Anthropogenic aerosol particles exert an—quantitatively very uncertain—effective radiative forcing due to aerosol-cloud interactions via an immediate altering of cloud albedo on the one hand and via rapid adjustments by alteration of cloud processes and by changes in thermodynamic profiles on the other hand. Large variability in cloud cover and properties and the therefore low signal-to-noise ratio for aerosol-induced perturbations hamper the identification of effects in observations. Six approaches are discussed as a means to isolate the impact of anthropogenic aerosol on clouds from natural cloud variability to estimate or constrain the effective forcing. These are (i) intentional cloud modification, (ii) ship tracks, (iii) differences between the hemispheres, (iv) trace gases, (v) weekly cycles and (vi) trends. Ship track analysis is recommendable for detailed process understanding, and the analysis of weekly cycles and long-term trends is most promising to derive estimates or constraints on the effective radiative forcing.

中文翻译：

---

观测人为气溶胶-云相互作用的方法。

由于气溶胶与云之间的相互作用，一方面通过立即改变云的反照率，另一方面通过通过改变云的过程以及通过热力学曲线的变化进行快速调节，从而使人为气溶胶颗粒产生了定量上非常不确定的有效辐射强迫。云层和性质的大变化性以及因气溶胶引起的扰动而产生的低信噪比，阻碍了观测结果的识别。讨论了六种方法，将人为气溶胶对云的影响与自然云的可变性隔离开来，以估计或约束有效强迫。这些是（i）有意进行的云改造，（ii）航迹，（iii）半球之间的差异，（iv）微量气体，（v）每周周期和（vi）趋势。