TSA_zero_curtain: Detect zero curtain periods during a snow cover period
In geocryology/PermafrostTools: PermafrostTools

Description Usage Arguments Details Value Author(s) Examples

Give one data.frame of a location or a list of data.frames of multiple locations and the function returns a table with the start and end dates of zero curtain periods during snow cover periods.

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TSA_zero_curtain(obs_stat, temp = 0.2, slopesd = 0.1, tempsd = 0.01,
  lengthzc = 2, v1 = 0.1, v2 = 0.3, lengthsnow = 5, MDr.sd = 0.3,
  snow.period = NULL)

`obs_stat`	one dataframe of one location of a list of dataframes of multiple locations A dataframe needs at least the following columns: Location name as loc_name; Mean daily GST as agg_avg; Maximum daily GST as agg_max; Daily sd as agg_sd (not necessarily needed); Date as time (in POSIXct and the following format: YYYY-MM-DD)
`temp`	The temperature boundary within the mean agg_avg of a zero curtain period has to be. Default: 0.2 degrees Celsius
`slopesd`	Fraction of the standard deviation of the slope used as threshold for the slope. Default: 0.1
`tempsd`	Fraction of the mean daily standard deviation used as threshold for the daily sd. Default: 0.01
`lengthzc`	Length that a zero curtain period should at least have. Default: 2 days.
`v1`	Max. daily standard deviation indicating snow for POSITIVE Ground Surface Temperature. Default is 0.1.
`v2`	Max. daily standard deviation indicating snow for NEGATIVE Ground Surface Temperature. Default is 0.3.
`lengthsnow`	Number of days that the snow cover should at least have to be selected as a valid snow cover. Default is 5 days
`MDr.sd`	Threshold for the mean daily standard deviation for a snow period.
`snow.period`	In case the snow period is already available for one location, it can be inserted here. The data frame of the now period needs to have the following columns: loc_name, Snow.Start, Snow.End, MDr

It is also possible to adjust the parameters for the TSA_snow_cover function in this function, as the warming periods are calculated for each snow cover period. Therefore, the TSA_snow_cover is run as well in this function.

Data fame with the following fields: loc_name: location name; Snow.Start: Start date of the analyzed snow period; Snow.End: End date of the analyzed snow period; Zero.Curtain.Start: Start date of a zero curtain period; Zero.Curtain.End: End date of a zero curtain period; Median.Temperature: Median temperature of a zero curtain period [C]; sd.Temperature: Standard deviation of the temperature of a zero curtain period;

Thomas Knecht <t.knecht@hotmail.com>

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con <- dbpf_con()
BC_SO01_01 <- TSA_data_import(con, "BC16-SO01_01")
ZeroCurtainTable <- TSA_zero_curtain(BC_SO01_01, temp= 0.2, slopesd= 0.1, tempsd= 0.01, lengthzc=2, v1 = 0.1, v2 = 0.3, lengthsnow = 5, MDr.sd = 0.3, snow.period=NULL)