Full Implementation of Matrix Approach to Biogeochemistry Module of CLM5
Full Implementation of Matrix Approach to Biogeochemistry Module of CLM5
复制标题
DOI：
10.1029/2020ms002105
复制
发表时间：
2020-11
影响因子：
6.8
通讯作者：
Xingjie Lu;Z. Du;Yuanyuan Huang;D. Lawrence;E. Kluzek;N. Collier;D. Lombardozzi;N. Sobhani;E. Schuur;Yiqi Luo
中科院分区：
文献类型：
--
作者：
Xingjie Lu;Z. Du;Yuanyuan Huang;D. Lawrence;E. Kluzek;N. Collier;D. Lombardozzi;N. Sobhani;E. Schuur;Yiqi Luo
近几十年来，地球系统模型（ESM）得到了迅速发展，以增进我们对气候变化-碳循环反馈的理解。然而，这些模型的编码量很大，需要昂贵的计算资源，并且难以诊断其性能。非常需要开发具有模块化和有效诊断功能的 ESM。为了实现这些目标，我们对社区土地模型第 5 版 (CLM5) 实施了矩阵方法来表示碳和氮循环。具体来说，我们将原始 CLM5 中 18 个植被库之间的碳氮循环的 18 个平衡方程重组为两个矩阵方程。同样，140 个土壤池中碳和氮循环的 140 个平衡方程被重组为两个额外的矩阵方程。植被碳和氮矩阵方程通过凋落物连接到土壤矩阵方程。矩阵方程完全再现了原始模型对碳和氮动力学的模拟。 CLM5 矩阵模型的转发模拟的计算成本比原始模型高 26%，这主要是由于计算额外的诊断变量，但旋转启动的计算成本却显着节省。我们展示了两个强迫数据集下模拟土壤碳储存的案例研究，以说明矩阵方法独特地提供的诊断能力，以了解全球碳和氮动态的模拟结果。 CLM5（最复杂的陆地模型之一）的矩阵方法的成功实施表明，大多数（如果不是全部）生物地球化学模型可以重组为矩阵形式，以获得高度模块化、有效诊断和加速旋转。
Earth system models (ESMs) have been rapidly developed in recent decades to advance our understanding of climate change‐carbon cycle feedback. However, those models are massive in coding, require expensive computational resources, and have difficulty in diagnosing their performance. It is highly desirable to develop ESMs with modularity and effective diagnostics. Toward these goals, we implemented a matrix approach to the Community Land Model version 5 (CLM5) to represent carbon and nitrogen cycles. Specifically, we reorganized 18 balance equations each for carbon and nitrogen cycles among the 18 vegetation pools in the original CLM5 into two matrix equations. Similarly, 140 balance equations each for carbon and nitrogen cycles among the 140 soil pools were reorganized into two additional matrix equations. The vegetation carbon and nitrogen matrix equations are connected to soil matrix equations via litterfall. The matrix equations fully reproduce simulations of carbon and nitrogen dynamics by the original model. The computational cost for forwarding simulation of the CLM5 matrix model was 26% more expensive than the original model, largely due to calculation of additional diagnostic variables, but the spin‐up computational cost was significantly saved. We showed a case study on modeled soil carbon storage under two forcing data sets to illustrate the diagnostic capability that the matrix approach uniquely offers to understand simulation results of global carbon and nitrogen dynamics. The successful implementation of the matrix approach to CLM5, one of the most complex land models, demonstrates that most, if not all, the biogeochemical models can be reorganized into the matrix form to gain high modularity, effective diagnostics, and accelerated spin‐up.