Indonesia, monthly Standardized Precipitation-Evapotranspiration Index (SPEI) blend 1960 - 2021

IDN_CLI_SPEI_blend_0p042_1961_2021 is currently the only comprehensive high resolution Indonesia gridded historical dataset of SPEI blend and available for public.

The SPEI - https://spei.csic.es/ is an extension of the widely used SPI. The SPEI is designed to take into account both precipitation and potential evapotranspiration (PET) in determining drought. Thus, unlike the SPI, the SPEI captures the main impact of increased temperatures on water demand.

The IDN_CLI_SPEI_blend_0p042_1960_2021 is derived using precipitation and potential evapotranspiration from TerraClimate data - https://www.climatologylab.org/terraclimate.html, it has 0.042 degree gridded resolution, a monthly and available from 1958 to 2021. The calibration period is January 1961 to December 2020. The starting date of the dataset is 1960 in order to provide common information across the different SPEI time-scales.

The SPEI blend integrate several SPEI scales into a single product, combine 3-, 6-, 9-, 12- and 24-month SPEI to estimate the overall dry/wet condition. 

The SPEI processed using climate_indices, an open source Python library providing reference implementations of commonly used climate indices. https://pypi.org/project/climate-indices/

IDN_CLI_SPEI_blend_0p042_1961_2021 是目前唯一一套覆盖全面、高分辨率的印度尼西亚网格化历史标准化降水蒸散指数（SPEI）融合数据集，且可公开获取。

标准化降水蒸散指数（SPEI，详见https://spei.csic.es/）是广泛使用的标准化降水指数（SPI）的扩展指标。SPEI 在干旱监测中同时纳入了降水与潜在蒸散量（PET）两个核心因子，因此与SPI不同，SPEI 能够捕捉升温对水分需求的主要影响。

本数据集IDN_CLI_SPEI_blend_0p042_1960_2021 依托TerraClimate数据（详见https://www.climatologylab.org/terraclimate.html）中的降水与潜在蒸散量生成，其网格化分辨率为0.042度，为逐月数据集，时间覆盖范围为1958年至2021年。其校准时段为1961年1月至2020年12月；数据集将起始时间设为1960年，旨在为不同时间尺度的SPEI计算提供统一的基准信息。

SPEI融合产品将多时间尺度的SPEI整合为单一数据集，通过结合3个月、6个月、9个月、12个月及24个月尺度的SPEI，以评估区域整体干湿状况。

本数据集的SPEI计算依托climate_indices开源Python库完成，该库提供了常用气候指数的参考实现，详见https://pypi.org/project/climate-indices/。