A5056528553- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Aeolian processes and effects
- Integrated Circuits and Semiconductor Failure Analysis
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Fire effects on ecosystems
- Meteorological Phenomena and Simulations
- Advanced Surface Polishing Techniques
- Force Microscopy Techniques and Applications
- Vehicle emissions and performance
- Odor and Emission Control Technologies
- Industrial Vision Systems and Defect Detection
- Image Processing Techniques and Applications
- Near-Field Optical Microscopy
- Maritime Transport Emissions and Efficiency
- Marine and coastal ecosystems
- Air Traffic Management and Optimization
- Climate variability and models
- Oceanographic and Atmospheric Processes
- Calibration and Measurement Techniques
- VLSI and Analog Circuit Testing
- Aerodynamics and Acoustics in Jet Flows
Langley Research Center
2019-2025
Scripps Institution of Oceanography
2015-2023
University of California, San Diego
2016-2023
Universities Space Research Association
2020-2023
National Postdoctoral Association
2021
University of San Diego
2020
Centre National de la Recherche Scientifique
2017-2019
Centre National de Recherches Météorologiques
2017-2019
Météo-France
2016-2018
Centre National d'Études Spatiales
2007-2017
Abstract Weather and climate models are challenged by uncertainties biases in simulating Southern Ocean (SO) radiative fluxes that trace to a poor understanding of cloud, aerosol, precipitation, processes, their interactions. Projects between 2016 2018 used situ probes, radar, lidar, other instruments make comprehensive measurements thermodynamics, surface radiation, cloud condensation nuclei (CCN), ice nucleating particles over the SO cold waters, ubiquitous liquid mixed-phase clouds common...
Abstract Observations from a wintertime and summertime field campaign are used to assess the relationship between black brown carbon (BC BrC, respectively) optical properties particle composition coating state. The campaign, in Fresno, CA, was impacted by primary emissions residential wood burning, secondary organic inorganic formation, BC motor vehicles. Two major types of BrC were observed wintertime. One occurred primarily at night—the result biomass burning emissions. second enhanced...
Biogenic sources contribute to cloud condensation nuclei (CCN) in the clean marine atmosphere, but few measurements exist constrain climate model simulations of their importance. The chemical composition individual atmospheric aerosol particles showed two types sulfate-containing air masses addition mass-based Estimated Salt particles. Both sulfate lack combustion tracers and correlate, for some conditions, or seawater dimethyl sulfide (DMS) concentrations, which means source was largely...
Abstract. We evaluate the sensitivity of size calibrations two commercially available, high-resolution optical particle sizers to changes in aerosol composition and complex refractive index (RI). The Droplet Measurement Technologies Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) TSI, Inc. Laser (LAS) are commonly used instruments for measuring portion distribution with diameters larger than nominally 60–90 nm. Both illuminate particles a laser relate single-particle light scattering...
Abstract The majority of the aerosol particle number (condensation nuclei or CN) in marine boundary layer (MBL) consists sulfate and organic compounds that have been shown to provide a large fraction cloud condensation (CCN). Here we use submicron non‐refractory Aerosol Mass Spectrometer (AMS) filter measurements components particles measured during four North Atlantic Marine Ecosystems Study (NAAMES) research cruises assess sources contributions for CCN concentrations MBL different seasons....
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 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...
Abstract Stratocumulus clouds over the Southern Ocean have fewer droplets and are more likely to exist in predominately supercooled phase than at similar temperatures northern oceans. One reason is that this region has few continental anthropogenic sources of cloud‐nucleating particles can form ice. In work, we present an overview aerosol particle types Ocean, including new measurements made below, above region. These others indicate biogenic sulfur‐based >0.1 μm diameter contribute...
Abstract. Long-range transport of biogenic emissions from the coast Antarctica, precipitation scavenging, and cloud processing are main processes that influence observed variability in Southern Ocean (SO) marine boundary layer (MBL) condensation nuclei (CN) (CCN) concentrations during austral summer. Airborne particle measurements on HIAPER GV north–south transects between Hobart, Tasmania, 62∘ S Clouds, Radiation Aerosol Transport Experimental Study (SOCRATES) were separated into four...
Abstract Inorganic and organic coatings on black carbon (BC) particles can enhance light absorption affect atmospheric lifetimes of BC‐containing thus have significant implications for climate. To study the physical chemical characteristics BC BC‐associated coatings, a soot particle‐aerosol mass spectrometer was deployed during winter 2014–2015 in Fresno, city located San Joaquin Valley California, to selectively analyze particles. Comparing measurements those from collocated single‐particle...
Although the characteristics of biomass burning events and ambient ecosystem determine emitted smoke composition, conditions that modulate partitioning black carbon (BC) brown (BrC) formation are not well understood, nor spatial or temporal frequency factors driving particle evolution, such as hydration, coagulation, oxidation, all which impact radiative forcing. In situ data from surface observation sites aircraft field campaigns offer deep insight into optical, chemical, microphysical...
