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Height Dependency of Aerosol‐Cloud Interaction Regimes
Author(s) -
Chen Jingyi,
Liu Yangang,
Zhang Minghua,
Peng Yiran
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd027431
Subject(s) - aerosol , supersaturation , atmospheric sciences , particle (ecology) , environmental science , cloud physics , cloud computing , meteorology , physics , geology , thermodynamics , oceanography , computer science , operating system
This study investigates the height dependency of aerosol‐cloud interaction regimes in terms of the joint dependence of the key cloud microphysical properties (e.g., cloud droplet number concentration and cloud droplet relative dispersion) on aerosol number concentration ( N a ) and vertical velocity ( w ). The three distinct regimes with different microphysical features are the aerosol‐limited regime, the updraft‐limited regime, and the transitional regime. The results reveal two new phenomena in updraft‐limited regime: (1) the “condensational broadening” of cloud droplet size distribution in contrast to the well‐known “condensational narrowing” in the aerosol‐limited regime and (2) above the level of maximum supersaturation; some cloud droplets are deactivated into interstitial aerosols in the updraft‐limited regime, whereas all droplets remain activated in the aerosol‐limited regime. Further analysis shows that the particle equilibrium supersaturation plays important role in understanding these unique features. Also examined is the height of warm rain initiation and its dependence on N a and w . The rain initiation height is found to depend primarily on either N a or w or both in different N a ‐ w regimes, suggesting a strong regime dependence of the second aerosol indirect effect.