Interpol.T (version 2.1.1)

Th_interp: 24-hourly interpolation of temperature

Description

The function creates 24 values of hourly temperature from minimum and maximum daily values. This function applies to single series and to single day couples of minimum and maximum temperature. It is called by functions Th_int_series and shape_calibration. The function uses four different curves: from time 00 to the minimum time: a horizontal-axis parabola (a line, if this choice is enabled and according to the daily thermal range of the day); from minimum to maximum time: an increasing sinusoidal curve; from maximum time to sunset: a decreasing sinusoidal curve; from sunset to time = 23: a horizontal-axis parabola (a line, if this choice is enabled and according to the daily thermal range of the day). Calibration parameters are series- and monthly-specific. This function is operationally called by Th_int_series, which requires the daily series and the calibration table as input (plus other parameters). A general user will conveniently use the latter function.

Usage

Th_interp(Tmin, Tmax, Tsuns = NULL, Th_24_before = NULL, day, tab_calibr, dtr_month = NULL, ratio_dtr = NULL, late_min = TRUE)

Arguments

Tmin

a daily table of 4 named columns, the first 3 being year, month, day, the 4th minimum temperature. The column names "month" and "T" are mandatory

Tmax

same for Tmax

Tsuns

temperature at sunset time

Th_24_before

temperature at time 24 of the previous day (time 00 of the present day)

day

progressive number of the day (row of both Tmin and Tmax), corresponding to a day

tab_calibr

"hour" parameter calibration table for the specific series. See par_calibration

dtr_month

monthly daily thermal range table (see function Mo.Th.Ra.)

ratio_dtr

parameter for the choice of the night curve shape; it is NULL if no calibration_shape is passed to the function by Th_int_series

late_min

logical; allows to shift the time of occurrence of minima to the late hours of the day (assumes the value of full.24.hrs.span_min, passed by functions Th_int_series) and shape_calibration)

Value

A vector containing the values from hour = 0 (element 1) to hour = 23 (element 24)

References

Eccel, E., 2010: What we can ask to hourly temperature recording. Part II: hourly interpolation of temperatures for climatology and modelling. Italian Journal of Agrometeorology XV(2):45-50 http://www.agrometeorologia.it/documenti/Rivista2010_2/AIAM%202-2010_pag45.pdf,www.agrometeorologia.it

Original algorithm from: Cesaraccio, C., Spano, D., Duce, P., Snyder, R.L., 2001. An improved model for determining degree-day values from daily temperature data. Int. J. Biometeorol. 45: 161-169. http://www.springerlink.com/content/qwctkmlq3tebthek/

See also: Eccel, E., 2010: What we can ask to hourly temperature recording. Part I: statistical vs. meteorological meaning of minimum temperature. Italian Journal of Agrometeorology XV(2):41-43. http://www.agrometeorologia.it/documenti/Rivista2010_2/AIAM%202-2010_pag41.pdf,www.agrometeorologia.it

See Also

Th_int_list