JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2024, Vol. 48 ›› Issue (4): 132-140.doi: 10.12302/j.issn.1000-2006.202205014

Special Issue: 专题报道Ⅲ:智慧林业之森林可视化研究

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Estimation of forest net primary productivity based on sentinel active and passive remote sensing data and canopy height

TIAN Chunhong(), LI Mingyang*(), LI Tao, LI Dengpan, TIAN Lei   

  1. College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, China
  • Received:2022-05-11 Revised:2022-08-07 Online:2024-07-30 Published:2024-08-05
  • Contact: LI Mingyang E-mail:1786767729@qq.com;lmy196727@126.com

Abstract:

【Objective】Using open source active and passive remote sensing data (Sentinel-1 & -2) combined with forest canopy height can improve the estimation accuracy of forest net primary productivity (NPP), to provide a scientific basis for the formulation of forest precision management stragtegies and a “carbon peaking and carbon neutrality” strategy.【Method】Zixing City, which is a key forest area in the south, was used as the research area. Based on Sentinel-1 and Sentinel-2 active and passive remote sensing data, four models, namely multiple stepwise regression, artificial neural network, K-nearest neighbor, and random forest, were used to estimate NPP. On this basis, the canopy height obtained by Sentinel-1 through the difference between InSAR and SRTM DEM was added to analyze its effect on the accuracy of NPP estimation.【Result】(1) The mean value of forest NPP in the study area in 2019 was 7.79 t/hm2, showing the spatial distribution characteristics of high in the central southwest and low in the northwest. (2) Among the four models, the accuracy of NPP estimation by active and passive remote sensing was higher than that by single remote sensing; the accuracy of random forest estimation of regional forest NPP was the highest, and the model performed the best. (3) Adding canopy height improved the estimation accuracy of forest NPP to a certain extent, with R2 increased from 0.70 to 0.75.【Conclusion】The accuracy of NPP estimation can be improved based on Sentinel active and passive remote sensing data and canopy height factor, which is obtained by DEM difference method.

Key words: forest net primary productivity, sentinel data, ICESat-2, forest canopy height, Zixing City, smart forestry and forest precision management

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