English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. In situ measurements of aerosol microphysical, chemical,and optical properties were made during global-scale flights from 2016–2018 as part of the Atmospheric Tomography Mission (ATom). The NASA DC-8 aircraft flew from ∼ 84∘ N to ∼ 86∘ S latitude over the Pacific, Atlantic, Arctic, and Southern oceans whileprofiling nearly continuously between altitudes of ∼ 160 m and∼ 12 km. These global circuits were made once each season.Particle size distributions measured in the aircraft cabin at dry conditionsand with an underwing probe at ambient conditions were combined with bulkand single-particle composition observations and measurements of watervapor, pressure, and temperature to estimate aerosol hygroscopicity andhygroscopic growth factors and calculate size distributions at ambientrelative humidity. These reconstructed, composition-resolved ambient sizedistributions were used to estimate intensive and extensive aerosolproperties, including single-scatter albedo, the asymmetry parameter,extinction, absorption, Ångström exponents, and aerosol opticaldepth (AOD) at several wavelengths, as well as cloudcondensation nuclei (CCN) concentrations at fixedsupersaturations and lognormal fits to four modes. Dry extinction andabsorption were compared with direct in situ measurements, and AOD derivedfrom the extinction profiles was compared with remotely sensed AODmeasurements from the ground-based Aerosol Robotic Network (AERONET); thiscomparison showed no substantial bias. The purpose of this work is to describe the methodology by which ambientaerosol properties are estimated from the in situ measurements, providestatistical descriptions of the aerosol characteristics of different remoteair mass types, examine the contributions to AOD from different aerosoltypes in different air masses, and provide an entry point to the ATomaerosol database. The contributions of different aerosol types (dust, seasalt, biomass burning, etc.) to AOD generally align with expectations basedon location of the profiles relative to continental sources of aerosols,with sea salt and aerosol water dominating the column extinction in mostremote environments and dust and biomass burning (BB) particles contributingsubstantially to AOD, especially downwind of the African continent.Contributions of dust and BB aerosols to AOD were also significant in thefree troposphere over the North Pacific. Comparisons of lognormally fitted size distribution parameters to values inthe Optical Properties of Aerosols and Clouds (OPAC) database commonly usedin global models show significant differences in the mean diameters andstandard deviations for accumulation-mode particles and coarse-mode dust. Incontrast, comparisons of lognormal parameters derived from the ATom datawith previously published shipborne measurements in the remote marineboundary layer show general agreement. The dataset resulting from this work can be used to improve global-scalerepresentation of climate-relevant aerosol properties in remote air massesthrough comparison with output from global models and assumptions used inretrievals of aerosol properties from both ground-based and satellite remote sensing.

Ambient aerosol properties in the remote atmosphere from global-scale in situ measurements