ssfi: Calculate Standardized StreamFlow Index (SSFI)

In flogrc/piflow: Precipitation and discharge analysis tools with zoo vector

Description

Calculate SSFI and the drought specifications with the length, the drought type and the intensity

Usage

ssfi(prec_data, Delta = 12, Distribution = "gamma")

Arguments

prec_data	[zoo] rainfall monthly data in zoo class with date in %Y-%m-%d
time_step	[numeric] by default = 12, time step to sum monthly data (1, 3, 6, 9, 12, 24 and 48)
distribution	[character] distribution of data (log_Logistic, gamma, grev, genlog, normal)

Value

list that contains

ssfi [zoo] zoo with the ssfi values with date in %Y-%m-%d

drought_type [zoo] zoo with the type of the period for each month

drought_number [data.frame] dataframe with the number of different period by type

• Extwet (ssfi > 2)
  

• Verywet (1.99 > ssfi > 1.5)
  

• Wet (1.49 > ssfi > 1)
  

• Normal (0.99 > ssfi > -0.99)
  

• Dry (-1 > ssfi > -1.49)
  

• VeryDry (-1.5 > ssfi > -1.99)
  

• ExtDry (-2 > ssfi)

Author(s)

Florine Garcia ([e-mail])

Pierre L'Hermite ([e-mail])

References

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

See Also

plot_trend: plot the index

Examples

How to use function

flogrc/piflow documentation built on May 24, 2019, 7:34 a.m.