A5042542945- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Aeolian processes and effects
- Atmospheric and Environmental Gas Dynamics
- Icing and De-icing Technologies
- Meteorological Phenomena and Simulations
- Air Quality and Health Impacts
- Ecology and Conservation Studies
- Advanced Aircraft Design and Technologies
- Plant Ecology and Soil Science
- Fire effects on ecosystems
- Arctic and Antarctic ice dynamics
- Climate variability and models
- Particle Dynamics in Fluid Flows
- Tropical and Extratropical Cyclones Research
- Ionosphere and magnetosphere dynamics
- Indoor Air Quality and Microbial Exposure
- Cryospheric studies and observations
- Regional Development and Environment
- Methane Hydrates and Related Phenomena
- Vehicle emissions and performance
- Air Traffic Management and Optimization
- Wind and Air Flow Studies
- Combustion and Detonation Processes
Scripps Institution of Oceanography
2015-2024
Oregon State University
2007-2024
Northwest Research Associates
2015-2024
University of California, San Diego
2015-2024
Handix Scientific (United States)
2023
University of Washington
1988-2021
National Institute of Meteorology
2010-2015
Zimmer Biomet (United States)
2012-2015
Clinical Orthopaedics and Related Research
2014
Radar (United States)
2014
Knowledge of cloud and precipitation formation processes remains incomplete, yet global is predominantly produced by clouds containing the ice phase. Ice first forms in warmer than -36 °C on particles termed nuclei. We combine observations from field studies over a 14-year period, variety locations around globe, to show that concentrations nuclei active mixed-phase conditions can be related temperature number larger 0.5 μm diameter. This new relationship reduces unexplained variability at...
Dusty Origins The formation of cirrus clouds begins with the production ice nuclei, on which water vapor then condenses. Cziczo et al. (p. 1320 , published online 9 May) determined kinds particles crystals form by sublimating samples collected research aircraft and analyzing chemical physical properties residual seeds. Most seed were either mineral dust or metallic.
Shallow, maritime cumuli are ubiquitous over much of the tropical oceans, and characterizing their properties is important to understanding weather climate. The Rain in Cumulus Ocean (RICO) field campaign, which took place during November 2004–January 2005 trades western Atlantic, emphasized measurements processes related formation rain shallow cumuli, how subsequently modifies structure ensemble statistics trade wind clouds. Eight weeks nearly continuous S-band polarimetric radar sampling,...
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...
The second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field study is described. program consisted nine flights in marine stratocumulus west-southwest San Diego, California. objective the was to better understand physics a n d dynamics stratocumulus. Toward this end special flight strategies, including predominantly nocturnal flights, were employed optimize estimates entrainment velocities at cloud-top, large-scale divergence within boundary layer, drizzle processes cloud,...
Many soil‐derived particles dominated by insoluble material, including Saharan dusts, are known to act as ice nuclei. If, however, dust can compete with other atmospheric particle types form liquid cloud droplets, they have a greater potential change climate through indirect effects on radiative properties and affect the hydrological cycle precipitation changes. By directly collecting analyzing residual nuclei of small we demonstrate that do commonly condensation (CCN) in eastern North...
A new approach is described for calculating the mass (m) and terminal velocity (Vt) of ice particles from airborne balloon-borne imaging probe data as well its applications remote sensing modeling studies. Unlike past studies that derived these parameters maximum (projected) dimension (D) habit alone, "two-parameter approach" uses D particle's projected cross-sectional area (A). Expressions were developed relate ratio (Ar; an particle normalized by a circle with diameter D) to effective...
In this study, aircraft data are used to derive effective ice particle densities. This density is defined as the mass divided by volume of an equivalent diameter sphere. Measured size distributions and total water contents densities for populations (ρe) a function [ρe(D)]. The values critical modeling remote sensing applications. method uses (PSDs) measured several spectrometers compute per unit air, assuming that particles spheres. Simultaneous direct measurements content from counterflow...
Abstract The mass–dimensional relationship put forth by Brown and Francis has been widely used for developing parameterizations representing ice cloud microphysical properties. This forms the cornerstone past forthcoming retrievals of properties from ground-based spaceborne active passive sensors but yet to be rigorously evaluated. study uses data six field campaigns evaluate this in a variety types temperatures account deviations observed with temperature size, based on particle ensembles....
