Johnathan W. Hair

Langley Research Center

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R. A. Ferrare

Langley Research Center

Marta A. Fenn

Langley Research Center

C. A. Hostetler

Langley Research Center

Taylor Shingler

Langley Research Center

Glenn S. Diskin

Langley Research Center

Richard H. Moore

Langley Research Center

Ewan Crosbie

Langley Research Center

Luke D. Ziemba

Langley Research Center

Armin Sorooshian

University of Arizona

Michael A. Shook

Langley Research Center

Cooperative Institutions

University of Colorado Boulder

174

Langley Research Center

169

Cooperative Institute for Research in Environmental Sciences

145

National Oceanic and Atmospheric Administration

135

NSF National Center for Atmospheric Research

111

NOAA Earth System Research Laboratory

110

Goddard Space Flight Center

106

National Aeronautics and Space Administration

Science Systems and Applications (United States)

California Institute of Technology

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Large‐scale ozone and aerosol distributions, air mass characteristics, and ozone fluxes over the western Pacific Ocean in late winter/early spring

Journal of Geophysical Research Atmospheres (2003)

E. V. Browell Marta A. Fenn Carolyn F. Butler William B. Grant Vincent G. Brackett

Large‐scale measurements of ozone (O 3 ) and aerosol distributions were made from the NASA DC‐8 aircraft during the Transport and Chemical Evolution over the Pacific (TRACE‐P) field experiment conducted in February–April 2001. Remote measurements were made with an airborne lidar to provide O 3 and multiple‐wavelength aerosol backscatter profiles from near the surface to above the tropopause along the flight track. In situ measurements of O 3 , aerosols, and a wide range of trace gases were made onboard the DC‐8. Five‐day backward trajectories were used in conjunction with the O 3 and aerosol distributions on each flight to indicate the possible origin of observed air masses, such as from biomass burning regions, continental pollution, desert regions, and oceanic regions. Average latitudinal O 3 and aerosol scattering ratio distributions were derived from all flights west of 150°E, and these distributions showed the average latitude and altitude dependence of different dynamical and chemical processes in determining the atmospheric composition over the western Pacific. TRACE‐P (TP) showed an increase in the average latitudinal distributions of both O 3 and aerosols compared to PEM‐West B (PWB), which was conducted in February–March 1994. O 3 , aerosol, and potential vorticity levels were used to identify nine air mass types and quantify their frequency of occurrence as a function of altitude. This paper discusses the characteristics of the different air mass types encountered during TP and compares them to PWB. These results confirmed that most of the O 3 increase in TP was due to photochemistry. The average latitudinal eastward O 3 flux in the western Pacific during TP was found to peak near 32°N with a total average O 3 flux between 14 and 46°N of 5.2 Tg/day. The eastward total CO flux was calculated to be 2.2 Tg‐C/day with ∼6% estimated from Asia. The Asian flux of CO 2 and CH 4 was estimated at 4.9 and 0.06 Tg‐C/day.

Trace gas

Tropopause

10.1029/2002jd003290

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Citations (52)

Microphysical evolution in mixed-phase mid-latitude marine cold-air outbreaks

Journal of the Atmospheric Sciences (2024)

Seethala Chellappan Paquita Zuidema Simon Kirschler Christiane Voigt Brian Cairns

Abstract Five cold-air outbreaks are investigated with aircraft offshore of continental northeast America. Flight paths aligned with the cloud-layer flow from January through March span cloud-top temperatures of −5 to −12 °C, in situ liquid water paths of up to 500 g m −2 , while in situ cloud droplet number concentrations exceeding 500 cm −3 maintain effective radii below 10 µ m. Rimed ice is detected in the 4 colder cases within the first cloud pass. After further fetch, ice particle number concentrations reaching 2.5 L −1 support an interpretation that secondary ice production is occurring. Rime-splintering is clearly evident, with dendritic growth increasing ice water contents within deeper clouds with colder cloud-top temperatures. Buoyancy fluxes reach 400-600 W m −2 near the Gulf Stream’s western edge, with 1-second updrafts reaching 5 m s −1 supporting closely-spaced convective cells. Near-surface rainfall rates of the 3 more intense cold-air outbreaks are a maximum near the Gulf Stream’s eastern edge, just before the clouds transition to more open-celled structures. The milder 2 cold-air outbreaks transition to lower-albedo cumulus with little or no precipitation. The clouds thin through cloud-top entrainment.

