solar_position: Solar position

In energyRt/merra2ools: R-tools to process MERRA-2 data (NASA) with focus on renewable energy

Solar position

Description

Solar position

Usage

solar_position(
  x,
  UTC = "UTC",
  yday = "yday",
  hour = "hour",
  lon = "lon",
  lat = "lat",
  integral_steps = 1,
  keep.all = TRUE,
  verbose = getOption("merra2.verbose"),
  ...
)

Arguments

x	data.frame with MERRA-2 subset
UTC	name (string) of the column in x with date and time in UTC format
yday	optional name of column in x with the day of the year (consistent with UTC time), will be used if "UTC" is not provided
hour	optional, the name of column with hour of the day (0 to 23, UTC time assumed)
lon	longitude of the location
lat	latitude of the location
integral_steps	integer number of steps for calculation of solar_time, hour_angle, and zenith within an hour, and the logical variable; default is 2 (start and the end of every hour)
keep.all	if TRUE, the interim variables declination, eq_time, solar_time, and hour_angle will be added to x and returned
verbose

Details

\loadmathjax

List or data.frame with estimated following solar geometry variables:

• Solar declination (\mjseqn\theta_d) \mjsdeqn\theta_d = \frac23.45\pi180\sin\big(2\pi\frac284+n365\big)

• Equation of time (\mjseqnE_qt) \mjsdeqn E_qt = \begincases -14.2\sin\big(\frac\pi(n+7)111\big)& & 1 \leq n \leq 106\newline 4.0\sin\big(\frac\pi(n-106)59\big)& & 107 \leq n \leq 166\newline -6.5\sin\big(\frac\pi(n-166)80\big)& & 167 \leq n \leq 246\newline 16.4\sin\big(\frac\pi(n-247)113\big)& & 247 \leq n \leq 365 \endcases

• Apparent solar time (\mjseqnT_solar) \mjsdeqnT_solar = T_UTC+\fracE_qt60+longitude/15

• Hour angle (\mjseqn\theta_hr) \mjsdeqn\theta_hr = \fracT_solar-1212\pi

• Zenith angle \mjsdeqnzenith = \arccos\big(\sin(latitude)\sin(\theta_d)+\cos(latitude)\cos(\theta_d)\cos(\theta_hr)\big)

• Azimuth angle \mjsdeqn azimuth = \begincases \arcsin(A)& & A \geq 0, B \geq 0\newline 180-\arcsin(A)& & B < 0\newline 360+\arcsin(A)& & A < 0, B \geq 0 \endcases where
  \mjseqnn - \textday of the year
  \mjseqnA = \sin(azimuth) = -\frac\sin(\theta_hr)\cos(\theta_d)\sin(zenith)
  \mjseqnB = \cos(azimuth) = \frac\sin(\theta_d)- \sin(latitude)\cos(zenith)\cos(latitude)\sin(zenith)

Examples

NA

energyRt/merra2ools documentation built on May 2, 2024, 4:53 a.m.