A5063644921- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Meteorological Phenomena and Simulations
- Atmospheric Ozone and Climate
- Aeolian processes and effects
- Precipitation Measurement and Analysis
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Icing and De-icing Technologies
- Tropical and Extratropical Cyclones Research
- Cryospheric studies and observations
- Arctic and Antarctic ice dynamics
- Fire effects on ecosystems
- Solar Radiation and Photovoltaics
- Oceanographic and Atmospheric Processes
- Marine and coastal ecosystems
- Ocean Waves and Remote Sensing
- Air Quality and Health Impacts
- Lightning and Electromagnetic Phenomena
- Air Quality Monitoring and Forecasting
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Methane Hydrates and Related Phenomena
- Wind and Air Flow Studies
- Planetary Science and Exploration
University of Oklahoma
2006-2025
Impact
2021-2025
Cooperative Institute for Mesoscale Meteorological Studies
2017-2024
Korea Institute of Science and Technology
2024
Seoul National University
2024
Ewha Womans University
2024
Korea Meteorological Administration
2024
University of Illinois Urbana-Champaign
2011-2021
Microscale (United States)
2020-2021
NSF National Center for Atmospheric Research
1995-2018
Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South Southeast Asia. The Ocean Experiment (INDOEX) documented this Indo‐Asian at scales ranging individual particles its contribution regional climate forcing. This study integrates multiplatform observations (satellites, aircraft, ships, surface stations, balloons) with one‐ four‐dimensional models derive aerosol forcing resulting direct, semidirect two indirect effects. consisted...
Mixed-phase clouds represent a three-phase colloidal system consisting of water vapor, ice particles, and coexisting supercooled liquid droplets. are ubiquitous in the troposphere, occurring at all latitudes from polar regions to tropics. Because their widespread nature, mixed-phase processes play critical roles life cycle clouds, precipitation formation, cloud electrification, radiative energy balance on both regional global scales. Yet, spite many decades observations theoretical studies,...
Abstract Results are presented from an intercomparison of single‐column and cloud‐resolving model simulations a cold‐air outbreak mixed‐phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) programme's Mixed‐Phase Arctic Cloud Experiment. The occurred in well‐mixed boundary layer with cloud‐top temperature − 15 °C. average liquid water path around 160 g m −2 was about two‐thirds adiabatic value far greater than mass ice which when integrated surface to top ....
The Mixed-Phase Arctic Cloud Experiment (M-PACE) was conducted from 27 September through 22 October 2004 over the Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) on North Slope Alaska. primary objectives were to collect a dataset suitable study interactions between microphysics, dynamics, and radiative transfer in mixed-phase clouds, develop/evaluate cloud property retrievals surface-and satellite-based remote sensing instruments. Observations...
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. Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles, yet fate these particles and their influence on regional global climate is poorly understood. ORACLES (ObseRvations Aerosols above CLouds intEractionS) 5-year NASA EVS-2 (Earth Venture Suborbital-2) investigation with three intensive observation periods designed to study key atmospheric processes that determine impacts aerosols. During Hemisphere winter spring (June–October), reaching 3–5...
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 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 central Great Plains region in North America has a nocturnal maximum warm-season precipitation. Much of this precipitation comes from organized mesoscale convective systems (MCSs). This is counterintuitive the sense that activity over out phase with local generation CAPE by solar heating surface. lower troposphere environment typically characterized low-level jet (LLJ) just above stable boundary layer (SBL), and available potential energy (CAPE) values peak SBL, resulting...
Aerosol-cloud interactions (ACIs) are considered to be the most uncertain driver of present-day radiative forcing due human activities. The nonlinearity cloud-state changes aerosol perturbations make it challenging attribute causality in observed relationships forcing. Using correlations infer can when meteorological variability also drives both and cloud independently. Natural anthropogenic from well-defined sources provide "opportunistic experiments" (also known as natural experiments)...
Abstract One of the most intense air mass transformations on Earth happens when cold flows from frozen surfaces to much warmer open water in cold-air outbreaks (CAOs), a process captured beautifully satellite imagery. Despite ubiquity CAO cloud regime over high-latitude oceans, we have rather poor understanding its properties, role energy and cycles, treatment weather climate models. The Cold-Air Outbreaks Marine Boundary Layer Experiment (COMBLE) was conducted better understand this...
During the Department of Energy's Atmospheric Radiation Measurement Program's Mixed‐Phase Arctic Cloud Experiment (M‐PACE) in fall 2004, University North Dakota Citation measured 53 profiles within single‐layer stratus clouds by executing spiral ascents and descents over Barrow Oliktok Point, Alaska, flying ramped between. phase was identified from an algorithm that uses voltage change Rosemount ice detector, size distribution (SD) shape Forward Scattering Spectrometer Probe (FSSP), manual...
