Atmospheric ice-nucleating particles (INPs) play a critical role in cloud freezing processes, with important implications for precipitation formation and cloud radiative properties, and thus for weather and climate. Additionally, INP emissions respond to changes in the Earth System and climate, for example, desertification, agricultural practices, and fires, and therefore may introduce climate feedbacks that are still poorly understood. As knowledge of the nature and origins of INPs has advanced, regional and global weather, climate, and Earth system models have increasingly begun to link cloud ice processes to model-simulated aerosol abundance and types. While these recent advances are exciting, coupling cloud processes to simulated aerosol also makes cloud physics simulations increasingly susceptible to uncertainties in simulation of INPs, which are still poorly constrained by observations. Advancing the predictability of INP abundance with reasonable spatiotemporal resolution will require an increased focus on research that bridges the measurement and modeling communities. This review summarizes the current state of knowledge and identifies critical knowledge gaps from both observational and modeling perspectives. In particular, we emphasize needs in two key areas: (a) observational closure between aerosol and INP quantities and (b) skillful simulation of INPs within existing weather and climate models. We discuss the state of knowledge on various INP particle types and briefly discuss the challenges faced in understanding the cloud impacts of INPs with present-day models. Finally, we identify priority research directions for both observations and models to improve understanding of INPs and their interactions with the Earth System.

中文翻译：

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影响云和气候的冰核粒子：观测和建模研究需求

大气冰核粒子（INPs）在云冻结过程中发挥着关键作用，对降水形成和云辐射特性具有重要意义，因此对天气和气候也有重要影响。此外，INP 排放会响应地球系统和气候的变化，例如荒漠化、农业实践和火灾，因此可能会引入仍然知之甚少的气候反馈。随着对 INP 的性质和起源的了解不断深入，区域和全球天气、气候和地球系统模型越来越多地开始将云冰过程与模型模拟的气溶胶丰度和类型联系起来。虽然这些最新进展令人兴奋，但将云过程与模拟气溶胶耦合也使得云物理模拟越来越容易受到 INP 模拟不确定性的影响，仍然很少受到观察的约束。以合理的时空分辨率提高 INP 丰度的可预测性将需要更多地关注连接测量和建模社区的研究。本综述总结了当前的知识状况，并从观察和建模的角度确定了关键的知识差距。特别是，我们强调了两个关键领域的需求：（a）气溶胶和 INP 数量之间的观测闭合和（b）在现有天气和气候模型中熟练模拟 INP。我们讨论了各种 INP 粒子类型的知识状态，并简要讨论了在使用当今模型理解 INP 的云影响方面面临的挑战。最后，