Siyuan Wang
A5100440552- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Fire effects on ecosystems
- Remote Sensing and Land Use
- Air Quality Monitoring and Forecasting
- Meteorological Phenomena and Simulations
- Environmental Changes in China
- Mercury impact and mitigation studies
- Marine and coastal ecosystems
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Climate variability and models
- Remote Sensing in Agriculture
- HIV, TB, and STIs Epidemiology
- Plant responses to elevated CO2
- Various Chemistry Research Topics
- Ocean Acidification Effects and Responses
- Science Education and Pedagogy
- Climate change and permafrost
- Vehicle emissions and performance
- Microbial Community Ecology and Physiology
- Spectroscopy and Laser Applications
Cooperative Institute for Research in Environmental Sciences
2013-2025
University of Colorado Boulder
2013-2025
NOAA Chemical Sciences Laboratory
2021-2025
National Oceanic and Atmospheric Administration
2021-2024
Anhui Sanlian University
2024
University of Nevada, Reno
2024
Laboratory for Atmospheric and Space Physics
2024
Goddard Space Flight Center
2024
Sichuan Agricultural University
2024
Interuniversity Institute for Marine Sciences in Eilat
2019-2024
Abstract Aircraft and satellite observations indicate the presence of ppt (ppt ≡ pmol/mol) levels BrO in free troposphere with important implications for tropospheric budgets ozone, OH, mercury. We can reproduce these GEOS‐Chem global chemistry model by including a broader consideration multiphase halogen (Br‐Cl) than has been done past. Important reactions regenerating from its nonradical reservoirs include HOBr + Br − /Cl both aerosols clouds, oxidation ClNO 3 ozone. Most is troposphere,...
Abstract This article provides an overview of the NASA Atmospheric Tomography (ATom) mission and a summary selected scientific findings to date. ATom was airborne measurements modeling campaign aimed at characterizing composition chemistry troposphere over most remote regions Pacific, Southern, Atlantic, Arctic Oceans, examining impact anthropogenic natural emissions on global scale. These dominate chemical reactivity are exceptionally important for air quality climate. data provide in situ...
Abstract. Aerosol indirect radiative forcing (IRF), which characterizes how aerosols alter cloud formation and properties, is very sensitive to the preindustrial (PI) aerosol burden. Dimethyl sulfide (DMS), emitted from ocean, a dominant natural precursor of non-sea-salt sulfate in PI pristine present-day (PD) atmospheres. Here we revisit atmospheric oxidation chemistry DMS, particularly under conditions, its impact on IRF. Based previous laboratory studies, expand simplified DMS scheme used...
Abstract The NOAA/NASA Fire Influence on Regional to Global Environments and Air Quality (FIREX‐AQ) experiment was a multi‐agency, inter‐disciplinary research effort to: (a) obtain detailed measurements of trace gas aerosol emissions from wildfires prescribed fires using aircraft, satellites ground‐based instruments, (b) make extensive suborbital remote sensing fire dynamics, (c) assess local, regional, global modeling fires, (d) strengthen connections observables the ground such as fuels...
Abstract The National Oceanic and Atmospheric Administration (NOAA) has developed an advanced regional air quality prediction system (AQPS) within the Unified Forecast System (UFS) framework to improve representations of wildfire emissions their impacts on predictions. This innovative integrates Environmental Protection Agency’s (EPA) Community Multiscale Air Quality (CMAQ) model as a column chemistry with UFS-based atmospheric model, operating in online mode. calculation gas particulate...
Abstract. Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone atmospheric aerosols, yet models remain largely untested for lack vertically resolved measurements bromine monoxide (BrO), iodine (IO) small oxygenated hydrocarbons like glyoxal (CHOCHO) in the troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) O2–O2 collision complexes (O4) were measured by University Colorado Airborne Multi-AXis Differential Optical Absorption...