Mixed phase

Middle latitudes

10.1175/jas-d-23-0203.1

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Injection of lightning‐produced NO _x , water vapor, wildfire emissions, and stratospheric air to the UT/LS as observed from DC3 measurements

Journal of Geophysical Research Atmospheres (2016)

Heidi Huntrieser Michael Lichtenstern M. Scheibe H. Aufmhoff Hans Schlager

Abstract During the Deep Convective Clouds and Chemistry (DC3) experiment in summer 2012, airborne measurements were performed in the anvil inflow/outflow of thunderstorms over the Central U.S. by three research aircraft. A general overview of Deutsches Zentrum für Luft‐ und Raumfahrt (DLR)‐Falcon in situ measurements (CO, O 3 , SO 2 , CH 4 , NO, NO x , and black carbon) is presented. In addition, a joint flight on 29 May 2012 in a convective line of isolated supercell storms over Oklahoma is described based on Falcon, National Science Foundation/National Center for Atmospheric Research Gulfstream‐V (NSF/NCAR‐GV), and NASA‐DC8 trace species in situ and lidar measurements. During DC3 some of the largest and most destructive wildfires in New Mexico and Colorado state's history were burning, which strongly influenced air quality in the DC3 thunderstorm inflow and outflow region. Lofted biomass burning (BB) plumes were frequently observed in the mid‐ and upper troposphere (UT) in the vicinity of deep convection. The impact of lightning‐produced NO x (LNO x ) and BB emissions was analyzed on the basis of mean vertical profiles and tracer‐tracer correlations (CO‐NO x and O 3 ‐NO). On a regular basis DC3 thunderstorms penetrated the tropopause and injected large amounts of LNO x into the lower stratosphere (LS). Inside convection, low O 3 air (~80 nmol mol −1 ) from the lower troposphere was rapidly transported to the UT/LS region. Simultaneously, O 3 ‐rich stratospheric air masses (~100–200 nmol mol −1 ) were present around and below the thunderstorm outflow and enhanced UT‐O 3 mixing ratios significantly. A 10 year global climatology of H 2 O data from the Aura Microwave Limb Sounder confirmed that the Central U.S. is a preferred region for convective injection into the LS.

Tropopause

Outflow

Lightning

10.1002/2015jd024273

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Citations (33)

Aerosol plume transport and transformation in high spectral resolution lidar measurements and WRF-Flexpart simulations during the MILAGRO Field Campaign

Atmospheric chemistry and physics (2011)

B. de Foy S. P. Burton R. A. Ferrare C. A. Hostetler Johnathan W. Hair

Abstract. The Mexico City Metropolitan Area (MCMA) experiences high loadings of atmospheric aerosols from anthropogenic sources, biomass burning and wind-blown dust. This paper uses a combination of measurements and numerical simulations to identify different plumes affecting the basin and to characterize transformation inside the plumes. The High Spectral Resolution Lidar on board the NASA LaRC B-200 King Air aircraft measured extinction coefficients and extinction to backscatter ratio at 532 nm, and backscatter coefficients and depolarization ratios at 532 and 1064 nm. These can be used to identify aerosol types. The measurement curtains are compared with particle trajectory simulations using WRF-Flexpart for different source groups. The good correspondence between measurements and simulations suggests that the aerosol transport is sufficiently well characterized by the models to estimate aerosol types and ages. Plumes in the basin undergo complex transport, and are frequently mixed together. Urban aerosols are readily identifiable by their low depolarization ratios and high lidar ratios, and dust by the opposite properties. Fresh biomass burning plumes have very low depolarization ratios which increase rapidly with age. This rapid transformation is consistent with the presence of atmospheric tar balls in the fresh plumes.

Depolarization ratio

Backscatter (email)

Extinction (optical mineralogy)

10.5194/acp-11-3543-2011

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Citations (48)

Biomass Burning Plumes in the Vicinity of the California Coast: Airborne Characterization of Physicochemical Properties, Heating Rates, and Spatiotemporal Features

Journal of Geophysical Research Atmospheres (2018)

Ali Hossein Mardi Hossein Dadashazar Alexander B. MacDonald Rachel A. Braun Ewan Crosbie

Abstract This study characterizes in situ airborne properties associated with biomass burning (BB) plumes in the vicinity of the California coast. Out of 231 total aircraft soundings in July–August 2013 and 2016, 81 were impacted by BB layers. A number of vertical characteristics of BB layers are summarized in this work (altitude, location relative to cloud top height, thickness, number of vertically adjacent layers, interlayer distances) in addition to differences in vertical aerosol concentration profiles due to either surface type (e.g., land or ocean) or time of day. Significant BB layer stratification occurred, especially over ocean versus land, with the majority of layers in the free troposphere and within 100 m of the boundary layer top. Heating rate profiles demonstrated the combined effect of cloud and BB layers and their mutual interactions, with enhanced heating in BB layers with clouds present underneath. Aerosol size distribution data are summarized below and above the boundary layer, with a notable finding being enhanced concentrations of supermicrometer particles in BB conditions. A plume aging case study revealed the dominance of organics in the free troposphere, with secondary production of inorganic and organic species and coagulation as a function of distance from fire source up to 450 km. Rather than higher horizontal and vertical resolution, a new smoke injection height method was the source of improved agreement for the vertical distribution of BB aerosol in the Navy Aerosol Analysis and Prediction System model when compared to airborne data.

