As a precursor process to cloud formation, aerosol activation over the Tibetan Plateau (TP) plays a pivotal role in regional cloud-precipitation and global climate. However, its characteristics remain unclear due to the absence of targeted observations in the TP. We conducted a ground in-situ aerosol-cloud-precipitation experiment in the southern TP (GACPE-STP), thereby unveiling the aerosol activation characteristics in this crucial region. Our findings reveal a weak aerosol activation capacity with low hygroscopicity (κ) values of less than 0.1 through multi-method κ measurements, contrasting starkly with the widely recommended κ value of 0.3 for continental regions. A κ parameterization is developed for predicting aerosol activation in this region, which can significantly reduce the overestimations of cloud droplet number concentration and hence aerosol indirect effects caused by using the recommended κ of 0.3. These findings address the unclear characteristics of aerosol activation in the TP region, contributing to the enhancement of regional cloud precipitation and global climate simulations.

作为云形成的前驱过程，青藏高原（TP）上空的气溶胶活化在区域云降水和全球气候中发挥着关键作用。但由于青藏高原缺乏针对性观测，其特征仍不清楚。我们在青藏高原南部进行了地面原位气溶胶云降水实验（GACPE-STP），揭示了该关键区域的气溶胶活化特征。我们的研究结果表明，通过多方法κ测量，气溶胶活化能力较弱，吸湿性 ( κ ) 值小于 0.1 ，这与大陆地区广泛推荐的κ值 0.3 形成鲜明对比。开发了κ参数化来预测该区域的气溶胶活化，这可以显着减少对云滴数浓度的高估，从而减少使用推荐的κ 0.3 引起的气溶胶间接影响。这些发现解决了青藏高原地区气溶胶活化的不明确特征，有助于加强区域云降水和全球气候模拟。