资源环境科技发展态势分析平台

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 kappa-Kohler 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 degrees 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.