Strikingly Positive Contributions of New Particle Formation to Cloud Condensation Nuclei under Low Supersaturation in China Based on Improved Numerical Models
YANG GAO, Chupeng Zhang, Shangfei Hai, Yuhang Wang, Shaoqing Zhang, Lifang Sheng, Bin Zhao, Shuxiao Wang, Jingkun Jiang, Xin Huang, Xiaojing Shen, Junying Sun, Aura Lupascu, ManishKumar Shrivastava, Jerome Fast, Wenxuan Cheng, Xiuwen Guo, Ming Chu, Nan Ma, Juan Hong, Qiaoqiao Wang, Xiaohong Yao, Huiwang Gao,
Ocean University of China Abstract Number: 167
Working Group: Aerosols, Clouds and Climate
AbstractNew particle formation (NPF) and subsequent particle growth are important sources of condensation nuclei (CN) and cloud condensation nuclei (CCN). While a number of observations have shown positive contributions of NPF to CCN at low supersaturation, simulation results, however, in general indicate negative NPF contributions. Using the observations in North China, we thoroughly evaluate the simulated number concentrations of CN and CCN using a NPF-explicit parameterization embedded in WRF-Chem model. By adjusting the process of gas-particle partitioning, including mass accommodation coefficient of sulfuric acid, the phase changes of primary organic aerosol emissions and the condensational amount of nitric acid, the concomitant improvement of the particle growth process yields a substantial reduction of overestimates of small particle number concentrations. Regarding CCN, SOA formed from the oxidation of semi-volatile and intermediate volatility organic vapors (SI-SOA) yield is an important contributor. Lowering the SI-SOA yield results in much improved simulations. On the basis of the bias-corrected model, we find substantial positive contributions of NPF to CCN at low supersaturation (~0.2%) over the broad areas of China, primarily due to the competing effects of increasing particle hygroscopicity surpassing that of particle size decrease. This study emphasizes that the potentially much larger NPF contributions to CCN on a regional and even global basis.