In situ microphysical measurements of three anvils were made 17 March, 1 April, and 4 April 1993 during the Central Equatorial Pacific Experiment for several constant altitude penetrations, in same direction or opposite ambient wind, from 7 to 14 km. Ice water contents (IWCs), derived an optical array probe, increased downward anvil; concentrations also increased, but not as quickly. Median mass dimensions, defined ice crystal maximum dimension below which half is contained, averages less...
Average ice crystal size distributions are parameterized as functions of temperature and water content (IWC), based on observations in cirrus produced outflows deep convection made during the Central Equatorial Pacific Experiment (CEPEX), sum a first-order gamma function, describing crystals with melted equivalent diameters (Dm) less than 100 μm, lognormal larger crystals. The fit parameters chosen to minimize chi-squared function difference between observed distribution functions....
In situ microphysical, remote sensing, and satellite observations of thin subvisible cirrus have been used to establish their frequency occurrence, determine mean optical depths radiative forcings, analyze association with deep convection. A spatially layer cirrus, both base top above 15 km, was observed in the central Pacific Tropics 29% time, a thickness 0.47 using nadir-pointing Nd:YAG lidar operating at 1.064 μm during Central Equatorial Experiment (CEPEX). microphysical data collected...
During the Department of Energy Atmospheric Radiation Measurement Program (DOE ARM) sponsored Tropical Warm Pool International Cloud Experiment (TWP‐ICE), ice crystals with maximum dimensions (D) < 50 μ m were measured in aged cirrus and fresh anvils by a Aerosol Spectrometer (CAS) Droplet Probe (CDP). The CAS/CDP ratio number concentrations droplets 3 D m, N 3−50 , averaged 0.98 ± 0.69 liquid clouds. However, CAS 91 127 times larger than from CDP had correlation coefficient 0.387...
Measurements from the US Department of Energy Atmospheric Radiation Measurement Program's 2004 Mixed‐Phase Arctic Cloud Experiment (M‐PACE) provide a unique opportunity to study poorly understood ice formation processes in mixed‐phase stratocumulus. Using meteorological, aerosol, and nucleus measurements initialize large‐eddy simulations with size‐resolved microphysics, we compare predicted liquid mass, number, size distribution observations typical flight. We find that ambient nuclei appear...
A comprehensive dataset describing tropical cloud systems and their environmental setting impacts has been collected during the Tropical Warm Pool International Cloud Experiment (TWPICE) Aerosol Chemical Transport in Convection (ACTIVE) campaign area around Darwin, Northern Australia, January February 2006. The aim of experiment was to observe evolution interaction with environment within an observational framework optimized for a range modeling activities goal improving representation...
Abstract The characteristics of Arctic mixed-phase stratiform clouds and their relation to vertical air motions are examined using ground-based observations during the Mixed-Phase Cloud Experiment (MPACE) in Barrow, Alaska, fall 2004. cloud macrophysical, microphysical, dynamical properties derived from a suite active passive remote sensors. Low-level, single-layer, typically topped by 400–700-m-deep liquid water layer which ice crystals precipitate. These strongly dominated (85% mass)...
The Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) is a research investigation using highly mobile platforms to examine the life cycles of mesoscale convective systems. It represents combination two related investigations study (a) bow echoes, principally those that produce damaging surface winds last at least 4 h, (b) larger systems long-lived vortices (MCVs). field phase BAMEX utilized three instrumented aircraft an array ground-based instruments. Two long-range turboprop were...
Abstract Large‐eddy simulations of mixed‐phase Arctic clouds by 11 different models are analyzed with the goal improving understanding and model representation processes controlling evolution these clouds. In a case based on observations from Indirect Semi‐Direct Aerosol Campaign (ISDAC), it is found that ice number concentration, N i , exerts significant influence cloud structure. Increasing leads to substantial reduction in liquid water path (LWP), agreement earlier studies. contrast...
Compared to other regions, little is known about clouds in Antarctica. This arises part from the challenging deployment of instrumentation this remote and harsh environment limitations traditional satellite passive sensing over polar regions. Yet have a critical influence on ice sheet's radiation budget its surface mass balance. The extremely low temperatures, absolute humidity levels, aerosol concentrations found Antarctica create unique conditions for cloud formation that greatly differ...
This paper presents airborne measurements of ice nuclei (IN) number concentration and elemental composition from the mixed-phase Arctic cloud experiment (M-PACE) in northern Alaska during October 2004. Although project average IN was low, less than 1 L -1 STP, there significant spatial temporal variability, with local maximum concentrations nearly 60 STP. Immersion and/or condensation freezing appear to be dominant mechanisms, whereas mechanisms that occur below water saturation played a...