Browsing by Autor "Samara Carbone"

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Data and Code for figures of "Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes"
(European Organization for Nuclear Research, 2022) Wiebke Scholz; Jiali Shen; Diego Aliaga; Cheng Wu; Samara Carbone; Isabel Moreno; Qiaozhi Zha; Wei Huang; Liine Heikkinen; Jean‐Luc Jaffrezo
This database includes the material to create the figures in "Measurement Report: Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes" and the analyzed time series of all atmospheric variables presented.
Data and Code for figures of "Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes"
(2022) Wiebke Scholz; Jiali Shen; Diego Aliaga; Cheng Wu; Samara Carbone; Isabel Moreno; Qiaozhi Zha; Wei Huang; Liine Heikkinen; Jean‐Luc Jaffrezo
This database includes the material to create the figures in "Measurement Report: Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes" and the analyzed time series of all atmospheric variables presented.
Data and Code for figures of "Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes"
(European Organization for Nuclear Research, 2022) Wiebke Scholz; Jiali Shen; Diego Aliaga; Cheng Wu; Samara Carbone; Isabel Moreno; Qiaozhi Zha; Wei Huang; Liine Heikkinen; Jean‐Luc Jaffrezo
This database includes the material to create the figures in "Measurement Report: Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes" and the analyzed time series of all atmospheric variables presented.
Identifying source regions of air masses sampled at the tropical high-altitude site of Chacaltaya using WRF-FLEXPART and cluster analysis
(Copernicus Publications, 2021) Diego Aliaga; Victoria A. Sinclair; Marcos Andrade; Paulo Artaxo; Samara Carbone; Evgeny Kadantsev; Paolo Laj; Alfred Wiedensohler; Radovan Krejčí; Federico Bianchi
Abstract. Observations of aerosol and trace gases in the remote troposphere are vital to quantify background concentrations and identify long-term trends in atmospheric composition on large spatial scales. Measurements made at high altitude are often used to study free-tropospheric air; however such high-altitude sites can be influenced by boundary layer air masses. Thus, accurate information on air mass origin and transport pathways to high-altitude sites is required. Here we present a new method, based on the source–receptor relationship (SRR) obtained from backwards WRF-FLEXPART simulations and a k-means clustering approach, to identify source regions of air masses arriving at measurement sites. Our method is tailored to areas of complex terrain and to stations influenced by both local and long-range sources. We have applied this method to the Chacaltaya (CHC) GAW station (5240 m a.s.l.; 16.35∘ S, 68.13∘ W) for the 6-month duration of the “Southern Hemisphere high-altitude experiment on particle nucleation and growth” (SALTENA) to identify where sampled air masses originate and to quantify the influence of the surface and the free troposphere. A key aspect of our method is that it is probabilistic, and for each observation time, more than one air mass (cluster) can influence the station, and the percentage influence of each air mass can be quantified. This is in contrast to binary methods, which label each observation time as influenced by either boundary layer or free-troposphere air masses. Air sampled at CHC is a mix of different provenance. We find that on average 9 % of the air, at any given observation time, has been in contact with the surface within 4 d prior to arriving at CHC. Furthermore, 24 % of the air has been located within the first 1.5 km above ground level (surface included). Consequently, 76 % of the air sampled at CHC originates from the free troposphere. However, pure free-tropospheric influences are rare, and often samples are concurrently influenced by both boundary layer and free-tropospheric air masses. A clear diurnal cycle is present, with very few air masses that have been in contact with the surface being detected at night. The 6-month analysis also shows that the most dominant air mass (cluster) originates in the Amazon and is responsible for 29 % of the sampled air. Furthermore, short-range clusters (origins within 100 km of CHC) have high temporal frequency modulated by local meteorology driven by the diurnal cycle, whereas the mid- and long-range clusters' (>200 km) variability occurs on timescales governed by synoptic-scale dynamics. To verify the reliability of our method, in situ sulfate observations from CHC are combined with the SRR clusters to correctly identify the (pre-known) source of the sulfate: the Sabancaya volcano located 400 km north-west from the station.
