Abstract. High contents of reactive nitrogen components aggravate air pollution and could also impact ecosystem structures and functioning across the terrestrial–aquatic–marine continuum. However, the long-term historical trends and future predictions of reactive nitrogen components at the global scale still remain highly uncertain. In our study, field observations, satellite products, model outputs, and many other covariates were integrated into the multi-stage machine-learning model to capture the global patterns of reactive nitrogen components during 2000–2019. In order to decrease the estimate uncertainties in the future scenarios, the constructed reactive nitrogen component dataset for the historical period was utilised as the constraint to calibrate the CMIP6 dataset in four scenarios. The results suggested that the cross-validation (CV) R2 values of four species showed satisfying performance (R2>0.55). The concentrations of estimated reactive nitrogen components in China experienced persistent increases during 2000–2013, while they suffered drastic decreases from 2013, except for NH3. This might be associated with the impact of clean-air policies. However, in Europe and the United States, these compounds have remained relatively stable since 2000. In the future scenarios, SSP3-7.0 (traditional-energy scenario) and SSP1-2.6 (carbon neutrality scenario) showed the highest and lowest reactive nitrogen component concentrations, respectively. Although the reactive nitrogen concentrations in some heavy-pollution scenarios (SSP3-7.0) also experienced decreases during 2020–2100, SSP1-2.6 and SSP2-4.5 (middle-emission scenario) still showed more rapidly decreasing trends. Our results emphasise the need for carbon neutrality pathways to reduce global atmospheric N pollution.
{"title":"Global estimates of ambient reactive nitrogen components during 2000–2100 based on the multi-stage model","authors":"Rui Li, Yining Gao, Lijia Zhang, Yubing Shen, Tianzhao Xu, Wenwen Sun, Gehui Wang","doi":"10.5194/acp-24-7623-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7623-2024","url":null,"abstract":"Abstract. High contents of reactive nitrogen components aggravate air pollution and could also impact ecosystem structures and functioning across the terrestrial–aquatic–marine continuum. However, the long-term historical trends and future predictions of reactive nitrogen components at the global scale still remain highly uncertain. In our study, field observations, satellite products, model outputs, and many other covariates were integrated into the multi-stage machine-learning model to capture the global patterns of reactive nitrogen components during 2000–2019. In order to decrease the estimate uncertainties in the future scenarios, the constructed reactive nitrogen component dataset for the historical period was utilised as the constraint to calibrate the CMIP6 dataset in four scenarios. The results suggested that the cross-validation (CV) R2 values of four species showed satisfying performance (R2>0.55). The concentrations of estimated reactive nitrogen components in China experienced persistent increases during 2000–2013, while they suffered drastic decreases from 2013, except for NH3. This might be associated with the impact of clean-air policies. However, in Europe and the United States, these compounds have remained relatively stable since 2000. In the future scenarios, SSP3-7.0 (traditional-energy scenario) and SSP1-2.6 (carbon neutrality scenario) showed the highest and lowest reactive nitrogen component concentrations, respectively. Although the reactive nitrogen concentrations in some heavy-pollution scenarios (SSP3-7.0) also experienced decreases during 2020–2100, SSP1-2.6 and SSP2-4.5 (middle-emission scenario) still showed more rapidly decreasing trends. Our results emphasise the need for carbon neutrality pathways to reduce global atmospheric N pollution.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-05DOI: 10.5194/acp-24-7637-2024
Tanguy Lunel, Maria Antonia Jimenez, Joan Cuxart, Daniel Martinez-Villagrasa, Aaron Boone, Patrick Le Moigne
Abstract. During the warm months of the year in Catalonia, the marine air overcomes the coastal mountain range and reaches the eastern Ebro sub-basin. This phenomenon is called marinada and has recently been thoroughly characterized for the first time by Jiménez et al. (2023), based on surface climatological data. However, the main physical mechanisms involved in its arrival and propagation remain to be discovered. This study aims to understand how the marinada is formed and how it interacts with the already developed atmospheric boundary layer. Surface and atmospheric observations are used in combination with the coupled surface–atmosphere model Meso-NH to reveal the mechanisms at play. It is shown that the marinada is generated by the advection of a cool marine air mass over the Catalan Pre-coastal Range by the action of the sea breeze and the upslope wind. This marine air mass then flows into the Ebro basin, creating what is known as the marinada. The characteristics and dynamics of the marinada allow it to be classified as a fall wind. It is also shown that the arrival, propagation and decay of the marinada is strongly dependent on the larger-scale weather situation: westerlies or thermal low. The current study provides a consistent framework for understanding the marinada, paving the way for better modeling and prediction of the phenomenon.
