Abstract. Atmospheric aerosols can act as ice nucleating particles (INPs) and thereby influence the formation and the microphysical properties of cirrus clouds resulting in distinct climate modifications. From laboratory experiments several types of aerosol particles have been identified as effective INPs at cirrus conditions. However, the global atmospheric distribution of INPs in the cirrus regime is still highly uncertain as in situ observations are scarce and limited in space and time. To study the influence of INPs on cirrus clouds and climate on the global scale these particles have been simulated with global chemistry-climate models. Typically, mineral dust and soot particles, which are known to initiate ice nucleation in cirrus clouds, have been considered in these models. In addition, laboratory studies suggest crystalline ammonium sulfate and glassy organic particles as effective INPs in the cirrus regime. However, the representation of these particles in global models is challenging as their phase state, i.e. crystalline or glassy, needs to be simulated. In turn, crystalline ammonium sulfate and glassy organics have only rarely been considered in global model studies and their impact on the global scale is still uncertain. Here, we present and analyse a global climatology of INPs derived from global model simulations performed with the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model including the aerosol microphysics submodel MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, third generation) coupled to a two-moment cloud microphysical scheme and a parametrization for aerosol-induced ice formation in cirrus clouds. This global INP-climatology comprises mineral dust and soot particles, as well as crystalline ammonium sulfate and glassy organics, including a simplified formulation of the particle phase state for the latter. By coupling the different INP-types to the microphysical cirrus cloud scheme, their ice nucleation potential at cirrus conditions is analysed, considering possible competition mechanisms between different INPs. The simulated INP concentrations in the range of about 1 to 100 L⁻¹ agree well with in situ observations and other global model studies. We show that INP concentrations of glassy organics and crystalline ammonium sulfate are strongly related to the ambient conditions which often inhibit the glassy or crystalline phase, respectively. Our model results suggest that glassy organic particles probably have only minor influence, as typical INP concentrations are mostly low in the cirrus regime. On the other hand, crystalline ammonium sulfate often shows large INP concentrations, has the potential to influence ice nucleation in cirrus clouds, and should be taken into account in future model applications.

中文翻译：

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来自 EMAC-MADE3 模型模拟的卷云条件下冰成核粒子的全球气候学

摘要。大气气溶胶可以充当冰核粒子（INP），从而影响卷云的形成和微观物理特性，从而导致明显的气候变化。从实验室实验中，几种类型的气溶胶颗粒已被确定为卷云条件下的有效 INP。然而，由于原位观测稀缺且空间和时间有限，因此卷云状态下 INP 的全球大气分布仍然高度不确定。为了研究 INPs 在全球范围内对卷云和气候的影响，这些粒子已经用全球化学气候模型进行了模拟。通常，在这些模型中已经考虑了矿物尘埃和煤烟颗粒，它们已知会在卷云中引发冰核。此外，实验室研究表明，结晶硫酸铵和玻璃状有机颗粒是卷云状态下的有效 INP。然而，这些粒子在全局模型中的表示具有挑战性，因为需要模拟它们的相态，即结晶或玻璃态。反过来，在全球模型研究中很少考虑结晶硫酸铵和玻璃态有机物，它们对全球范围的影响仍然不确定。在这里，我们展示并分析了 INP 的全球气候学，该 INPs 源自使用 ECHAM/MESSy 大气化学 (EMAC) 大气环流模型执行的全球模型模拟，包括气溶胶微物理子模型 MADE3（欧洲模态气溶胶动力学模型，适用于全球应用，第三代）耦合到两矩云微物理方案和卷云中气溶胶诱导的冰形成的参数化。这种全球 INP 气候学包括矿物粉尘和烟尘颗粒，以及结晶硫酸铵和玻璃状有机物，包括后者的颗粒相态的简化公式。通过将不同的 INP 类型与微物理卷云方案耦合，分析了它们在卷云条件下的冰成核潜力，考虑了不同 INP 之间可能的竞争机制。模拟的 INP 浓度范围约为 1 至 100 L 包括后者的粒子相态的简化公式。通过将不同的 INP 类型与微物理卷云方案耦合，分析了它们在卷云条件下的冰成核潜力，考虑了不同 INP 之间可能的竞争机制。模拟的 INP 浓度范围约为 1 至 100 L 包括后者的粒子相态的简化公式。通过将不同的 INP 类型与微物理卷云方案耦合，分析了它们在卷云条件下的冰成核潜力，考虑了不同 INP 之间可能的竞争机制。模拟的 INP 浓度范围约为 1 至 100 L^-1与现场观测和其他全球模型研究非常吻合。我们表明，玻璃态有机物和结晶硫酸铵的 INP 浓度与通常分别抑制玻璃态或结晶相的环境条件密切相关。我们的模型结果表明，玻璃状有机颗粒可能只有很小的影响，因为典型的 INP 浓度在卷云状态下大多较低。另一方面，结晶硫酸铵通常显示出较大的 INP 浓度，有可能影响卷云中的冰成核，应在未来的模型应用中加以考虑。