SI2-SSI: Lightweight Infrastructure for Land Atmosphere Coupling (LILAC): A Tool for Easy Integration of the Community Land Model into Multiple Modeling Systems

地球上的每个人都生活在地面上，因此大气和陆地表面之间的相互作用是气候系统中至关重要的一部分，了解这些相互作用对天气预报、农业和城市水资源管理都很重要。地球系统模型（ESMs）是代表复杂自然系统的复杂软件系统。它们是诊断、理解和预测大气、海洋和陆地生态系统相互作用和变化的关键工具。该项目将开发一个新的软件系统，用于耦合地球系统模型的陆地和大气成分，特别是用于世界上最广泛使用的气候模型：社区地球系统模型（CESM）。新系统将能够模拟近地面的气候，包括植被与空气之间的热量、水、碳交换，以及河流和土壤湿度。作为CESM的官方支持组件，它将被世界各地成千上万的科学家和学生使用。与它的前身不同，新系统将能够以高分辨率模拟小区域的重要应用和测试。该项目还将支持一名计算机科学研究生以及帮助开发和测试该软件的学者和科学家。pi将通过一系列研讨会和网络研讨会以及专业协会和出版物与全球软件开发人员和用户社区进行接触。ppi认识到，在计算机科学和大气科学领域，女性和少数民族的代表性长期不足。为了解决这个问题，他们将为来自代表性不足群体（URGs）的中学生举办一个计算机科学夏令营，并与现有的K-12教师气候课程、K-12学校的科学推广以及PI运营的一个非常成功的REU-Site密切合作。这个项目将极大地提高现有最广泛使用的气候模型的可用性。世界各地的数百名开发人员和数千名用户将受益于此模型的更大的灵活性和用例。社区土地模型将与更大范围的大气代码相结合，用于天气预报、空气质量应用和气候预测，从而提高各地人民的生活质量。社区地球系统模型（CESM）是一个独特的开放ESM，拥有数百名开发人员和全球数千名用户的分布式社区。与其他esm相比，CESM是“气候模型中的Linux”。CESM的土地部分，即社区土地模型（CLM），拥有自己充满活力和多样化的用户和开发社区，这为构建一个特别全面的陆地系统模型提供了支持。它包括一系列丰富的过程，使我们能够考察自然陆地生态系统和人类管理的土地影响气候和天气以及受气候和天气影响的物理、生物和化学过程。CESM只能在全球范围内运行，但人们对将CLM与其他高分辨率大气模式耦合以研究存在于小尺度和大尺度之间的具有挑战性的科学问题有着广泛的兴趣。然而，这项研究的一个障碍是CLM不能轻易地与其他大气模型相结合。CLM耦合接口只支持与CESM耦合基础设施（CPL7）通信，这对大气组件如何与CLM通信提出了严格的要求。一个关键的要求是大气模型在耦合发生之前完成一个完整的时间步长。这一要求需要对许多大气模型进行重大重构，以便它们通过CPL7耦合到CLM。此外，构建和配置CLM的工具目前很难在CESM上下文之外使用。由于所有这些原因，CLM从未以可持续的方式与其他大气模型相结合。科罗拉多州立大学（CSU）与美国国家大气研究中心（NCAR）合作，提议开发陆地-大气耦合轻型基础设施（LILAC），这将大大简化CLM与其他大气模型的耦合。LILAC耦合器和相关的拟议的CLM工具链的精简和简化将在一个原型高分辨率大气模型（CSU SAM云分辨模型）上进行开发和测试，并将扩展到任何任意目标大气模型。LILAC和相关工具的开发将使许多小组能够将CLM与他们的大气模型结合起来，并在最新的CLM模型可用时快速更新到最新的CLM模型版本。这将为陆地大气研究开辟新的途径，利用高分辨率大气模型的优势，利用CLM的生物地球物理和生物地球化学综合能力。它将使陆地-大气相互作用的研究跨越各种尺度，从塔台和飞机数据的湍流解析模拟，到云解析模拟，以研究小尺度的土地特征，如山坡、山谷、湖泊、河流、城市地区和农场如何共同改变地表气候和大气边界层特征，到大陆尺度模拟土地覆盖和土地利用变化对天气和气候的影响。该项目由计算机与信息科学与工程理事会的高级网络基础设施办公室以及地球科学理事会的极地计划办公室和大气与地球空间科学部提供支持。

Everyone on Earth lives on the ground, so interactions between the atmosphere and the land surface are a critically important part of the climate system and understanding these interactions is important for weather prediction, agriculture, and urban water management. Earth System Models (ESMs) are complex software systems representing complex natural systems. They are critical tools for diagnosing, understanding, and predicting interactions and change in the atmosphere, oceans, and land ecosystems. This project will develop a new software system for coupling the land and atmosphere components of Earth System models, specifically for the most widely-used climate model in the world: the Community Earth System Model (CESM). The new system will be capable of simulating climates near the ground including exchanges of heat, water ,and carbon between vegetated land and the air as well as streamflow and soil moisture. As an officially-supported component of CESM, it will be used by thousands of scientists and students around the world. Unlike its predecessor, the new system will be able to simulate small areas at high resolution for important applications and testing. The project will also support a computer science graduate student as well as academics and scientists who will help develop and test the software. The PIs will engage a global community of software developers and users through a series of workshops and webinars as well as through professional societies and publications. The PIs recognize the chronic under-representation of women and ethnic minorities in both Computer Science and Atmospheric Science. To address this, they will host a computer science summer camp for middle school students from underrepresented groups (URGs), and close collaboration with existing climate courses for K-12 teachers, science outreach in K-12 schools, and a highly successful REU-Site operated by the PI. This project will dramatically improve the usability of the most