mc_calib_moisture {myClim}

Calculates coefficients for TMS moisture conversion to VWC

Description

Specialized function for calibration of TOMST TMS moisture sensor. Function calculate correction parameters for individual logger (slope and intercept) from TMS moisture measurements in demineralized water and dry air.

Usage

mc_calib_moisture(
  raw_air,
  raw_water,
  t_air = 24,
  t_water = 24,
  ref_air = 114.534,
  ref_water = 3634.723,
  ref_t = mc_const_CALIB_MOIST_REF_T,
  acor_t = mc_const_CALIB_MOIST_ACOR_T,
  wcor_t = mc_const_CALIB_MOIST_WCOR_T
)

Arguments

raw_air

Raw TMS moisture signal in air

raw_water

Raw TMS moisture signal in water

t_air

temperature of air (default 24)

t_water

temperature of water (default 24)

ref_air

raw air signal of reference logger used to derive soil calibration parameters (default 114.534)

ref_water

raw air signal of reference logger used to derive soil calibration parameters (default 3634.723)

ref_t

reference logger temperature (default 24)

acor_t

temperature drift correction parameter in the air (default 1.911)

wcor_t

temperature drift correction parameter in the water (default 0.641)

Details

This function calculate calibration parameters cor_factor and cor_intercept accounting for individual differencies in TMS moisture sensor signal in air and in water against reference loggers which were used for estimation of parameters of soil VWC conversion curves. These parameters must be loaded into myClim object mc_prep_calib_load() prior to calling mc_calc_vwc(). Parameters for soils available in my_Clim were derived for TMS3 logger version, with slightly different typical air and water signal. Correction parameters for TMS4 loggers therefore can be expected in the range of values: cor_factor = (-150; -450) and cor_slope = (100, 450)

Value

list with correction factor and correction slope

Examples

# load example data
files <- c(system.file("extdata", "data_94184102_0.csv", package = "myClim"))
tomst_data <- mc_read_files(files, "TOMST")

# vwc without calibration
tomst_data <- mc_calc_vwc(tomst_data, soiltype = "universal", output_sensor = "VWC_universal")

# load calibration
my_cor <- mc_calib_moisture(raw_air = 394, raw_water = 3728, t_air = 21, t_water = 20)
my_calib_tb <- data.frame(serial_number = c("94184102"), sensor_id = "TMS_moist",
                          datetime = as.POSIXct("2020-01-01 00:00"),
                          cor_factor = my_cor$cor_factor, cor_slope = my_cor$cor_slope)
tomst_data_cal <- mc_prep_calib_load(tomst_data, my_calib_tb)
# vwc using calibration
tomst_data_cal <- mc_calc_vwc(tomst_data_cal, soiltype = "universal",
                              output_sensor = "VWC_universal_calib")
# plot results
sensors <- mc_info(tomst_data_cal)$sensor_name
(mc_plot_line(tomst_data_cal, sensors = c(sensors[startsWith(sensors,"VWC")]))
     + ggplot2::scale_color_viridis_d(begin = 0.2, end = 0.8))