Browsing by Autor "Qiaozhi Zha"

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Comment on egusphere-2022-1182
(2023) Qiaozhi Zha; Wei Huang; Diego Aliaga; Otso Peräkylä; Liine Heikkinen; Alkuin Maximilian Koenig; Cheng Wu; Joonas Enroth; Yvette Gramlich; Jing Cai
Air ions are the key components for a series of atmospheric physicochemical interactions, such as ion-catalyzed reactions, ion-molecule reactions, and ion-induced new particle formation. They also control atmospheric electrical properties with effects on global climate. We performed molecular-level measurements of cluster ions at the high-altitude research station Chacaltaya (CHC; 5240 m a.s.l.), located in the Bolivian Andes, from January to May 2018 using an atmospheric pressure interface time-of-flight mass spectrometer. The negative ions mainly consisted of (H2SO4)0–3•HSO4−, (HNO3)0–2•NO3−, SO5−, (NH3)1–6•(H2SO4)3–7•HSO4−, malonic acid-derived, and CHO/CHON•(HSO4−/NO3−) cluster ions. Their temporal variability exhibited distinct diurnal and seasonal patterns due to the changes in the corresponding neutral species’ molecular properties (such as electron affinity and proton affinity) and concentrations resulting from the air masses arriving at CHC from different source regions. The positive ions were mainly composed of protonated amines and organic cluster ions, but exhibited no clear diurnal variation. H2SO4-NH3 cluster ions likely contributed to the new particle formation process, particularly during wet-to-dry transition period and dry season when CHC was more impacted by air masses originating from source regions with elevated SO2 emissions. Our study provides new insights into the chemical composition of atmospheric cluster ions and their role in new particle formation in the high-altitude mountain environment of the Bolivian Andes.
Comment on egusphere-2022-1182
(2023) Qiaozhi Zha; Wei Huang; Diego Aliaga; Otso Peräkylä; Liine Heikkinen; Alkuin Maximilian Koenig; Cheng Wu; Joonas Enroth; Yvette Gramlich; Jing Cai
Air ions are the key components for a series of atmospheric physicochemical interactions, such as ion-catalyzed reactions, ion-molecule reactions, and ion-induced new particle formation. They also control atmospheric electrical properties with effects on global climate. We performed molecular-level measurements of cluster ions at the high-altitude research station Chacaltaya (CHC; 5240 m a.s.l.), located in the Bolivian Andes, from January to May 2018 using an atmospheric pressure interface time-of-flight mass spectrometer. The negative ions mainly consisted of (H2SO4)0–3•HSO4−, (HNO3)0–2•NO3−, SO5−, (NH3)1–6•(H2SO4)3–7•HSO4−, malonic acid-derived, and CHO/CHON•(HSO4−/NO3−) cluster ions. Their temporal variability exhibited distinct diurnal and seasonal patterns due to the changes in the corresponding neutral species' molecular properties (such as electron affinity and proton affinity) and concentrations resulting from the air masses arriving at CHC from different source regions. The positive ions were mainly composed of protonated amines and organic cluster ions, but exhibited no clear diurnal variation. H2SO4-NH3 cluster ions likely contributed to the new particle formation process, particularly during wet-to-dry transition period and dry season when CHC was more impacted by air masses originating from source regions with elevated SO2 emissions. Our study provides new insights into the chemical composition of atmospheric cluster ions and their role in new particle formation in the high-altitude mountain environment of the Bolivian Andes.
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.
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.
