radiomet_data_for_pathcenter#

pycraf.pathprof.radiomet_data_for_pathcenter(lon, lat, d_tm, d_lm)[source]#

Calculate delta_N, beta_0, and N_0 values from digitized maps, according to ITU-R P.452-16 Eq (2-4).

Parameters:

lon, latQuantity: Geographic longitude and latitude of path center [deg]
d_tmQuantity, optional: longest continuous land (inland + coastal) section of the great-circle path [km]
d_lmQuantity, optional: longest continuous inland section of the great-circle path [km]

Returns:

delta_NQuantity: Average radio-refractive index lapse-rate through the lowest 1 km of the atmosphere [N-units/km == 1/km]
beta_0Quantity: the time percentage for which refractive index lapse-rates exceeding 100 N-units/km can be expected in the first 100 m of the lower atmosphere [%]
N_0Quantity: Sea-level surface refractivity [N-units == dimless]

Notes

The values for delta_N and N_0 are queried from a radiometeorological map provided with ITU-R Rec. P.452.
Radio-climaticzones can be obtained from ITU Digitized World Map (IDWM). For many applications, it is probably the case, that only inland zones are present along the path of length d. In this case, d_tm = d_lm = d.