Identifying source regions of air masses sampled at the tropicalhigh-altitude site of Chacaltaya using WRF-FLEXPART and clusteranalysis
(2021) Diego Aliaga; Victoria A. Sinclair; Marcos Andrade; Paulo Artaxo; Samara Carbone; Evgeny Kadantsev; Paolo Laj; Alfred Wiedensohler; Radovan Krejčí; Federico Bianchi
Abstract. Observations of aerosol and trace gases in the remote troposphere are vital to quantify background concentrations and identify long term trends in atmospheric composition on large spatial scales. Measurements made at high altitude are often used to study free tropospheric air however such high-altitude sites can be influenced by boundary layer air masses. Thus, accurate information on air mass origin and transport pathways to high altitude sites is required. Here we present a new method, based on the source-receptor relationship (SRR) obtained from backwards WRF-FLEXPART simulations and a k-means clustering approach, to identify source regions of air masses arriving at measurement sites. Our method is tailored to areas of complex terrain and to stations influenced by both local and long-range sources. We have applied this method to the Chacaltaya (CHC) GAW station (5240 m a.s.l.,16.35° S, 68.13° W) for the 6-month duration of the “Southern hemisphere high altitude experiment on particle nucleation and growth” (SALTENA) to identify where sampled air masses originate and to quantify the influence of the boundary layer and the free troposphere. A key aspect of our method is that it is probabilistic and for each observation time, more than one air mass (cluster) can influence the station and the percentage influence of each air mass can be quantified. This is in contrast to binary methods, which label each observation time as influenced either by boundary layer or free troposphere air masses. We find that on average, 9% of the air sampled at CHC, at any given observation time, has been in contact with the surface within 4 days prior to arriving at CHC, 24% of the air was located below 1.5 km above ground level and consequently, 76% of the measured air masses at CHC represent free tropospheric air. However, pure free-tropospheric influences are rare and often samples are concurrently influenced by both boundary-layer and free-tropospheric air masses. A clear diurnal cycle is present with very few air masses that have been in contact with the surface being detected at night. The 6-month analysis also shows that the most dominant air mass (cluster) originates in the Amazon and is responsible for 29% of the sampled air. Furthermore, short-range clusters (origins within 100 km of CHC) have high temporal frequency modulated by local meteorology driven by the diurnal cycle whereas the mid- and long-range clusters’ (>200 km) variability occurs on timescales governed by synoptic-scale dynamics. To verify the reliability of our method, in-situ sulfate observations from CHC are combined with the SRR clusters to correctly identify the (pre-known) source of the sulfate: the Sabancaya volcano located 400 km northwest from the station.
Measurement Report: Long-range transport and fate of DMS-oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes
(2022) Wiebke Scholz; Jiali Shen; Diego Aliaga; Cheng Wu; Samara Carbone; Isabel Moreno; Qiaozhi Zha; Wei Huang; Liine Heikkinen; Jean‐Luc Jaffrezo
Abstract. Dimethyl sulfide (DMS) is the primary natural contributor to the atmospheric sulfur burden. Observations concerning the fate of DMS oxidation products after long-range transport in the remote free troposphere are, however, sparse. Here we present quantitative chemical ionization mass spectrometric measurements of DMS and its oxidation products H2SO4, MSA, DMSO, DMSO2, MSIA, MTF, CH3S(O)2OOH and CH3SOH in the gas-phase as well as measurements of the sulfate and methane- sulfonate aerosol mass fractions at the Global Atmosphere Watch (GAW) station Chacaltaya in the Bolivian Andes located at 5240 m above sea level (a.s.l.). DMS and DMS oxidation products are brought to the Andean high-altitude station by Pacific air masses during the dry season after convective lifting over the remote Pacific ocean to 6000–8000 m a.s.l. and subsequent long-range transport in the free troposphere (FT). Most of the DMS reaching the station is already converted to the rather unreactive sulfur reservoirs dimethyl sulfone (DMSO2) in the gas phase and methanesulfonate (MS−) in the particle phase, which carried nearly equal amounts of sulfur to the station. The particulate sulfate at Chacaltaya is however dominated by regional volcanic emissions during the time of the measurement and not significantly affected by the marine air masses. In one of the FT events, even some DMS was observed next to reactive intermediates such as methyl thioformate, dimethyl sulfoxide, and methane sulfinic acid. Also for this event, backtrajectory calculations show, that the air masses came from above the ocean (distance >330 km) with no local sur- face contacts. This study demonstrates the potential impact of marine DMS emissions on the availability of sulfur-containing vapors in the remote free troposphere far away from the ocean.
