Aerosol Loading and Radiation Budget Perturbations in Densely Populated and Highly Polluted Indo‐Gangetic Plain by COVID‐19: Influences on Cloud Properties and Air Temperature

Khatri, Pradeep; Hayasaka, Tadahiro; Holben, B. N.; Tripathi, Sachchida Nand; Misra, Prakhar; Patra, Prabir K.; Hayashida, Sachiko; Dumka, U. C.

doi:10.1029/2021gl093796

Cited by 13 publications

(8 citation statements)

References 56 publications

(77 reference statements)

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“…Further, the decrease of CTH causes cloud top temperature to increase, enhancing cloud top radiative cooling to further facilitate CTH decrement. On the other hand, CF increases with the increase of AOT in all atmospheric regimes similar to a large volume of past studies performed at different regions of the earth (Khatri et al., 2021; Menon et al., 2008; Quaas et al., 2010; Sekiguchi et al., 2003). A broad range of mechanisms, including ACI process, meteorological factors, cloud droplet evaporation, and so on, can facilitate the increase of CF with the increase of AOT (Quaas et al., 2010; Su et al., 2008).…”

Section: Resultssupporting

confidence: 85%

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Aerosols, tiny suspended particles in the atmosphere, are known to have profound impacts on climate system and hydrological cycle (Ramanathan et al, 2005;Rosenfeld et al, 2008) via two broad pathways: aerosol-radiation interaction (ARI) and aerosol-cloud interaction (ACI). In the former, aerosols scatter and absorb solar and terrestrial radiation (Khatri et al, 2009(Khatri et al, , 2021Wang et al, 2014); and in the latter, these aerosols form cloud condensation nuclei (CCN) and ice nuclei (IN) to modify cloud properties (Khatri et al, 2022;Sekiguchi et al, 2003;Twomey, 1974Twomey, , 1977. Overall, these processes have net cooling effect to offset global warming effect of greenhouse gases (Ramanathan et al, 2005), although the net cooling effects of these processes are still subject of large uncertainties.

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confidence: 99%

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Aerosol Effects on Water Cloud Properties in Different Atmospheric Regimes

Khatri,

Yoshida,

Hayasaka

2023

JGR Atmospheres

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Aerosol‐cloud interaction remains one of the least understood processes in climate science arena, despite its profound impacts in radiation and water budget perturbations. The aerosol effects on clouds largely depend on aerosol characteristics. Here, we implemented 17‐year (2003–2020) data set of aerosol, cloud, and meteorological factors collected over East Asia—a highly polluted region with recent decreasing trend of air pollution due to control measures—to elucidate atmospheric regime‐dependent aerosol effects on water cloud properties by simultaneously accessing the response of air pollution control measures in cloud field. The study found a very close relationship between aerosol loading and cloud properties modifications in the continental region of East Asia with a significant response of air pollution control measures in the cloud field. The study further revealed that aerosols of the polluted continental atmosphere affected cloud micro‐ and macro‐physics differently than aerosols of the clean maritime atmosphere: in the former, increased aerosol loading increased the stability under cloud base and then enhanced cloud droplet collision‐coalescence process, resulting to increase cloud droplet size by decreasing cloud top height; whereas in the latter, increased aerosol loading decreased cloud droplet size without notable influence in the atmosphere thermodynamics and cloud top height. This study further showed a complex aerosol‐cloud interaction process in the polluted maritime atmosphere due to the mixed effect of polluted continental and clean maritime atmospheres. In all atmospheric regimes, cloud fraction was found to increase with the increase of aerosol loading.

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Section: Resultssupporting

confidence: 85%

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confidence: 99%

Aerosol Effects on Water Cloud Properties in Different Atmospheric Regimes

Khatri,

Yoshida,

Hayasaka

2023

JGR Atmospheres

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“…Although such manifold factors can be responsible for differences in CER values between the SGLI and sky radiometer, most of the data samples show higher CER values from SGLI than from the sky radiometer, resulting in negative values of MBE for both water and ice clouds. This result is in line with previous studies that showed higher values from satellite observations compared with values obtained from surface and/or aircraft observations (e.g., Painemal and Zuidema, 2011;Chiu et al, 2012;King et al, 2013).…”

Section: Overall Comparisonsupporting

confidence: 93%

Quality assessment of Second-generation Global Imager (SGLI)-observed cloud properties using SKYNET surface observation data

et al. 2022

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Abstract. The Second-generation Global Imager (SGLI) onboard the Global Change Observation Mission – Climate (GCOM-C) satellite, launched on 23 December 2017, observes various geophysical parameters with the aim of better understanding the global climate system. As part of that aim, SGLI has great potential to unravel several uncertainties related to clouds by providing new cloud products along with several other atmospheric products related to cloud climatology, including aerosol products from polarization channels. However, very little is known about the quality of the SGLI cloud products. This study uses data about clouds and global irradiances observed from the Earth's surface using a sky radiometer and a pyranometer, respectively, to understand the quality of the two most fundamental cloud properties – cloud optical depth (COD) and cloud-particle effective radius (CER) – of both water and ice clouds. The SGLI-observed COD agrees well with values observed from the surface, although it agrees better for water clouds than for ice clouds, while the SGLI-observed CER exhibits poorer agreement than does the COD, with SGLI values being generally higher than the sky radiometer values. These comparisons between the SGLI and sky radiometer cloud properties are found to differ for different cloud types of both the water and ice cloud phases and different solar and satellite viewing angles by agreeing better for relatively uniform and flat cloud type and for relatively low solar zenith angle. Analyses of SGLI-observed reflectance functions and values calculated by assuming plane-parallel cloud layers suggest that SGLI-retrieved cloud properties can have biases in the solar and satellite viewing angles, similar to other satellite sensors including the Moderate Resolution Imaging Spectroradiometer (MODIS). Furthermore, it is found that the SGLI-observed cloud properties reproduce global irradiances quite satisfactorily for both water and ice clouds by resembling several important features of the COD comparison, such as better agreement for water clouds than for ice clouds and the tendency to underestimate (resp. overestimate) the COD in SGLI observations for optically thick (resp. thin) clouds.

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“…Anthropogenic aerosols can act as cloud condensation nuclei (CCN), increase the cloud droplet number concentration (Andreae, 2008; Haywood & Boucher, 2000; Ramanathan et al., 2002), modify the cloud liquid water path (Hill et al., 2009), limit the cloud droplet size under a certain liquid water path, and affect the albedo (Twomey, 1977), life, and area (Albrecht, 1989) of clouds. Therefore, the increase of aerosol loading has great impacts on the radiation budget (Haywood & Shine, 1995; Kim & Ramanathan, 2008), cloud properties (Khatri et al., 2021; Stevens & Feingold, 2009; Yang et al., 2019) and types, intensities, and distributions of precipitation (Cao et al., 2021; Jiang et al., 2016).…”

Section: Introductionmentioning

confidence: 99%