Significance Our measurements show that tropospheric halogen chemistry has a larger capacity to destroy O 3 and oxidize atmospheric mercury than previously recognized. Halogen is currently missing in most global climate models, effective at removing altitudes where intercontinental transport occurs. It further helps explain the low levels preindustrial times. Public health concerns arise from bioaccumulation of neurotoxin fish. results emphasize bromine free troposphere oxidizes faster rate,...
Atmospheric iodine monoxide (IO) is a radical that catalytically destroys heat trapping ozone and reacts further to form aerosols. Here, we report the detection of IO in tropical free troposphere (FT). We present vertical profiles from airborne measurements over Pacific Ocean show significant up 9.5 km altitude locate, on average, two-thirds total column above marine boundary layer. was observed both recent deep convective outflow aged tropospheric air, suggesting widespread abundance FT...
Bromine atoms play a central role in atmospheric reactive halogen chemistry, depleting ozone and elemental mercury, thereby enhancing deposition of toxic particularly the Arctic near-surface troposphere. However, direct bromine atom measurements have been missing to date, due lack analytical capability with sufficient sensitivity for ambient measurements. Here we present measurements, conducted springtime Arctic. Measured levels reached 14 parts per trillion (ppt, pmol mol-1; 4.2 × 108 cm-3)...
Abstract We report airborne measurements of acetaldehyde (CH 3 CHO) during the first and second deployments National Aeronautics Space Administration Atmospheric Tomography Mission (ATom). The budget CH CHO is examined using Community Model with chemistry (CAM‐chem), a newly developed online air‐sea exchange module. upper limit global ocean net emission estimated to be 34 Tg/a (42 if considering bubble‐mediated transfer), impacts on tropospheric are mostly confined marine boundary layer. Our...
Abstract Methanol is the second‐most abundant organic gas in remote atmosphere after methane, but its sources are poorly understood. Here, we report a global budget of methanol constrained by observations from ATom aircraft campaign as implemented GEOS‐Chem atmospheric chemistry model. under background marine conditions can be fit model with surface ocean concentration 61 nM and yield 13% newly CH 3 O 2 + OH reaction. While terrestrial biogenic emissions dominate budget, secondary production...
Inland sources of particulate chloride for atmospheric nitryl (ClNO2) formation remain unknown and unquantified, hindering air quality assessments. Globally each winter, tens millions tons road salt are spread on roadways deicing. Here, we identify aerosol as the primary source, accounting 80–100% ClNO2 formation, at an inland urban area in wintertime. This study provides experimental evidence connection between through production this important reservoir nitrogen oxides chlorine radicals,...
Abstract Elevated levels of reactive bromine and chlorine species in the springtime Arctic boundary layer contribute to ozone depletion mercury oxidation, as well reactions with volatile organic compounds. Recent laboratory field studies have revealed that snowpack photochemistry leads Br 2 Cl production, mechanisms which remain poorly understood. In this work, we use a photochemical box model, simplified snow module, examine halogen chemistry occurring during March 2012 Bromine, Ozone,...
Abstract Acetone is one of the most abundant oxygenated volatile organic compounds (VOCs) in atmosphere. The oceans impose a strong control on atmospheric acetone, yet oceanic fluxes acetone remain poorly constrained. In this work, global budget evaluated using two models: CAM‐chem and GEOS‐Chem. uses an online air‐sea exchange framework to calculate bidirectional fluxes, which coupled data‐oriented machine‐learning approach. algorithm trained suite seawater measurements. GEOS‐Chem fixed...
Abstract. In situ measurements of aerosol microphysical, chemical, and optical properties were made during global-scale flights from 2016–2018 as part the Atmospheric Tomography Mission (ATom). The NASA DC-8 aircraft flew ∼ 84∘ N to 86∘ S latitude over Pacific, Atlantic, Arctic, Southern oceans while profiling nearly continuously between altitudes 160 m 12 km. These global circuits once each season. Particle size distributions measured in cabin at dry conditions with an underwing probe...
