Spatial scale effects of grassland phenology on the Qinghai-Tibet Plateau

doi:10.11947/j.AGCS.2024.20230256

Abstract

Abstract:

Accurate high-altitude vegetation phenology remote sensing products are fundamental data for maintaining ecological balance, accurately reflecting surface energy balance, and stabilizing the cryosphere. However, currently used remote sensing data for phenology extraction have diverse spatial resolutions, and phenology extracted based on different spatial scales may exhibit scale effects, which have not received widespread attention. In this study, utilizing Sentinel-2 data with a spatial resolution of 10 m, MODIS data with spatial resolutions of 500 and 5600 m, and employing the NDGI vegetation index, phenology products with corresponding spatial resolutions for the Qinghai-Tibet Plateau in 2022 were extracted on the Google Earth Engine (GEE) cloud platform. The study explored the differences in phenology at different spatial resolutions, quantitatively analyzed the scale effects of phenology products, and elucidated their variations with terrain complexity. The research revealed that, compared to high spatial resolution remote sensing products (10 m), there is a noticeable lag phenomenon in the spring phenology of coarser spatial resolution (500 and 5600 m). When detecting grassland phenology using remote sensing products with different spatial resolutions, scale effects are generally present, with the scale effect of autumn phenology being smaller than that of spring phenology. Additionally, the scale effect of vegetation phenology is influenced by terrain and increases with the complexity of terrain.

Key words: Qinghai-Tibet Plateau, NDGI, phenology, spatial scale effect, topography

CLC Number:

P237

Dujuan MA, Jiangliu XIE, Rui CHEN, Xinyu YAN, Gaofei YIN. Spatial scale effects of grassland phenology on the Qinghai-Tibet Plateau[J]. Acta Geodaetica et Cartographica Sinica, 2024, 53(5): 860-868.

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