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Xu M, Chen JM, Liu Y, Wang R, Shang R, Leng J, Shu L, Liu J, Liu R, Liu Y, Yang R, Yan Y. Comparative assessment of leaf photosynthetic capacity datasets for estimating terrestrial gross primary productivity. Sci Total Environ 2024; 926:171400. [PMID: 38461974 DOI: 10.1016/j.scitotenv.2024.171400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 01/30/2024] [Accepted: 02/28/2024] [Indexed: 03/12/2024]
Abstract
The maximum Rubisco carboxylation rate normalized to 25 °C (Vcmax25) is a key parameter in terrestrial biosphere models for simulating carbon cycling. Recently, global distributions of Vcmax25 have been derived through various methods and different data, including field measurements, ecological optimality theory (EOT), leaf chlorophyll content (LCC), and solar-induced chlorophyll fluorescence (SIF). However, direct validation poses challenges due to high uncertainty arising from limited ground-based observations. This study conducted an indirect evaluation of four Vcmax25 datasets by assessing the accuracy of gross primary productivity (GPP) simulated using the Biosphere-atmosphere Exchange Process Simulator (BEPS) at both site and global scales. Results indicate that, compared to utilizing Vcmax25 fixed by plant functional types (PFT) derived from field measurements, incorporating Vcmax25 derived from SIF and LCC (SIF + LCC), or solely LCC, into BEPS significantly reduces simulated errors in the annual total GPP, with a 23.2 %-25.1 % decrease in the average absolute bias across 196 FLUXNET2015 sites. Daily GPP for evergreen needleleaf forests, deciduous broadleaf forests, shrublands, grasslands, and croplands shows a 7.8 %-27.6 % decrease in absolute bias, primarily attributed to reduced simulation errors during off-peak seasons of vegetation growth. Conversely, the annual total GPP error simulated using EOT-derived Vcmax25 increases slightly (2.2 %) compared to that simulated using PFT-fixed Vcmax25. This is primarily due to a significant overestimation in evergreen broadleaf forests and underestimation in croplands, despite slight increased accuracy for other PFTs. The global annual GPP simulated using Vcmax25 with seasonal variations (i.e., LCC Vcmax25 and SIF + LCC Vcmax25) yields a 4.3 %-7.3 % decrease compared to that simulated using PFT-fixed Vcmax25. Compared to FLUXCOM and GOSIF GPP products, the GPP simulated based on SIF + LCC Vcmax25 and LCC Vcmax25 demonstrates better consistency (R2 = 0.91-0.93, RMSE = 314.2-376.6 g C m-2 yr-1). This study underscores the importance of accurately characterizing the spatiotemporal variations in Vcmax25 for the accurate simulation of global vegetation productivity.
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Affiliation(s)
- Mingzhu Xu
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
| | - Jing M Chen
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; Department of Geography and Program in Planning, University of Toronto, Toronto, ON M5S 3G3, Canada.
| | - Yihong Liu
- Department of Geography and Program in Planning, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Rong Wang
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
| | - Rong Shang
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
| | - Jiye Leng
- Department of Geography and Program in Planning, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Lei Shu
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
| | - Jane Liu
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; Department of Geography and Program in Planning, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Ronggao Liu
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Yang Liu
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongjuan Yang
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yulin Yan
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
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