Premium
A New Method for Distinguishing Unactivated Particles in Cloud Condensation Nuclei Measurements: Implications for Aerosol Indirect Effect Evaluation
Author(s) -
Wang Yuan,
Niu Shengjie,
Lv Jingjing,
Lu Chunsong,
Xu Xiaoqi,
Wang Yuying,
Ding Jie,
Zhang Hongwei,
Wang Tianshu,
Kang Boshi
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl085379
Subject(s) - cloud condensation nuclei , supersaturation , aerosol , condensation , atmospheric sciences , environmental science , materials science , chemistry , meteorology , physics , thermodynamics
An ongoing challenge for cloud condensation nuclei (CCN) measurements is the inclusion of unactivated particles, which affects droplet activation parameterizations and aerosol indirect effects in models. For the first time, a reciprocal relationship between the critical diameter and critical supersaturation of activated droplets from the κ ‐Köhler theory is derived to accurately count unactivated particles in CCN measurements. We conducted 4‐day continuous observations to simultaneously measure the number concentration of CCN ( N CCN ) and aerosol. The results show that as supersaturation ( SS ) decreases from 0.186% at 25 °C, the proportion of the unactivated particles in the CCN measurements increases, reaching 88% at SS of 0.07%. Owing to the N CCN overestimation caused by N CCN ‐ SS parameterizations with uncorrected N CCN , there is significant overestimation of aerosol indirect effects, especially under low SS conditions. After removing unactivated particles, N CCN ‐ SS parameterizations are adjusted accordingly, which can improve simulations of aerosol‐cloud‐radiation interactions in models.