EAGER: Development of a Bulk-Emulating Microphysics Scheme

数值天气和气候模式使用云微物理方案来表示大量云粒子如何生长、相互作用和衰变。明确地模拟云的全部特征，例如不同颗粒大小的分布，在大多数情况下在计算上是不可行的，因此研究人员设计了一些方案，可以准确地表示对模型很重要的某些数量。然而，有一些过程在很大程度上依赖于诸如粒度分布等方面，因此更好地理解两种方法之间的差异将有助于识别问题。这项工作将创建一个基于显式云建模的云方案，但可与计算不太先进的方案相媲美，以便进行直接比较。主要的社会影响将是对天气和气候模式的下游影响。该项目还为研究生提供培训。本项目旨在开发一个体仿真微物理方案。有两种常见的微物理方案，明确预测粒度分布的仓方案和预测1-3个整数粒度分布的散装方案。Bin方案在计算上很昂贵，在全球气候模式中使用也不可行。然而，最近科学界提出，大量方案不能恰当地表示气溶胶与云的相互作用。该项目将开发一种工具和方法来测试大量微物理方案的概念和数值限制，最终目标是告知社区未来应该如何设计新方案。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Numerical weather and climate models use cloud microphysical schemes to represent how a large collection of cloud particles grow, interact, and decay. Explicitly modeling the full characteristics of a cloud, such as the distribution of different particle sizes, is not computationally feasible for most purposes, so researchers have devised schemes that can accurately represent certain quantities that are important for the models. However, there are some processes that depend greatly on aspects such as the particle size distribution, so having an improved understanding of the differences between the two approaches would be useful to identify problems. This work will create a cloud scheme that is based upon explicit cloud modeling but is comparable to the less computationally advanced schemes so that direct comparisons can be conducted. The main societal impact would be the downstream effect on weather and climate models. The project also provides training for a graduate student.This project aims to develop a bulk-emulating microphysics scheme. There are two common classes of microphysics schemes, the bin scheme where the particle size distribution is explicitly predicted, and the bulk scheme where 1-3 integral quantities of the particle size distribution are predicted. Bin schemes are computationally expensive and not feasible for use in global climate models. However, it has been recently suggested by the scientific community that bulk schemes are incapable of properly representing aerosol-cloud interactions. This project will develop a tool and method for testing the conceptual and numerical limitations of bulk microphysics schemes with an end goal of informing the community how new schemes should be designed in the future.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.