Joshua P. DiGangi
A5050316507- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Spectroscopy and Laser Applications
- Fire effects on ecosystems
- Vehicle emissions and performance
- Meteorological Phenomena and Simulations
- Odor and Emission Control Technologies
- Ionosphere and magnetosphere dynamics
- Aeolian processes and effects
- Climate variability and models
- Methane Hydrates and Related Phenomena
- Advanced Aircraft Design and Technologies
- Hydrocarbon exploration and reservoir analysis
- Geophysics and Gravity Measurements
- Icing and De-icing Technologies
- Water Quality Monitoring and Analysis
- Marine and coastal ecosystems
- Advanced Chemical Sensor Technologies
- Gas Dynamics and Kinetic Theory
- CO2 Sequestration and Geologic Interactions
- Toxic Organic Pollutants Impact
Langley Research Center
2016-2025
National Aeronautics and Space Administration
2015-2025
Bellingham Technical College
2018
Princeton University
2012-2015
University of Wisconsin–Madison
2008-2014
University of Illinois Urbana-Champaign
2007
Abstract. The understanding of oxidation in forest atmospheres is being challenged by measurements unexpectedly large amounts hydroxyl (OH). A significant number these OH were made laser-induced fluorescence low-pressure detection chambers (called Fluorescence Assay with Gas Expansion (FAGE)) using the Penn State Ground-based Tropospheric Hydrogen Oxides Sensor (GTHOS). We deployed a new chemical removal method to measure parallel traditional FAGE California forest. gives on average only...
Abstract Contrail cirrus account for the major share of aviation’s climate impact. Yet, links between jet fuel composition, contrail microphysics and impact remain unresolved. Here we present unique observations from two DLR-NASA aircraft campaigns that measured exhaust characteristics an Airbus A320 burning either standard fuels or low aromatic sustainable aviation blends. Our results show soot particles can regulate number ice crystals current emission levels. We provide experimental...
Wildfires are a substantial but poorly quantified source of tropospheric ozone (O3). Here, to investigate the highly variable O3 chemistry in wildfire plumes, we exploit situ chemical characterization western wildfires during FIREX-AQ flight campaign and show that production can be predicted as function experimentally constrained OH exposure, volatile organic compound (VOC) reactivity, fate peroxy radicals. The exhibits rapid transition regimes. Within few daylight hours, formation...
Significance Understanding the sources of tropospheric ozone is important for effective air quality management and accurate radiative forcing attribution. Biomass burning emits large quantities precursors to lower atmosphere. This source can drive regional-scale production, but its impact on global poorly constrained. Here, we present unique in situ aircraft observations continental pollution tracers. Ozone enhancements attributable biomass equal or exceed those from urban emissions, a...
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. The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs) beginning in 2004 from over 30 current or past measurement sites around the world, using solar absorption spectroscopy near infrared region. TCCON GHG data have been used extensively for multiple purposes, including studies carbon cycle and anthropogenic emissions as well to validate improve observations made spacebased sensors. Here, we describe an update...
Airborne NASA Langley Research Center (LaRC) High Spectral Resolution Lidar-2 (HSRL-2) measurements acquired during the recent Earth Venture Suborbital-3 (EVS-3) Aerosol Cloud Meteorology Interactions over Western Atlantic Experiment (ACTIVATE) revealed elevated particulate linear depolarization associated with aerosols within marine boundary layer. These observations were off east coast of United States both winter and summer 2020 2021 when HSRL-2 was deployed on LaRC King Air aircraft....
Abstract The NASA Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP 2 Ex) employed the P-3, Stratton Park Engineering Company (SPEC) Learjet 35, a host of satellites surface sensors to characterize coupling aerosol processes, cloud physics, atmospheric radiation within Maritime Continent’s complex southwest monsoonal environment. Conducted in late summer 2019 from Luzon, Philippines, conjunction with Office Naval Research Propagation Intraseasonal Tropical Oscillations...
Abstract. The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs), beginning in 2004, from over 30 current or past measurement sites around the world using solar absorption spectroscopy near-infrared (near-IR) region. TCCON GHG data have been used extensively for multiple purposes, including studies carbon cycle and anthropogenic emissions, as well to validate improve observations space-based sensors. Here, we describe an...
Abstract. Extensive airborne measurements of non-methane organic gases (NMOGs), methane, nitrogen oxides, reduced species, and aerosol emissions from US wild prescribed fires were conducted during the 2019 NOAA/NASA Fire Influence on Regional to Global Environments Air Quality campaign (FIREX-AQ). Here, we report atmospheric enhancement ratios (ERs) inferred emission factors (EFs) for compounds measured board NASA DC-8 research aircraft nine wildfires one fire, which encompass a range...
Abstract. Organic aerosol (OA) is an important fraction of submicron aerosols. However, it challenging to predict and attribute the specific organic compounds sources that lead observed OA loadings, largely due contributions from secondary production. This especially true for megacities surrounded by numerous regional create background. Here, we utilize in situ gas observations collected on board NASA DC-8 during NASA–NIER KORUS-AQ (Korea–United States Air Quality) campaign investigate...