Stratification (seeds)

10.1029/2018jd029134

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Citations (52)

A New Technique for the Retrieval of Near Surface Water Vapor Using DIAL Measurements

Syed Ismail S. A. Kooi R. A. Ferrare David M. Winker Johnathan W. Hair

Water vapor is one of the most important atmospheric trace gas species and influences radiation, climate, cloud formation, surface evaporation, precipitation, storm development, transport, dynamics, and chemistry. For improvements in NWP (numerical weather prediction) and climate studies, global water vapor measurements with higher accuracy and vertical resolution are needed than are currently available. Current satellite sensors are challenged to characterize the content and distribution of water vapor in the Boundary Layer (BL) and particularly near the first few hundred meters above the surface within the BL. These measurements are critically needed to infer surface evaporation rates in cloud formation and climate studies. The NASA Langley Research Center Lidar Atmospheric Sensing Experiment (LASE) system, which uses the Differential Absorption Lidar (DIAL) technique, has demonstrated the capability to provide high quality water vapor measurements in the BL and across the troposphere. A new retrieval technique is investigated to extend these DIAL water vapor measurements to the surface. This method uses signals from both atmospheric backscattering and the strong surface returns (even over low reflectivity oceanic surfaces) using multiple gain channels to cover the large signal dynamic range. Measurements can be made between broken clouds and in presence of optically thin cirrus. Examples of LASE measurements from a variety of conditions encountered during NASA hurricane field experiments over the Atlantic Ocean are presented. Comparisons of retrieved water vapor profiles from LASE near the surface with dropsonde measurements show very good agreement. This presentation also includes a discussion of the feasibility of developing space-based DIAL capability for high resolution water vapor measurements in the BL and above and an assessment of the technology needed for developing this capability.

Dial

Dropsonde

Cirrus

Trace gas

Source

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Measurement report: Cloud and environmental properties associated with aggregated shallow marine cumulus and cumulus congestus

Atmospheric chemistry and physics (2024)

Ewan Crosbie Luke D. Ziemba Michael A. Shook Taylor Shingler Johnathan W. Hair

Abstract. Mesoscale organization of marine convective clouds into linear or clustered states is prevalent across the tropical and subtropical oceans, and its investigation served as a guiding focus for a series of process study flights conducted as part of the Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) during summer 2020, 2021, and 2022. These select ACTIVATE flights involved a novel strategy for coordinating two aircraft, with respective remote sensing and in situ sampling payloads, to probe regions of organized shallow convection for several hours. The main purpose of this measurement report is to summarize the aircraft sampling approach, describe the characteristics and evolution of the cases, and provide an overview of the datasets that can serve as a starting point for more detailed modeling and analysis studies. Six flights are described, involving a total of 80 dropsonde profiles that capture the environment surrounding clustered shallow convection. The flights include detailed observations of the vertical structure of cloud systems, comprising up to 20 in situ sampling levels. Four cases involved deepening convection rooted in the marine boundary layer that developed vertically to 2–5 km with varying precipitation amounts, while two cases captured more complex and developed cumulus congestus systems extending above 5 km. In addition to the thermodynamic and dynamic characterization afforded by dropsonde and in situ measurements, the datasets include cloud and aerosol microphysics, trace gas concentrations, aerosol and droplet composition, and cloud and aerosol remote sensing from high-spectral-resolution lidar and polarimetry.

10.5194/acp-24-6123-2024

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Citations (1)

Convective and wave signatures in ozone profiles over the equatorial Americas: Views from TC4 2007 and SHADOZ

Journal of Geophysical Research Atmospheres (2010)

