evalHomogeneity(X)dataclim object or a data.frame.
dataclim method, the years are
returned. For the data.frame method, a row-index is returned. dataclim, the function calls
the 4 homogeneity tests Standard Normal
Homogeneity test (SNHtest), the BuisHand Range test (BHRtest), the PETtitt
test (PETtest) and the VON Neumann ratio (VONtest) and, for temperature,
applies them to annual means of daily temperature ranges (Tmax-Tmin)
and the day-to-day difference of the daily temperature ranges. For
precipitation, the annual counts of days with more than 1mm of rain
are evaluated.If no more than one test indicates a break at the 1% level of significance, the temperature or precipitation observations are considered as "useful". If two tests indicate a break at the 1% level, the respective observations are considered as "doubtful". With three or more tests indicating breaks at the 1% level, the respective observations are considered as "suspect". The two derived temperature characteristics are aggregated by using the maximum number of 1%-significant breaks.
Note that the four tests cannot handle NAs. If X is a
dataclim
object and the derived annual means have missing values, the function
checks whether there are at least 20 valid years and at least 70% of
the years are valid for all variables. In this case, the missing
values are linearly interpolated.
If X is a data.frame, the function assumes the data.frame to
contain equidistant non-NA observations. The series are tested
directly, without any processing of derived quantities as in the case
of the dataclim object.
SNHtest, BHRtest,
PETtest, VONtest
data(potsdam)
date <- as.Date(potsdam$date)
myDataclim <- createDataclim(date=date, tmin=potsdam$tmin, tmax=potsdam$tmax,
prec=potsdam$prec, basePeriod=1981:2010)
evalHomogeneity(myDataclim)
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