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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Observation of O3 events with LMOL during the TRACER-AQ campaign

The TRACER-AQ campaign in Houston TX, happened in August-September 2021 in Houston, Texas. The Langley Mobile Ozone Lidar (LMOL) was located on the Houston campus and performed observations of ozone alongside basic estimation of aerosol backscatter. In presentation, we highlight the latest results from LMOL during that campaign. We show how the latest improvements of the lidar along with secondary measurements, such as from ozonesondes, and modeling enable better observations and understanding of ozone events in coastal environments.

Guillaume Gronoff↗
NASA NTRS2024

Lightning and Radar Measures of Mixed Phase Updraft Variability in Tracked Storms During the TRACER Field Campaign in Houston, Texas

Properties of 7488 thunderstorms are summarized for June-September 2022 during the TRACER field campaign Houston, Texas using polarimetric weather radar and VHF 3D lightning mapping array data. Automated tracking of storms linked each instrument’s measurements to a data-defined, time-evolving storm footprint. Within each storm, the depth and magnitude of episodic columns of radar differential reflectivity and specific differential phase quantified the prevalence of updrafts that activated mixed-phase precipitation pathways. Lightning measurements further distinguished the degree of rimed precipitation formation: the fraction of tracks with lightning varied from day to day, and cells with lightning had stronger polarimetric columns. Track-level correlation of lightning flash rate with radar polarimetric measures had substantial spread, showing that lightning provides an additional signal of mixed-phase precipitation processes that can complement future studies of thermodynamic and aerosol controls on cloud microphysics in the Houston region.

TRACER field campaign↗
NASA NTRSDate not supplied

Updated assessment of TROPOMI NO2 and HCHO columns using airborne spectrometers during the MOOSE and TRACER-AQ field campaigns

Airborne spectrometer data offers the opportunity to evaluate satellite product performance without the impact of subpixel heterogeneity between the different satellite and ground-based measurement footprints. Previous measurements during the Long Island Sound Tropospheric Ozone Study were used to evaluate TROPOMI’s v1.3 NO2 product and found very strong relationships (r2=0.96) between the airborne spectrometer and TROPOMI with a systematic low bias mostly attributed to the coarse a priori profile assumption within the standard TROPOMI retrieval. This presentation will update that analysis using the most up-to-date version 2 TROPOMI NO2 product as well as expand analysis to the HCHO product. In summer 2021, NASA GeoCAPE Airborne Simulator (GCAS) collected measurements over southeast Michigan/western Ontario for the Michigan-Ontario Ozone Source Experiment (MOOSE) and Houston, Texas during the TRacking Aerosol Convection ExpeRiment – Air Quality (TRACER-AQ). Flight strategies for both deployments included repeated systematic sampling over common areas of interest coinciding with TROPOMI. During these flights, GCAS NO2 tropospheric columns are available at 250 m x 560 m resolution. Preliminary evaluation of GCAS NO2 retrievals with Pandora spectrometer data in Houston, Texas (3 sites) shows a median percent difference of 1.4% with an interquartile range of -15.5-14.9% (r2=0.72). Column HCHO was also retrieved at a slightly coarser resolution in Houston, Texas (750 m x 1680 m) showing distinct spatial patterns associated with secondary production through the oxidation of VOCs downwind of industrial facilities. Comparison to Pandora HCHO showed a low bias of ~25% (r2=0.29) with further investigation needed to identify the cause for this bias. This presentation will share how the GCAS/Pandora/TROPOMI NO2 and HCHO intercompare and will also extend analysis toward thinking about how these assets will contribute to the validation of future geostationary observations.

Laura Judd↗
NASA NTRS1995

Stratospheric Tracers of Atmospheric Transport (STRAT) Campaign: ER-2 Participation

The NASA Stratospheric Tracers of Atmospheric Transport (STRAT) mission was initiated to advance knowledge of the major transport mechanisms of the upper troposphere-lower stratosphere. This is the region of the atmosphere within which exchange processes take place that critically determine the response of the climate system and ozone distribution to changing conditions triggered by the release of chemicals at the surface. The mission series that extended from October 1995 to November 1997 was extremely successful. The scientific advances that emerged from that mission include analyses of: (1)troposphere-to-stratosphere transport in the lowermost stratosphere from measurements of H2O, CO2, N2O, and O3; (2) the effects of tropical cirrus clouds on the abundance of lower stratospheric ozone; and (3) the role of HO(x) in super- and subsonic aircraft exhaust plumes; and dehydration and denitrification in the arctic polar vortex during the 1995-96 winter.