Measurement report: Long-range transport and the fate of dimethyl sulfide oxidation products in the free troposphere derived from observations at the high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes
(Copernicus Publications, 2023) Wiebke Scholz; Jiali Shen; Diego Aliaga; Cheng Wu; Samara Carbone; Isabel Moreno; Qiaozhi Zha; Wei Huang; Liine Heikkinen; Jean‐Luc Jaffrezo
Abstract. Dimethyl sulfide (DMS) is the primary natural contributor to the atmospheric sulfur burden. Observations concerning the fate of DMS oxidation products after long-range transport in the remote free troposphere are, however, sparse. Here we present quantitative chemical ionization mass spectrometric measurements of DMS and its oxidation products sulfuric acid (H2SO4), methanesulfonic acid (MSA), dimethylsulfoxide (DMSO), dimethylsulfone (DMSO2), methanesulfinic acid (MSIA), methyl thioformate (MTF), methanesulfenic acid (MSEA, CH3SOH), and a compound of the likely structure CH3S(O)2OOH in the gas phase, as well as measurements of the sulfate and methanesulfonate aerosol mass fractions. The measurements were performed at the Global Atmosphere Watch (GAW) station Chacaltaya in the Bolivian Andes located at 5240 m above sea level (a.s.l.). DMS and DMS oxidation products are brought to the Andean high-altitude station by Pacific air masses during the dry season after convective lifting over the remote Pacific ocean to 6000–8000 m a.s.l. and subsequent long-range transport in the free troposphere (FT). Most of the DMS reaching the station is already converted to the rather unreactive sulfur reservoirs DMSO2 in the gas phase and methanesulfonate (MS−) in the particle phase, which carried nearly equal amounts of sulfur to the station. The particulate sulfate at Chacaltaya is however dominated by regional volcanic emissions during the time of the measurement and not significantly affected by the marine air masses. In one of the FT events, even some DMS was observed next to reactive intermediates such as methyl thioformate, dimethylsulfoxide, and methanesulfinic acid. Also for this event, back trajectory calculations show that the air masses came from above the ocean (distance >330 km) with no local surface contacts. This study demonstrates the potential impact of marine DMS emissions on the availability of sulfur-containing vapors in the remote free troposphere far away from the ocean.
