ICDC TDS Catalog https://icdc.cen.uni-hamburg.de/thredds/catalog/ftpthredds/standard_precipitation_index_SPI/catalog.html

Dataset Size Last Modified
     Folder  standard_precipitation_index_SPI   --
         Folder  CRU4/   --
         Folder  ECAD/   --

ICDC TDS at Integrated Climate Data Center (ICDC) / University of Hamburg see Info
Documentation