Airborne HSRL-2 measurements of elevated aerosol depolarization associated with non-spherical sea salt

Frontiers in Remote Sensing, Journal Year: 2023, Volume and Issue: 4

Published: April 3, 2023

Airborne NASA Langley Research Center (LaRC) High Spectral Resolution Lidar-2 (HSRL-2) measurements acquired during the recent Earth Venture Suborbital-3 (EVS-3) Aerosol Cloud Meteorology Interactions over Western Atlantic Experiment (ACTIVATE) revealed elevated particulate linear depolarization associated with aerosols within marine boundary layer. These observations were off east coast of United States both winter and summer 2020 2021 when HSRL-2 was deployed on LaRC King Air aircraft. During 20 63 total flight days, particularly days cold air outbreaks, at 532 nm exceeded 0.15–0.20 lowest several hundred meters atmosphere, indicating that these particles non-spherical. Higher values typically measured 355 lower 1,064 nm. Several lines evidence suggest non-spherical sea salt including aerosol extinction/backscatter ratio (“lidar ratio”) 20–25 sr by HSRL-2, higher low (< 60%) relative humidity, coincident airborne in situ size composition measurements, transport simulations. The not correlated wind speed but mass fraction effective radius humidity below 60%. median extinction about Mm −1 found optical depth (AOD) contributed remained small (0.03–0.04) represented average 30%–40% column AOD. Cloud-Aerosol Lidar Orthogonal Polarization (CALIOP) spaceborne lidar outbreaks CALIOP retrievals using AOD constraints operational algorithms can misclassify as dusty rather than aerosols. Such misclassification leads to ∼40–50% overestimates assumed subsequent extinction.

Language: Английский

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Dropsonde observations during the Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment

Scientific Data, Journal Year: 2023, Volume and Issue: 10(1)

Published: Nov. 1, 2023

The Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) field campaign provides accurate data for aerosol characterization and trace gas profiles, establishes knowledge of relationships between aerosols water. dropsonde dataset an in situ vertical thermodynamic structure atmosphere during 165 research flights by NASA Langley's King Air aircraft February 2020 June 2022 four test December 2019 November 2021. covered North Atlantic region, off coast Eastern United States around Bermuda all seasons. profiles provide observations temperature, pressure, relative humidity, horizontal winds surface about 9 km. 801 dropsondes were released, which 796 processed 788 complete parameters flight level with normal parachute performance. Here, we describe dataset, processing measurements, general statistics, applications this rich dataset.

Language: Английский

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Analysis of MONARC and ACTIVATE Airborne Aerosol Data for Aerosol-Cloud Interaction Investigations: Efficacy of Stairstepping Flight Legs for Airborne In Situ Sampling

Atmosphere, Journal Year: 2022, Volume and Issue: 13(8), P. 1242 - 1242

Published: Aug. 5, 2022

A challenging aspect of conducting airborne in situ observations the atmosphere is how to optimize flight plans for specific objectives and constraints associated with weather restrictions. For aerosol-cloud interaction research, two recent campaigns utilized a “stairstepping” approach whereby an aircraft conducts level legs at various altitudes while moving forward each subsequent leg: 2019 MONterey Aerosol Research Campaign (MONARC) over northeast Pacific 2020–2022 Cloud meTeorology Interactions oVer western ATlantic Experiment (ACTIVATE) northwest Atlantic. We examine homogeneity several atmospheric variables both vertically horizontally marine boundary layer focus on sub-cloud environment. In well-mixed layers, there was generally good horizontal vertical potential temperature, winds, water vapor mixing ratio, trace gases, many aerosol variables. Selected exhibited most variability owing sensitivity humidity near-cloud conditions (supermicrometer concentrations), coastal pollution gradients (e.g., organic mass), small spatial scale phenomena such as new particle formation (aerosol number concentration particles diameter >3 nm). Illustrative cases are described when stairstepping can pose issues requiring extra caution data analysis: (i) poor layers decoupled from those below; (ii) multiple cloud layers; (iii) fluctuating base/top top heights; (iv) across features leading sharp right near coastlines Gulf Stream strong sea surface temperature changes. Results this study provide guide future studies aiming these mission datasets designing campaigns.

