Deriving leaf area index reference maps using temporally continuous data: a comparison of upscaling approaches

Brown, LA; Ogutu, BO; Camacho, F; Fuster, B; Dash, J

Abstract

To further progress the validation of global leaf area index (LAI) products, temporally continuous reference data are a key requirement, as periodic field campaigns fail to adequately characterize temporal dynamics. Progress in cost-effective automated measurement techniques has been made in recent years, but appropriate upscaling methodologies are less mature. Recently, the use of multitemporal transfer functions has been proposed as a potential solution. Using data collected during an independent field campaign, we evaluated the performance of both vegetation index-based multitemporal transfer functions and a radiative transfer model (RTM)-based upscaling approach. Whether assessed using cross validation or data from the independent field campaign, the RTM-based approach provided the best performance (r 2 ≥ 0.88, RMSE ≤ 0.41, NRMSE <; 13%). For upscaling temporally continuous in situ data, the ability of RTM-based approaches to account for seasonal changes in sun-sensor geometry is a key advantage over vegetation index-based multitemporal transfer functions.

Citation

Brown, L., Ogutu, B., Camacho, F., Fuster, B., & Dash, J. (2020). Deriving leaf area index reference maps using temporally continuous data: a comparison of upscaling approaches. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 14, 624-630. https://doi.org/10.1109/JSTARS.2020.3040080

• Journal Article Type: Article
• Publication Date: Nov 24, 2020
• Deposit Date: Oct 28, 2022
• Publicly Available Date: Oct 28, 2022
• Journal: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
• Print ISSN: 1939-1404
• Electronic ISSN: 2151-1535
• Publisher: Institute of Electrical and Electronics Engineers
• Volume: 14
• Pages: 624-630
• DOI: https://doi.org/10.1109/JSTARS.2020.3040080
• Publisher URL: https://doi.org/10.1109/JSTARS.2020.3040080