Data from nine stratocumulus clouds in the northeastern Pacific Ocean were analyzed to determine effect of aerosol particles on cloud microphysical and radiative properties. Seven nighttime two daytime cases included. The number concentration below‐cloud (>0.10 μm diameter) was highly correlated with droplet concentration. Droplet concentrations typically about 75% particle range studied (≤400 cm −3 ). Particle anticorrelated size liquid water content drizzle‐sized drops. Radiative impact...
Abstract A framework for an empirical parameterization (EP) of heterogeneous nucleation ice crystals by multiple species aerosol material in clouds was proposed a 2008 paper the authors. The present reports improvements to specification few its parameters. These include temperatures onset freezing, baseline surface areas observed field campaigns over Colorado, and new parameters properties black carbon, such as hydrophilicity organic coatings. EP’s third group nucleus (IN) aerosols is...
Many investigations using satellite data have determined that aerosol optical depth and cloud cover are correlated some interpreted the correlation as evidence of an indirect effect on clouds. This study uses in situ aircraft observations taken during Indian Ocean Experiment (INDOEX), February–March 1999, mostly over northern Ocean, to show average, relative humidity increases distance boundaries small marine trade cumulus decreases. The increase is sufficient cause substantial growth...
Fourteen research flights were conducted in the Pacific Dust Experiment (PACDEX) during April and May 2007 to sample pollution dust outbreaks from east Asia as they traveled across northern Ocean into North America interacted with maritime storms. Significant concentrations of black carbon (BC, consisting soot other light‐absorbing particles measured a photometer 2 instrument) observed both west Asian plumes pollution. BC through much troposphere, but major finding is that percentage these...
In 2006, NASA led a field campaign to investigate the factors that control fate of African easterly waves (AEWs) moving westward into tropical Atlantic Ocean. Aircraft and surface-based equipment were based on Cape Verde's islands, helping fill some data void between Africa Caribbean. Taking advantage international Monsoon Multidisciplinary Analysis (AMMA) program over continent, NASA-AMMA (NAMMA) used enhanced upstream data, whereas NOAA aircraft farther west in studied several storms...
Abstract In situ observations of cloud properties made by airborne probes play a critical role in ice research through their process studies, parameterization development, and evaluation simulations remote sensing retrievals. To determine how vary with environmental conditions, data collected during different field projects processed groups must be used. However, because the diverse algorithms codes that are used to measurements, it can challenging compare results. Therefore is vital...
Abstract Southern Ocean (S. Ocean) clouds are important for climate prediction. Yet previous global models failed to accurately represent cloud phase distributions in this observation‐sparse region. In study, data from the Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES) experiment is compared constrained simulations a model (the Community Atmosphere Model, CAM). Nudged versions of CAM found reproduce many features detailed situ observations, such as location, phase, and...
Abstract Controls on pristine aerosol over the Southern Ocean (SO) are critical for constraining strength of global indirect forcing. Observations summertime SO clouds and aerosols in synoptically varied conditions during 2018 SOCRATES aircraft campaign reveal novel mechanisms influencing aerosol‐cloud interactions. The free troposphere (3–6 km) is characterized by widespread, frequent new particle formation events contributing to much larger concentrations (≥1,000 mg −1 ) condensation...
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 Wildfires in the western United States are large sources of particulate matter, and area burned by wildfires is predicted to increase future. Some particles released from can affect cloud formation serving as ice‐nucleating (INPs). INPs have numerous impacts on radiative properties precipitation development. potentially important INPs, indicated previous measurements, but their abundance free troposphere has not been quantified. The Western Wildfire Experiment for Cloud Chemistry,...
Condensed water content (CWC) measured using a counterflow virtual impactor (CVI) with Lyman-α hygrometer downstream is compared that by other airborne instruments (a hot-wire probe, PMS FSSP, and 2D-C). Results indicate the CVI system provides reliable measurement of CWC in both liquid- ice-phase clouds measures contained large small hydrometeors; this means condensed present phases virtually all hydrometeor sizes can be single device. Small ice contents few milligrams per cubic meter...
A case study of new particle formation in the region downwind a mesoscale convective system stretching across much central United States is presented. Airborne measurements were made condensation nuclei (CN), cloud surface area, water vapor, and other gases. CN concentrations greatly enhanced above cirrus anvil, with maximum 45,000 per standard cm 3 . Volatility electron microscope indicated that most particles likely to be small sulfate particles. The enhancement extended over at least...