Seasonal Kendall Test for Trend
US Geological Survey, 2005
Data set: Example SKL1a - Seasonal Kendall with LOWESS, input type 1
The record is 12 complete water years with 12 seasons per year
beginning in water year 1974.
Flow-adjusted concentrations were calculated as
residuals from a LOWESS smooth line (f = 0.50)
for concentration vs. streamflow
The tau correlation coefficient is -0.176
S = -42.
z = -1.808
p = 0.0705
p = 0.1985 adjusted for correlation among seasons
(such as serial dependence)
The adjusted p-value should be used only for data with
more than 10 annual values per season.
The estimated trend may be described by the equation:
Residual = 0.000 + -3.761 * Time
where Time = Year (as a decimal) - 1973.75 (beginning of first water year)