A5035272354- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Ionosphere and magnetosphere dynamics
- Climate variability and models
- Air Quality Monitoring and Forecasting
- Air Quality and Health Impacts
- Aeolian processes and effects
- Tropical and Extratropical Cyclones Research
- Spaceflight effects on biology
- Advanced Aircraft Design and Technologies
- Icing and De-icing Technologies
- Aerospace and Aviation Technology
- Gas Dynamics and Kinetic Theory
- Solar and Space Plasma Dynamics
- Fire effects on ecosystems
- Inertial Sensor and Navigation
- Ocean Waves and Remote Sensing
- nanoparticles nucleation surface interactions
- Particle Dynamics in Fluid Flows
- Astro and Planetary Science
- Oceanographic and Atmospheric Processes
- Climate Change and Geoengineering
Ames Research Center
2016-2025
Bay Area Environmental Research Institute
2020-2024
National Aeronautics and Space Administration
1999-2023
Hue University
2023
Stratton Park Engineering Company (United States)
2022
University of Colorado Boulder
1999-2021
Cooperative Institute for Research in Environmental Sciences
1999-2021
Vietnam Academy of Science and Technology
2020
Howard Hughes Medical Institute
2010
Johns Hopkins University
2010
Dimethyl sulfide (DMS), emitted from the oceans, is most abundant biological source of sulfur to marine atmosphere. Atmospheric DMS oxidized condensable products that form secondary aerosols affect Earth's radiative balance by scattering solar radiation and serving as cloud condensation nuclei. We report atmospheric discovery a previously unquantified oxidation product, hydroperoxymethyl thioformate (HPMTF, HOOCH2SCHO), identified through global-scale airborne observations demonstrate it be...
Abstract. From 2016 to 2018 a DC-8 aircraft operated by the US National Aeronautics and Space Administration (NASA) made four series of flights, profiling atmosphere from 180 m ∼12 km above sea level (km a.s.l.) Arctic Antarctic over both Pacific Atlantic oceans. This program, Atmospheric Tomography Mission (ATom), sought sample troposphere in representative manner, making measurements atmospheric composition each season. paper describes aerosol microphysical derived quantities obtained...
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...
A new configuration of the Community Earth System Model (CESM)/Community Atmosphere with full chemistry (CAM-chem) supporting capability horizontal mesh refinement through use spectral element (SE) dynamical core is developed and called CESM/CAM-chem-SE. Horizontal in CESM/CAM-chem-SE unique novel that pollutants such as ozone are accurately represented at human exposure relevant scales while also directly including global feedbacks. down to ∼14 km over conterminous US (CONUS) beginning...
The concentrations of the hydrogen radicals OH and HO2 in middle upper troposphere were measured simultaneously with those NO, O3, CO, H2O, CH4, non-methane hydrocarbons, ultraviolet visible radiation field. data allow a direct examination processes that produce O3 this region atmosphere. Comparison calculations based on their production from water vapor, ozone, methane demonstrate these sources are insufficient to explain observed radical troposphere. photolysis carbonyl peroxide compounds...
Large particles containing nitric acid (HNO3) were observed in the 1999/2000 Arctic winter stratosphere. These situ observations made over a large altitude range (16 to 21 kilometers) and horizontal extent (1800 on several airborne sampling flights during period of weeks. With diameters 10 20 micrometers, these sedimenting have significant potential denitrify lower A microphysical model trihydrate is able simulate growth sedimentation sizes stratosphere, but nucleation process not yet known....
Optically thin cirrus near the tropical tropopause regulate humidity of air entering stratosphere, which in turn has a strong influence on Earth’s radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes formed region: ( i ) vertically extensive with low ice number concentrations, extinctions, large supersaturations (up to ∼70%) respect ice; ii layers much higher concentrations that effectively deplete vapor excess...
A Meteorological Measurement System (MMS) was designed and installed on one of the NASA high-altitude ER-2 aircraft (NASA 706). The MMS provides in situ measurements free-stream pressure (±0.3 mb), temperature (±0.3°C), wind vector (±1 m s−1). It incorporates a high-resolution inertial navigation system (INS) specially configured for scientific applications, radome differential airflow angles, compact, computer-controlled data acquisition to sample, process store 45 variables tape disc....
