m<sup>−1</sup> min<sup>−1</sup> during precipitation. Then, we analyzed selected case studies in detail. The response of the |PG| to thunderstorm clouds, i.e., Cumulonimbus, is an increase to values of thousands of V m<sup>−1</sup>. The temporal evolution of the |PG| allowed us to identify the type of cloud and its life cycle stage. We suggest that using state-of-the-art 1 Hz measurements of the |PG| and deducing cloud patterns at strategic locations, such as in arid regions like southern Israel, may improve the nowcasting capabilities of localized heavy precipitation events.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107757"},"PeriodicalIF":4.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637408","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}
Vertical distributions of chemical components of particulate matter (PM) are essential for better understanding the climate, environmental and health effects. The steep slope from western SiChuan Basin (SCB) to eastern Tibetan Plateau (TP) provides a good platform for obtaining the gradient variations of PM chemical components. Daytime and nighttime PM1 (particulate matter smaller than 1 μm) samples were collected with the medium-volume sampler at six sites with elevation ranging from 500 m to 3500 m (Chengdu, Sanbacun, Wenchuan, Lixian, Maerkang and Hongyuan). The secondary inorganic ions and carbonaceous aerosols were the largest contributor to PM1 concentrations. The chemical components from the anthropogenic sources existed strong stratification with high concentrations inside the basin, while primary natural ions showed little discrepancy among the sites. The concentrations of primary inorganic ions from anthropogenic sources were much higher at nighttime than daytime, which was contrary to the diurnal cycle of secondary inorganic ions. Spatial heterogeneity of PM chemical components was large between basin and plateau sites, especially for NO3− and NH4+, large depending on season and daylight. The excess NH4+ concentrations existed in spring, summer and fall, while SO42− and NO3− cannot be completely neutralized by NH4+ in winter. The proportion of secondary formation in all sources significantly increased from about 10 % to 30 %–40 % with the increased elevation, while the contribution of motor vehicles declined from western SCB to eastern TP. This study will fill the scarce observations of PM chemical components at the sloped terrain and deepen the understanding of formation mechanism of heavy pollution inside the basin.
{"title":"Gradient variations of formation mechanisms and sources of PM1 at the steep slope from western SiChuan Basin to eastern Tibetan Plateau","authors":"Daiying Yin , Suping Zhao , Ye Yu , Shaofeng Qi , Xiaoling Zhang","doi":"10.1016/j.atmosres.2024.107755","DOIUrl":"10.1016/j.atmosres.2024.107755","url":null,"abstract":"<div><div>Vertical distributions of chemical components of particulate matter (PM) are essential for better understanding the climate, environmental and health effects. The steep slope from western SiChuan Basin (SCB) to eastern Tibetan Plateau (TP) provides a good platform for obtaining the gradient variations of PM chemical components. Daytime and nighttime PM<sub>1</sub> (particulate matter smaller than 1 μm) samples were collected with the medium-volume sampler at six sites with elevation ranging from 500 m to 3500 m (Chengdu, Sanbacun, Wenchuan, Lixian, Maerkang and Hongyuan). The secondary inorganic ions and carbonaceous aerosols were the largest contributor to PM<sub>1</sub> concentrations. The chemical components from the anthropogenic sources existed strong stratification with high concentrations inside the basin, while primary natural ions showed little discrepancy among the sites. The concentrations of primary inorganic ions from anthropogenic sources were much higher at nighttime than daytime, which was contrary to the diurnal cycle of secondary inorganic ions. Spatial heterogeneity of PM chemical components was large between basin and plateau sites, especially for NO<sub>3</sub><sup>−</sup> and NH<sub>4</sub><sup>+</sup>, large depending on season and daylight. The excess NH<sub>4</sub><sup>+</sup> concentrations existed in spring, summer and fall, while SO<sub>4</sub><sup>2−</sup> and NO<sub>3</sub><sup>−</sup> cannot be completely neutralized by NH<sub>4</sub><sup>+</sup> in winter. The proportion of secondary formation in all sources significantly increased from about 10 % to 30 %–40 % with the increased elevation, while the contribution of motor vehicles declined from western SCB to eastern TP. This study will fill the scarce observations of PM chemical components at the sloped terrain and deepen the understanding of formation mechanism of heavy pollution inside the basin.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"312 ","pages":"Article 107755"},"PeriodicalIF":4.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637409","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 : 2024-11-05DOI: 10.1016/j.atmosres.2024.107770
Jiaqi Shi , Yao Yao , Ruiwei Guo , Binhe Luo , Linhao Zhong
The frequency and duration of heatwaves are rapidly increasing worldwide under the background of global warming. This trend is also observed in the mid–lower reaches of the Yangtze River valley (MLYRV), raising great public concern due to its significant impacts. This study identifies a wave train involving the positive phase of the North Atlantic Oscillation (NAO), the Ural blocking (UB), and an anticyclone over the MLYRV, which is closely linked to MLYRV heatwaves during 1970–2023. Our findings indicate that the development of the anticyclone over the MLYRV is associated with the energy dispersion of the UB under the regulation of the North Atlantic jet (NAJ). Further analyses reveal that the correlation of heatwave frequency with the NAO index and UB days is significantly stronger during 2001–2023 (P2) compared to 1970–2000 (P1). This strengthening may be attributable to the northeastward extension of the NAJ to northern Eurasia during P2, modulated by the positive phase of the Atlantic Multidecadal Oscillation (AMO). Such strong zonal winds over high latitudes of Eurasia are expected to favor low-latitude UB, and its robust downstream energy dispersion enhances the development of heatwaves during P2. In contrast, the weaker zonal winds over high latitudes of Eurasia during P1 favor high-latitude UB under the regulation of the negative phase of the AMO, and the correlation between the UB and heatwaves is less significant due to weak energy dispersion from the high-latitude UB to the MLYRV. Consequently, the UB acts as a crucial bridge within this wave train, facilitating the energy transfer necessary for heatwave formation.
