This dataset contains the Standardised Streamflow Index (SSI) data for 303 catchments across the United Kingdom from 1891 to 2015. The SSI is a drought index based on the cumulative probability of a given monthly mean streamflow occurring for a given catchment. Here, the SSI is calculated for the following accumulation periods: 1, 3, 6, 9, 12, 18 and 24 months. Each accumulation period is calculated for calendar end-months. The standard period used to fit the Tweedie distribution is 1961-2010.
The SSI was produced by the RCUK-funded Historic Droughts project in order to characterise and explore hydrological drought severity over the period 1891-2015. This dataset is an outcome of the Historic Droughts Project (grant number: NE/L01016X/1).
Publication date: 2018-03-12
This dataset is part of the following
The SSI is calculated as defined in Svensson, et al., (2017 https://doi.org/ 10.1002/2016WR019276) and is based on the cumulative probability of a given monthly mean streamflow occurring for a given catchment. Here the SSI is calculated for the following accumulation periods: 1, 3, 6, 9, 12, 18 and 24 months. The Tweedie distribution was fitted to each accumulated time series of monthly mean flows. The 'SCI' package for R was used to calculate the SSI and a new function was written to enable the SCI package to call the 'tweedie' package for R. The input data used is monthly mean streamflow derived from modelled reconstructed streamflow (Smith et al., 2018 https://doi.org/10.5285/f710bed1-e564-47bf-b82c-4c2a2fe2810e). Data were exported in comma separated value files (.csv format) and ingested into the EIDC.