{"title":"The marinada fall wind in the eastern Ebro sub-basin: physical mechanisms and role of the sea, orography and irrigation","authors":"Tanguy Lunel, Maria Antonia Jimenez, Joan Cuxart, Daniel Martinez-Villagrasa, Aaron Boone, Patrick Le Moigne","doi":"10.5194/acp-24-7637-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7637-2024","url":null,"abstract":"Abstract. During the warm months of the year in Catalonia, the marine air overcomes the coastal mountain range and reaches the eastern Ebro sub-basin. This phenomenon is called marinada and has recently been thoroughly characterized for the first time by Jiménez et al. (2023), based on surface climatological data. However, the main physical mechanisms involved in its arrival and propagation remain to be discovered. This study aims to understand how the marinada is formed and how it interacts with the already developed atmospheric boundary layer. Surface and atmospheric observations are used in combination with the coupled surface–atmosphere model Meso-NH to reveal the mechanisms at play. It is shown that the marinada is generated by the advection of a cool marine air mass over the Catalan Pre-coastal Range by the action of the sea breeze and the upslope wind. This marine air mass then flows into the Ebro basin, creating what is known as the marinada. The characteristics and dynamics of the marinada allow it to be classified as a fall wind. It is also shown that the arrival, propagation and decay of the marinada is strongly dependent on the larger-scale weather situation: westerlies or thermal low. The current study provides a consistent framework for understanding the marinada, paving the way for better modeling and prediction of the phenomenon.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-05DOI: 10.5194/egusphere-2024-1382
Theertha Kariyathan, Ana Bastos, Markus Reichstein, Wouter Peters, Julia Marshall
Abstract. The carbon uptake period (CUP) refers to the time of each year during which the rate of photosynthetic uptake surpasses that of respiration in the terrestrial biosphere, resulting in a net absorption of CO2 from the atmosphere to the land. Since climate drivers influence both photosynthesis and respiration, the CUP offers valuable insights into how the terrestrial biosphere responds to climate variations and affects the carbon budget. Several studies have assessed large-scale changes in CUP based on seasonal metrics from CO2 mole fraction measurements. However, an in-depth understanding of the sensitivity of the CUP as derived from the CO2 mole fraction data (CUPMR) to actual changes in the CUP of the net ecosystem exchange (CUPNEE) is missing. In this study, we specifically assess the impact of (i) atmospheric transport (ii) inter-annual variability in CUPNEE (iii) regional contribution to the signals that integrate at different background sites where CO2 dry air mole fraction measurements are made. We conducted idealized simulations where we imposed known changes (∆) to the CUPNEE in the Northern Hemisphere to test the effect of the aforementioned factors in CUPMR metrics at ten Northern Hemisphere sites. Our analysis indicates a significant damping of changes in the simulated ∆CUPMR due to the integration of signals with varying CUPNEE timing across regions. CUPMR at well-studied sites such as Mauna Loa, Barrow, and Alert showed only 50 % of the applied ∆CUPNEE under non interannually-varying atmospheric transport conditions. Further, our synthetic analyses conclude that interannual variability (IAV) in atmospheric transport accounts for a significant part of the changes in the observed signals. However, even after separating the contribution of transport IAV, the estimates of surface changes in CUP by previous studies are not likely to provide an accurate magnitude of the actual changes occurring over the surface. The observed signal experiences significant damping as the atmosphere averages out non-synchronous signals from various regions.
{"title":"How atmospheric CO2 can inform us on annual and decadal shifts in the biospheric carbon uptake period","authors":"Theertha Kariyathan, Ana Bastos, Markus Reichstein, Wouter Peters, Julia Marshall","doi":"10.5194/egusphere-2024-1382","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1382","url":null,"abstract":"<strong>Abstract.</strong> The carbon uptake period (CUP) refers to the time of each year during which the rate of photosynthetic uptake surpasses that of respiration in the terrestrial biosphere, resulting in a net absorption of CO<sub>2</sub> from the atmosphere to the land. Since climate drivers influence both photosynthesis and respiration, the CUP offers valuable insights into how the terrestrial biosphere responds to climate variations and affects the carbon budget. Several studies have assessed large-scale changes in CUP based on seasonal metrics from CO<sub>2</sub> mole fraction measurements. However, an in-depth understanding of the sensitivity of the CUP as derived from the CO<sub>2</sub> mole fraction data (CUP<sub>MR</sub>) to actual changes in the CUP of the net ecosystem exchange (CUP<sub>NEE</sub>) is missing. In this study, we specifically assess the impact of (i) atmospheric transport (ii) inter-annual variability in CUP<sub>NEE</sub> (iii) regional contribution to the signals that integrate at different background sites where CO<sub>2</sub> dry air mole fraction measurements are made. We conducted idealized simulations where we imposed known changes (∆) to the CUP<sub>NEE</sub> in the Northern Hemisphere to test the effect of the aforementioned factors in CUP<sub>MR</sub> metrics at ten Northern Hemisphere sites. Our analysis indicates a significant damping of changes in the simulated ∆CUP<sub>MR</sub> due to the integration of signals with varying CUP<sub>NEE</sub> timing across regions. CUP<sub>MR</sub> at well-studied sites such as Mauna Loa, Barrow, and Alert showed only 50 % of the applied ∆CUP<sub>NEE</sub> under non interannually-varying atmospheric transport conditions. Further, our synthetic analyses conclude that interannual variability (IAV) in atmospheric transport accounts for a significant part of the changes in the observed signals. However, even after separating the contribution of transport IAV, the estimates of surface changes in CUP by previous studies are not likely to provide an accurate magnitude of the actual changes occurring over the surface. The observed signal experiences significant damping as the atmosphere averages out non-synchronous signals from various regions.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-05DOI: 10.5194/egusphere-2024-1381
