Journal
WATER RESOURCES MANAGEMENT
Volume 26, Issue 9, Pages 2453-2473Publisher
SPRINGER
DOI: 10.1007/s11269-012-0026-0
Keywords
Meteorological drought; SPI; Gamma; Log-normal; Normal probability distributions
Categories
Funding
- research programme INTERREG III B - MEDOCC - Measure - 4 [2005-05-4.4-P-105]
Ask authors/readers for more resources
The Standardized Precipitation Index (SPI) is widely used as drought meteorological index, to identify the duration and/or severity of a drought. The SPI is usually computed by fitting the gamma probability distribution to the observed precipitation data. In this work, the possibility to calculate SPI by fitting to the precipitation data the normal and the log-normal probability distributions was studied. For this purpose, 19 time series of monthly precipitation of 76 years were used, and the assumption that the gamma probability distribution would provide better representation of the precipitation data than log-normal and normal distributions, at various time scales (1, 3, 6, 12 and 24 months) was tested. It is concluded that for SPI of 12 or 24 months, the log-normal or the normal probability distribution can be used for simplicity, instead of gamma, producing almost the same results.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available