Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation
Land surface phenology (LSP) products that are derived from different data sources have different definitions and biophysical meanings. Discrepancies among these products and their linkages with carbon fluxes across plant functional types and climatic regions remain somewhat unclear. In this study,...
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| Format: | Article |
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MDPI AG
2021-12-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/24/5080 |
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| author | Xiaojun Xu Yan Tang Yiling Qu Zhongsheng Zhou Junguo Hu |
| author_facet | Xiaojun Xu Yan Tang Yiling Qu Zhongsheng Zhou Junguo Hu |
| author_sort | Xiaojun Xu |
| collection | DOAJ |
| description | Land surface phenology (LSP) products that are derived from different data sources have different definitions and biophysical meanings. Discrepancies among these products and their linkages with carbon fluxes across plant functional types and climatic regions remain somewhat unclear. In this study, to differentiate LSP related to gross primary production (GPP) from LSP related to remote sensing data, we defined the former as vegetation photosynthetic phenology (VPP), including the starting and ending days of GPP (SOG and EOG, respectively). Specifically, we estimated VPP based on a combination of observed VPP from 145 flux-measured GPP sites together with the vegetation index and temperature data from MODIS products using multiple linear regression models. We then compared VPP estimates with MODIS LSP on a global scale. Our results show that the VPP provided better estimates of SOG and EOG than MODIS LSP, with a root mean square error (RMSE) for SOG of 12.7 days and a RMSE for EOG of 10.5 days. The RMSE was approximately three weeks for both SOG and EOG estimates of the non-forest type. Discrepancies between VPP and LSP estimates varied across plant functional types (PFTs) and climatic regions. A high correlation was observed between VPP and LSP estimates for deciduous forest. For most PFTs, using VPP estimates rather than LSP improved the estimation of GPP. This study presents a useful method for modeling global VPP, investigates in detail the discrepancies between VPP and LSP, and provides a more effective global vegetation phenology product for carbon cycle modeling than the existing ones. |
| first_indexed | 2024-03-10T03:11:15Z |
| format | Article |
| id | doaj.art-0e8066ffea2e4998a2f0a1355fffc86e |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T03:11:15Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
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| series | Remote Sensing |
| spelling | doaj.art-0e8066ffea2e4998a2f0a1355fffc86e2023-11-23T10:24:35ZengMDPI AGRemote Sensing2072-42922021-12-011324508010.3390/rs13245080Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and EvaluationXiaojun Xu0Yan Tang1Yiling Qu2Zhongsheng Zhou3Junguo Hu4State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, ChinaState Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, ChinaState Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, ChinaState Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, ChinaKey Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration of Zhejiang Province, Zhejiang A&F University, Hangzhou 311300, ChinaLand surface phenology (LSP) products that are derived from different data sources have different definitions and biophysical meanings. Discrepancies among these products and their linkages with carbon fluxes across plant functional types and climatic regions remain somewhat unclear. In this study, to differentiate LSP related to gross primary production (GPP) from LSP related to remote sensing data, we defined the former as vegetation photosynthetic phenology (VPP), including the starting and ending days of GPP (SOG and EOG, respectively). Specifically, we estimated VPP based on a combination of observed VPP from 145 flux-measured GPP sites together with the vegetation index and temperature data from MODIS products using multiple linear regression models. We then compared VPP estimates with MODIS LSP on a global scale. Our results show that the VPP provided better estimates of SOG and EOG than MODIS LSP, with a root mean square error (RMSE) for SOG of 12.7 days and a RMSE for EOG of 10.5 days. The RMSE was approximately three weeks for both SOG and EOG estimates of the non-forest type. Discrepancies between VPP and LSP estimates varied across plant functional types (PFTs) and climatic regions. A high correlation was observed between VPP and LSP estimates for deciduous forest. For most PFTs, using VPP estimates rather than LSP improved the estimation of GPP. This study presents a useful method for modeling global VPP, investigates in detail the discrepancies between VPP and LSP, and provides a more effective global vegetation phenology product for carbon cycle modeling than the existing ones.https://www.mdpi.com/2072-4292/13/24/5080vegetation photosynthetic phenologyland surface phenologyMODIS productclimatic regionstarting day of GPPending day of GPP |
| spellingShingle | Xiaojun Xu Yan Tang Yiling Qu Zhongsheng Zhou Junguo Hu Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation Remote Sensing vegetation photosynthetic phenology land surface phenology MODIS product climatic region starting day of GPP ending day of GPP |
| title | Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation |
| title_full | Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation |
| title_fullStr | Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation |
| title_full_unstemmed | Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation |
| title_short | Global Vegetation Photosynthetic Phenology Products Based on MODIS Vegetation Greenness and Temperature: Modeling and Evaluation |
| title_sort | global vegetation photosynthetic phenology products based on modis vegetation greenness and temperature modeling and evaluation |
| topic | vegetation photosynthetic phenology land surface phenology MODIS product climatic region starting day of GPP ending day of GPP |
| url | https://www.mdpi.com/2072-4292/13/24/5080 |
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