A5102026958- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Meteorological Phenomena and Simulations
- Icing and De-icing Technologies
- Aeolian processes and effects
- Cryospheric studies and observations
- Climate variability and models
- Spacecraft and Cryogenic Technologies
- Precipitation Measurement and Analysis
- Wind and Air Flow Studies
- Radiative Heat Transfer Studies
- Particle Dynamics in Fluid Flows
- Atmospheric and Environmental Gas Dynamics
- Arctic and Antarctic ice dynamics
- Aerospace Engineering and Energy Systems
- Lightning and Electromagnetic Phenomena
- Ionosphere and magnetosphere dynamics
- Advanced Aircraft Design and Technologies
- nanoparticles nucleation surface interactions
- Air Quality Monitoring and Forecasting
- Fire effects on ecosystems
- Tropical and Extratropical Cyclones Research
- Planetary Science and Exploration
- Plant Water Relations and Carbon Dynamics
Stratton Park Engineering Company (United States)
2015-2024
Lawrence Livermore National Laboratory
2004-2024
Environment and Climate Change Canada
2022
University of Oklahoma
2020
University of Illinois Urbana-Champaign
2012
NOAA Earth System Research Laboratory
2012
NOAA National Severe Storms Laboratory
2012
University of Wisconsin–Madison
2012
Brookhaven National Laboratory
2012
Lancaster University
2005
Abstract The design, laboratory calibrations, and flight tests of a new optical imaging instrument, the two-dimensional stereo (2D-S) probe, are presented. Two orthogonal laser beams cross in middle sample volume. Custom, high-speed, 128-photodiode linear arrays electronics produce shadowgraph images with true 10-μm pixel resolution at aircraft speeds up to 250 m s−1. An overlap region is defined by two beams, improving volume boundaries sizing small (<∼100 μm) particles, compared...
Measured ice crystal concentrations in natural clouds at modest supercooling (temperature ~>−10°C) are often orders of magnitude greater than the number concentration primary nucleating particles. Therefore, it has long been proposed that a secondary production process must exist is able to rapidly enhance population following initial nucleation events. Secondary important for prediction and subsequent evolution some types clouds, but physical basis not understood rates well constrained. In...
Understanding the formation and evolution of ice in clouds requires detailed information on size, shape, mass, optical properties individual cloud hydrometeors their bulk over a broad range atmospheric conditions. Since 1960s, instrumentation research aircraft have evolved, providing increasingly more accurate larger quantities data about particle properties. In this chapter, current status electrical powered, situ measurement systems are reviewed with respect to strengths weaknesses...
A comprehensive dataset of microphysical and radiative properties aerosols clouds in the boundary layer vicinity Barrow, Alaska, was collected April 2008 during Indirect Semi-Direct Aerosol Campaign (ISDAC). ISDAC's primary aim to examine effects aerosols, including those generated by Asian wildfires, on that contain both liquid ice. ISDAC utilized Atmospheric Radiation Measurement Pro- gram's permanent observational facilities at Barrow specially deployed instruments measuring aerosol, ice...
Abstract The goal of this chapter is to synthesize information about what now known one the three main types clouds, cirrus, and identify areas where more knowledge needed. Cirrus composed ice particles, form in upper troposphere, temperatures are generally below −30°C. Satellite observations show that maximum-occurrence frequency cirrus near tropics, with a large latitudinal movement seasonally. In situ measurements obtained over wide range types, formation mechanisms, temperatures,...
Abstract The rapid glaciation of tropical cumulus clouds has been an enigma and debated in the literature for over 60 years. Possible mechanisms responsible freezing have postulated, but until now direct evidence lacking. Recent high-speed photography electrostatically suspended supercooled drops laboratory shown that events produce small secondary ice particles. Aircraft observations from Ice Clouds Experiment–Tropical (ICE-T), strongly suggest drop-freezing production mechanism is...
Abstract. This study presents airborne in situ and satellite remote sensing climatologies of cirrus clouds humidity. The serve as a guide to the properties clouds, with new database providing detailed insights into boreal midlatitudes tropics, while satellite-borne data set offers global overview. To this end, an extensive, quality-checked archive, Cirrus Guide II database, is created from measurements during 150 flights 24 campaigns. archive contains meteorological parameters, ice water...
Abstract. This study attempts a new identification of mechanisms secondary ice production (SIP) based on the observation small faceted crystals (hexagonal plates or columns) with typical sizes smaller than 100 µm. Due to their young age, such can be used as tracers for identifying conditions SIP. Observations reported here were conducted in oceanic tropical mesoscale convective systems (MCSs) and midlatitude frontal clouds temperature range from 0 −15 ∘C heavily seeded by aged particles. It...
Microphysical data were collected by the NCAR C‐130 research aircraft during First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment Arctic (FIRE ACE). Boundary layer clouds 100 to 400 m thick observed on 11 of 16 missions. The all‐water varied from being adiabatic and homogeneous with monomodal drop spectra subadiabatic inhomogeneous bimodal drizzle. be actively mixing near cloud top. provided a test performance liquid water content (LWC) probes but only in low...
