Spatial Heterogeneity of Aerosol Effect on Liquid Cloud Microphysical Properties in the Warm Season Over Tibetan Plateau

Abstract

The effect of aerosol on liquid cloud microphysical properties over the Tibetan Plateau (TP) during the warm season is investigated by using aerosol index (AI) and cloud property parameters data. Distinct differences in aerosol effect on liquid cloud microphysical properties have been found between the northern Tibetan Plateau (NTP) and southernTibetan Plateau (STP). The composite liquid cloud droplet effective radius liquid cloud droplet effective radius (LREF) anomalies for positive AI events are positive in the NTP and negative in the STP. In both NTP and STP, when the AI anomalies are positive, the LREF anomalies are also positive, which suggests that the increased aerosol loading reduces the solar radiation reaching the ground and thus enhances the atmospheric stability, which reduces the cloud base height and makes the liquid cloud area thicker, which gives cloud droplets more space to grow by collision‐coalescence. This indicates that the aerosol radiative effect is not likely the reason causing the distinct differences of aerosol effects on liquid cloud properties between NTP and STP. Further analysis shows that in the STP, the LREF first increases and then decreases with the increase of AI, while in the NTP, the LREF always increases with the increase of AI, suggesting a spatial difference in aerosol microphysical effect. In the STP, the influence of aerosol on liquid clouds is mainly dependent on liquid water path and convective available potential energy, while in the NTP, the influence of aerosol on liquid cloud is more likely related to large aerosol particles.

Impact of Aerosols on the Macrophysical and Microphysical Characteristics of Ice-Phase and Mixed-Phase Clouds over the Tibetan Plateau

“…There are differences in ACIs among different cloud phases. Due to the less complex microphysical processes in liquid-phase clouds, which do not involve mixed-phase and ice-phase processes, there have been many research findings on the interaction between aerosols and liquid-phase clouds [9,12,[19][20][21][22][23][24][25][26][27][28]. Numerous studies have found a negative correlation between cloud droplet size and aerosol concentration in liquid-phase clouds, consistent with the traditional aerosol indirect effect or "Twomey effect" by using satellites, aircraft, ground-based observations, etc.…”

Aerosol influence on cloud macrophysical and microphysical properties over the Tibetan Plateau and its adjacent regions

“…Previous studies have also found that dust aerosols dominate the aerosol composition in the WTP (Duo et Liu et al 2015). In WTP, the warm season is higher in water vapor content than the cold season, which is more conducive to the activation of dust aerosols with larger particle sizes to form cloud droplets and promotes the increase of the effective radius of cloud droplets (Zhao et al 2023). In IGP, during the warm season, positive correlations are observed between AOD anomaly and both LREF anomaly and IREF anomaly.…”

“…Under stable atmospheric conditions, aerosol leads to the activation of cloud droplets through vapor consumption. The droplets then continue to grow through condensation (Zhao et al 2023). The growth of cloud droplets may further promote the development of cloud macrophysical properties.…”

“…Similar ndings are presented by Hua et al (2020), who suggested that TP aerosols have a more substantial in uence on the radiative forcing of ice clouds than liquid clouds. Zhao et al (2023) discovered that the in uence of TP aerosols on the microphysical properties of liquid clouds shows signi cant spatial variations. In the southern TP, the aerosol in uence on liquid clouds predominantly relies on liquid water path and convective available potential energy, while in the northern TP, the aerosol in uence on liquid clouds could be more related to large aerosol particles.…”

Physical Properties, Chemical Components, and Transport Mechanisms of Atmospheric Aerosols Over a Remote Area on the South Slope of the Tibetan Plateau

“…The direct radiative forcing effects of light absorbing aerosols are very important on the TP and consequently affect the Asian monsoon (Kumar et al., 2011; Lau et al., 2006; Qian et al., 2011). Atmospheric aerosols also affect cloud formation and consequently affect cloud albedo and hydrological cycles on the TP (Jin, 2006; Zhao et al., 2023; Zhao, Xiao, et al., 2022). The TP has glacier and snow cover, and atmospheric aerosols such as black carbon can accelerate the melting of snow and ice (Lee et al., 2017; Li et al., 2018; Sharma et al., 2022) and affect hydrological cycles via deposition (Yao et al., 2012).…”