其中，“标准降水指数公式包.dll”内含计算“标准降水指数SPI”及“降水百分位指数PDECI”的四个Excel函数：SPI、PDECI、SPILEVEL、PDECILEVEL。该公式包为Excel COM加载项，故与Excel高度集成，使用方便，在Excel中加载一次，即可运行。-Among them, "standard precipitation index formula calculation." standard "contains DLL precipitation index SPI" and "precipitation PDECI index percentile of the" four Excel function: PDECI, SPILEVEL, SPI, PDECILEVEL. This formula for a bag, Excel COM loaded with Excel is highly integrated, use convenient, in Excel loading time, can run.