Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands
The temporal resolution of vegetation indices (VIs) determines the details of seasonal variation in vegetation dynamics observed by remote sensing, but little has been known about how the temporal resolution of VIs affects the retrieval of land surface phenology (LSP) of grasslands. This study evalu...
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2020-04-01
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| Series: | GIScience & Remote Sensing |
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| Online Access: | http://dx.doi.org/10.1080/15481603.2020.1723279 |
| _version_ | 1797679076605952000 |
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| author | Tengfei Cui Lawrence Martz Liang Zhao Xulin Guo |
| author_facet | Tengfei Cui Lawrence Martz Liang Zhao Xulin Guo |
| author_sort | Tengfei Cui |
| collection | DOAJ |
| description | The temporal resolution of vegetation indices (VIs) determines the details of seasonal variation in vegetation dynamics observed by remote sensing, but little has been known about how the temporal resolution of VIs affects the retrieval of land surface phenology (LSP) of grasslands. This study evaluated the impact of temporal resolution of MODIS NDVI, EVI, and per-pixel green chromatic coordinate (GCCpp) on the quality and accuracy of the estimated LSP metrics of prairie grasslands. The near-surface PheonoCam phenology data for grasslands centered over Lethbridge PhenoCam grassland site were used as the validation datasets due to the lack of in situ observations for grasslands in the Prairie Ecozone. MODIS Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) data from 2001 to 2017 were used to compute the time series of daily reference and to simulate 2–32 day MODIS VIs. The daily reference and simulated multi-day time series were fitted with the double logistic model, and the LSP metrics were then retrieved from the modeled daily time series separately. Comparison within satellite-based estimates showed no significant difference in the phenological metrics derived from daily reference and multi-day VIs resampled at a time step less than 18 days. Moreover, a significant decline in the ability of multi-day VIs to predict detailed temporal dynamics of daily reference VIs was revealed as the temporal resolution increased. Besides, there were a variety of trends for the onset of phenological transitions as the temporal resolution of VIs changed from 1 to 32 days. Comparison with PhenoCam phenology data presented small and insignificant differences in the mean bias error (MBE) and the mean absolute error (MAE) of grassland phenological metrics derived from daily, 8-, 10-, 14-, and 16-day MODIS VIs. Overall, this study suggested that the MODIS VIs resampled at a time step less than 18 days are favorable for the detection of grassland phenological transitions and detailed seasonal dynamics in the Prairie Ecozone. |
| first_indexed | 2024-03-11T23:09:11Z |
| format | Article |
| id | doaj.art-2848ec6de706433e99762278b8df9164 |
| institution | Directory Open Access Journal |
| issn | 1548-1603 1943-7226 |
| language | English |
| last_indexed | 2024-03-11T23:09:11Z |
| publishDate | 2020-04-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | GIScience & Remote Sensing |
| spelling | doaj.art-2848ec6de706433e99762278b8df91642023-09-21T12:34:16ZengTaylor & Francis GroupGIScience & Remote Sensing1548-16031943-72262020-04-0157339541010.1080/15481603.2020.17232791723279Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslandsTengfei Cui0Lawrence Martz1Liang Zhao2Xulin Guo3University of SaskatchewanUniversity of SaskatchewanJilin UniversityUniversity of SaskatchewanThe temporal resolution of vegetation indices (VIs) determines the details of seasonal variation in vegetation dynamics observed by remote sensing, but little has been known about how the temporal resolution of VIs affects the retrieval of land surface phenology (LSP) of grasslands. This study evaluated the impact of temporal resolution of MODIS NDVI, EVI, and per-pixel green chromatic coordinate (GCCpp) on the quality and accuracy of the estimated LSP metrics of prairie grasslands. The near-surface PheonoCam phenology data for grasslands centered over Lethbridge PhenoCam grassland site were used as the validation datasets due to the lack of in situ observations for grasslands in the Prairie Ecozone. MODIS Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) data from 2001 to 2017 were used to compute the time series of daily reference and to simulate 2–32 day MODIS VIs. The daily reference and simulated multi-day time series were fitted with the double logistic model, and the LSP metrics were then retrieved from the modeled daily time series separately. Comparison within satellite-based estimates showed no significant difference in the phenological metrics derived from daily reference and multi-day VIs resampled at a time step less than 18 days. Moreover, a significant decline in the ability of multi-day VIs to predict detailed temporal dynamics of daily reference VIs was revealed as the temporal resolution increased. Besides, there were a variety of trends for the onset of phenological transitions as the temporal resolution of VIs changed from 1 to 32 days. Comparison with PhenoCam phenology data presented small and insignificant differences in the mean bias error (MBE) and the mean absolute error (MAE) of grassland phenological metrics derived from daily, 8-, 10-, 14-, and 16-day MODIS VIs. Overall, this study suggested that the MODIS VIs resampled at a time step less than 18 days are favorable for the detection of grassland phenological transitions and detailed seasonal dynamics in the Prairie Ecozone.http://dx.doi.org/10.1080/15481603.2020.1723279modisphenologytemporal resolutionprairie grasslands |
| spellingShingle | Tengfei Cui Lawrence Martz Liang Zhao Xulin Guo Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands GIScience & Remote Sensing modis phenology temporal resolution prairie grasslands |
| title | Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands |
| title_full | Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands |
| title_fullStr | Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands |
| title_full_unstemmed | Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands |
| title_short | Investigating the impact of the temporal resolution of MODIS data on measured phenology in the prairie grasslands |
| title_sort | investigating the impact of the temporal resolution of modis data on measured phenology in the prairie grasslands |
| topic | modis phenology temporal resolution prairie grasslands |
| url | http://dx.doi.org/10.1080/15481603.2020.1723279 |
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