regionalSeaken: Trend Test

In USGS-R/restrend: EStimate TRENDs

Trend Test

Description

Compute the regional seasonal Kendall trend test.

Usage

regionalSeaken(series, nseas = 12)

Arguments

series	a matrix of the regular series for each site. Each column is the regular series of observations for that site. Missing values are permitted.
nseas	the number of seasons per year.

Value

An object of class "rsktest" containing the following components:

method	a description of the method.
statistic	the value of Kendall's tau.
p.values	the p-value. See Note.
estimate	the Sen estimate of the slope in units per year–the median of the site medians.
data.name	a string containing the actual name of the input series with the number of years and seasons.

Note

The values of p.values are the attained p-values considering the raw results, corrected for serial correlation, corrected for spatial correlation using the method of Dietz and Killeen (1981), and the corrected value for spatial correlation using the method of Douglas and others (2000).

References

Dietz, E.J., and Killeen, T.J., 1981, A nonparametric multivariate test for monotone trend with pharmaceutical applications: Journal of the American Statistical Association, v. 76, p 169–174.
Douglas, E.M., Vogel, R.M., and Kroll, C.N., 2000, Trends in floods and low flows in the United States: impact of spatial correlation: Journal of Hydrology, v. 240, p. 90–105. Sprague, L.A., Mueller, D.K., Schwarz, G.E., and Lorenz, D.L., 2009, Nutrient trends in streams and rivers of the United States, 1993–2003: U.S. Geolgical Survey Scientific Investigations Report 2008-5202, 196 p.

Examples

## Not run: 
data(RK3b)
# Build matrix, site 11 is missing 2004, would be row 60
Ammonia <- with(RK3b, matrix(c(value[1:59], NA, value[60:299]),
 ncol=25))
regionalSeaken(Ammonia, 1)

## End(Not run)

USGS-R/restrend documentation built on Oct. 11, 2022, 6:10 a.m.