Abstract Wildland fires involve complicated processes that are challenging to represent in chemical transport models. Recent airborne measurements reveal remarkable tomography fresh wildland fire plumes, which remain yet be fully explored using Here, we present a high‐resolution large eddy simulation model coupled chemistry study the evolution plume. The is configured for heavily sampled during Fire Influence on Regional Global Environments and Air Quality field campaign, variety of used...
We present a novel method, the Gaussian observational model for edge to center heterogeneity (GOMECH), quantify horizontal chemical structure of plumes. GOMECH fits observations short-lived emissions or products against long-lived tracer (e.g., CO) provide relative metrics plume width (wi/wCO) and (bi/wCO). To validate GOMECH, we investigate OH NO3 oxidation processes in smoke plumes sampled during FIREX-AQ (Fire Influence on Regional Global Environments Air Quality, 2019 wildfire study). An...
Organic nitrates (ONs) can impact spatial distribution of reactive nitrogen species and ozone formation in the atmosphere. While photolysis ONs is known to result release NO2 back atmosphere, rate constants mechanisms monoterpene-derived (MT-ONs) have not been well constrained. We investigated gas-phase three synthetic derived from α-pinene, β-pinene, d-limonene through chamber experiments. The measured ranged (0.55 ± 0.10) × 10–5 (2.3 0.80) s–1 under black lights. When extrapolated solar...
Abstract. We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box model to infer total gas-phase inorganic (Bry) over the tropical western Pacific Ocean (tWPO) during CONTRAST field campaign (January–February 2014). The observed BrO inferred Bry profiles peak in marine boundary layer (MBL), suggesting need for a source from sea-salt aerosol (SSA), addition organic (CBry). Both are found be C-shaped with local maxima upper free troposphere (FT)....
Atomic chlorine (Cl) is a strong atmospheric oxidant that shortens the lifetimes of pollutants and methane in springtime Arctic, where molecular halogens Cl2 BrCl are known Cl precursors. Here, we quantify contributions reactive trace gases present first observations, to our knowledge, ClNO2 (another precursor), N2O5, HO2NO2 Arctic. During March – May 2016 near Utqiaġvik, Alaska, up 21 ppt ClNO2, 154 Cl2, 27 ClO, 71 BrCl, 153 were measured using chemical ionization mass spectrometry. The...
Abstract We present the analysis of atmospheric budget nitrophenols and nitrocresols, a class nitroaromatics that raise great ecosystem health concerns due to their phytotoxic genotoxic properties, during spring wheat harvest season in Eastern China. Significant quantities with maximum concentrations over 100 pptv distinct diurnal patterns peak around midnight maintain low levels throughout day were observed, coincidence extensive open crop residue burning activities conducted vicinity. An...
Abstract Secondary organic aerosols (SOA) formed from common anthropogenic and biogenic volatile compounds (VOCs) account for a significant portion of particulate matter in the ambient atmosphere. The Pearl River Delta (PRD) southern China, located subtropics as region with intensive manufacturing industries, has emissions both VOCs. Two recent SOA tracer‐based measurement studies, one Hong Kong (located at mouth PRD) other site 20 to 50 km downwind urban Guangzhou districts middle PRD, show...
Abstract. The elevated deposition of atmospheric mercury over the southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles bromine monoxide (BrO) radicals, a key component oxidation chemistry, to better understand processes altitudes at which being oxidized in atmosphere. We use data from ground-based MAX-DOAS instrument located coastal site ∼ 1 km Gulf Mexico Breeze, FL, where had previously detected tropospheric BrO (Coburn et al.,...
The near-real-time legacy product of Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (3B42RT) and the equivalent products Integrated Retrievals for Global Measurement mission (IMERG-E IMERG-L) were evaluated compared over Mainland China from 1 January 2015 to 31 December 2016 at daily timescale, against rain gauge measurements. Results show that: (1) Both 3B42RT IMERG overestimate light (0.1–9.9 mm/day), while underestimate moderate (10.0–24.9 mm/day) heavy...