Language: Английский

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Spatially coordinated airborne data and complementary products for aerosol, gas, cloud, and meteorological studies: the NASA ACTIVATE dataset

Earth system science data, Journal Year: 2023, Volume and Issue: 15(8), P. 3419 - 3472

Published: Aug. 3, 2023

Abstract. The NASA Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) produced a unique dataset for research into aerosol–cloud–meteorology interactions, with applications extending from process-based studies to multi-scale model intercomparison and improvement as well remote-sensing algorithm assessments advancements. ACTIVATE used two Langley Research Center aircraft, HU-25 Falcon King Air, conduct systematic spatially coordinated flights over northwest Atlantic Ocean, resulting in 162 joint 17 other single-aircraft between 2020 2022 across all seasons. Data cover 574 592 cumulative hours respectively. conducted profiling at different level legs below, in, just above boundary layer clouds (< 3 km) obtained situ measurements of trace gases, aerosol particles, clouds, atmospheric state parameters. Under cloud-free conditions, similarly within immediately layer. Air (the high-flying aircraft) flew approximately ∼ 9 km remote sensing lidar polarimeter while also launching dropsondes (785 total). Collectively, simultaneous data both aircraft help characterize same vertical column atmosphere. In addition individual instrument files, are combined “merge files” on publicly available archive that created time resolutions interest (e.g., 1, 5, 10, 15, 30, 60 s, or matching an product's start stop times). This paper describes flight strategy, complementary products, access usage details, application notes. accessible through https://doi.org/10.5067/SUBORBITAL/ACTIVATE/DATA001 (ACTIVATE Science Team, 2020).

Language: Английский

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Relationships between supermicrometer particle concentrations and cloud water sea salt and dust concentrations: analysis of MONARC and ACTIVATE data

Environmental Science Atmospheres, Journal Year: 2022, Volume and Issue: 2(4), P. 738 - 752

Published: Jan. 1, 2022

Airborne field data are used to examine relationships between giant cloud condensation nuclei (GCCN) and composition advance knowledge of poorly characterized GCCN–cloud interactions.

Language: Английский

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New particle formation in the tropical free troposphere during CAMP²Ex: statistics and impact of emission sources, convective activity, and synoptic conditions

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(17), P. 9853 - 9871

Published: Sept. 6, 2023

Abstract. Nucleation in the free troposphere (FT) and subsequent growth of new particles represent a globally important source cloud condensation nuclei (CCN). Whereas particle formation (NPF) has been shown to occur frequently upper over tropical oceans, there have few studies NPF at lower altitudes. In addition, impact urban emissions biomass burning on marine FT remains poorly understood. this study, we examine mid-troposphere (3–8.5 km) ocean coastal region using airborne measurements during recent Cloud, Aerosol Monsoon Processes Philippines Experiment (CAMP2Ex). was mostly observed above 5.5 km coincided with elevated relative humidity (RH) reduced sink (CS), suggesting that occurs convective outflow. The frequency increases altitude, reaching ∼ 50 % 8 km. An abrupt decrease coincides early monsoon transition is attributed increased CS resulting from activity more frequent transport aged plumes. Surprisingly, large fraction events background air were morning, likely made possible by very low despite actinic flux. Convectively detrained biomass-burning plumes fresh enhance as result precursor concentrations scavenging pre-existing particles. contrast, suppressed where reactive precursors are consumed, while relatively high. This study shows strong FT. results also illustrate competing influences different variables interactions among anthropogenic emissions, clouds, meteorology, which lead under variety conditions environments.

Language: Английский

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Dimethylamine in cloud water: a case study over the northwest Atlantic Ocean

Environmental Science Atmospheres, Journal Year: 2022, Volume and Issue: 2(6), P. 1534 - 1550

Published: Jan. 1, 2022

This study analyzes characteristics of an important alkyl amine species, dimethylamine (DMA), in cloud water over the northwest Atlantic.

