Drought bulletins and maps

Main information on the state of drought in the current season are summarized in drought bulletins for SE Europe. The bulletins are being published monthly and seasonally since spring 2010 and can be found at the following link:
In the frame of DriDanube project, a Drought Watch tool was developed, which is an open web-based application that allows monitoring of drought conditions in near-real time over the Danube region through various drought indices. Based on remote-sensing and modeled data (see Datasets Provided sub-chapter of user manual), they are provided daily, weekly or 10-daily and therefore allow a regular insight into the current state of soil and vegetation across the region.

Preliminary maps of the SPI, Precipitation and Percentiles for the region are available using GPCC data. First-guess maps are available after 5th day of the next month and final data maps with two months delay are available after the 20th day of the current month. Final data maps are available from January 1986 onward, first-guess maps from August 2004. Maps for period 1951-2000 are available here. Latest maps are accessible through the form below:
One of the most robust drought indices is so called Standardized Precipitation Index (SPI). The SPI can be calculated at various time scales which reflect the impact of the drought on the availability of water resources. The SPI calculation is based on the distribution of precipitation over long time periods (30 years (1961-1990) was used). The long term precipitation record is fit to a probability distribution, which is then normalised so that the mean (average) SPI for any place and time period is zero.
SPI values above zero indicate wetter periods and values less than 0 indicate drier periods.

Please select year, month, time scale and data type:


Precipitation and percentiles
Another way to define drought are percentiles. A percentile is the value of a variable below which a certain percent of observations fall. Long term precipitation record is sort by rank by month; 50 years period (1951-2000) was used. The 5th (10th, 15th etc.) percentile is the value below which 5 (10, 15 etc.) percent of the observations may be found. The 25th percentile is also known as the first quartile; the 50th percentile as the median.

Percentile values above 50 indicate wetter periods and values less than 50 indicate drier periods.

Please select data, year, month and data type:


About the maps

For making maps monthly precipitation data from GPCC were used. This data are land-only in latitude/longitude format in resolution 1 degree x 1 degree. For calculating monthly percentiles (5, 10, 15, 20 and 25 - with R) data from VASClimO (resolution 0.5 degree x 0.5 degree) for all period (1951-2000) were used. Data were imported into GRASS GIS and interpolated to 100x (50x) better resolution (0.01 degree). For reprojecting maps into Lambert Conformal Conic Projection (lcc) nearest interpolation method was used.

WCS enables you to download raster data in TIFF and PNG format. These services are useful for performing analyses of drought-related resources in specific software as the functionality of analysing raster maps in a map viewer is limited. You can select SPI on different time scales and WBA (Water balance anomaly) on two months time-scale, provided by NWP.