A5072868812- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Vehicle emissions and performance
- Air Quality Monitoring and Forecasting
- Gas Dynamics and Kinetic Theory
- Ionosphere and magnetosphere dynamics
- Advanced Aircraft Design and Technologies
- Computational Fluid Dynamics and Aerodynamics
- Calibration and Measurement Techniques
- Arctic and Russian Policy Studies
- Radiative Heat Transfer Studies
- Arctic and Antarctic ice dynamics
- Rocket and propulsion systems research
- Wind and Air Flow Studies
- Combustion and flame dynamics
- Climate variability and models
- Geochemistry and Geologic Mapping
- Ocean Acidification Effects and Responses
- Remote Sensing in Agriculture
- Advanced Database Systems and Queries
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
Ames Research Center
2006-2016
National Aeronautics and Space Administration
2013
NASA Earth Science
2009
Langley Research Center
2004
Picarro (United States)
2003
Stanford University
1985
Vaughn College of Aeronautics and Technology
1985
Abstract. Recent results from diverse air, ground, and laboratory studies using both radiometric in situ techniques show that the fractions of black carbon, organic matter, mineral dust atmospheric aerosols determine wavelength dependence absorption (often expressed as Absorption Angstrom Exponent, or AAE). Taken together, these hold promise improving information on aerosol composition remote measurements. The main purpose this paper is to AAE values for an Aerosol Robotic Network (AERONET)...
The Reno Aerosol Optics Study (RAOS) was designed and conducted to compare the performance of many existing new instruments for in situ measurement aerosol optical properties with a focus on determination light absorption. For this study, simple test aerosols black white particles were generated combined external mixtures under low relative humidity conditions delivered each system. mixing delivery system constantly monitored using particle counters nephelometers ensure that same number...
We estimated daily ground-level PM2.5 concentrations combining Collection 6 deep blue (DB) Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) data (10 km resolution) with land use regression in California, United States, for the period 2006-2012. The DB method AOD provided more reliable retrievals over California's bright surface areas than previous sets. Our and suggested that predictability could be enhanced by temporally varying relations at least a seasonal...
Large uncertainties in the effects that aerosols have on climate require improved situ measurements of extinction coefficient and single-scattering albedo. This paper describes use continuous wave cavity ring-down (CW-CRD) technology to address this problem. The innovations instrument are CW-CRD measure aerosol coefficient, simultaneous measurement scattering its small size, suitable for a wide range aircraft applications. prototype measures at 690 nm 1550 nm. itself is (60 cm × 48 15 cm)...
The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (AIOP, May 2003) yielded one the best measurement sets obtained to date assess our ability measure vertical profile ambient aerosol extinction σ ep (λ) in lower troposphere. During month, a heavily instrumented aircraft with well‐characterized sampling carrying well‐proven and new instrumentation devoted most 60 available flight hours flying profiles over ARM Southern Great Plains...
Abstract Avoiding the worst effects of global warming requires a multipronged approach including decarbonizing as quickly possible, adaptation, greenhouse gas removal, and climate intervention. Additional research is needed to ensure that intervention strategies will be safe, effective, environmentally acceptable. The importance Arctic in influencing has led investigators propose various specific (Strawa et al., 2020, https://doi.org/10.1016/j.orbis.2020.08.010 ). One approach, proposed by...
This paper describes recent measurements of carbonaceous aerosol made by wire impactors during the Photochemistry Ozone Loss in Arctic Region Summer (POLARIS) campaign and assesses their role stratospheric photochemistry. Ninety‐five percent collected this was form black carbon (BCA), or soot. A new method analyzing impactor samples is described that accounts for particle bounce models BCA as fractal aggregates to modify aerodynamic collection efficiency determine surface area. Results are...
Previous studies show that new particle formation takes place in the outflows of marine stratus and cumulus clouds. Here we measurements high concentrations ultrafine particles, diameters ( D p ) from 4 to 9 nm N 4–9 ), interstitial cloud aerosol. These particles indicate situ occurs interstitially cirrus Measurements were made at altitudes 7 16 km over Florida with instruments on WB‐57F aircraft during Cirrus Regional Study Tropical Anvils Layers‐Florida Area Experiments (CRYSTAL‐FACE) July...
Gravito‐photophoresis, a sunlight‐induced force acting on particles which are geometrically asymmetric and have uneven surface distribution of thermal accommodation coefficients, explains vertical transport fractal soot aerosol emitted by aircraft in conventional flight corridors (10–12 km altitude) into the mesosphere (>80 altitude). While direct optical effects this appear nonsignificant, it is conceivable that they play role mesospheric physics providing nuclei for polar cloud...
Experiments have been carried out in a variable pressure flow facility with the objective of studying structure co-flowing jet diffusion flame. The is visualized using an optical scheme which superimposes luminous image flame on its Schlieren image. This gives useful picture relationship between bright, yellow-orange, soot-laden core and edge surrounding hot gas envelope. A loudspeaker used to force central fuel at several frequencies. In unforced over most driving frequency range forced...