New Particle Formation dynamics in the central Andes: Contrasting urban and mountain-top environments
(2024) Diego Aliaga; Victoria A. Sinclair; Radovan Krejčí; Marcos Andrade; Paulo Artaxo; Luis Blacutt; Runlong Cai; Samara Carbone; Yvette Gramlich; Liine Heikkinen
Abstract. In this study, we investigate atmospheric new particle formation (NPF) across 65 days in the Bolivian Central Andes at two locations: the mountain-top Chacaltaya station (CHC, 5.2 km above sea level) and an urban site in El Alto-La Paz (EAC), 19 km apart and at 1.1 km lower altitude. We categorize days into four groups based on NPF intensity, determined with the daily maximum concentration of 4–7 nm particles: (A) high at both sites, (B) medium at both, (C) high at EAC but low at CHC, (D) and low at both. This categorization was premised on the assumption that similar NPF intensities imply similar atmospheric processes. Our findings show significant differences across the categories in terms of particle size and volume, precursor gases, aerosol compositions, pollution levels, meteorological conditions, and air mass origins. Specifically, intense NPF events (A) increased Aitken-mode particle concentrations (14–100 nm) significantly on 28 % of the days when air masses passed over the Altiplano. At CHC, larger Aitken-mode particle concentrations (40–100 nm) increased from 1.1×103 cm-3 (background) to 6.2×103 cm-3 very likely linked to the ongoing NPF process. High pollution levels from urban emissions on 24 % of the days (B) were found to interrupt particle growth at CHC and diminish nucleation at EAC. Meanwhile, on 14 % of the days, high concentrations of sulphate and large particle volumes (C) were observed, correlating with significant influences from air masses originating from the actively degassing Sabancaya Volcano and a depletion of positive 2–4 nm ions at CHC. During these days, reduced NPF intensity was observed at CHC but not at EAC. The study highlights the role of NPF in modifying atmospheric particles and underscores the varying impacts of urban versus mountain-top environments on particle formation processes in the Andean region.
New particle formation dynamics in the central Andes: contrasting urban and mountaintop environments
(2025) Diego Aliaga; Victoria A. Sinclair; Radovan Krejčí; Marcos Andrade; Paulo Artaxo; Luis Blacutt; Runlong Cai; Samara Carbone; Yvette Gramlich; Liine Heikkinen
Abstract. In this study, we investigate atmospheric new particle formation (NPF) across 65 d in the Bolivian central Andes at two locations: the mountaintop Chacaltaya station (CHC, 5.2 km above sea level) and an urban site in El Alto–La Paz (EAC), 19 km apart and at 1.1 km lower altitude. We classified the days into four categories based on the intensity of NPF, determined by the daily maximum concentration of 4–7 nm particles: (1) high at both sites, (2) medium at both, (3) high at EAC but low at CHC, and (4) low at both. These categories were then named after their emergent and most prominent characteristics: (1) Intense-NPF, (2) Polluted, (3) Volcanic, and (4) Cloudy. This classification was premised on the assumption that similar NPF intensities imply similar atmospheric processes. Our findings show significant differences across the categories in terms of particle size and volume, sulfuric acid concentration, aerosol compositions, pollution levels, meteorological conditions, and air mass origins. Specifically, intense NPF events (1) increased Aitken mode particle concentrations (14–100 nm) significantly on 28 % of the days when air masses passed over the Altiplano. At CHC, larger Aitken mode particle concentrations (40–100 nm) increased from 1.1 × 103 cm−3 (background) to 6.2 × 103 cm−3, and this is very likely linked to the ongoing NPF process. High pollution levels from urban emissions on 24 % of the days (2) were found to interrupt particle growth at CHC and diminish nucleation at EAC. Meanwhile, on 14 % of the days, high concentrations of sulfate and large particle volumes (3) were observed, correlating with significant influences from air masses originating from the actively degassing Sabancaya volcano and a depletion of positive 2–4 nm ions at CHC but not at EAC. During these days, reduced NPF intensity was observed at CHC but not at EAC. Lastly, on 34 % of the days, overcast conditions (4) were associated with low formation rates and air masses originating from the lowlands east of the stations. In all cases, event initiation (∼ 09:00 LT) generally occurred about half an hour earlier at CHC than at EAC and was likely modulated by the daily solar cycle. CHC at dawn is in an air mass representative of the regional residual layer with minimal local surface influence due to the barren landscape. As the day progresses, upslope winds bring in air masses affected by surface emissions from lower altitudes, which may include anthropogenic or biogenic sources. This influence likely develops gradually, eventually creating the right conditions for an NPF event to start. At EAC, the start of NPF was linked to the rapid growth of the boundary layer, which favored the entrainment of air masses from above. The study highlights the role of NPF in modifying atmospheric particles and underscores the varying impacts of urban versus mountain top environments on particle formation processes in the Andean region.