Measurement report: Molecular-level investigation of atmospheric cluster ions at the tropical high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes
(Copernicus Publications, 2023) Qiaozhi Zha; Wei Huang; Diego Aliaga; Otso Peräkylä; Liine Heikkinen; Alkuin Maximilian Koenig; Cheng Wu; Joonas Enroth; Yvette Gramlich; Jing Cai
Abstract. Air ions are the key components for a series of atmospheric physicochemical interactions, such as ion-catalyzed reactions, ion-molecule reactions, and ion-induced new particle formation (NPF). They also control atmospheric electrical properties with effects on global climate. We performed molecular-level measurements of cluster ions at the high-altitude research station Chacaltaya (CHC; 5240 m a.s.l.), located in the Bolivian Andes, from January to May 2018 using an atmospheric-pressure-interface time-of-flight mass spectrometer. The negative ions mainly consisted of (H2SO4)0–3⚫HSO4-, (HNO3)0–2⚫NO3-, SO5-, (NH3)1–6⚫(H2SO4)3–7⚫HSO4-, malonic-acid-derived, and CHO / CHON⚫(HSO4- / NO3-) cluster ions. Their temporal variability exhibited distinct diurnal and seasonal patterns due to the changes in the corresponding neutral species' molecular properties (such as electron affinity and proton affinity) and concentrations resulting from the air masses arriving at CHC from different source regions. The positive ions were mainly composed of protonated amines and organic cluster ions but exhibited no clear diurnal variation. H2SO4–NH3 cluster ions likely contributed to the NPF process, particularly during the wet-to-dry transition period and the dry season, when CHC was more impacted by air masses originating from source regions with elevated SO2 emissions. Our study provides new insights into the chemical composition of atmospheric cluster ions and their role in new particle formation in the high-altitude mountain environment of the Bolivian Andes.
Measurement report: Molecular-level investigation of atmospheric cluster ions at the tropical high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes
(2022) Qiaozhi Zha; Wei Huang; Diego Aliaga; Otso Peräkylä; Liine Heikkinen; Alkuin Maximilian Koenig; Cheng Wu; Joonas Enroth; Yvette Gramlich; Jing Cai
Abstract. Air ions are the key components for a series of atmospheric physicochemical interactions, such as ion-catalyzed reactions, ion-molecule reactions, and ion-induced new particle formation. They also control atmospheric electrical properties with effects on global climate. We performed molecular-level measurements of cluster ions at the high-altitude research station Chacaltaya (CHC; 5240 m a.s.l.), located in the Bolivian Andes, from January to May 2018 using an atmospheric pressure interface time-of-flight mass spectrometer. The negative ions mainly consisted of (H2SO4)0–3•HSO4−, (HNO3)0–2•NO3−, SO5−, (NH3)1–6•(H2SO4)3–7•HSO4−, malonic acid-derived, and CHO/CHON•(HSO4−/NO3−) cluster ions. Their temporal variability exhibited distinct diurnal and seasonal patterns due to the changes in the corresponding neutral species’ molecular properties (such as electron affinity and proton affinity) and concentrations resulting from the air masses arriving at CHC from different source regions. The positive ions were mainly composed of protonated amines and organic cluster ions, but exhibited no clear diurnal variation. H2SO4-NH3 cluster ions likely contributed to the new particle formation process, particularly during wet-to-dry transition period and dry season when CHC was more impacted by air masses originating from source regions with elevated SO2 emissions. Our study provides new insights into the chemical composition of atmospheric cluster ions and their role in new particle formation in the high-altitude mountain environment of the Bolivian Andes.
Oxidized organic molecules in the tropical free troposphere over Amazonia
(Oxford University Press, 2023) Qiaozhi Zha; Diego Aliaga; Radovan Krejčí; Victoria A. Sinclair; Cheng Wu; Giancarlo Ciarelli; Wiebke Scholz; Liine Heikkinen; Eva Partoll; Yvette Gramlich
New particle formation (NPF) in the tropical free troposphere (FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules (OOMs) produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical observations. We performed in situ molecular-level OOMs measurements at the Bolivian station Chacaltaya at 5240 m above sea level, on the western edge of Amazonia. For the first time, we demonstrate the presence of OOMs, mainly with 4-5 carbon atoms, in both gas-phase and particle-phase (in terms of mass contribution) measurements in tropical FT air from Amazonia. These observations, combined with air mass history analyses, indicate that the observed OOMs are linked to isoprene emitted from the rainforests hundreds of kilometers away. Based on particle-phase measurements, we find that these compounds can contribute to NPF, at least the growth of newly formed nanoparticles, in the tropical FT on a continental scale. Thus, our study is a fundamental and significant step in understanding the aerosol formation process in the tropical FT.
