Fraction of Absorbed Photosynthetically Active Radiation (FPAR) products over Tibetan Plateau

In total solar radiation (TSR), the component essential for photosynthesis is known as photosynthetically active radiation (PAR), which encompasses wavelengths from approximately 400 to 700 nm. The Fraction of Absorbed PAR is a key physiological variable in the study of carbon cycling and is one of the basic variables to describe vegetation ecosystems. The classification results of vegetation types in the Tibetan Plateau region were obtained based on the 30–m resolution Landsat reflectance data. Additionally, for different vegetation types during the growing season, the 98% (NDVI_max) and 2% (NDVI_min) cumulative frequencies of Normalized Difference Vegetation Index (NDVI) were calculated. To overcome the issues of underestimation and overestimation in FPAR estimation, which are based solely on the simple infrared/red ratio (SR) and NDVI, a hybrid model that combines SR and NDVI has been developed for more accurate FPAR estimation. This model was employed to generate average FPAR products for various vegetation types over the Tibetan Plateau between April and September spanning from 1987 to 2022. These FPAR data are instrumental in calculating vegetation carbon sequestration and assessing the status of vegetation ecosystems. The products have been stored in the GeoTIFF format, utilizing the GCS_WGS_1984 spatial reference system (EPSG: 4326).