Defines some astronomical information for a series of dates at a given latitude.
The series of dates must be a valid DateArray object. If its frequency is weekly or less (monthly, quarterly), the series is internally converted to a daily frequency, but its original frequency is saved in the freq attribute. A NotImplementedError is raised if the initial frequency is hourly or higher.
All of the attributes are stored internally with a daily frequency. Public versions are available: in that case, the attribute is reconverted to the initial frequency freq.
Parameters:  dates : DateArray
latitude : float


Methods
clearsky_solar_radiations  
frac_day_of_year  
solar_radiations_from_sunshinehours  
solar_radiations_from_temperatures 
Frequency specifier of the input dates.
See also
The following attributes are TimeSeries objects, with the same dates and freq attributes as the instance. If the initial frequency is less than daily (for example, monthly), the values of the series correspond to daily values average over the period.
Returns the average inverse relative distance Earthsun , calculated as:
where is the fractional day of the year (1./365 for Jan., 1st and 1. for Dec.,31st).
Returns the solar declination as [Spencer_1971]:
where is the fractional year in radians, the day of the year (1 for Jan, 1st) and the number of days in the year.
Returns the sunset hour angle, as a TimeSeries. The sunset hour angle is calculated from the solar declination and the latitude as
The extraterrestrial solar radiation is the solar radiation received at the top of the atmosphere on an horizontal surface. It depends on the solar constant , the solar radiation hitting a surface perpendicular to the sun’s rays at the top of the atmosphere, and the angle between the sun rays and the normal to the atmosphere.
An expression of [MJ.m^{2}.d^{1}] is given by Duffie & Beckman (1981) [Duffie_Beckman_1981]:
where is the sunset hour angle (sunset_angle), the inverse relative EarthSun distance(earth_sun_distance), the solar declination (solar_declination), the site latitude (latitude).
Returns the fractional days of the year, as a TimeSeries. The fractional day of the year is a float between 0 (or 1./365) for Jan., 1st and 1. for Dec., 31st.
Parameters:  offset : {False, True}