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,...
Abstract. We report the first observations of formaldehyde (HCHO) flux measured via eddy covariance, as well HCHO concentrations and gradients, observed by Madison Fiber Laser-Induced Fluorescence Instrument during BEACHON-ROCS 2010 campaign in a rural, Ponderosa Pine forest northwest Colorado Springs, CO. A median noon upward ~80 μg m−2 h−1 (~24 pptv m s−1) was with range 37 to 131 h−1. Enclosure experiments were performed determine branch (3.5 m-2 h−1) soil (7.3 direct emission rates...
Abstract. We present the first data on concentration of sea-salt aerosol throughout most depth troposphere and over a wide range latitudes, which were obtained during Atmospheric Tomography (ATom) mission. Sea-salt concentrations in upper are very small, usually less than 10 ng per standard m3 (about parts trillion by mass) often 1 m−3. This puts stringent limits contribution to halogen nitric acid chemistry troposphere. Within broad regions is roughly proportional water vapor, supporting...
Abstract The February–March 2014 deployment of the National Aeronautics and Space Administration (NASA) Airborne Tropical Tropopause Experiment (ATTREX) provided unique in situ measurements western Pacific tropical tropopause layer (TTL). Six flights were conducted from Guam with long-range, high-altitude, unmanned Global Hawk aircraft. ATTREX payload water vapor, meteorological conditions, cloud properties, tracer chemical radical concentrations, radiative fluxes. campaign was partially...
Abstract. The San Joaquin Valley (SJV) experiences some of the worst ozone air quality in US, frequently exceeding California 8 h standard 70.4 ppb. To improve our understanding trends number violations SJV, we analyze observed relationships between organic reactivity, nitrogen oxides (NOx), and daily maximum temperature southern SJV using measurements made as part at Nexus Air Quality Climate Change 2010 (CalNex-SJV). We find daytime speciated reactivity with respect to OH during CalNex-SJV...
Abstract We examine the distribution and fate of nitrogen oxides (NO x ) in lower troposphere over Northeast United States (NE US) using aircraft observations from Wintertime INvestigation Transport, Emissions, Reactivity (WINTER) campaign February–March 2015, as well GEOS‐Chem chemical transport model concurrent ground‐based observations. find that National Emission Inventory U.S. Environmental Protection Agency is consistent with WINTER total reactive ( T NO y to within 10% on average,...
The Korea – United States Air Quality Study (May June 2016) deployed instrumented aircraft and ground-based measurements to elucidate causes of poor air quality related high ozone aerosol concentrations in South Korea. This work synthesizes data pertaining aerosols (specifically, particulate matter with aerodynamic diameters <2.5 micrometers, PM2.5) conditions leading violations Korean standards (24-hr mean PM2.5 < 35 µg m–3). variability from AirKorea monitors across is...
Abstract The largest share in the climate impact of aviation results from contrail cirrus clouds. Here, dependence microphysical ice properties and extinction on temperature humidity is investigated. Contrail measurements were performed at various altitudes during 2018 ECLIF II/NDMAX campaign with NASA DC‐8 chasing DLR A320. Ice number concentrations coefficients are near 9.5 km, typical for short‐ medium‐range air traffic. At higher 11.5 low ambient water vapor lead to smaller particle...
Abstract Wildfire smoke influences on air quality and atmospheric chemistry have been underscored by the increasing fire prevalence in recent years, yet, connection between fire, emissions, subsequent transformation of this atmosphere remains poorly constrained. Toward improving these linkages, we present a new method for coupling high time‐resolution satellite observations radiative power with situ aerosols trace gases. We apply technique to 13 plumes comprehensively characterized during...
Oceans emit large quantities of dimethyl sulfide (DMS) to the marine atmosphere. The oxidation DMS leads formation and growth cloud condensation nuclei (CCN) with consequent effects on Earth's radiation balance climate. quantitative assessment impact emissions CCN concentrations necessitates a detailed description in presence existing aerosol particles clouds. In unpolluted atmosphere, is efficiently oxidized hydroperoxymethyl thioformate (HPMTF), stable intermediate chemical trajectory...
Abstract Earth's atmosphere oxidizes the greenhouse gas methane and other gases, thus determining their lifetimes oxidation products. Much of this occurs in remote, relatively clean free troposphere above planetary boundary layer, where chemistry is thought to be much simpler better understood than it urban regions or forests. The NASA airborne Atmospheric Tomography study (ATom) was designed produce cross sections detailed atmospheric composition remote over Pacific Atlantic Oceans during...
Abstract. Wildfires are increasing in size across the western US, leading to increases human smoke exposure and associated negative health impacts. The impact of biomass burning (BB) smoke, including wildfires, on regional air quality depends emissions, transport, chemistry, oxidation emitted BB volatile organic compounds (BBVOCs) by hydroxyl radical (OH), nitrate (NO3), ozone (O3). During daytime, when light penetrates plumes, BBVOCs oxidized mainly O3 OH. In contrast, at night or optically...