interarrival {seas}

Calculate the interarrivals between and within precipitation events

Description

Calculate the interarrivals (or spell periods), which are the number of days between precipitation events (dry days), and the number of days of continuous precipitation (wet days).

Usage

interarrival(x, var = "precip", p.cut = 0.3, inv = FALSE)

Arguments

x

a data.frame with Date and var columns of data; x can also have id or name attributes

var

a variable on to which the interarrivals are calculated; default is "precip"

p.cut

days with precipitation values greater than p.cut are considered to be wet days, and the complement are dry days; a trace amount of 0.3 mm is suggested

inv

logical; invert convention of the starting date such that the date is the first wet day if inv=FALSE (default), or the date is the first dry day if inv=TRUE

Details

The interarrival is the same as the spell period (i.e., dry spell), however this function simultaneously counts the number of dry and wet days relative to a single date. The date represents the first day of precipitation (if inv=TRUE, this convention is inverted to the first day of non-precipitation).

Missing or NA precipitation values voids the number of counted days between and within segments, which implies that days without precipitation need to explicitly have zeros.

Value

interarrival object (which inherits the data.frame class) with date, wet, dry columns.

The table has id and name attributes (if available from x).

Author(s)

Mike Toews

References

von Storch, H. and Zwiers, F.W., 1999. Statistical analysis in climate research, Cambridge: Cambridge University Press, 484 p.

See Also

plot.interarrival

Examples

data(mscdata)

van.int <- interarrival(mksub(mscdata, id=1108447))
summary(van.int)
van.int[which.max(van.int$dry),]
van.int[which.max(van.int$wet),]

plot(van.int, ylog=FALSE, maxy=30)