{"title":"The intensifying relationship between heatwaves in the mid–lower reaches of the Yangtze River valley and the upstream atmospheric wave train after the 2000s","authors":"Jiaqi Shi , Yao Yao , Ruiwei Guo , Binhe Luo , Linhao Zhong","doi":"10.1016/j.atmosres.2024.107770","DOIUrl":"10.1016/j.atmosres.2024.107770","url":null,"abstract":"<div><div>The frequency and duration of heatwaves are rapidly increasing worldwide under the background of global warming. This trend is also observed in the mid–lower reaches of the Yangtze River valley (MLYRV), raising great public concern due to its significant impacts. This study identifies a wave train involving the positive phase of the North Atlantic Oscillation (NAO), the Ural blocking (UB), and an anticyclone over the MLYRV, which is closely linked to MLYRV heatwaves during 1970–2023. Our findings indicate that the development of the anticyclone over the MLYRV is associated with the energy dispersion of the UB under the regulation of the North Atlantic jet (NAJ). Further analyses reveal that the correlation of heatwave frequency with the NAO index and UB days is significantly stronger during 2001–2023 (P2) compared to 1970–2000 (P1). This strengthening may be attributable to the northeastward extension of the NAJ to northern Eurasia during P2, modulated by the positive phase of the Atlantic Multidecadal Oscillation (AMO). Such strong zonal winds over high latitudes of Eurasia are expected to favor low-latitude UB, and its robust downstream energy dispersion enhances the development of heatwaves during P2. In contrast, the weaker zonal winds over high latitudes of Eurasia during P1 favor high-latitude UB under the regulation of the negative phase of the AMO, and the correlation between the UB and heatwaves is less significant due to weak energy dispersion from the high-latitude UB to the MLYRV. Consequently, the UB acts as a crucial bridge within this wave train, facilitating the energy transfer necessary for heatwave formation.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107770"},"PeriodicalIF":4.5,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637417","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}
In light of increasing climate hazards globally that pose risk to public health, the compounded effects of two major hazards, heatwaves and air pollution, have become a focal point for environmental and health research. This study explores the intricate relationship between extreme temperature events in North China (NC) and South China (SC) – two prominent areas of aerosol exposure in East Asia – and the associated changes in aerosol optical depth (AOD) across the region. The heatwave events and regional AOD distribution revealed distinct patterns in their respective regions from June to September. Both NC and SC showed reduced AOD during heatwave events, while downstream regions experienced increased AOD levels. From the perspective of heatwaves in NC and SC, we present a more holistic picture of how large-scale modulators contribute to inducing air pollution hazards across East Asia. The analysis revealed a link between blocking high-pressure system and heatwave occurrences in NC, while a dominant Rossby wave train, influenced by the South China Sea, was identified as a major modulator in SC. Additionally, other large-scale circulatory systems, such as the Western Pacific Subtropical High, the East Asian jet stream, and the South Asian High, also play crucial roles in shaping these events. This suggests the potential for predicting downstream AOD events. The study underscores the importance of understanding the interconnectedness of meteorological and air quality phenomena to mitigate the adverse environmental impacts in East Asia.
