China Multi-scale Daily SPEI Dataset Incorporating CO₂ Physiological Forcing (1950-2023)

This dataset provides a long-term, high-resolution Standardized Precipitation Evapotranspiration Index (SPEI) product for China, spanning from 1950 to 2023. Its primary innovation lies in systematically incorporating the physiological effects of rising atmospheric CO₂ concentrations into drought assessment.Key Features:CO₂ Integration: Potential evapotranspiration (PET) is calculated using a modified Penman-Monteith method (PM-CO₂), which accounts for CO₂-induced increases in surface resistance, thereby reducing the "drying bias" prevalent in conventional drought indices.Optimized Fitting: For enhanced accuracy, the optimal probability distribution function (Log-Logistic, GEV, Normal, or Pearson Type III) for SPEI calculation is selected at each grid cell and timescale (30, 90, 180, 360 days) using the Akaike Information Criterion (AIC).Spatio-temporal Coverage: Covers mainland China with a spatial resolution of 0.1° and a daily temporal resolution. Multi-scale aggregation allows for analyzing droughts of various durations.Source Data:The dataset is derived from ERA5-Land reanalysis meteorological data and reconstructed gridded atmospheric CO₂ concentration records.