Quantifying the effect of SVOC condensation on cloud droplet number in different airmass types
(2020) Liine Heikkinen; Samuel Lowe; Cheng Wu; Diego Aliaga; Wei Huang; Yvette Gramlich; Samara Carbone; Qiaozhi Zha; Fernando Velarde; Valeria Mardóñez
&lt;p&gt;Clouds are made of droplets that arise from the activation of suitable aerosol particles (termed cloud condensation nuclei, CCN). In the activation process, water vapor saturation ratio exceeds a critial ratio enabling CCN runaway-growth to cloud droplet sizes. The number concentration of cloud droplets (CDNC) is highly dependent on the aerosol population properties (size distribution and composition), relative humidity, and the vertical wind component. While the activation of CCN consisting of non-volatile particulate matter is fairly well understood, the same process involving semi-volatile organic vapors (SVOCs) has received less attention despite their significant presence in ambient air. A recent cloud parcel modeling study shows substanial CDNC enhancement due to SVOC condensation (Topping &lt;em&gt;et al&lt;/em&gt;., 2013). Surprisingly, the topic has not been widely investigated nor the results replicated with other cloud parcel models (CPM). Thus, in the current study we seek to quantify the CDNC enhancement by SVOC condensation using a recently developed CPM framework (Lowe &lt;em&gt;et al.&lt;/em&gt;, 2020, &lt;em&gt;in prep&lt;/em&gt;.). Moreover, the CPM initialization is performed, for the first time, with state-of-the art measurement data including measured SVOC data for multiple airmass types.&lt;/p&gt;&lt;p&gt;Here, the CPM, which uses spectral microphysics for the simulation of CCN activation and hydrometeor growth, also includes a SVOC condensation equation analogous to those of water vapor. Equilibrium initialization of the SVOC volatility basis set (VBS) partitioning coefficients is performed iteratively, and constrained by the organic to inorganic ratio in the particle phase determined by ambient measurements performed at the Chacaltaya Global Atmospheric Watch (GAW) Station located at 5240 m a.s.l. in the Bolivian Andes, in spring 2018. The uniquely comprehensive data set recorded, which tracks all of the relevant aerosol population characteristics in near real-time, reveals a high degree of variability in aerosol composition, size distribution and loading depending on the air mass origin. Lagrangian backward simulations during the measurement period at Chacaltaya GAW reveal at least 18 significantly different airmass origins (Aliaga &lt;em&gt;et al.&lt;/em&gt;, 2020, &lt;em&gt;in prep.&lt;/em&gt;). Such variability served multiple model initialization scenarios for individual case studies. We will show a suite of CDNC enhancements by SVOC condensation under different initialization scenarios actualized in data recorded at Chacaltaya GAW Station, including airmasses originating from the Amazon (biomass burning and biogenic VOCs), Andean plateau (volcanic activity), and La Paz/El Alto metropolitan areas (anthropogenic emissions).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;div&gt;Topping, D., Connolly, P. and McFiggans, G., 2013. Cloud droplet number enhanced by co-condensation of organic vapours. &lt;em&gt;Nature Geoscience&lt;/em&gt;, &lt;em&gt;6&lt;/em&gt;(6), p.443.&lt;/div&gt;
Referee comment on egusphere-2022-887
(2022) Wiebke Scholz; Jiali Shen; Diego Aliaga; Cheng Wu; Samara Carbone; Isabel Moreno; Qiaozhi Zha; Wei Huang; Liine Heikkinen; Jean‐Luc Jaffrezo
Abstract. Dimethyl sulfide (DMS) is the primary natural contributor to the atmospheric sulfur burden. Observations concerning the fate of DMS oxidation products after long-range transport in the remote free troposphere are, however, sparse. Here we present quantitative chemical ionization mass spectrometric measurements of DMS and its oxidation products H2SO4, MSA, DMSO, DMSO2, MSIA, MTF, CH3S(O)2OOH and CH3SOH in the gas-phase as well as measurements of the sulfate and methane- sulfonate aerosol mass fractions at the Global Atmosphere Watch (GAW) station Chacaltaya in the Bolivian Andes located at 5240 m above sea level (a.s.l.). DMS and DMS oxidation products are brought