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

Abstract

Aerosol vertical distribution generally determines their health impacts and climate effects. By using long‐term (2007–2019) CALIPSO lidar measurements, we present a large‐scale insight into the climatology of aerosol types and their vertical structure over East Asia. Despite the low sampling frequency, comparison with MODIS aerosol optical depth (AOD) shows that the integrated CAIPSO vertical extinction can reasonably reproduce spatial patterns of the aerosol loading. With the unique advantage of active detection, CALIPSO reveals an obvious enhancement of the night‐time AOD due to worse diffusion conditions. Moreover, long‐range transport of different aerosols including dust, polluted dust, and smoke has substantial contribution to the aerosol loading over East Asia. Pure dust particles are mainly concentrated over the deserts with notable dust transport belts (dust AOD > 0.2 at 532 nm) along downwind regions during winter and spring. By contrast, polluted dust is prevalent over the downstream eastern China with much higher AODs throughout the year. In particular, AOD of polluted dust (~0.5) is higher in winter rather than in spring, which is consistent with their seasonal occurrences. Smoke aerosols usually appear in the night‐time over southern China. The top heights of aerosols are around 4–6 km, with dust and smoke having higher extinction at upstream regions. The climatology of these aerosol types and vertical distribution can provide a significant constraint for associated studies of air quality and climate effects.

Identifying Seasonal and Diurnal Variations and the Most Frequently Impacted Zone of Aerosols in the Aral Sea Region

“…In general, the vertical distribution of aerosols dictates their health and climate implications [ 91 ]. The vertical profiles of the occurrence frequencies of the aerosol subtype layers observed in the daytime and nighttime over the Aral Sea region in different seasons are shown in Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 9 .…”

Multi-Satellite Detection of Long-Range Transport and Transformation of Atmospheric Emissions from the Hunga Tonga-Hunga Ha’apai Volcano

“…Also, measurements of the attenuated backscatter and depolarization ratio can be used to identify the type of aerosols and clouds based on position, height, and surface types [32]. CALIPSO, in combination with other satellites in A-Train, can effectively detect the vertical structure and characteristics of clouds and aerosol layers [33]. Version V4.1 L2 CALIPSO aerosol products have been significantly improved in terms of extinction, optical depth [34], and aerosol classification [35].…”

Characteristics of Daytime‐And‐Nighttime AOD Differences Over China: A Perspective From CALIOP Satellite Observations and GEOS‐Chem Model Simulations

“…At regional scale, the CALIOP data show that AOD at nighttime is larger than that in the daytime over eastern China (Gui et al, 2022;Huang et al, 2013) and the North China Plain (Xu et al, 2019). The larger nighttime AOD is ascribed to weaker convection and diffusion caused by lower temperature at night (Gui et al, 2022), greater hygroscopic growth of aerosols at low levels at nighttime than during the day (Xu et al, 2019), and undetected daytime low aerosol concentrations at high levels caused by solar radiation interference (Xu et al, 2019). In contrast, Su et al (2020) found that CALIOP AOD is larger during the daytime than at night over northeastern China and hypothesized that this difference is caused by greater anthropogenic emissions during the day than at night.…”

“…The factors in these large differences have not been investigated with rigor. At regional scale, the CALIOP data show that AOD at nighttime is larger than that in the daytime over eastern China (Gui et al., 2022; Huang et al., 2013) and the North China Plain (Xu et al., 2019). The larger nighttime AOD is ascribed to weaker convection and diffusion caused by lower temperature at night (Gui et al., 2022), greater hygroscopic growth of aerosols at low levels at nighttime than during the day (Xu et al., 2019), and undetected daytime low aerosol concentrations at high levels caused by solar radiation interference (Xu et al., 2019).…”