Hourly Air Temperature Interpolation

Computes hourly estimates of air temperature (Ta) from daily Tmin, Tmax, and day length using the method of Goudriaan (1994). The function assumes a sinusoidal temperature variation during daylight hours and an exponential decay after sunset.

Usage

tt_hourly_pp(tmin, tmax, tmax_b, tmin_a, lat, doy)

Arguments

tmin

Numeric. Minimum temperature of the day (°C).

tmax

Numeric. Maximum temperature of the day (°C).

tmax_b

Numeric. Maximum temperature from the previous day (°C).

tmin_a

Numeric. Minimum temperature of the following day (°C).

lat

Numeric. Latitude of the location (degrees, -90 to 90).

doy

Integer. Day of the year (1 to 366).

Value

A numeric vector of length 24 containing the estimated hourly air temperatures (°C).

Details

- **Daytime interpolation**: During sunlight hours, Ta is estimated using a sinusoidal curve fitted between Tmin and Tmax. - **Nighttime interpolation**: After sunset, Ta follows an exponential decline from the sunset temperature to the next morning's Tmin. - **Sunrise and Sunset Calculation**: - Sunrise hour: `hsrise = 12 - d/2` - Sunset hour: `hsset = 12 + d/2` - Tmax occurs at hour = 13.5.

If the Controlled Environment module is used for weather data, the function takes hourly values from that instead of computing them.

References

Goudriaan, J. (1994). Advanced Methods for Calculating Radiation Models. Netherlands Journal of Agricultural Science, 42(4), 315-323.

Examples

tmin <- 10
tmax <- 20
tmax_b <- 21
tmin_a <- 11
lat <- -27
doy <- 10
hourly_temps <- tt_hourly_pp(tmin, tmax, tmax_b, tmin_a, lat, doy)