to the Andean high-altitude station by Pacific air masses during the dry season after convective lifting over the remote Pacific ocean to 6000–8000 m a.s.l. and subsequent long-range transport in the free troposphere (FT). Most of the DMS reaching the station is already converted to the rather unreactive sulfur reservoirs dimethyl sulfone (DMSO2) in the gas phase and methanesulfonate (MS−) in the particle phase, which carried nearly equal amounts of sulfur to the station. The particulate sulfate at Chacaltaya is however dominated by regional volcanic emissions during the time of the measurement and not significantly affected by the marine air masses. In one of the FT events, even some DMS was observed next to reactive intermediates such as methyl thioformate, dimethyl sulfoxide, and methane sulfinic acid. Also for this event, backtrajectory calculations show, that the air masses came from above the ocean (distance >330 km) with no local sur- face contacts. This study demonstrates the potential impact of marine DMS emissions on the availability of sulfur-containing vapors in the remote free troposphere far away from the ocean.
Review of acp-2021-126
(2021) Diego Aliaga; Victoria A. Sinclair; Marcos Andrade; Paulo Artaxo; Samara Carbone; Evgeny Kadantsev; Paolo Laj; Alfred Wiedensohler; Radovan Krejčí; Federico Bianchi
Abstract. Observations of aerosol and trace gases in the remote troposphere are vital to quantify background concentrations and identify long-term trends in atmospheric composition on large spatial scales. Measurements made at high altitude are often used to study free-tropospheric air; however such high-altitude sites can be influenced by boundary layer air masses. Thus, accurate information on air mass origin and transport pathways to high-altitude sites is required. Here we present a new method, based on the source–receptor relationship (SRR) obtained from backwards WRF-FLEXPART simulations and a k-means clustering approach, to identify source regions of air masses arriving at measurement sites. Our method is tailored to areas of complex terrain and to stations influenced by both local and long-range sources. We have applied this method to the Chacaltaya (CHC) GAW station (5240 m a.s.l.; 16.35∘ S, 68.13∘ W) for the 6-month duration of the “Southern Hemisphere high-altitude experiment on particle nucleation and growth” (SALTENA) to identify where sampled air masses originate and to quantify the influence of the surface and the free troposphere. A key aspect of our method is that it is probabilistic, and for each observation time, more than one air mass (cluster) can influence the station, and the percentage influence of each air mass can be quantified. This is in contrast to binary methods, which label each observation time as influenced by either boundary layer or free-troposphere air masses. Air sampled at CHC is a mix of different provenance. We find that on average 9 % of the air, at any given observation time, has been in contact with the surface within 4 d prior to arriving at CHC. Furthermore, 24 % of the air has been located within the first 1.5 km above ground level (surface included). Consequently, 76 % of the air sampled at CHC originates from the free troposphere. However, pure free-tropospheric influences are rare, and often samples are concurrently influenced by both boundary layer and free-tropospheric air masses. A clear diurnal cycle is present, with very few air masses that have been in contact with the surface being detected at night. The 6-month analysis also shows that the most dominant air mass (cluster) originates in the Amazon and is responsible for 29 % of the sampled air. Furthermore, short-range clusters (origins within 100 km of CHC) have high temporal frequency modulated by local meteorology driven by the diurnal cycle, whereas the mid- and long-range clusters' (>200 km) variability occurs on timescales governed by synoptic-scale dynamics. To verify the reliability of our method, in situ sulfate observations from CHC are combined with the SRR clusters to correctly identify the (pre-known) source of the sulfate: the Sabancaya volcano located 400 km north-west from the station.