Standardized Integrated Water Vapor (SIWV) at 1- and 3-month scales from seven CMIP6 models under SSP1-2.6 and SSP5-8.5, 1850–2100, on a 1° global grid

This dataset provides the Standardized Integrated Water Vapor (SIWV) index at 1- and 3-month accumulation scales (SIWV1, SIWV3), derived from monthly outputs of seven CMIP6 global climate models (ACCESS-CM2, AWI-CM-1-1-MR, CMCC-ESM2, FGOALS-f3-L, FIO-ESM-2-0, INM-CM5-0 and IPSL-CM6A-LR) for the historical experiment and two Shared Socioeconomic Pathways (SSP1-2.6 and SSP5-8.5), covering [1850–2100]. Integrated water vapor (IWV) was computed by vertically integrating specific humidity over eight pressure levels (1000, 925, 850, 700, 600, 500, 400 and 300 hPa). Pressure levels below the model surface were excluded from the integration. [State units and the use of 1/g.] All fields were regridded to a common 1° × 1° global grid using bilinear interpolation. SIWV was computed following the Standardized Precipitation Index (SPI) procedure: IWV was accumulated over 1- and 3-month windows, fitted with a gamma distribution for each calendar month, and transformed to the standard normal distribution. The distribution was fitted separately for each 50-year period ([list exact period boundaries]); SIWV therefore represents standardized anomalies relative to the climatology of each period and does not retain long-term changes in mean IWV.