Michel Legrand, Mstislav Vorobyev, Daria Bokuchava, Stanislav Kutuzov, Andreas Plach, Andreas Stohl, Alexandra Khairedinova, Vladimir Mikhalenko, Maria Vinogradova, Sabine Eckhardt, Susanne Preunkert
Abstract. To investigate the historical levels of atmospheric ammonia (NH3) pollution in south-eastern Europe, a 182 m long ice core was extracted from Mount Elbrus in the Caucasus, Russia. This ice core contains a record of ammonium (NH4+) levels from ~1750 CE (Common Era) to 2009 CE. The NH4+ ice core record indicates a 3.5-fold increase of annual concentrations from 34 ± 7 ng g-1 (~1750–1830) to 117 ± 23 ng g-1 over the recent decades (1980–2009). The increase remained moderate until 1950 CE (mean concentration of 49 ± 14 ng g-1 over the 1830–1950 period), and then accelerated to reach a maximum close to 120 ng g-1 in 1989. This ice core trend is compared to estimated past anthropogenic NH3 emissions in Europe by using state-of-the-art atmospheric transport modeling of submicron aerosols (FLEXPART model driven with 0.5° x 0.5° ERA5 reanalysis data). It is shown that in summer, when both vertical atmospheric mixing and agricultural NH3 emissions are strengthened, the NH4+ ice core trend is in good agreement with the course of estimated NH3 emissions from south-eastern Europe since ~1750 with a main contribution from south European Russia, Turkey, Georgia, and Ukraine. Examination of Mount Elbrus ice deposited over the second half of the 18th century when agricultural activities were less than 10% of those during the 1990s, suggest a pre-1750 annual NH4+ ice concentration related to natural emissions of 25 ng g-1. This pre-1750 natural level mainly related to natural soil emissions represents ~20% of the 1980–2009 NH4+ level, a level mainly related to current agricultural emissions that almost completely outweigh biogenic emissions from natural soils.
{"title":"Measurement Report: Changes of ammonia emissions since the 18th century in south-eastern Europe inferred from an Elbrus (Caucasus, Russia) ice core record","authors":"Michel Legrand, Mstislav Vorobyev, Daria Bokuchava, Stanislav Kutuzov, Andreas Plach, Andreas Stohl, Alexandra Khairedinova, Vladimir Mikhalenko, Maria Vinogradova, Sabine Eckhardt, Susanne Preunkert","doi":"10.5194/egusphere-2024-1381","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1381","url":null,"abstract":"<strong>Abstract.</strong> To investigate the historical levels of atmospheric ammonia (NH<sub>3</sub>) pollution in south-eastern Europe, a 182 m long ice core was extracted from Mount Elbrus in the Caucasus, Russia. This ice core contains a record of ammonium (NH<sub>4</sub><sup>+</sup>) levels from ~1750 CE (Common Era) to 2009 CE. The NH<sub>4</sub><sup>+</sup> ice core record indicates a 3.5-fold increase of annual concentrations from 34 ± 7 ng g<sup>-1</sup> (~1750–1830) to 117 ± 23 ng g<sup>-1</sup> over the recent decades (1980–2009). The increase remained moderate until 1950 CE (mean concentration of 49 ± 14 ng g<sup>-1</sup> over the 1830–1950 period), and then accelerated to reach a maximum close to 120 ng g<sup>-1 </sup>in 1989. This ice core trend is compared to estimated past anthropogenic NH<sub>3</sub> emissions in Europe by using state-of-the-art atmospheric transport modeling of submicron aerosols (FLEXPART model driven with 0.5° x 0.5° ERA5 reanalysis data). It is shown that in summer, when both vertical atmospheric mixing and agricultural NH<sub>3</sub> emissions are strengthened, the NH<sub>4</sub><sup>+</sup> ice core trend is in good agreement with the course of estimated NH<sub>3</sub> emissions from south-eastern Europe since ~1750 with a main contribution from south European Russia, Turkey, Georgia, and Ukraine. Examination of Mount Elbrus ice deposited over the second half of the 18<sup>th</sup> century when agricultural activities were less than 10% of those during the 1990s, suggest a pre-1750 annual NH<sub>4</sub><sup>+ </sup>ice concentration related to natural emissions of 25 ng g<sup>-1</sup>. This pre-1750 natural level mainly related to natural soil emissions represents ~20% of the 1980–2009 NH<sub>4</sub><sup>+ </sup>level, a level mainly related to current agricultural emissions that almost completely outweigh biogenic emissions from natural soils.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. This study investigated the potential effects of changes in inorganics on aerosol water uptake and, thus, on secondary organic aerosol (SOA) formation in wintertime haze based on the size-resolved measurements of non-refractory fine particulate matter (NR-PM2.5) in Xi'an, northwestern China. The composition of inorganic aerosol showed significant changes in winter 2018–2019 compared to winter 2013–2014, shifting from a sulfate-rich profile to a nitrate-rich profile. In particular, the fraction of sulfate and chloride decreased, but that of nitrate increased in the entire size range, while ammonium mainly increased at larger particle sizes. These changes thus resulted in a size-dependent evolution in water uptake. Increased water uptake was observed in most cases, mainly associated with enhanced contributions of both nitrate and ammonium, with the highest increase ratio reaching 5 %–35 % at larger particle sizes and higher relative humidity (RH>70 %). The non-negligible influence of chloride on aerosol water uptake was also emphasized. The random forest analysis coupled with a Shapley additive explanation algorithm (SHAP) further showed an enhanced relative importance of aerosol water in impacting SOA formation. Aerosol water exhibited a significant contribution to SOA formation during winter 2018–2019, particularly at larger particle sizes. The SHAP value of aerosol water increased alongside higher levels of aerosol water, indicating an enhanced contribution of aerosol water to SOA formation. This implies that the majority of enhanced aerosol water uptake at larger particle sizes and high RH might facilitate the efficient aqueous-phase SOA formation. This study highlights the key role of aerosol water as a medium to link inorganics and organics in their multiphase processes. As challenges to further improve China's air quality remain and because SOA plays an increasing role in haze pollution, these results provide insight into the size-resolved evolution characteristics and offer guidance for future controls.