{"title":"Compound spatial extremes of heatwaves and downstream air pollution events in East Asia","authors":"Wan-Ling Tseng , Yi-Chun Chen , Yi-Chi Wang , Hung-Ying Tseng , Huang-Hsiung Hsu","doi":"10.1016/j.atmosres.2024.107772","DOIUrl":"10.1016/j.atmosres.2024.107772","url":null,"abstract":"<div><div>In light of increasing climate hazards globally that pose risk to public health, the compounded effects of two major hazards, heatwaves and air pollution, have become a focal point for environmental and health research. This study explores the intricate relationship between extreme temperature events in North China (NC) and South China (SC) – two prominent areas of aerosol exposure in East Asia – and the associated changes in aerosol optical depth (AOD) across the region. The heatwave events and regional AOD distribution revealed distinct patterns in their respective regions from June to September. Both NC and SC showed reduced AOD during heatwave events, while downstream regions experienced increased AOD levels. From the perspective of heatwaves in NC and SC, we present a more holistic picture of how large-scale modulators contribute to inducing air pollution hazards across East Asia. The analysis revealed a link between blocking high-pressure system and heatwave occurrences in NC, while a dominant Rossby wave train, influenced by the South China Sea, was identified as a major modulator in SC. Additionally, other large-scale circulatory systems, such as the Western Pacific Subtropical High, the East Asian jet stream, and the South Asian High, also play crucial roles in shaping these events. This suggests the potential for predicting downstream AOD events. The study underscores the importance of understanding the interconnectedness of meteorological and air quality phenomena to mitigate the adverse environmental impacts in East Asia.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"312 ","pages":"Article 107772"},"PeriodicalIF":4.5,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637420","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 : 2024-11-05DOI: 10.1016/j.atmosres.2024.107756
Gengjiao Ye , Hui Yu , Xiangyu Ao , Xu Zhang
The urban effects on the planetary boundary layer (PBL) wind structures of landfalling tropical cyclones (TCs) have rarely been explored. In this study, numerical simulations for Typhoon Lekima (2019), with and without multilayer building effect parameterization (BEP) and urban land cover, were executed to investigate the urban effects on TC PBL wind structures. Validations against observations demonstrate that the simulation incorporating BEP and urban surface replicates the track, intensity and 10-m wind field of Lekima better. Based on the comparison between the simulations with and without urban land cover, urban effects were analyzed, and the possible mechanisms were examined from the perspective of turbulent transport. Results show that urban surfaces have a deceleration effect on TC wind fields overall. This deceleration effect is most pronounced near the surface and decreases with height under 1 km above ground level. Urban surfaces reduce tangential winds and radial inflow in the near-surface layer, leading to a slight decrease in TC intensity. This is primarily attributed to the enhanced downward transfer of tangential momentum and upward transfer of radial momentum within the PBL, which results in larger magnitudes of negative tangential wind tendencies and positive radial wind tendencies induced by the divergence of subgrid-scale (SGS) momentum fluxes. Additionally, stronger tangential winds and radial outflow above the elevated PBL height correspond well to the increased tangential and radial wind tendencies in nearby areas. The analysis illustrates that turbulent transport provides insights into how urban surfaces affect the PBL wind structures of TCs.
{"title":"The urban effects on the planetary boundary layer wind structures of Typhoon Lekima (2019)","authors":"Gengjiao Ye , Hui Yu , Xiangyu Ao , Xu Zhang","doi":"10.1016/j.atmosres.2024.107756","DOIUrl":"10.1016/j.atmosres.2024.107756","url":null,"abstract":"<div><div>The urban effects on the planetary boundary layer (PBL) wind structures of landfalling tropical cyclones (TCs) have rarely been explored. In this study, numerical simulations for Typhoon Lekima (2019), with and without multilayer building effect parameterization (BEP) and urban land cover, were executed to investigate the urban effects on TC PBL wind structures. Validations against observations demonstrate that the simulation incorporating BEP and urban surface replicates the track, intensity and 10-m wind field of Lekima better. Based on the comparison between the simulations with and without urban land cover, urban effects were analyzed, and the possible mechanisms were examined from the perspective of turbulent transport. Results show that urban surfaces have a deceleration effect on TC wind fields overall. This deceleration effect is most pronounced near the surface and decreases with height under 1 km above ground level. Urban surfaces reduce tangential winds and radial inflow in the near-surface layer, leading to a slight decrease in TC intensity. This is primarily attributed to the enhanced downward transfer of tangential momentum and upward transfer of radial momentum within the PBL, which results in larger magnitudes of negative tangential wind tendencies and positive radial wind tendencies induced by the divergence of subgrid-scale (SGS) momentum fluxes. Additionally, stronger tangential winds and radial outflow above the elevated PBL height correspond well to the increased tangential and radial wind tendencies in nearby areas. The analysis illustrates that turbulent transport provides insights into how urban surfaces affect the PBL wind structures of TCs.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"313 ","pages":"Article 107756"},"PeriodicalIF":4.5,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637452","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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