Anderson, James G.↗
NASA NTRS1999

Stratospheric Tracers of Atmospheric Transport (STRAT) Campaign: ER-2 Participation

The NASA Stratospheric Tracers of Atmospheric Transport (STRAT) mission was initiated to advance knowledge of the major transport mechanisms of the upper troposphere-lower stratosphere. This is the region of the atmosphere within which exchange processes take place that critically determine the response of the climate system and ozone distribution to changing conditions triggered by the release of chemicals at the surface. The mission series that extended from October 1995 to November 1997 was extremely successful. The scientific advances that emerged from that mission include analyses of: (1) troposphere-to-stratosphere transport in the lowermost stratosphere from measurements of H2O, CO2, N2O, and O3; (2) the effects of tropical cirrus clouds on the abundance of lower stratospheric ozone; (3) the role of HO(sub x) in super- and subsonic aircraft exhaust plumes; and (4) dehydration and denitrification in the arctic polar vortex during the 1995-96 winter. The abstracts from published papers are included.

Anderson, James G.↗
NASA NTRS1999

Stratospheric Tracers of Atmospheric Transport (STRAT) Campaign: ER-2 Participation

The NASA Stratospheric Tracers of Atmospheric Transport (STRAT) mission was initiated to advance knowledge of the major transport mechanisms of the upper troposphere-lower stratosphere. This is the region of the atmosphere within which exchange processes take place that critically determine the response of the climate system and ozone distribution to changing conditions triggered by the release of chemicals at the surface. The mission series that extended from October 1995 to November 1997 was extremely successful. The scientific advances that emerged from that mission include analyses of- troposphere-to-stratosphere transport in the lowermost stratosphere from measurements of H2O, CO2, N2O, and O3; the effects of tropical cirrus clouds on the abundance of lower stratospheric ozone; the role of HO, in super- and subsonic aircraft exhaust plumes; and dehydration and denitrification in the arctic polar vortex during the 1995-96 winter.

Anderson, James G.↗
NASA NTRS2023

TRACER Lightning Mapping Array Field Campaign Report

Our observational contribution to the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility’s Tracking Aerosol Convection Interactions Experiment (TRACER) was the deployment of additional Lightning Mapping Array sensors to provide enhanced capability to the Houston Lightning Mapping Array (HLMA) during the TRACER intensive operational period. To that end, the Texas Tech University personnel (Professor Bruning and Dr. Brunner, and graduate students Jessica Souza, David Singewald, Stephanie Weiss, and Matthew Miller) deployed two portable LMA antennae at locations G and B shown in the map below. The map also shows the predicted lightning flash detection efficiency in black contours, as well as color-shaded very-high-frequency (VHF) source detection efficiency, which roughly corresponds to the sensitivity to lightning channel detail.

Tracking Aerosol Convection Interactions Experimen↗
NASA NTRSDate not supplied

Observation of Pollution Events at Low Altitude During TRACER-AQ – The Advantage of Adaptive Resolution Lidar

The TRACER-AQ campaign happened in August-September 2021 in Houston, Texas. Its objective was to better understand the pollution events in the coastal environment and to evaluate models and satellite observations. As a supporting instrument, NASA’s Langley Mobile Ozone Lidar (LMOL) was installed on the Houston campus, adjacent to University of Houston’s air-quality site, and performed observations of ozone and aerosols. Co-located instrumentation included a Pandora spectrophotometer, in-situ trace-gas measurements, and ozonesonde launches. Thanks to an adaptive resolution retrieval scheme, LMOL was able to detect thin-layer O3 structures at low (~200m) altitude that are not captured by the ozonesondes, and would ordinarily be missed with traditional coarse TOLNet lidar vertical averaging. We show that some of these features are not present in the models and are likely coming from local, industry-generated, emissions.

