Significant inconsistency of vegetation carbon density in CMIP5 Earth system models against observational data

doi:10.1002/2017JG003914

	Significant inconsistency of vegetation carbon density in CMIP5 Earth system models against observational data
	Song, Xia 1,2; Hoffman, Forrest M.3,4; Iversen, Colleen M.3,4; Yin, Yunhe 5; Kumar, Jitendra 3,4; Ma, Chun 1; Xu, Xiaofeng 1,2,6
刊名	JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
	2017-09-01
卷号	122 期号:9 页码:2282-2297
关键词	carbon density root vegetation root vegetation ratio Earth system models
ISSN号	2169-8953
DOI	10.1002/2017JG003914
通讯作者	Song, Xia(xsong@mail.sdsu.edu) ; Xu, Xiaofeng(xxu@mail.sdsu.edu)
英文摘要	Earth system models (ESMs) have been widely used for projecting global vegetation carbon dynamics, yet how well ESMs performed for simulating vegetation carbon density remains untested. We compiled observational data of vegetation carbon density from literature and existing data sets to evaluate nine ESMs at site, biome, latitude, and global scales. Three variablesroot (including fine and coarse roots), total vegetation carbon density, and the root:total vegetation carbon ratios (R/T ratios), were chosen for ESM evaluation. ESM models performed well in simulating the spatial distribution of carbon densities in root (r=0.71) and total vegetation (r=0.62). However, ESM models had significant biases in simulating absolute carbon densities in root and total vegetation biomass across the majority of land ecosystems, especially in tropical and arctic ecosystems. Particularly, ESMs significantly overestimated carbon density in root (183%) and total vegetation biomass (167%) in climate zones of 10 degrees S-10 degrees N. Substantial discrepancies between modeled and observed R/T ratios were found: the R/T ratios from ESMs were relatively constant, approximately 0.2 across all ecosystems, along latitudinal gradients, and in tropic, temperate, and arctic climatic zones, which was significantly different from the observed large variations in the R/T ratios (0.1-0.8). There were substantial inconsistencies between ESM-derived carbon density in root and total vegetation biomass and the R/T ratio at multiple scales, indicating urgent needs for model improvements on carbon allocation algorithms and more intensive field campaigns targeting carbon density in all key vegetation components. Plain Language Summary Earth system models (ESMs) have been widely used for projecting global vegetation carbon dynamics, yet how well ESMs performed remains untested. We used observational data to evaluate nine ESMs. ESMs performed well in simulating the spatial distribution of carbon densities in root and total vegetation biomass. However, ESMs performed poorly in simulating absolute carbon densities in root and total vegetation biomass across the majority of land ecosystems, especially in tropical and arctic ecosystems. Particularly, ESMs significantly overestimated carbon density in root and total vegetation biomass in climate zones of 10 degrees S-10 degrees N. Substantial discrepancies between modeled and observed root:total vegetation ratios were found: the root:total vegetation ratios from ESMs were relatively constant, approximately 0.2 across all ecosystems, along latitudinal gradients, and in tropic, temperate, and arctic climatic zones, which was significantly different from the observed large variations in the root:total vegetation ratios (0.1-0.8). The findings in this study indicate an urgent need for model improvements regarding carbon allocation algorithms and more intensive field campaigns targeting carbon density in all key vegetation components.
资助项目	Biogeochemistry Feedbacks Scientific Focus Area (BGC Feedbacks SFA) ; Regional and Global Climate Modeling (RGCM) Program in the Climate and Environmental Sciences Division (CESD) of the Biological and Environmental Research (BER) Program in the U.S. Department of Energy Office of Science ; San Diego State University ; University of Texas at El Paso ; Office of Biological and Environmental Research in the U.S. Department of Energy Office of Science ; U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research ; US Department of Energy[DE-AC05-00OR22725] ; National Science Foundation[ACI-1053575]
WOS关键词	SOIL ORGANIC-CARBON ; TERRESTRIAL ECOSYSTEMS ; CLIMATE-CHANGE ; GLOBAL ANALYSIS ; ROOT TURNOVER ; CYCLE ; CO2 ; NITROGEN ; DYNAMICS ; BENCHMARKING
WOS研究方向	Environmental Sciences & Ecology ; Geology
语种	英语
出版者	AMER GEOPHYSICAL UNION
WOS记录号	WOS:000412729100008
资助机构	Biogeochemistry Feedbacks Scientific Focus Area (BGC Feedbacks SFA) ; Regional and Global Climate Modeling (RGCM) Program in the Climate and Environmental Sciences Division (CESD) of the Biological and Environmental Research (BER) Program in the U.S. Department of Energy Office of Science ; San Diego State University ; University of Texas at El Paso ; Office of Biological and Environmental Research in the U.S. Department of Energy Office of Science ; U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research ; US Department of Energy ; National Science Foundation
内容类型	期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/62265]
专题	中国科学院地理科学与资源研究所
通讯作者	Song, Xia; Xu, Xiaofeng
作者单位	1.San Diego State Univ, Dept Biol, San Diego, CA 92182 USA 2.Univ Texas El Paso, Dept Biol, El Paso, TX 79968 USA 3.Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA 4.Oak Ridge Natl Lab, Climate Change Sci Inst, Oak Ridge, TN USA 5.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Beijing, Peoples R China 6.Chinese Acad Sci, Northeast Inst Geog & Agroecol, Changchun, Jilin, Peoples R China
推荐引用方式 GB/T 7714	Song, Xia,Hoffman, Forrest M.,Iversen, Colleen M.,et al. Significant inconsistency of vegetation carbon density in CMIP5 Earth system models against observational data[J]. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES,2017,122(9):2282-2297.
APA	Song, Xia.,Hoffman, Forrest M..,Iversen, Colleen M..,Yin, Yunhe.,Kumar, Jitendra.,...&Xu, Xiaofeng.(2017).Significant inconsistency of vegetation carbon density in CMIP5 Earth system models against observational data.JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES,122(9),2282-2297.
MLA	Song, Xia,et al."Significant inconsistency of vegetation carbon density in CMIP5 Earth system models against observational data".JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 122.9(2017):2282-2297.