Language: Английский

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Tropospheric aerosols over the western North Atlantic Ocean during the winter and summer deployments of ACTIVATE 2020: life cycle, transport, and distribution

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(4), P. 2087 - 2121

Published: Feb. 19, 2025

Abstract. The Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) is a NASA mission to characterize aerosol–cloud interactions over North Atlantic Ocean (WNAO). Such characterization requires understanding of life cycle, composition, transport pathways, and distribution aerosols WNAO. This study uses GEOS-Chem model simulate aerosol distributions properties that are evaluated against aircraft, ground-based, satellite observations during winter summer field deployments in 2020 ACTIVATE. Transport boundary layer (BL) behind cold fronts was major mechanism for American continental outflow pollution WNAO winter. Turbulent mixing main driver upward sea salt within ventilation out BL composition dominated by salt, which increased summer, followed organics sulfate. Aircraft situ measurements provided useful constraints on wet scavenging GEOS-Chem. generally captured observed features such as outflow, land–ocean gradient, anthropogenic with salt. Model sensitivity experiments elevated smoke injection heights mid-troposphere (versus BL) better reproduced from US wildfires summer. analysis suggests strong hygroscopic growth particles their seeding marine clouds (< 35° N). Future modeling efforts should focus improving parameterizations scavenging, implementing realistic heights, applying high-resolution models resolve vertical transport.

Language: Английский

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New Particle Formation Events Over the Southeast Atlantic Coincide With the African Biomass Burning Season

Geophysical Research Letters, Journal Year: 2025, Volume and Issue: 52(8)

Published: April 19, 2025

Abstract We investigated the occurrence and evolution of new particle formation (NPF) events over southeast Atlantic. The studied region is under influence long‐range transport aerosols gases during southern African biomass burning season, from June to October every year. Interestingly, NPF was observed coincide with although wet removal pre‐existing needed these events. Surface airborne measurements show that likely occurred in upper marine boundary layer, newly formed were further transported surface via vertical air motions. Using a box model, we predicted large fraction particles could grow sizes related cloud condensation nuclei. Our study shows can occur Atlantic, biomass‐burning plume contributed occurrence.

Language: Английский

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Examining the vertical heterogeneity of aerosols over the Southern Great Plains

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(24), P. 15671 - 15691

Published: Dec. 20, 2023

Abstract. Atmospheric aerosols affect the global energy budget by scattering and absorbing sunlight (direct effects) changing microphysical structure, lifetime, coverage of clouds (indirect effects). Both aerosol direct indirect effects are affected vertical distribution in atmosphere, which is further influenced a range processes, such as dynamics, long-range transport, entrainment. However, many observations these processes based on ground measurements, limiting our ability to understand simulate their impact climate. In this work, we examined heterogeneity over Radiation Measurement (ARM) Southern Great Plains (SGP) using data collected from Holistic Interactions Shallow Clouds, Aerosols Land Ecosystems (HI-SCALE) campaign. The profiles meteorological physiochemical properties up 2500 m above 38 flights conducted during HI-SCALE SGP show strong seasonal variabilities. concentrations at surface highest due emissions level. general, mode diameter summer (∼ 100 nm) larger than that spring 30 nm), result enhanced condensational growth enriched volatile organic compounds summer. concentration below nm boundary layer (BL) (e.g., 1000 m) higher summer, stronger new particle formation (NPF) events reduced condensation sink spring. BL, size gradually increases with altitude cloud processing. chemical composition remained similar, organics sulfates representing 59.8 ± 2.2 % 22.7 2.1 %, respectively, total mass BL. Through properties, observed NPF upper BL 7 out research flights, where newly formed particles continue grow they mixed down surface. There also an indication deep convection brings free troposphere (FT) surface, contribute nuclei (CCN). Overall, dynamics (new formation, growth, processing) transport (mixing entrainment, convective downward transport). Case studies showing influence factors discussed.

Language: Английский

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