In May 2003, the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program sponsored Aerosol Intensive Operating Period (AIOP) which was conducted over ARM Climate Research Facility (ACRF) in central Oklahoma. One new instrument that flew AIOP, called Cadenza, employed a cavity ring‐down technique to measure extinction coefficient and reciprocal nephelometer simultaneously scattering coefficient. This is described this paper, measurements are compared those conventional...
Abstract. Recent results from diverse air, ground, and laboratory studies using both radiometric in situ techniques show that the fractions of black carbon, organic matter, mineral dust atmospheric aerosols determine wavelength dependence absorption (expressed as Absorption Angstrom Exponent, or AAE). Taken together, these hold promise improving information on aerosol composition remote measurements. The purpose this paper is to AAE values for Aerosol Robotic Network (AERONET) retrievals...
A combination of multiplatform satellite observations and statistical data analysis are used to improve the correlation between estimates PM2.5 (particulate mass with aerodynamic diameter less that 2.5 µm) retrieved from ground-level measured PM2.5. Accurate measurements can be assess impact air pollution levels on human health environment validate models. The area under study is California's San Joaquin Valley (SJV) has a history poor particulate quality. Attempts use simple linear...
Atmospheric Radiation Measurements Enhanced Shortwave Experiment (ARESE) was conducted to study the magnitude and spectral characteristics of absorption solar radiation by clear cloudy atmosphere. Three aircraft platforms, a Grob Egrett, NASA ER‐2, Twin Otter, were used during ARESE in conjunction with (ARM) central extended facilities north Oklahoma. The coordinated simultaneously measure irradiances total broadband (0.224–3.91 μm), near infrared (0.678–3.3 seven narrow band‐pass (∼10 nm...
With the aim of improving consistency terrestrial and atmospheric longwave radiation measurements within Baseline Surface Radiation Network, five Eppley Precision Infrared Radiometer (PIR) pyrgeometers one modified Meteorological Research Flight (MRF) pyrgeometer were individually calibrated by 11 specialist laboratories. The round-robin experiment was conducted in a “blind” sense that participants had no knowledge results others until whole series calibrations ended. responsivities C(μV/W...
In May 2003, a Twin Otter airplane, equipped with instruments for making in situ measurements of aerosol optical properties, was deployed during the Atmospheric Radiation Measurements (ARM) Program's Aerosol Intensive Operational Period Oklahoma. Several flights were flown formation an instrumented light aircraft (Cessna 172XP) that makes routine profile over site. This paper presents comparisons measured scattering coefficients at 467 nm, 530 and 675 nm between identical commercial...
A sensor based on laser-induced fluorescence has been installed at the 20-MW NASA Ames Aerodynamic Heating Facility. The provided new, quantitative, real-time information about properties of arcjet flow in highly dissociated, partially ionized, nonequilibrium regime. Number densities atomic oxygen, velocities, heavy particle translational temperatures, and collisional quenching rates have measured. These results used to test refine computational models flow. calculated number densities,...
A method for discriminating Types Ia and Ib Polar Stratospheric Clouds (PSCs) from Ozone Aerosol Measurement (POAM) satellite occultation measurements of aerosol extinction coefficient is described. The has been validated by applying several statistical tests to the results using Differential Absorption Lidar (DIAL) Experiment (OLEX) lidar observations made during Gas (SAGE) III Loss Validation Experiment/Third European on II (SOLVE/THESEO 2000). Type PSCs are believed be composed large...
The High Resolution Dynamics Limb Sounder (HIRDLS) cloud detection and top determination algorithm is described applied to 2005–2007 HIRDLS radiance profiles. Statistical averages of correlative data are highly correlated. 1998–2005 Halogen Occultation Experiment (HALOE) time averaged pressures have a correlation coefficient 0.87 0.93 in the tropics midlatitudes, respectively. Time series temperature T < 195 K hemispherical area, on 450 potential surface, total number polar stratospheric...
We present an overview of polar stratospheric cloud (PSC) measurements obtained by POAM III in the 1999/2000 Northern Hemisphere winter. PSCs were observed at latitudes from mid‐November to 15 March. early season generally occurred between 17 and 25 km. The central altitude PSC observations, roughly 21 km, is unchanged November late January. not 7 27 February. When they reappeared, formed distinctly lower altitudes, centered 16 also both qualitative quantitative comparisons with airborne...
Experiments have been carried out with the objective of studying relationship between flow structure, excitation and reaction process in near field a low-speed coflowing jet diffusion flame. The effect axial forcing increasing pressure on structure controllability flame has studied an attempt to elucidate some underlying mechanisms control. experiments were conducted variable-pressure facility which permits study reacting flows at pressures ranging from 10 1000 kPa (0.1 atm.). was excited by...