R: Mann-Kendall trend test for monthly environmental time series
SeasonalMannKendall
R Documentation
Mann-Kendall trend test for monthly environmental time series
Description
Hirst et al. (1982) suggested this test for monthly water quality time series.
The test is also discussed by Hipel and McLeod (2005).
The score is computed separately for each month.
The purpose of this test is to test for monotonic trend. A common misconception
is to look for trends in the individual monthly time series. Usually this does
not make a lot of sense, in the context of environmental time series,
since if there is a real trend of interest in the series
it would not be expected to be greatly changed by seasonality. If indeed one
were interested in detecting a trend a particular month then one could use
the MannKendall trend test for that particular month or group of months.
Usage
SeasonalMannKendall(x)
Arguments
x
a vector or a time series comprised of consecutive monthly values
Value
A list with class Kendall.
tau
Kendall's tau statistic
sl
two-sided p-value
S
Kendall Score
D
Denominator, tau=S/D
varS
variance of S
Generic function print.Kendall and summary.Kendall are provided.
Note
If you want to use the output from SeasonalMannKendall,
save the result as in res<-SeasonalMannKendall(x,y) and then select from the list res the
value(s) needed.
Author(s)
A.I. McLeod, aimcleod@uwo.ca
References
Hirsch, R.M., Slack, J.R. and Smith, R.A. (1982),
Techniques for trend assessment for monthly water quality data,
Water Resources Research 18, 107-121.
Hipel, K.W. and McLeod, A.I., (2005).
Time Series Modelling of Water Resources and Environmental Systems.
Electronic reprint of our book orginally published in 1994.
http://www.stats.uwo.ca/faculty/aim/1994Book/.
See Also
MannKendall
Examples
#test for monotonic trend in monthly average river height data
#for the Rio Negro at Manaus. This data is included in the
#package boot.
library(boot)
data(manaus)
SeasonalMannKendall(manaus)
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> library(Kendall)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/Kendall/SeasonalMannKendall.Rd_%03d_medium.png", width=480, height=480)
> ### Name: SeasonalMannKendall
> ### Title: Mann-Kendall trend test for monthly environmental time series
> ### Aliases: SeasonalMannKendall
> ### Keywords: ts nonparametric
>
> ### ** Examples
>
> #test for monotonic trend in monthly average river height data
> #for the Rio Negro at Manaus. This data is included in the
> #package boot.
> library(boot)
> data(manaus)
> SeasonalMannKendall(manaus)
tau = 0.0877, 2-sided pvalue =2.2559e-05
>
>
>
>
>
> dev.off()
null device
1
>