Abstract The winter synoptic evolution of the western North Atlantic and its influence on atmospheric boundary layer is described by means a regime classification based Self‐Organizing Maps applied to 12 years data (2009–2020). regimes are classified into categories according daily 600‐hPa geopotential height: dominant ridge, trough ridge eastward transition (trough‐ridge), trough, (ridge–trough). A fifth resembles climatological mean. Coherent changes in sea‐level pressure large‐scale winds...
Abstract Supercooled liquid clouds are ubiquitous over the Southern Ocean (SO), even to temperatures below −20°C, and comprise a large fraction of marine boundary layer (MBL) clouds. Earth system models reanalysis products have struggled reproduce observed cloud phase distribution occurrence ice in region. Recent simulations found microphysical representation nucleation growth has impact on these properties, however, measurements SO nucleating particles (INPs) validate sparse. This study...
Abstract. Fires emit sufficient sulfur to affect local and regional air quality climate. This study analyzes SO2 emission factors variability in smoke plumes from US wildfires agricultural fires, as well their relationship sulfate hydroxymethanesulfonate (HMS) formation. Observed for various fuel types show good agreement with the latest reviews of biomass burning factors, producing an factor range 0.47–1.2 g kg−1 C. These vary geographic location a way that suggests deposition coal...
Abstract The 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field experiment obtained a diverse set of in situ remotely sensed measurements before during pyrocumulonimbus (pyroCb) event over the Williams Flats fire Washington State. This unique dataset confirms that pyroCb activity is an efficient vertical smoke transport pathway into upper troposphere lower stratosphere (UTLS). magnitude plumes observed UTLS has increased significantly recent years,...
Abstract. Due to their fast evolution and large natural variability in macro- microphysical properties, the accurate representation of boundary layer clouds current climate models remains a challenge. One regions with intermodel spread Coupled Model Intercomparison Project Phase 6 ensemble is western North Atlantic Ocean. Here, statistically representative situ measurements can help develop constrain parameterization global models. To this end, we performed comprehensive clouds, aerosol,...
Abstract Global climate models (GCMs) are challenged by difficulties in simulating cloud phase and radiative effect over the Southern Ocean (SO). Some of new‐generation GCMs predict too much liquid little ice mixed‐phase clouds. This misrepresentation results weaker negative feedback SO a higher sensitivity. Based on model comparison with observational data obtained during Cloud Radiation Aerosol Transport Experimental Study, this study addresses key uncertainty Community Earth System Model...
Abstract. The importance of vertical wind velocities (in particular positive or updrafts) in atmospheric science has motivated the need to deploy multi-hole probes developed for manned aircraft small remotely piloted (RPA). In research, lightweight RPAs (< 2.5 kg) are now able accurately measure vectors, even a cloud, which provides essential observing tools understanding aerosol–cloud interactions. European project BACCHUS (impact Biogenic versus Anthropogenic emissions on Clouds and...
Abstract Meteorology and microphysics affect cloud formation, droplet distributions, shortwave reflectance. The Eastern Pacific Emitted Aerosol Cloud Experiment the Stratocumulus Observations of Los‐Angeles Emissions Derived Aerosol‐Droplets studies provided measurements in six case thermodynamic properties, initial particle number distribution composition, drop distribution. In this study, we use simulations from a chemical microphysical aerosol‐cloud parcel (ACP) model with explicit...
Abstract Organic aerosol mass (OM) components were investigated at Fresno in winter and Fontana summer by positive matrix factorization of high‐resolution time‐of‐flight spectra Fourier Transform infrared spectra, as well k ‐means clustering light‐scattering (LS) single‐particle spectra. The results comparable for all three methods both sites, showing different contributions primary secondary organic sources to PM 1 . At biomass burning contributed 27% OM on low‐fog days, nitrate‐related...
Very few measurements exist of the composition and contribution to cloud condensation nuclei (CCN) organic mass (OM) at different sizes for particles over Southern Ocean. Airborne shipboard composition, aerosol number size distributions, CCN spectra during Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES) provide a comparison contributions three ranges: (1) by scanning transmission X-ray microscope (STXM) with near edge absorption fine structure (NEXAFS) 0.25–1.75 µm...
Abstract The ways in which marine biological activity affects climate, by modifying aerosol properties, are not completely understood, causing high uncertainties climate predictions. In this work, situ measurements of chemical composition, particle number size distribution, cloud condensation nuclei (CCN), and ice‐nucleating (INP) concentrations combined with high‐resolution sea surface chlorophyll‐a concentration (CHL) back‐trajectory data to elucidate the relationship between oceanic...
Abstract. Marine biogenic particle contributions to atmospheric aerosol concentrations are not well understood though they important for determining cloud optical and cloud-nucleating properties. Here we examine the relationship between marine measurements (with satellites model fields of ocean biology) meteorological variables during North Atlantic Aerosols Ecosystems Study (NAAMES). NAAMES consisted four field campaigns November 2015 April 2018 that aligned with major phases annual...