widely-used climate model in existence. Hundreds of developers and thousands of users around the world will benefit from the far greater flexibility and use cases for this model. The Community Land Model will be coupled to a much greater range of atmospheric codes for weather prediction, air quality applications, and climate projections that enhance the quality of life for people everywhere. The Community Earth System Model CESM) is a uniquely open ESM with a distributed community of hundreds of developers and thousands of users around the world. Compared to other ESMs, CESM is the "Linux of climate models." The land component of CESM, the Community Land Model (CLM), has its own vibrant and diverse user and development community, which has supported the construction of a particularly comprehensive terrestrial system model. It includes a rich array of processes that enable examination of the physical, biological, and chemical processes by which natural terrestrial ecosystems and human-managed land affect and are affected by climate and weather. CESM can only be run globally, but there is widespread interest in coupling CLM to alternative high-resolution atmosphere models to study the challenging scientific problems that exist at the interface between small and large spatial scales. A barrier to this research, however, is that CLM cannot readily be coupled to alternative atmosphere models. The CLM coupling interface only supports communication with the CESM coupling infrastructure (CPL7), which imposes strict requirements on how an atmospheric component can communicate with CLM. One key requirement is for the atmosphere model to complete a full time step before coupling can occur. This requirement necessitates significant refactoring of many atmospheric models in order for them to couple to CLM via CPL7. In addition, the tools to build and configure CLM are currently difficult to use outside of the CESM context. For all of these reasons, CLM has never been coupled to alternative atmospheric models in a sustainable fashion. Colorado State University (CSU), in partnership with the National Center for Atmospheric Research (NCAR), proposes to develop a Lightweight Infrastructure for Land-Atmosphere Coupling (LILAC) that will significantly simplify the coupling of CLM to alternative atmospheric models. The LILAC coupler and the associated proposed streamlining and simplification of the CLM tool chain will be developed and tested with a prototype high-resolution atmosphere model, the CSU SAM Cloud Resolving Model, and will be extended for use with any arbitrary Target Atmosphere Model. The development of LILAC and associated tools will enable numerous groups to couple CLM to their atmospheric models, and to quickly update to new state-of-the-art CLM model versions as they become available. This will open up new avenues of land-atmosphere research that can exploit the combined biogeophysical and biogeochemical capabilities of CLM with the strengths of high-resolution atmosphere models. It will enable research into land-atmosphere interactions across a variety of scales, ranging from turbulence-resolving simulations of tower and aircraft data to cloud-resolving simulations to study how small-scale land features such as hillslopes, valleys, lakes, rivers, urban areas and farms conspire to alter surface climate and atmospheric boundary layer characteristics to continental-scale simulations of the impact of land cover and land use change on weather and climate.This project is supported by the Office of Advanced Cyberinfrastructure in the Directorate for Computer & Information Science and Engineering and the Office of Polar Programs and Division of Atmospheric and Geospace Science in the Directorate for Geosciences.