R: Calibrates the shape of the night interpolating curve
shape_calibration
R Documentation
Calibrates the shape of the night interpolating curve
Description
Calibrates the shape of the night interpolating curve,
either horizontal-axe parabola or line, by changing the
exponent z (see reference). It functions according to the
comparison of the daily thermal range and the climate
(reference) monthly one.
measured hourly values file (table), where
the first column is the series' ID
date.format
input date format (formats for
function chron)
cal_times_list
calibration list of "time"
parameters (output of par_calibration)
band_min
band of hours of occurrence of day
minimum in the daily series (continuous). See
Note
band_max
same for maximum time
ratio_dtr_range
range for seeking the optimal
value of ratio_dtr
nr_cycles
number of calibration trials within the
calibration ranges (all)
min_mo.length
minimum number of days to calculate
any monthly values of dtr (is passed to function
Mo.Th.Ra.)
full.24.hrs.span_min
logical, if set to
FALSE does not allow to shift minimum time to the
late hours of the day
silent
logical, if set to TRUE suppresses
any warning issue
Value
A list containing the optimum values of ratio_dtr
Note
meas must be organized as 4-field records, all
series in the same file, no headers. Column order:
station ID, date, time (hour), T, [others fields, if
any...] separated by spaces. This field order is
mandatory.
Default date format is "ymd" (yyyy/mm/dd). Different
combinations can be passed to function with
date.format, but separator must be "/"
band_min and band_max are the time bands
according to which the minimum and maximum temperature
were calculated in the daily series to be interpolated.
In general, they range from 0 to 23, unless the series
has had some restriction in the calculation of minimum
and maximum values. Hence, these bands can be different
from those used to calibrate the most frequent occurrence
of min and max.
The optimal value of ratio_dtr (k, eq. 7,
in the quoted reference Eccel (2010a)) is chosen as the
one with the (absolute) minimum value of the bias
(irrespective of its sign). ratio_dtr is the ratio
between the daily thermal range of the day to be
interpolated and the mean monthly value for that series.
The corresponding values of mean absolute error and RMSE
can be checked in the resulting list.
min_mo.length (passed to function
Mo.Th.Ra.) refers to the sum of days along all the
series for each specific month, not for any single month
in one year.
full.24.hrs.span_min is TRUE as default. If
must be set to FALSE only if minimum values of the
daily series have been calculated on a restricted time
band, which is included in band_min (see function
par_calibration). If this is the case, the minimum
of the interpolated curve will always fall within
band_min (early hours of the day). If this option
is erroneously chosen, errors as large as 0.6 deg C can
arise in the average of mean daily T.
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/
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> library(Interpol.T)
Loading required package: date
Loading required package: chron
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/Interpol.T/shape_calibration.Rd_%03d_medium.png", width=480, height=480)
> ### Name: shape_calibration
> ### Title: Calibrates the shape of the night interpolating curve
> ### Aliases: shape_calibration
>
> ### ** Examples
>
> library(Interpol.T)
> data(Trentino_hourly_T)
>
> stations <- c("T0001","T0010","T0129")
>
> calibration_shape <- shape_calibration(meas = h_d_t[h_d_t$V1 %in% stations,],
+ cal_times_list = calibration_l[stations],
+ band_min = 0:23, band_max = 0:23, ratio_dtr_range = c(0,4),
+ min_mo.length=21)
[1] Calibration of ratio_dtr...
[1]
[1] T0001
[1] T0010
[1] T0129
[1]
[1] Calibration of ratio_dtr completed successfully!
[1]
>
>
>
>
>
> dev.off()
null device
1
>