Spectral Characteristics Analysis of Different Vegetation Subformations on the Qinghai-Tibet Plateau

The spectral curve is an important representation of vegetation physiological traits. The study of vegetation spectra is significant for monitoring vegetation growth and health status. Current research on vegetation spectra mainly analyzes different vegetation within the same vegetation type, and there are few reports on the systematic integration of spectral characteristics of different vegetation subformations. The ecological pattern of the Tibetan Plateau has changed significantly in recent years. To conduct research on vegetation spectral characteristics on a large scale in the Qinghai-Tibet Plateau region and to explore the spectral separability among different vegetation subformations based on high-resolution Sentinel-2A/B remote sensing images, the spectral curves of 19 vegetation subformations were analyzed by using the first derivative of the spectrum and vegetation indices. The results showed that: (1) The spectral curves of vegetation sub-formations exhibit significant differences in the near-infrared band, and their reflectance value can be used to distinguish different vegetation sub-formations; (2) First-order derivative processing can elucidate the three-edge features characteristics of vegetation, the first-order derivative spectra of vegetation are of certain regularity, with significant differences in the red edge; (3) Vegetation indices of different vegetation subformations are consistent with changes of the red edge characteristics parameter, and the vegetation indices are discriminative, although their values are relatively small;(4) By combining near-infrared peaks, three-edge characteristics parameters, and vegetation indices, different vegetation subformations can be distinguished. This study analyzed the spectral curve characteristics of different vegetation at the vegetation subformations scale. The experimental results can provide data support for improving the vegetation subformations spectral database and have practical significance for the fine identification of vegetation subtypes on the Qinghai-Tibet Plateau.