SPEI and SSI time-series datasets for the Indus Basin of Pakistan

The file contains 2 datasets namely:
1-Standard Precipitation and Evapotranspiration Index (SPEI) for four catchments (Chenab,Jhelum, Indus and Kabul) of the Indus Basin
2-Standard Streamflow Index (SSI) for four catchments of the Indus Basin.

SPEI:
The Standard Precipitation and Evapotranspiration Index (SPEI) (Vicente-Serrano et al., 2010a) is the indicator used 
for quantification and monitoring of meteorological droughts.
SPEI is calculated for the four catchments (Chenab,Jhelum, Indus and Kabul) at each catchment level using gridded climate data from the CRU data set (Harris et al., 2020). 
For catchment level SPEI calculations, gridded precipitation and Potential Evapotranspiration values extracted from CRU dataset are averaged over the catchment. A map(study_area) delineating the four catchments is provided.

SSI:
The Standard Streamflow Index (SSI) (Nalbantis and Tsakiris, 2009; Modarres, 2007) is used (also called the Streamflow
Drought Index and the Streamflow Runoff Index) to quantify and analyze hydrological droughts.SSIs are computed at catchment outlets as shown in the attached map (study_area). Streamflow station names are Marala(for Chenab),Mangla (Jhelum), Tarbela(for Indus) and Nowshera(for Kabul).

Units: Both the datasets are dimensionless 

References:

Harris, I. C. and Jones, P. D.: CRU TS4.03: Climatic Research Unit (CRU) Time-Series (TS) version 4.03 of high-resolution gridded data of month-by-month variation in climate (Jan. 1901- Dec. 2018), https://doi.org/10.5285/10d3e3640f004c578403419aac167d82, university of East Anglia Climatic Research Unit; Centre for Environmental Data Analysis, 2020.

Modarres, R.: Streamflow drought time series forecasting, Stochastic Environmental Research and Risk Assessment, 21, 223–233, https://doi.org/10.1007/s00477-006-0058-1, 2007.

Nalbantis, I. and Tsakiris, G.: Assessment of hydrological drought revisited, Water Resources Management, 23, 881–897,
https://doi.org/10.1007/s11269-008-9305-1, 2009.

Vicente-Serrano, S. M., Beguería, S., and López-Moreno, J. I.: A Multiscalar Drought Index Sensitive to GlobalWarming: The Standardized Precipitation Evapotranspiration Index, Journal of Climate, 23, 1696–1718, https://doi.org/10.1175/2009JCLI2909.1, https://doi.org/10.1175/2009JCLI2909.1, 2010a.