Transport, removal, and transformation of the aerosol particles. The spatiotemporal scales at which the extensive and intensive properties vary are directly linked to the processes governing the emission, Properties such as aerosol optical depth (AOD), extinction, scattering, and absorption are predominantly dependent on the quantity of aerosol particles Speciation (e.g., organic aerosols, black carbon, sulfate, nitrate, ammonium, dust, or sea salt) (Kacenelenbogen et al., 2022). These intensive propertiesĭepend on the intrinsic properties of the aerosol in terms of its size, shape, and composition (Russell et al., 2010) and can capture the dominant aerosol Represent the aerosol optical properties that do not scale with aerosol concentration or mass, such as the Ångström exponent (AE), fine-modeįraction (FMF), single-scattering albedo, asymmetry parameter, index of refraction, and hemispheric backscatter fraction. In addition to impacting aerosol size, aerosolĬoncentration processes such as aerosol emission, transport, and removal mostly impact the AOD.Īerosol interactions with light are governed by their intensive and extensive properties (Rajesh and Ramachandran, 2020). Mostly impact the dominant aerosol size (characterized by, e.g., FMF / AE) and to some degree AOD. Scales shorter than aerosol concentration processes at which microphysical processes such as aerosol particle formation, growth, and coagulation Interrelated, the spatial variability and relative variability of these parameters in this study indicate that microphysical processes vary at High spatiotemporal variability occurs during the dynamic period (25–31 May), and low spatiotemporal variability occurs during the blocking pattern (1–7 June). While there are observational and modelĭifferences, the predominant factor influencing spatial–temporal homogeneity is the meteorological period. Reduction in correlation by 15 % is 65.0 km for AOD and shorter at 22.7 km for AE. Averaging between measurements and models for the entire KORUS-AQ period, the We observed that, contrary to the prevalent understanding, AE and FMF are more spatially variable than AOD during KORUS-AQ, even whenĪccounting for potential sampling biases by using Monte Carlo resampling. Interpolating between sparse aerosol observation sites or modeled pixels, potentially reducing uncertainties in the upcoming observationalĬapabilities. Understanding the variability of aerosols helps reduce uncertainties in the aerosol direct radiative effect by quantifying the errors due to GOCI-derived FMF, which was found to be slightly low compared to AErosol RObotic NETwork (AERONET) sites (Choi et al., 2018), is lower than 4STAR's observations during KORUS-AQ. Even though there are large variations, for 18 out of the 20 flight days, the column AOD measurements by 4STAR along the NASA DC-8 flight trajectories match the South Korean regional average derived from GOCI. The majority of AOD due to fine-mode aerosol is observed at altitudes lower than 2 km. Measurements from 4STAR when flying below 1000 m show an average AOD at 501 nm of 0.36 and an average AE of 1.11 with large standard deviation (0.12 and 0.15 for AOD and AE, respectively), likely due to mixing of different aerosol types (fine and coarse mode). We use measurements and retrievals of aerosol optical properties from airborne instruments for remote sensing (4STAR Spectrometers for Sky-Scanning Sun-Tracking Atmospheric Research) and in situ (LARGE NASA Langley Aerosol Research Group Experiment) on board the NASA DC-8 and geostationary satellites (GOCI Geostationary Ocean Color Imager Yonsei aerosol retrieval – YAER, version 2) as well as from reanalysis (MERRA-2 Modern-Era Retrospective Analysis for Research and Applications, version 2). Korea during the 2016 KORUS-AQ (KORea–US Air Quality) atmospheric experiment. Spatial scales of changes in AOD (aerosol optical depth) and aerosol size (using Ångström exponent – AE fine-mode fraction – FMF) over Years and over hundreds of kilometers) or the air quality (hours to days and from meters to hundreds of kilometers). Aerosol particles can be emitted, transported, removed, or transformed, leading to aerosol variability at scales impacting the climate (days to
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