decomp: Decomposition of time-series

In hanel/musica: Multiscale Climate Model Assessment

Description

Calculate series of averages over the periods specified in the period argument into the inpur data.table.

Usage

decomp(x, period = c("Y1", "M6", "M3", "M1", "D15", "D1"), agg_by = quarter,
  full_return = FALSE, remove_incomplete = TRUE, year_starts = months(2))

Arguments

x	data.table with columns DTM (date), variable and value. Any number of variables are in principle allowed.
period	The periods over which the averages will be calculated, see Details
agg_by	Function for specification of the period (season, month) to be additionaly included in output, see Details
full_return	(logical) Should the average be repeated for each scale along with original time series? Default is FALSE (e.g. for M1 only monthly and not daily time series is returned)
remove_incomplete	Should the incomplete years be removed from results? Default is TRUE. For use with monthly data always set to FALSE.
year_starts	Indication of the start of the year - determines how the months will be grouped into the seasons. Note that the sub_period output variable is with respect to the year_starts

Details

The original time series in daily time step is decomposed into series of averages ove periods specified in periods argument using letter codes 'D' - day(s), 'M' - month(s), 'Y' - year(s) followed by number corresponding to number of periods and 'G1' the overall mean. The periods must be given in order from longest to shortest, the overall mean is always included (and needs not to be specified in period). Shorter periods are always identified within the closest longer periods, i.e. each shorter period is included in exactly one longer period. As a result, the averages may be calculated over shorter periods than specified. This is due to varying length of "month" and "year" periods. The actual length used for averaging is included in the output. To make further assessment of the decomposed objects easier, indicator of period within the year (e.g. quarter or month) as specified by agg_by argument is included in the output.

Value

data.table with variables:

variable

factor indicating the variable

DTM

date

period

specification of the averaging length with 'D' - day(s), 'M' - month(s), 'Y' - year(s) and 'G1' - the overall mean

value

value of the variable for given averaging length

sub_period

indication of the aggregating scale specified by agg_by argument

period_pos

average date of the interval

N

real length of the vectors used for calculating averages

TS

averaging length in hours

Examples

data(basin_PT)
str(basin_PT)
basin_PT[['obs_ctrl']]
dobs = decomp(basin_PT[['obs_ctrl']], period = c('1 year', '1 month', '1 day'))

hanel/musica documentation built on May 17, 2019, 2:28 p.m.