Solar time formula — sol_time_formula • fieldClim

Calculates the solar time formula, which corrects the solar medium suntime to account for the Earth's elliptical orbit and axial tilt.

Usage

sol_time_formula(...)

# Default S3 method
sol_time_formula(datetime, lon, ...)

# S3 method for class 'weather_station'
sol_time_formula(weather_station, ...)

Arguments

...: Named station fields, site parameters or model assumptions.
datetime: POSIXlt or POSIXct date-time vector.
lon: Longitude in degrees.
weather_station: A weather_station object.

Value

Hour.

Details

The solar time formula ($E_t$) is calculated as: $$E_t = 0.1644 \cdot \sin(2L) - 0.1277 \cdot \sin(M)$$ where: $L$ is the ecliptic longitude, $M$ is the solar medium anomaly.

References

Bendix 2004, p. 243.

Examples

# Calculate solar time formula
sol_time_formula(as.POSIXlt("2022-06-21 12:00:00"), lon = 10)
#> [1] 0.02560119