摘要本研究基于对中国西北部西安市非难降解细颗粒物（NR-PM2.5）的粒径分辨测量，研究了无机物变化对气溶胶吸水的潜在影响，进而研究了冬季灰霾天气中二次有机气溶胶（SOA）形成的潜在影响。与2013-2014年冬季相比，2018-2019年冬季无机气溶胶的组成发生了显著变化，从富含硫酸盐的剖面转变为富含硝酸盐的剖面。其中，硫酸盐和氯化物的比例有所下降，但硝酸盐的比例在整个粒径范围内均有所上升，而铵主要在粒径较大时有所增加。因此，这些变化导致了摄水量随粒径而变化。在大多数情况下都能观察到吸水量的增加，这主要与硝酸盐和铵的增加有关，在粒径较大和相对湿度较高（相对湿度>70%）的情况下，吸水量增加比率最高，达到 5%-35%。氯化物对气溶胶吸水的影响也不容忽视。随机森林分析与沙普利加法解释算法（SHAP）相结合，进一步显示了气溶胶水在影响 SOA 形成方面的相对重要性。在2018-2019年冬季，气溶胶水对SOA的形成有显著贡献，尤其是在粒径较大的情况下。气溶胶水的SHAP值随着气溶胶水含量的增加而增加，表明气溶胶水对SOA形成的贡献增强。这意味着在粒径较大和相对湿度较高的情况下，气溶胶吸水的大部分增强可能会促进水相 SOA 的有效形成。这项研究强调了气溶胶水作为介质在无机物和有机物的多相过程中的关键作用。由于进一步改善中国空气质量的挑战依然存在，而且SOA在灰霾污染中扮演着越来越重要的角色，这些结果提供了对粒径分辨演变特征的深入了解，并为未来的控制提供了指导。
{"title":"Measurement report: Size-resolved secondary organic aerosol formation modulated by aerosol water uptake in wintertime haze","authors":"Jing Duan, Ru-Jin Huang, Ying Wang, Wei Xu, Haobin Zhong, Chunshui Lin, Wei Huang, Yifang Gu, Jurgita Ovadnevaite, Darius Ceburnis, Colin O'Dowd","doi":"10.5194/acp-24-7687-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7687-2024","url":null,"abstract":"Abstract. This study investigated the potential effects of changes in inorganics on aerosol water uptake and, thus, on secondary organic aerosol (SOA) formation in wintertime haze based on the size-resolved measurements of non-refractory fine particulate matter (NR-PM2.5) in Xi'an, northwestern China. The composition of inorganic aerosol showed significant changes in winter 2018–2019 compared to winter 2013–2014, shifting from a sulfate-rich profile to a nitrate-rich profile. In particular, the fraction of sulfate and chloride decreased, but that of nitrate increased in the entire size range, while ammonium mainly increased at larger particle sizes. These changes thus resulted in a size-dependent evolution in water uptake. Increased water uptake was observed in most cases, mainly associated with enhanced contributions of both nitrate and ammonium, with the highest increase ratio reaching 5 %–35 % at larger particle sizes and higher relative humidity (RH>70 %). The non-negligible influence of chloride on aerosol water uptake was also emphasized. The random forest analysis coupled with a Shapley additive explanation algorithm (SHAP) further showed an enhanced relative importance of aerosol water in impacting SOA formation. Aerosol water exhibited a significant contribution to SOA formation during winter 2018–2019, particularly at larger particle sizes. The SHAP value of aerosol water increased alongside higher levels of aerosol water, indicating an enhanced contribution of aerosol water to SOA formation. This implies that the majority of enhanced aerosol water uptake at larger particle sizes and high RH might facilitate the efficient aqueous-phase SOA formation. This study highlights the key role of aerosol water as a medium to link inorganics and organics in their multiphase processes. As challenges to further improve China's air quality remain and because SOA plays an increasing role in haze pollution, these results provide insight into the size-resolved evolution characteristics and offer guidance for future controls.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-05DOI: 10.5194/egusphere-2024-2008
Albert Ansmann, Cristofer Jimenez, Johanna Roschke, Johannes Bühl, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Tom Gaudek, Patric Seifert, Ulla Wandinger
Abstract. The number of wildfire smoke layers in the upper troposphere per fire season increased at mid and high northern latitudes during the last years. To consider smoke in weather and climate models appropriately, the influence of smoke on a variety of atmospheric processes needs to be explored in detail. In this study, we focus on the potential impact of wildfire smoke on cirrus formation. For the first time, state-of-the-art aerosol and cirrus observations with lidar and radar, presented in part 1 of a series of two articles, are closely linked to comprehensive modeling of gravity-wave-induced ice nucleation in cirrus evolution processes, presented in part 2. The complex study is based on aerosol and ice cloud observations in the central Arctic during the one-year MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition. For almost a year (from the summer of 2019 to the spring of 2020), aged Siberian wildfire smoke polluted the tropopause region over the central Arctic and many cirrus systems developed in the polluted upper troposphere. Goal of the data analysis (part 1) is to provide observational evidence for a dominating impact of aged wildfire smoke (organic aerosol particles) on cirrus formation in the central Arctic (over the MOSAiC research icebreaker Polarstern) during the winter half year of 2019–2020. Aim of the simulations in part 2 is to gain a deeper and more detailed insight into the potential smoke impact on ice nucleation as a function of observed aerosol and meteorological conditions (temperature, relative humidity) and by considering realistic gravity wave characteristics (updraft speed, wave amplitude). Vertical movements of air parcels are essential to initiate cloud formation. The measurements presented in part 1 were conducted during the winter half year (October to March), aboard the ice breaker Polarstern. The research vessel Polarstern drifted with the pack ice in the central Arctic mainly at latitudes >85 °N during the winter half year. The cirrus statistics show typical properties of ice clouds of the synoptic cirrus category (top-down generation of cirrus structures). The ice clouds mostly started to evolve at heights close to the tropopause. Cirrus top temperatures accumulated between −60 and −75 °C. The cirrus optical thickness (COT at 532 nm) of the ice clouds covered a wide range of values from < 0.03 (subvisible cirrus fraction, 25 % out of all cases) over 0.03–0.3 (visible thin cirrus, 40 %) to > 0.3 (opaque cirrus fraction, 35 %). In about 30 % out of all high altitude lidar observations, cirrus signatures were detected, much more than expected (10 %). This fact may be taken as a first hint that wildfire smoke was significantly involved in Arctic cirrus formation. The smoke particle surface area concentration around the tropopause was of the order of 5–15 µm2 cm−3 and indicated considerably enhanced levels of aerosol pollutio
