Investigation of Aerosol-Cloud Interactions under Different Absorptive Aerosol Regimes using ARM SGP Ground-Based Measurements Institutional Repository Document uri icon


  • Abstract. The physicochemical properties of aerosols and their impacts on cloud microphysical properties are examined using data collected from the Department of Energy Atmospheric Radiation Measurement (ARM) facility over the Southern Great Plains region of the United States (ARM-SGP). A total of 16 low-level stratus cloud cases under daytime coupled boundary layer conditions are selected. The aerosol-cloud interaction index (ACIr) is used to quantify the aerosol impacts with respect to cloud-droplet effective radius. The mean value of ACIr calculated from all selected samples is 0.1450.05 and ranges from 0.09 to 0.24 at a range of cloud liquid water paths (LWP=20300gm2). The magnitude of ACIr decreases with increasing LWP which suggests a cloud microphysical response to diminished aerosol loading presumably due to enhanced collision-coalescence processes and enlarged particle size. In the presence of weak light-absorbing aerosols, the low-level clouds feature a higher number concentration of cloud condensation nuclei (NCCN) and smaller effective radii (re) while the opposite is true for strong light-absorbing aerosols. Furthermore, the mean activation ratio of aerosols to CCN (NCCN/Na) for weakly (strongly) absorbing aerosols is 0.54 (0.45), owing to the different hygroscopic abilities associated with the dominant aerosol species. In terms of the sensitivity of cloud droplet number concentration (Nd) to aerosol loading, the conversion ratio of Nd/NCCN for weakly (strongly) absorptive aerosols is 0.68 (0.54). Consequently, we expect larger shortwave radiative cooling effect from clouds influenced by weakly absorbing aerosols than strongly absorbing aerosols.

altmetric score

  • 1.25

author list (cited authors)

  • Zheng, X., Xi, B., Dong, X., Logan, T., Wang, Y., & Wu, P.

citation count

  • 0

complete list of authors

  • Zheng, Xiaojian||Xi, Baike||Dong, Xiquan||Logan, Timothy||Wang, Yuan||Wu, Peng

Book Title

  • EGUsphere

publication date

  • June 2019