Characterization of Aerosol Type Over East Asia by 4.4 km MISR Product: First Insight and General Performance

Abstract

The lack of aerosol type information has largely hindered satellite products from further applications such as constraining model simulations and quantifying aerosol climate effects. The recent Version (V) 23 Multi‐angle Imaging Spectroradiometer (MISR) aerosol products with an enhanced spatial resolution at 4.4 km enable an unprecedented chance to explore aerosol types and associated processes in the regional scale. Here we provide a comprehensive insight into the characterization of MISR aerosol optical and microphysical properties, as well as their performance, over East Asia. Ground validation shows a remarkable improvement in the accuracy of V23 MISR aerosol optical depth (AOD) with ~80% of its retrieval bias within ±(0.05 + 20%AODAERONET). However, an underestimation of MISR AOD is still prevalent in the high‐AOD (>0.6) conditions, due to the surface‐atmosphere separation problem and insufficient absorbing aerosol mixtures being selected. MISR AOD of different size bins agrees well with AErosol RObotic NETwork (AERONET) results, demonstrating an evident advantage in discriminating natural dust from anthropogenic particles. Although MISR nonspherical and absorbing retrievals display a consistent variation with the AERONET inversions, their component AODs have a poor reliability over East Asia due to the inappropriate aerosol component models or their mixtures as in V22. In particular, the most striking problem is the sparse and discrete MISR absorbing retrievals with spatial discontinuity. Generally, the high‐resolution V23 MISR products exhibit a great potential in characterizing the regional variations of aerosol type, which can be further refined by considering the prior aerosol knowledge over East Asia.

Climatology of aerosol types and their vertical distribution over East Asia based on CALIPSO lidar measurements

“…Most population and urban/industrial emissions are concentrated in northern China. By contrast, the terrain of southern China is by mountains and hills with much lower aerosol loading (Tao et al ., 2020a). Five CALIPSO L3 grids in TD, GD, Beijing‐Tianjin‐Hebei (BTH), central China (CC), and southern China (SC) are selected to examine vertical extinction of aerosols.…”

“…On the other hand, extinction coefficients near surface in SC are much higher than in BTH. Since anthropogenic emissions are mostly concentrated in northern China (Tao et al, 2020a), the extreme high values (~0.6-1.0) of extinction coefficients in SC during should be paid to more attention. Considering the CALIPSO results used are seasonal mean values of during 2007-2019, with the low sampling frequency (Table 1), extinction profiles of the numerous aerosol transport events with distinct vertical variations can be largely smoothed.…”

“…During the last decades, the advent of dedicated satellite instruments such as Moderate Resolution Imaging Spectroradiometer (MODIS), Multi‐angle Imaging Spectroradiometer (MISR), and Polarization and Directionality of the Earth's Reflectance (POLDER) has greatly renewed the knowledge of global aerosol loading and major sources (Kaufman et al ., 2002). Although multi‐angle and polarized measurements enables the retrievals of aerosol optical and microphysical properties, notable uncertainties exist due to deficiencies in algorithm assumptions and forward models (Dubovik et al ., 2019; Tao et al ., 2019; 2020a). By now, the most widely used satellite aerosol parameter is still MODIS aerosol optical depth (AOD).…”

Introducing the MISR level 2 near real-time aerosol product

“…Atmospheric aerosols have long been recognized to influence the climate, environment, and human health (e.g., IPCC, 2013;Lelieveld et al, 2015;Shindell et al, 2013;Turnock et al, 2020). They also affect satellite remote sensing of important geophysical parameters such as ocean color (e.g., Frouin et al, 2019;Gordon, 1997) and greenhouse gas abundance (Butz et al, 2009;Frankenberg et al, 2012;Houweling et al, 2005).…”

Application Potential of Satellite Thermal Anomaly Products in Updating Industrial Emission Inventory of China

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Combustion of fossil fuels in global industrial activities emits large amounts of atmospheric pollutants and greenhouse gases every year, which is considered as the main anthropogenic factor in air pollution and climate change (Guo et al, 2019;Krotkov et al, 2016;Oberschelp et al, 2019). During the last decades, industrial emissions of atmospheric pollutants in China have experienced dramatic changes due to both fast-growing economy and strict control measures (Li et al, 2020;Tao et al, 2020;Zheng et al, 2018). As an essential input of air quality and climate models, accurately quantifying emissions of industrial activities is fundamental in understanding the changing climate and air quality.

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