{"title":"Impact of wildfire smoke on Arctic cirrus formation, part 1: analysis of MOSAiC 2019–2020 observations","authors":"Albert Ansmann, Cristofer Jimenez, Johanna Roschke, Johannes Bühl, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Tom Gaudek, Patric Seifert, Ulla Wandinger","doi":"10.5194/egusphere-2024-2008","DOIUrl":"https://doi.org/10.5194/egusphere-2024-2008","url":null,"abstract":"<strong>Abstract.</strong> The number of wildfire smoke layers in the upper troposphere per fire season increased at mid and high northern latitudes during the last years. To consider smoke in weather and climate models appropriately, the influence of smoke on a variety of atmospheric processes needs to be explored in detail. In this study, we focus on the potential impact of wildfire smoke on cirrus formation. For the first time, state-of-the-art aerosol and cirrus observations with lidar and radar, presented in part 1 of a series of two articles, are closely linked to comprehensive modeling of gravity-wave-induced ice nucleation in cirrus evolution processes, presented in part 2. The complex study is based on aerosol and ice cloud observations in the central Arctic during the one-year MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition. For almost a year (from the summer of 2019 to the spring of 2020), aged Siberian wildfire smoke polluted the tropopause region over the central Arctic and many cirrus systems developed in the polluted upper troposphere. Goal of the data analysis (part 1) is to provide observational evidence for a dominating impact of aged wildfire smoke (organic aerosol particles) on cirrus formation in the central Arctic (over the MOSAiC research icebreaker Polarstern) during the winter half year of 2019–2020. Aim of the simulations in part 2 is to gain a deeper and more detailed insight into the potential smoke impact on ice nucleation as a function of observed aerosol and meteorological conditions (temperature, relative humidity) and by considering realistic gravity wave characteristics (updraft speed, wave amplitude). Vertical movements of air parcels are essential to initiate cloud formation. The measurements presented in part 1 were conducted during the winter half year (October to March), aboard the ice breaker Polarstern. The research vessel Polarstern drifted with the pack ice in the central Arctic mainly at latitudes >85 °N during the winter half year. The cirrus statistics show typical properties of ice clouds of the synoptic cirrus category (top-down generation of cirrus structures). The ice clouds mostly started to evolve at heights close to the tropopause. Cirrus top temperatures accumulated between −60 and −75 °C. The cirrus optical thickness (COT at 532 nm) of the ice clouds covered a wide range of values from < 0.03 (subvisible cirrus fraction, 25 % out of all cases) over 0.03–0.3 (visible thin cirrus, 40 %) to > 0.3 (opaque cirrus fraction, 35 %). In about 30 % out of all high altitude lidar observations, cirrus signatures were detected, much more than expected (10 %). This fact may be taken as a first hint that wildfire smoke was significantly involved in Arctic cirrus formation. The smoke particle surface area concentration around the tropopause was of the order of 5–15 µm<sup>2</sup> cm<sup>−3</sup> and indicated considerably enhanced levels of aerosol pollutio","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-05DOI: 10.5194/acp-24-7609-2024
Oliver Schneising, Michael Buchwitz, Maximilian Reuter, Michael Weimer, Heinrich Bovensmann, John P. Burrows, Hartmut Bösch
Abstract. Global crude steel production is expected to continue to increase in the coming decades to meet the demands of the growing world population. Currently, the dominant steelmaking technology worldwide is the conventional highly CO2-intensive blast furnace–basic oxygen furnace production route (also known as the Linz–Donawitz process), which uses iron ore as raw material and coke as a reducing agent. As a result, large quantities of special gases that are rich in carbon monoxide (CO) are by-products of the various stages of the steelmaking process. Given the challenges associated with satellite-based estimates of carbon dioxide (CO2) emissions at the scale of emitting installations due to significant background levels, co-emitted CO may serve as a valuable indicator of the carbon footprint of steel plants. We show that regional CO release from steel production sites can be monitored from space using 5 years of measurements (2018–2022) from the TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel-5 Precursor satellite, benefiting from its relatively high spatial resolution and daily global coverage. We analyse all German steel plants with blast furnaces and basic oxygen furnaces and obtain associated CO emissions in the range of 50–400 kt yr−1 per site. A comparison with the respective CO2 emissions on the level of emitting installations available from emissions trading data of the European Union Emissions Trading System yields a linear relationship with a sector-specific CO/CO2 emission ratio for the analysed steelworks of 3.24 % [2.73–3.89; 1σ], suggesting the feasibility of using CO as a proxy for CO2 emissions from comparable steel production sites. An evaluation at other steel production sites indicates that the derived CO/CO2 emission ratio is also representative of other highly optimised state-of-the-art Linz–Donawitz steelworks outside Germany and that the emission ratio is potentially valuable for estimating sector-specific CO2 emissions from remotely sensed CO emissions, provided that the underlying CO emission estimate is not affected by other sources.
