Across‐model spread and shrinking in predicting peatland carbon dynamics under global change

作者：Enqing Hou, Shuang Ma, Yuanyuan Huang, Yu Zhou, Hyung‐Sub Kim, Efrèn López‐Blanco, Lifen Jiang, Jianyang Xia, Feng Tao, C. A. Williams, Mathew Williams, Daniel Ricciuto, Paul J. Hanson, Yiqi Luo · 发表于：Global Change Biology · 年份：2023 · DOI：10.1111/gcb.16643 · 被引用次数：12 · 研究领域：Peatlands and Wetlands Ecology、Fire effects on ecosystems、Coastal wetland ecosystem dynamics

Abstract Large across‐model spread in simulating land carbon (C) dynamics has been ubiquitously demonstrated in model intercomparison projects (MIPs), and became a major impediment in advancing climate change prediction. Thus, it is imperative to identify underlying sources of the spread. Here, we used a novel matrix approach to analytically pin down the sources of across‐model spread in transient peatland C dynamics in response to a factorial combination of two atmospheric CO 2 levels and five temperature levels. We developed a matrix‐based MIP by converting the C cycle module of eight land models (i.e., TEM, CENTURY4, DALEC2, TECO, FBDC, CASA, CLM4.5 and ORCHIDEE) into eight matrix models. While the model average of ecosystem C storage was comparable to the measurement, the simulation differed largely among models, mainly due to inter‐model difference in baseline C residence time. Models generally overestimated net ecosystem production (NEP), with a large spread that was mainly attributed to inter‐model difference in environmental scalar. Based on the sources of spreads identified, we sequentially standardized model parameters to shrink simulated ecosystem C storage and NEP to almost none. Models generally captured the observed negative response of NEP to warming, but differed largely in the magnitude of response, due to differences in baseline C residence time and temperature sensitivity of decomposition. While there was a lack of response of NEP to elevated CO 2 (eCO 2 ) ...