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.
Source region cluster analysis in the high-altitude measuring site of Chacaltaya with WRF and FLEXPART
(2020) Diego Aliaga; Victoria A. Sinclair; Qiaozhi Zha; Marcos Andrade; Claudia Mohr; Radovan Krejčí
&lt;p&gt;Measuring aerosol at high altitude sites is useful as it enables sampling of the free troposphere over long time frames. However, in order to draw conclusions from station measurement data, we need to determine which air mass sources are present at any given sampling time. This task is challenging at mountain sites, due to complex topography which in turn drives complex meteorology. Between December 2017 and May 2018, the Southern hemisphere high ALTitude Experiment on particle Nucleation And growth (SALTENA) campaign was conducted at Chacaltaya in Bolivia at 5240 m a.s.l. The data set obtained in this campaign contains records of nearly all relevant aerosol characteristics and aerosol precursors. To identify the source regions of the observed air masses we performed high resolution (down to 1 km) simulations with the Weather Research and Forecasting Model (WRF). The WRF model output is then used to as input to the Lagrangian particle dispersion model (FLEXPART). FLEXPART simulations are initialised every hour and 20 thousand particles are released per hour and track backwards in time for 96 hours. The FLEXPART footprint output is regridded onto a log-polar cylindrical grid where we perform a &amp;#8216;K-means&amp;#8217; cluster analysis on the 3D cells defined by the grid. The cells are clustered based on the time series of their source receptor relationship (i.e. emission sensitivities), producing regions (clusters) resolved not only in the horizontal but also the vertical domain. Our results show that regions located close to the station (&lt;100km) have a low but persistent influence with diurnal variations and close contact to the surface. Mid-range regions (100-800km) have the highest influence with a higher percentage of air masses from the free troposphere. Long-range regions (&gt;800km) have a higher influence than the short-range regions but lower than the middle-range regions. Most of the air masses from these long-range regions come from the free troposphere. With this method we have successfully resolved the various air mass influences at the measurement site. The high meteorological resolution and the stochastic nature of FLEXPART are seminal for capturing the transport pathways.&lt;/p&gt;
The SALTENA Experiment: Comprehensive Observations of Aerosol Sources, Formation, and Processes in the South American Andes
(American Meteorological Society, 2021) Federico Bianchi; Victoria A. Sinclair; Diego Aliaga; Qiaozhi Zha; Wiebke Scholz; Cheng Wu; Liine Heikkinen; Robin L. Modini; Eva Partoll; Fernando Velarde
Abstract This paper presents an introduction to the Southern Hemisphere High Altitude Experiment on Particle Nucleation and Growth (SALTENA). This field campaign took place between December 2017 and June 2018 (wet to dry season) at Chacaltaya (CHC), a GAW (Global Atmosphere Watch) station located at 5,240 m MSL in the Bolivian Andes. Concurrent measurements were conducted at two additional sites in El Alto (4,000 m MSL) and La Paz (3,600 m MSL). The overall goal of the campaign was to identify the sources, understand the formation mechanisms and transport, and characterize the properties of aerosol at these stations. State-of-the-art instruments were brought to the station complementing the ongoing permanent GAW measurements, to allow a comprehensive description of the chemical species of anthropogenic and biogenic origin impacting the station and contributing to new particle formation. In this overview we first provide an assessment of the complex meteorology, airmass origin, and boundary layer–free troposphere interactions during the campaign using a 6-month high-resolution Weather Research and Forecasting (WRF) simulation coupled with Flexible Particle dispersion model (FLEXPART). We then show some of the research highlights from the campaign, including (i) chemical transformation processes of anthropogenic pollution while the air masses are transported to the CHC station from the metropolitan area of La Paz–El Alto, (ii) volcanic emissions as an important source of atmospheric sulfur compounds in the region, (iii) the characterization of the compounds involved in new particle formation, and (iv) the identification of long-range-transported compounds from the Pacific or the Amazon basin. We conclude the article with a presentation of future research foci. The SALTENA dataset highlights the importance of comprehensive observations in strategic high-altitude locations, especially the undersampled Southern Hemisphere.