摘要未来几十年，全球粗钢产量预计将继续增加，以满足不断增长的世界人口的需求。目前，全球最主要的炼钢技术是传统的高炉--碱性氧气炉生产工艺（又称林茨-多纳维茨工艺），该工艺以铁矿石为原料，焦炭为还原剂，是一种高度二氧化碳密集型工艺。因此，炼钢过程的各个阶段都会产生大量富含一氧化碳（CO）的特殊气体副产品。由于大量的背景水平，基于卫星的二氧化碳（CO2）排放量估算在排放装置的规模上面临挑战，因此共同排放的 CO 可以作为衡量钢铁厂碳足迹的重要指标。我们利用哨兵-5 号前兆卫星上的 TROPOspheric Monitoring Instrument（TROPOMI）进行了为期 5 年（2018-2022 年）的测量，结果表明，利用其相对较高的空间分辨率和每日全球覆盖范围，可以从太空监测钢铁生产基地的区域性二氧化碳排放。我们对德国所有拥有高炉和氧气炉的钢铁厂进行了分析，获得了每个钢铁厂每年 50-400 kt-1 的相关二氧化碳排放量。根据欧盟排放交易系统的排放交易数据，我们将排放装置的二氧化碳排放量与相应的二氧化碳排放量进行了比较，结果发现，在所分析的钢铁厂中，特定行业的二氧化碳/一氧化碳排放比为 3.24 % [2.73-3.89; 1σ]，这表明使用二氧化碳作为可比钢铁生产基地二氧化碳排放量的替代物是可行的。对其他钢铁生产基地的评估表明，推导出的 CO/CO2 排放比也能代表德国以外其他高度优化的林茨-多纳维茨（Linz-Donawitz）先进钢铁厂，并且只要基本的 CO 排放估算不受其他来源的影响，该排放比对于从遥感 CO 排放中估算特定行业的 CO2 排放量具有潜在价值。
{"title":"Towards a sector-specific CO∕CO2 emission ratio: satellite-based observations of CO release from steel production in Germany","authors":"Oliver Schneising, Michael Buchwitz, Maximilian Reuter, Michael Weimer, Heinrich Bovensmann, John P. Burrows, Hartmut Bösch","doi":"10.5194/acp-24-7609-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7609-2024","url":null,"abstract":"Abstract. Global crude steel production is expected to continue to increase in the coming decades to meet the demands of the growing world population. Currently, the dominant steelmaking technology worldwide is the conventional highly CO2-intensive blast furnace–basic oxygen furnace production route (also known as the Linz–Donawitz process), which uses iron ore as raw material and coke as a reducing agent. As a result, large quantities of special gases that are rich in carbon monoxide (CO) are by-products of the various stages of the steelmaking process. Given the challenges associated with satellite-based estimates of carbon dioxide (CO2) emissions at the scale of emitting installations due to significant background levels, co-emitted CO may serve as a valuable indicator of the carbon footprint of steel plants. We show that regional CO release from steel production sites can be monitored from space using 5 years of measurements (2018–2022) from the TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel-5 Precursor satellite, benefiting from its relatively high spatial resolution and daily global coverage. We analyse all German steel plants with blast furnaces and basic oxygen furnaces and obtain associated CO emissions in the range of 50–400 kt yr−1 per site. A comparison with the respective CO2 emissions on the level of emitting installations available from emissions trading data of the European Union Emissions Trading System yields a linear relationship with a sector-specific CO/CO2 emission ratio for the analysed steelworks of 3.24 % [2.73–3.89; 1σ], suggesting the feasibility of using CO as a proxy for CO2 emissions from comparable steel production sites. An evaluation at other steel production sites indicates that the derived CO/CO2 emission ratio is also representative of other highly optimised state-of-the-art Linz–Donawitz steelworks outside Germany and that the emission ratio is potentially valuable for estimating sector-specific CO2 emissions from remotely sensed CO emissions, provided that the underlying CO emission estimate is not affected by other sources.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-04DOI: 10.5194/acp-24-7591-2024
Andrea E. Gordon, Cameron R. Homeyer, Jessica B. Smith, Rei Ueyama, Jonathan M. Dean-Day, Elliot L. Atlas, Kate Smith, Jasna V. Pittman, David S. Sayres, David M. Wilmouth, Apoorva Pandey, Jason M. St. Clair, Thomas F. Hanisco, Jennifer Hare, Reem A. Hannun, Steven Wofsy, Bruce C. Daube, Stephen Donnelly
Abstract. Tropopause-overshooting convection in the midlatitudes provides a rapid transport pathway for air from the lower troposphere to reach the upper troposphere and lower stratosphere (UTLS) and can result in the formation of above-anvil cirrus plumes (AACPs) that significantly hydrate the stratosphere. Such UTLS composition changes alter the radiation budget and impact climate. Novel in situ observations from the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field campaign are used in this study to examine UTLS impacts from AACP-generating overshooting convection. Namely, a research flight on 31 May 2022 sampled active convection over the state of Oklahoma for more than 3 h with the NASA ER-2 high-altitude research aircraft. An AACP was bisected during this flight, providing the first such extensive in situ sampling of this phenomenon. The convective observations reveal pronounced changes in air mass composition and stratospheric hydration up to altitudes of 2.3 km above the tropopause and concentrations more than double background levels. Unique dynamic and trace gas signatures were found within the AACP, including enhanced vertical mixing near the AACP edge and a positive correlation between water vapor and ozone. Moreover, the water vapor enhancement within the AACP was found to be limited to the saturation mixing ratio of the low temperature overshoot and AACP air. Comparison with all remaining DCOTSS flights demonstrates that the 31 May 2022 flight had some of the largest tropospheric tracer and water vapor perturbations in the stratosphere and within the AACP.