Guillaume Gronoff↗
NASA NTRS2014

Wildfire Emissions and Their Interaction with Urban and Rural Pollution: Data and Simulations

In recent years NASA has conducted a series of airborne campaigns (e. g. SEAC4RS*, ARCTAS, INTEX-A/B) over North America using an instrumented DC-8 aircraft equipped to measure a very large number of gaseous and aerosol constituents including several unique tracers. In these campaigns wild fires were extensively sampled near source as well as downwind after aging. The data provided detailed information on the composition and chemistry of fire emissions under a variety of atmospheric conditions as well as their interactions with rural and urban air pollution. Major fires studied including the California Rim fire in 2013 (SEAC4RS), the 2008 California wildfires (ARCTAS), and the Alaskan fires downwind over eastern US (INTEX-A). Although some fire plumes contained virtually no O3 enhancement, others showed significant ozone formation. Over Los Angeles, the highest O3 mixing ratios were observed in fire influenced urban air masses. Attempts to simulate these interactions using state of the art models were only minimally successful and indicated several shortcomings in simulating fire emission influences on urban smog formation. A variety of secondary oxidation products (e. g. O3, PAN, HCHO) were substantially underestimated. We will discuss the data collected in fire influenced air masses and their potential air quality implications.

FIre Emissions↗
NASA NTRSDate not supplied

A21I-1875: Leveraging TEMPO Formaldehyde Observations to Assess Surface Air Quality

Surface ozone (O3) pollution is detrimental to human health, crop yields, and ecosystem productivity. Ground-based ozone observations are sparse and surface ozone retrievals from space are challenging. The process of producing ozone from the oxidation of volatile organic compounds (VOCs) in the presence of nitrogen oxides (NOx) results in formaldehyde (HCHO), which can be observed from satellite and by surface-based remote sensing. From limited field campaign observations, column formaldehyde has been shown to exhibit a strong relationship with surface ozone and, therefore, could be an useful proxy for detecting unmonitored regions of elevated ozone pollution. The spatiotemporal characteristics of this relationship are explored using ground-based Pandora spectrometers and airborne remote sensing data with surface ozone monitors across the United States during recent field campaigns over major cities (TRACER-AQ and STAQS). We extend our analysis to take advantage of HCHO column observations from recently launched Tropospheric Emissions: Monitoring of Pollution (TEMPO), a geostationary satellite over North America. TEMPO observations show preliminary promise in mapping regions of elevated surface ozone from space using column HCHO. We demonstrate the use of column HCHO in assessing the strength of the surface monitoring network, and in detecting the extent of regional ozone exceedances.

Prajjwal Rawat↗
NASA NTRS2016

Aircraft-Measured Indirect Cloud Effects from Biomass Burning Smoke in the Arctic and Subarctic

The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300 over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were 50 smaller than in background clouds. Based on the relationship between cloud droplet number (N(liq))/ and various biomass burning tracers (BBt/ across the multi-campaign dataset, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACI, where ACI = (1/3) x dln(N(liq))/dln(BBt)) to be 0.12 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (0.02 gm/ cu m) and very high aerosol concentrations (2000-3000 cu m) in the most polluted clouds, the estimated ACI value was only 0.06. In this case, competition for water vapor by the high concentration of CCN strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease shortwave radiative flux by 2 and 4 W/sq or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. We lastly show evidence to suggest that numerous northern latitude background Aitken particles can interact with combustion particles, perhaps impacting their properties as cloud condensation and ice nuclei. However, the influence of background particles on smoke-driven indirect effects is currently unclear.

Arctic↗
NASA NTRS2016

Aircraft-Measured Indirect Cloud Effects from Biomass Burning Smoke in the Arctic and Subarctic

The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300% over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were approx. 40- 60% smaller than in background clouds. Based on the relationship between cloud droplet number (N(liq)/ and various biomass burning tracers (BBt/ across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACIs, where ACI = (1/3) x dln(N(liq))/dln(BBt)) to be approx. 0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (0.02 gm/cu m and very high aerosol concentrations (2000- 3000/ cu cm in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 W/sq m or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic.We lastly explore evidence suggesting that numerous northern-latitude background Aitken particles can interact with combustion particles, perhaps impacting their properties as cloud condensation and ice nuclei.

cloud microphysics↗
NASA NTRS2013

Source Attributions of Pollution to the Western Arctic During the NASA ARCTAS Field Campaign

