Estimation of forest leaf water content through inversion of a radiative transfer model from LiDAR and hyperspectral data

Xi Zhu*, Andrew K. Skidmore, Roshanak Darvishzadeh, Tiejun Wang

*Corresponding author for this work

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    The accurate estimation of leaf water content (LWC) and knowledge about its spatial variation are important for forest and agricultural management since LWC provides key information for evaluating plant physiology. Hyperspectral data have been widely used to estimate LWC. However, the canopy reflectance can be affected by canopy structure, thereby introducing error to the retrieval of LWC from hyperspectral data alone. Radiative transfer models (RTM) provide a robust approach to combine LiDAR and hyperspectral data in order to address the confounding effects caused by the variation of canopy structure. In this study, the INFORM model was adjusted to retrieve LWC from airborne hyperspectral and LiDAR data. Two structural parameters (i.e. stem density and crown diameter) in the input of the INFORM model that affect canopy reflectance most were replaced by canopy cover which could be directly obtained from LiDAR data. The LiDAR-derived canopy cover was used to constrain in the inversion procedure to alleviate the ill-posed problem. The models were validated against field measurements obtained from 26 forest plots and then used to map LWC in the southern part of the Bavarian Forest National Park in Germany. The results show that with the introduction of prior information of canopy cover obtained from LiDAR data, LWC could be retrieved with a good accuracy (R2 = 0.87, RMSE = 0.0022 g/cm2 , nRMSE = 0.13). The adjustment of the INFORM model facilitated the introduction of prior information over a large extent, as the estimation of canopy cover can be achieved from airborne LiDAR data.

    Original languageEnglish
    Pages (from-to)120-129
    Number of pages10
    JournalInternational Journal of Applied Earth Observation and Geoinformation
    Volume74
    DOIs
    Publication statusPublished - Feb 2019

    Keywords

    • Leaf water content
    • INFORM
    • Prior information
    • Canopy cover

    Fingerprint Dive into the research topics of 'Estimation of forest leaf water content through inversion of a radiative transfer model from LiDAR and hyperspectral data'. Together they form a unique fingerprint.

  • Cite this