Anne M. Thompson Alaina M. MacFarlane Gary A. Morris John E. Yorks S. K. Miller

During the TC4 (Tropical Composition, Clouds, and Climate Coupling) campaign in July–August 2007, daily ozonesondes were launched over coastal Las Tablas, Panamá (7.8°N, 80°W) and several times per week at Alajuela, Costa Rica (10°N, 84°W). Wave activity, detected most prominently in 100–300 m thick ozone laminae in the tropical tropopause layer, occurred in 50% (Las Tablas) and 40% (Alajuela) of the soundings. These layers, associated with vertical displacements and classified as gravity waves (GW, possibly Kelvin waves) by laminar identification, occur with similar structure and frequency over the Paramaribo (5.8°N, 55°W) and San Cristóbal (0.92°S, 90°W) Southern Hemisphere Additional Ozonesondes (SHADOZ) sites. GW‐labeled laminae in individual soundings correspond to cloud outflow as indicated by DC‐8 tracers and other aircraft data, confirming convective initiation of equatorial waves. Layers representing quasi‐horizontal displacements, referred to as Rossby waves by the laminar technique, are robust features in soundings from 23 July to 5 August. The features associated with Rossby waves correspond to extratropical influence, possibly stratospheric, and sometimes to pollution transport. Comparison of Las Tablas and Alajuela ozone budgets with 1999–2007 Paramaribo and San Cristóbal soundings shows that TC4 is typical of climatology for the equatorial Americas. Overall during TC4, convection and associated waves appear to dominate ozone transport in the tropical tropopause layer; intrusions from the extratropics occur throughout the free troposphere.

Tropopause

Tropical cyclogenesis

Kelvin wave

10.1029/2009jd012909

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Citations (34)

Supplementary material to "Measurement Report: Cloud and environmental properties associated with aggregated shallow marine cumulus and cumulus congestus"

Ewan Crosbie Luke D. Ziemba Michael A. Shook Taylor Shingler Johnathan W. Hair

10.5194/egusphere-2024-148-supplement

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Citations (1)

Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth using airborne high spectral resolution lidar data

Atmospheric measurement techniques (2014)

Raymond R. Rogers Mark Vaughan C. A. Hostetler S. P. Burton R. A. Ferrare

Abstract. The Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud–Aerosol Lidar and Pathfinder Satellite Observations (CALIPSO) spacecraft has provided over 8 yr of nearly continuous vertical profiling of Earth's atmosphere. In this paper we investigate the V3.01 and V3.02 CALIOP 532 nm aerosol layer optical depth (AOD) product (i.e the AOD of individual layers) and the column AOD product (i.e., the sum AOD of the complete column) using an extensive database of coincident measurements. The CALIOP AOD measurements and AOD uncertainty estimates are compared with collocated AOD measurements collected with the NASA High Spectral Resolution Lidar (HSRL) in the North American and Caribbean regions. In addition, the CALIOP aerosol lidar ratios are investigated using the HSRL measurements. In general, compared with the HSRL values, the CALIOP layer AOD are biased high by less than 50% for AOD < 0.3 with higher errors for higher AOD. Less than 60% of the HSRL AOD measurements are encompassed within the CALIOP layer 1 SD uncertainty range (around the CALIOP layer AOD), so an error estimate is created to encompass 68% of the HSRL data. Using this new metric, the CALIOP layer AOD error is estimated using the HSRL layer AOD as ±0.035 ± 0.05 · (HSRL layer AOD) at night and ±0.05 ± 0.05 · (HSRL layer AOD) during the daytime. Furthermore, the CALIOP layer AOD error is found to correlate with aerosol loading as well as aerosol subtype, with the AODs in marine and dust layers agreeing most closely with the HSRL values. The lidar ratios used by CALIOP for polluted dust, polluted continental, and biomass burning layers are larger than the values measured by the HSRL in the CALIOP layers, and therefore the AODs for these types retrieved by CALIOP were generally too large. We estimated the CALIOP column AOD error can be expressed as ±0.05 ± 0.07 · (HSRL column AOD) at night and ±0.08 ± 0.1 · (HSRL column AOD) during the daytime. Multiple sources of error contribute to both positive and negative errors in the CALIOP column AOD, including multiple layers in the column of different aerosol types, lidar ratio errors, cloud misclassification, and undetected aerosol layers. The undetected layers were further investigated and we found that the layer detection algorithm works well at night, although undetected aerosols in the free troposphere introduce a mean underestimate of 0.02 in the column AOD in the data set examined. The decreased signal-to-noise ratio (SNR) during the daytime led to poorer performance of the layer detection. This caused the daytime CALIOP column AOD to be less accurate than during the nighttime, because CALIOP frequently does not detect optically thin aerosol layers with AOD < 0.1. Given that the median vertical extent of aerosol detected within any column was 1.6 km during the nighttime and 1.5 km during the daytime, we can estimate the minimum extinction detection threshold to be 0.012 km−1 at night and 0.067 km−1 during the daytime in a layer median sense. This extensive validation of level 2 CALIOP AOD products extends previous validation studies to nighttime lighting conditions and provides independent measurements of the lidar ratio; thus, allowing the assessment of the effect on the CALIOP AOD of using inappropriate lidar ratio values in the extinction retrieval.

10.5194/amt-7-4317-2014

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Citations (85)