- DOI for Scientific and Technical Data10.5676/DWD_GPCC/DI_M_100 (for 1.0° resolution)- SubtitleGlobally Gridded Drought Index with averaging periods 1,3,6,9,12,24,48 months- CitationFor 1.0° grid resolution:Ziese, Markus; Becker, Andreas; Finger, Peter; Meyer-Christoffer, Anja; Rudolf, Bruno; Schneider, Udo (2013): GPCC Drought Index Product (GPCC_DI) at 1.0° DOI: 10.5676/DWD_GPCC/DI_M_100- CreatorsZiese, Markus; Becker, Andreas; Finger, Peter; Meyer-Christoffer, Anja; Rudolf, Bruno; Schneider, Udo- PublisherGlobal Precipitation Climatology Centre (GPCC, http://gpcc.dwd.de/) at Deutscher Wetterdienst (DWD)- Publication Year2013- SummaryThe Global Precipitation Climatology Centre drought index (GPCC_DI) is a combination of the Standardized Precipitation Index (SPI; McKee et al., 1993) in the DWD modification according to Pietzsch et al. (2011) and the Standardized Precipitation Evapotranspiration Index (SPEI) according to Vicento-Serrano et al. (2009). The 'First Guess Product' DOI:10.5676/DWD_GPCC/FG_M_100 is used as precipitation input data. For the monthly mean temperature data NOAA's Climate Precdiction Center (CPC) Monthly Global Surface Air Temperature Data Set is utilized (Fan and van den Dool, 2008). The temperature data are applied to calculate the potential evapotranspiration (PET) according to Thornthwaite (1948). Parameters to calculate SPI and SPEI were referenced to 1961-1990. Due to the non-applicability of the gamma distribution for precipitation in arid regions the SPI can not be calculated there. On the other hand the PET can not be computed in cold regions applying the formula from Thornthwaite. Hence the GPCC_DI is calculated as the mean of the SPI and SPEI. If one of these indices can not be computed, the one available is used, yielding an almost global coverage of the GPCC_DI. The GPCC_DI is computed with averaging periods of 1, 3, 6, 9, 12, 24 and 48 months. The GPCC_DI has a spatial resolution of 1° latitude by longitude using gridded input data fields at the same resolution. To issue a monthly GPCC_DI product all seven averaging periods are compiled into one netCDF-file. The GPCC_DI is availabile for all months since January 2013.References:Fan et al., 2008, A global monthly land surface air temperature analysis for 1948 - present, Journal of Geophysical Research, Vol. 113, p. D01103, DOI:10.1029/2007JD008470McKee et al., 1993, The Relationship of Drought Frequency and Duration to Time Scales, Eighth Conference on Applied ClimatologyPietzsch et al., 2011, A modified drought index for WMO RA VI, Adv. in Science and Research, Vol. 6, p. 275-279, DOI:10.5194/asr-6-275-2011Thornthwaite, 1948, An approach towards a rational classification of climate, Geographical Review, Vol. 38, p. 55-94Vicente-Serrano et al., 2009, A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index, Journal of Climate, Vol. 23, p. 1696-1718, DOI:10.1175/2009JCLI2909.1- Temporal Coverage2013/01 - present expired month; updated monthly- Spatial CoverageLatitude: -90.0 to 90.0; Longitude: -180.0 to 180.0- Data Formatgzip compressed NetCDF (1 file per month/year, all seven averaging periods are summarized in 7 variables per gridcell)- ToolsList of Software for Manipulating or Displaying NetCDF Data Panoply netCDF, HDF and GRIB Data Viewer Climate Data Operators CDO NOAA's Weather and Climate Toolkit - Metadata ISO 19115:2003/19139:2007- Datasize~ 250 KByte (1.0 °) per gzip file