We use the NASA GEOS-5 transport model with tagged tracers to investigate the contributions of different regional sources of CO and black carbon (BC) to their concentrations in the Western Arctic (i.e., 50-90 deg N and 190- 320 deg E) in spring and summer 2008. The model is evaluated by comparing the results with airborne measurements of CO and BC from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaigns to demonstrate the strengths and limitations of our simulations. We also examine the reliability of tagged CO tracers in characterizing air mass origins using the measured fossil fuel tracer of dichloromethane and the biomass burning tracer of acetonitrile. Our tagged CO simulations suggest that most of the enhanced CO concentrations (above background level from CH4 production) observed during April originate from Asian anthropogenic emissions. Boreal biomass burning emissions and Asian anthropogenic emissions are of similar importance in July domain wise, although the biomass burning CO fraction is much larger in the area of the ARCTAS field experiments. The fraction of CO from Asian anthropogenic emissions is larger in spring than in summer. European sources make up no more than 10% of CO levels in the campaign domain during either period. Comparisons of CO concentrations along the flight tracks with regional averages from GEOS-5 show that the alongtrack measurements are representative of the concentrations within the large domain of the Western Arctic in April but not in July.

Black Carbon↗
NASA NTRS2003

Aerosol Chemical Composition in Asian Continental Outflow during the TRACE-P Campaign: Comparison with PEM-West B

Aerosol associated soluble ions and the radionuclide tracers (7)Be and (210)Pb were quantified in 414 filter samples collected in spring 2001 from the DC-8 during the Transport and Chemical Evolution over the Pacific (TRACE-P) campaign. Binning the data into near Asia (flights from Hong Kong and Japan) and remote Pacific (all other flights) revealed large enhancements of NO3(-), SO4(-), C2O4(-), NH4(+), K(+), Mg2(+), and Ca2(+) near Asia. The boundary layer and lower troposphere were most strongly influenced by continental outflow, and the largest enhancements were seen in Ca2(+) (a dust tracer) and NO3(-) (reflecting uptake of HNO3 onto the dust). Comparing the TRACE P near Asia bin with earlier results from the same region during PEM-West B (in 1994) shows at least twofold enhancements during TRACE P in most of the ions listed above. Calcium and NO3(-) were most enhanced in this comparison as well (more than sevenfold higher in the boundary layer and threefold higher in the lower troposphere). Independent estimation of Asian emissions of gaseous precursors of the aerosol-associated ions suggest only small changes between the two missions, and precipitation fields do not suggest any significant difference in the efficiency of the primary sink, precipitation scavenging. It thus appears that with the possible exception of dust, the enhancements of aerosol-associated species during TRACE P cannot be explained by stronger sources or weaker sinks. We argue that the enhancements largely reflect the fact that TRACE P focused on characterizing Asian outflow, and thus the DC-8 was more frequently flown into regions that were influenced by well-organized flow off the continent.

Dibb, Jack E.↗
NASA NTRS1994

Gravity Waves and Turbulence as Observed in ASHOE/MAESA

Previous investigators have demonstrated that midlatitude convection is capable of generating gravity waves that propagate into the stratosphere. Gravity waves contribute significantly to the overall mass circulation of the stratosphere, which is driven by the breaking of planetary and mesoscale waves generated in the troposphere. In the southern hemisphere stratosphere, where planetary wave amplitudes are substantially smaller than in the northern hemisphere, gravity wave breaking may play a more important role. At the same time, the major mechanism for exciting gravity waves, namely flow over rough terrain, is much less widespread in the ocean-covered southern hemisphere. This presentation examines gravity waves as observed in the first three deployments of the ASHOE/MAESA campaign. Among the issues to be examined are: 1: The incidence of turbulence during the flights as compared to the arctic campaigns. 2: The relationship of turbulence to vertical tracer gradients. 3: The relationship of observed gravity waves to underlying satellite imagery.

Pfister, Leonhard↗
NASA NTRS2016

A41a-0017: Using TES Retrievals of HCN to Determine Fire Influence of Aura-TES Footprints

Hydrogen cyanide (HCN) has successfully been used as a tracer of biomassburning in the context of aircraft campaigns. We show HCN observations fromAura-TES for a major fire in Indonesia in 2006, and globally over differentseasons. We develop a fire-influence flag for TES observations and show howthis relates to enhancements of other TES products, such as PAN, carbonmonoxide, and ozone.

ozone↗