A Learjet research aircraft was used to collect microphysical data, including cloud particle imager (CPI) measurements of ice size and shape, in 22 midlatitude cirrus clouds. The dataset collected while the flew 104 horizontal legs, totaling over 15 000 km Cloud temperatures ranged from −28° −61°C. show that distributions are mostly bimodal, displaying a maximum number concentration, area, mass near 30 μm another smaller 200–300 μm. CPI images particles with rosette shapes, which include...
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...
Abstract. Recently, considerable attention has been focused on the issue of large ice particles shattering inlets and tips cloud particle probes, which produces copious that can be mistakenly measured as real particles. Currently two approaches are being used to mitigate problem: (1) Based recent high-speed video in icing tunnels, probe have designed reduce number shattered reach sample volume, (2) Post processing techniques such image using arrival time each individual particle. This paper...
Abstract In this study several ice cloud retrieval products that utilize active and passive A-Train measurements are evaluated using in situ data collected during the Small Particles Cirrus (SPARTICUS) field campaign. The datasets include water content (IWC), effective radius r e , visible extinction σ from CloudSat level-2C property product (2C-ICE), level-2B radar-visible optical depth (2B-CWC-RVOD), radar–lidar (DARDAR), Cloud–Aerosol Lidar Infrared Pathfinder Satellite Observations (...
Cloud and aerosol data acquired by the National Research Council of Canada (NRC) Convair‐580 aircraft in, above, below single‐layer arctic stratocumulus cloud during Indirect Semi‐Direct Aerosol Campaign (ISDAC) in April 2008 were used to test three indirect effects hypothesized act mixed‐phase clouds: riming effect, glaciation thermodynamic effect. The showed a correlation R = 0.78 between liquid drop number concentration, N liq inside ambient concentration PCASP cloud. This, combined with...
Abstract. The composition of residual particles from evaporated cirrus ice crystals near the tropical tropopause as well unfrozen aerosols were measured with a single particle mass spectrometer. Subvisible residuals predominantly composed internal mixtures neutralized sulfate organic material and chemically indistinguishable sulfate-organic aerosols. Ice also similar in size to aerosol. Heterogeneous nuclei such mineral dust not enhanced these subvisible residuals. Biomass burning depleted...
Abstract. In this study the effect of dust aerosol on upper tropospheric cirrus clouds through heterogeneous ice nucleation is investigated in Community Atmospheric Model version 5 (CAM5) with two parameterizations. Both parameterizations consider homogeneous and competition between mechanisms clouds, but differ significantly number concentration nuclei (IN) from dust. Heterogeneous reduces occurrence frequency thus crystal Northern Hemisphere (NH) compared to simulations pure nucleation....
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...
A first-of-a-kind, extended-term cloud aircraft campaign was conducted to obtain an in situ statistical characterization of continental boundary layer clouds needed investigate processes and refine retrieval algorithms. Coordinated by the Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF), Routine AAF Clouds with Low Optical Water Depths (CLOWD) Radiative Observations (RACORO) field operated over ARM Southern Great Plains (SGP) site from 22 January 30 June 2009, collecting 260 h...
Abstract In situ data collected by three research aircraft in four geographical locations are analyzed to determine the relationship between cloud-base temperature, drop size distribution, and development of supercooled water drops ice strong updraft cores convective clouds. Data were towering cumulus feeder cells Caribbean, over Gulf Mexico, land near Coast, southeastern United States, high plains Colorado Wyoming. Convective clouds Mexico its coast, States all develop millimeter-diameter...
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. Subvisible cirrus (SVC) clouds are often observed within the tropical tropopause layer (TTL). Some studies suggest that SVC has a significant impact on earth radiation budget. The Costa Rica Aura Validation Experiment (CR-AVE) sponsored by National Aeronautics and Space Administration (NASA) took place near San Jose, from 14 January–15 February 2006. NASA WB-57F sampled in TTL −75°C to −90°C with an improved set of cloud particle probes. first digital images ice particles compared...
Abstract Ice water content in natural clouds is an important but difficult quantity to measure. The goal of a number past studies was find average relationships between the masses and lengths ice particles determine from situ data, such as those routinely recorded with two-dimensional imaging probes. general approach these measure maximum length L mass M dataset crystals collected at ground site. Linear regression analysis performed on logarithms data estimate mass-to-length relationship...
Abstract The microphysical characteristics, radiative impact, and life cycle of a long-lived, surface-based mixed-layer, mixed-phase cloud with an average temperature approximately −20°C are presented discussed. was observed during the Surface Heat Budget Arctic experiment (SHEBA) from 1 to 10 May 1998. Vertically resolved properties liquid ice phases retrieved using remote sensors, utilize adiabatic assumption for component, aided by validated aircraft measurements 4 7 May. radar...
Abstract. In past modeling studies, it has generally been assumed that the predominant mechanism for nucleation of ice in uppermost troposphere is homogeneous freezing aqueous aerosols. However, recent situ and remote-sensing measurements properties cirrus clouds at very low temperatures tropical tropopause layer (TTL) are broadly inconsistent with theoretial predictions based on assumption. The nearly ubiquitous occurence gravity waves TTL makes from theory particularly difficult to...