Nozière Barbara, Baduel Christine, Jaffrezo Jean-Luc
1] Stockholm University, Department of Applied Environmental Science (ITM), Svante Arrhenius väg 8, Stockholm 106 91, Sweden [2].
Université Joseph Fourier-Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement UMR 5183, Grenoble F-38041, France.
Nat Commun. 2014 Feb 25;5:3335. doi: 10.1038/ncomms4335.
The activation of aerosol particles into cloud droplets in the Earth's atmosphere is both a key process for the climate budget and a main source of uncertainty. Its investigation is facing major experimental challenges, as no technique can measure the main driving parameters, the Raoult's term and surface tension, σ, for sub-micron atmospheric particles. In addition, the surfactant fraction of atmospheric aerosols could not be isolated until recently. Here we present the first dynamic investigation of the total surfactant fraction of atmospheric aerosols, evidencing adsorption barriers that limit their gradient (partitioning) in particles and should enhance their cloud-forming efficiency compared with current models. The results also show that the equilibration time of surfactants in sub-micron atmospheric particles should be beyond the detection of most on-line instruments. Such instrumental and theoretical shortcomings would be consistent with atmospheric and laboratory observations and could have limited the understanding of cloud activation until now.
地球大气中气溶胶颗粒活化成云滴，既是气候收支的关键过程，也是不确定性的主要来源。对其进行研究面临重大实验挑战，因为尚无技术能够测量亚微米级大气颗粒的主要驱动参数——拉乌尔项和表面张力σ。此外，直到最近才能够分离出大气气溶胶中的表面活性剂成分。在此，我们首次对大气气溶胶中的总表面活性剂成分进行了动态研究，证明了吸附屏障限制了它们在颗粒中的梯度（分配），并且与当前模型相比，应能提高它们的成云效率。结果还表明，亚微米级大气颗粒中表面活性剂的平衡时间应超出大多数在线仪器的检测范围。这些仪器和理论上的不足与大气和实验室观测结果相符，并且可能至今限制了我们对云活化的理解。