{"title":"Airborne observations of upper troposphere and lower stratosphere composition change in active convection producing above-anvil cirrus plumes","authors":"Andrea E. Gordon, Cameron R. Homeyer, Jessica B. Smith, Rei Ueyama, Jonathan M. Dean-Day, Elliot L. Atlas, Kate Smith, Jasna V. Pittman, David S. Sayres, David M. Wilmouth, Apoorva Pandey, Jason M. St. Clair, Thomas F. Hanisco, Jennifer Hare, Reem A. Hannun, Steven Wofsy, Bruce C. Daube, Stephen Donnelly","doi":"10.5194/acp-24-7591-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7591-2024","url":null,"abstract":"Abstract. Tropopause-overshooting convection in the midlatitudes provides a rapid transport pathway for air from the lower troposphere to reach the upper troposphere and lower stratosphere (UTLS) and can result in the formation of above-anvil cirrus plumes (AACPs) that significantly hydrate the stratosphere. Such UTLS composition changes alter the radiation budget and impact climate. Novel in situ observations from the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field campaign are used in this study to examine UTLS impacts from AACP-generating overshooting convection. Namely, a research flight on 31 May 2022 sampled active convection over the state of Oklahoma for more than 3 h with the NASA ER-2 high-altitude research aircraft. An AACP was bisected during this flight, providing the first such extensive in situ sampling of this phenomenon. The convective observations reveal pronounced changes in air mass composition and stratospheric hydration up to altitudes of 2.3 km above the tropopause and concentrations more than double background levels. Unique dynamic and trace gas signatures were found within the AACP, including enhanced vertical mixing near the AACP edge and a positive correlation between water vapor and ozone. Moreover, the water vapor enhancement within the AACP was found to be limited to the saturation mixing ratio of the low temperature overshoot and AACP air. Comparison with all remaining DCOTSS flights demonstrates that the 31 May 2022 flight had some of the largest tropospheric tracer and water vapor perturbations in the stratosphere and within the AACP.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141546209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-07-04DOI: 10.5194/egusphere-2024-1222
Petra Bauerová, Josef Keder, Adriana Šindelářová, Ondřej Vlček, William Patiño, Jaroslav Resler, Pavel Krč, Jan Geletič, Hynek Řezníček, Martin Bureš, Kryštof Eben, Michal Belda, Jelena Radović, Vladimír Fuka, Radek Jareš, Igor Ezau
Abstract. Within the TURBAN project, a "Legerova campaign" focusing on air quality and meteorology in the traffic-loaded part of the Prague city (Czech Republic) was carried out from 30 May 2022 to 28 March 2023. The network comprised of 20 combined low-cost sensor (LCS) stations for NO2, O3, PM10 and PM2.5 concentrations, along with a mobile meteorological mast, a single-channel microwave radiometer and Doppler LIDAR for measurement of vertical temperature and wind profiles. Significant individual deviations of LCSs were detected during the 165 day initial field test of all units at the urban background Prague 4-Libuš reference station (coefficient of variation 17–28 %). Implementing the Multivariate Adaptive Regression Splines method for correction reduced the LCS inter-individual variability and improved correlation with reference monitors in all pollutants (R2 0.88–0.97). The LCSs' data drifts and ageing were checked by the double mass curve method for the entire measurement period. During the Legerova campaign, the highest NO2 concentrations were in traffic-loaded street canyons with continuous building blocks and several traffic lights. Aerosol pollution showed very little variation between the monitored streets. The highest PM10 and PM2.5 concentrations were recorded during temperature inversions and an episode involving pollution transported from a large forest fire in northern Czech Republic in July 2022. This report provides valuable data to support the validation of various predictive models dealing with complex urban environment, such as microscale LES model PALM tested in the TURBAN project.