Overflights of a tropical cyclone during the Australian winter monsoon field experiment Stratosphere‐Troposphere Exchange Project (STEP) show presence two mesoscale phenomena: vertically propagating gravity wave with horizontal wavelength about 110 km and feature scale comparable to that cyclone's entire cloud shield (wavelength 250 or greater). The larger is fairly steady, though its physical interpretation ambiguous. 110‐km transient, having maximum amplitude early in flight decreasing...
Abstract. In situ measurements of ice crystal concentrations and sizes made with aircraft instrumentation over the past two decades have often indicated presence numerous relatively small (< 50 μm diameter) crystals in cirrus clouds. Further, these frequently indicate that account for a large fraction extinction The fact instruments used to make measurements, such as Forward Scattering Spectrometer Probe (FSSP) Cloud Aerosol (CAS), ingest into sample volume through inlets has led...
In situ observations of H 2 O and HDO in the midlatitude stratosphere are used to evaluate role convection determining stratospheric water budget. The show that vapor overworld (potential temperature > 380 K) is isotopically heavier than expected. Measurements an airmass with anomalously high concentrations isotopic signatures characteristic evaporated ice lofted from troposphere during convective storms. Observed plume enhanced background suggest extratropical can account for a...
Emission of bromine from sea‐salt aerosol, frost flowers, ice leads, and snow results in the nearly complete removal surface ozone during Arctic spring. Regions enhanced total column BrO observed by satellites have traditionally been associated with these emissions. However, airborne measurements O 3 within convective boundary layer (CBL) ARCTAS ARCPAC field campaigns at times bear little relation to BrO. We show that locations numerous satellite “hotspots” spring are consistent observations...
Hyperactivity of the Myc oncogenic transcription factor dramatically reprograms gene expression to facilitate cellular proliferation and tumorigenesis. To elicit these effects, coordinates activation repression an extensive network protein-coding genes and, as has recently been appreciated, noncoding RNAs including microRNAs (miRNAs). Consistent with their ability potently influence cancer phenotypes, regulation miRNAs by affects virtually all aspects program, proliferation, survival,...
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. Ozone is a greenhouse gas and air pollutant that harmful to human health plants. During the summer in southeastern US, many regional global models are biased high for surface ozone compared observations. Past studies have suggested different solutions including need updates model representation of clouds, chemistry, deposition, emissions nitrogen oxides (NOx) or biogenic hydrocarbons. Here, due more comprehensive updated isoprene terpene chemistry added into CESM/CAM-chem...
Abstract On 27 August 2013, during the Studies of Emissions and Atmospheric Composition, Clouds Climate Coupling by Regional Surveys field mission, NASA's ER‐2 research aircraft encountered a region enhanced water vapor, extending over depth approximately 2 km minimum areal extent 20,000 in stratosphere (375 K to 415 potential temperature), south Great Lakes (42°N, 90°W). Water vapor mixing ratios this plume, measured Harvard Vapor instrument, constitute highest values recorded situ at these...
Significance Climate models use pre-industrial atmosphere as the reference to evaluate impacts of human activities on Earth’s radiation balance. Sea spray aerosols (SSA) are key component in relatively pristine preindustrial conditions that substantially affect model calculations. Currently, abundance SSA is poorly constrained. In particular, studies influence sea surface temperature production have shown disparate results. This uncertainty arises from limited field measurements, especially...
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...
Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality climate. Emissions feed atmospheric models estimated using burned area fire radiative power (FRP) methods rely satellite products. These approaches show wide variability large uncertainties, their accuracy is challenging to evaluate due limited aircraft ground measurements. Here, we present novel method estimate plume-integrated total carbon speciated emission rates...
Pyrocumulonimbus (pyroCb) are wildfire-generated convective clouds that can inject smoke directly into the stratosphere. PyroCb have been tracked for years, yet their apparent rarity and episodic nature lead to highly uncertain climate impacts. In situ measurements of pyroCb reveal its distinctive exceptionally stable aerosol properties define long-term influence activity on stratospheric budget. Analysis 13 years airborne observations shows responsible 10 25% black carbon organic aerosols...
The hydroxyl radical (OH) fuels atmospheric chemical cycling as the main sink for methane and a driver of formation loss many air pollutants, but direct OH observations are sparse. We develop evaluate an observation-based proxy short-term, spatial variations in (Proxy