{"title":"Measurement report: TURBAN observation campaign combining street-level low-cost air quality sensors and meteorological profile measurements in Prague","authors":"Petra Bauerová, Josef Keder, Adriana Šindelářová, Ondřej Vlček, William Patiño, Jaroslav Resler, Pavel Krč, Jan Geletič, Hynek Řezníček, Martin Bureš, Kryštof Eben, Michal Belda, Jelena Radović, Vladimír Fuka, Radek Jareš, Igor Ezau","doi":"10.5194/egusphere-2024-1222","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1222","url":null,"abstract":"<strong>Abstract.</strong> Within the TURBAN project, a \"Legerova campaign\" focusing on air quality and meteorology in the traffic-loaded part of the Prague city (Czech Republic) was carried out from 30 May 2022 to 28 March 2023. The network comprised of 20 combined low-cost sensor (LCS) stations for NO<sub>2</sub>, O<sub>3</sub>, PM<sub>10</sub> and PM<sub>2.5 </sub>concentrations, along with a mobile meteorological mast, a single-channel microwave radiometer and Doppler LIDAR for measurement of vertical temperature and wind profiles. Significant individual deviations of LCSs were detected during the 165 day initial field test of all units at the urban background Prague 4-Libuš reference station (coefficient of variation 17–28 %). Implementing the Multivariate Adaptive Regression Splines method for correction reduced the LCS inter-individual variability and improved correlation with reference monitors in all pollutants (R<sup>2</sup> 0.88–0.97). The LCSs' data drifts and ageing were checked by the double mass curve method for the entire measurement period. During the Legerova campaign, the highest NO<sub>2</sub> concentrations were in traffic-loaded street canyons with continuous building blocks and several traffic lights. Aerosol pollution showed very little variation between the monitored streets. The highest PM<sub>10</sub> and PM<sub>2.5</sub> concentrations were recorded during temperature inversions and an episode involving pollution transported from a large forest fire in northern Czech Republic in July 2022. This report provides valuable data to support the validation of various predictive models dealing with complex urban environment, such as microscale LES model PALM tested in the TURBAN project.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141546212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The supercooled liquid fraction (SLF) in mixed-phase clouds (MPCs) is an essential variable of cloud microphysical processes and climate sensitivity. However, the SLF is currently calculated in spaceborne remote sensing only as the cloud phase–frequency ratio of adjacent pixels, which results in a loss of the original resolution in observations of cloud liquid or ice content within MPCs. Here, we present a novel method for retrieving the SLF in MPCs based on the differences in radiative properties of supercooled liquid droplets and ice particles at visible (VIS) and shortwave infrared (SWI) channels of the geostationary Himawari-8. Liquid and ice water paths are inferred by assuming that clouds are composed of only liquid or ice, with the real cloud water path (CWP) expressed as a combination of these two water paths (SLF and 1-SLF as coefficients), and the SLF is determined by referring to the CWP from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). The statistically relatively small cloud phase spatial inhomogeneity at a Himawari-8 pixel level indicates an optimal scene for cloud retrieval. The SLF results are comparable to global SLF distributions observed by active instruments, particularly for single-layered cloud systems. While accessing the method's feasibility, SLF averages are estimated between 74 % and 78 % in Southern Ocean (SO) stratocumulus across seasons, contrasting with a range of 29 % to 32 % in northeastern Asia. The former exhibits a minimum SLF around midday in summer and a maximum in winter, while the latter trend differs. This novel algorithm will be valuable for research to track the evolution of MPCs and constrain the related climate impact.
{"title":"Technical note: Retrieval of the supercooled liquid fraction in mixed-phase clouds from Himawari-8 observations","authors":"Ziming Wang, Husi Letu, Huazhe Shang, Luca Bugliaro","doi":"10.5194/acp-24-7559-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7559-2024","url":null,"abstract":"Abstract. The supercooled liquid fraction (SLF) in mixed-phase clouds (MPCs) is an essential variable of cloud microphysical processes and climate sensitivity. However, the SLF is currently calculated in spaceborne remote sensing only as the cloud phase–frequency ratio of adjacent pixels, which results in a loss of the original resolution in observations of cloud liquid or ice content within MPCs. Here, we present a novel method for retrieving the SLF in MPCs based on the differences in radiative properties of supercooled liquid droplets and ice particles at visible (VIS) and shortwave infrared (SWI) channels of the geostationary Himawari-8. Liquid and ice water paths are inferred by assuming that clouds are composed of only liquid or ice, with the real cloud water path (CWP) expressed as a combination of these two water paths (SLF and 1-SLF as coefficients), and the SLF is determined by referring to the CWP from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). The statistically relatively small cloud phase spatial inhomogeneity at a Himawari-8 pixel level indicates an optimal scene for cloud retrieval. The SLF results are comparable to global SLF distributions observed by active instruments, particularly for single-layered cloud systems. While accessing the method's feasibility, SLF averages are estimated between 74 % and 78 % in Southern Ocean (SO) stratocumulus across seasons, contrasting with a range of 29 % to 32 % in northeastern Asia. The former exhibits a minimum SLF around midday in summer and a maximum in winter, while the latter trend differs. This novel algorithm will be valuable for research to track the evolution of MPCs and constrain the related climate impact.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141546211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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