Recommendation ITU-R P.837

This Recommendation provides a method to compute the characteristics of precipitation for propagation modelling

Title PDF Latest approved in
Recommendation ITU-R P.837 [PDF] 2017-06
Characteristics of precipitation for propagation modelling
Current recommendation version (In force)   Date
Recommendation ITU-R P.837-7 [PDF] 06/2017
Recommendations implemented in ITU-Rpy   Date
Recommendation ITU-R P.837-7 [PDF] 06/2017
Recommendation ITU-R P.837-6 [PDF] 02/2012
Recommendations not implemented in ITU-Rpy   Date
Recommendation ITU-R P.837-5 [PDF] 08/2007
Recommendation ITU-R P.837-4 [PDF] 04/2003
Recommendation ITU-R P.837-3 [PDF] 02/2001
Recommendation ITU-R P.837-2 [PDF] 10/1999
Recommendation ITU-R P.837-1 [PDF] 08/1994

Introduction

Rainfall rate statistics with a 1-min integration time are required for the prediction of rain attenuation in terrestrial and satellite links. Data of long-term measurements of rainfall rate may be available from local sources, but only with higher integration times. This Recommendation provides maps of meteorological parameters that have been obtained using the European Centre for Medium-Range Weather Forecast (ECMWF) ERA-40 re-analysis database, which are recommended for the prediction of rainfall rate statistics with a 1-min integration time, when local measurements are missing.

Module description

itur.models.itu837.change_version(new_version)[source]

Change the version of the ITU-R P.837 recommendation currently being used.

This function changes the model used for the ITU-R P.837 recommendation to a different version.

Parameters:new_version (int) –

Number of the version to use. Valid values are:

  • 7: Activates recommendation ITU-R P.837-7 (12/17) (Current version)
  • 6: Activates recommendation ITU-R P.837-6 (02/12) (Superseded)
itur.models.itu837.get_version()[source]

Obtain the version of the ITU-R P.837 recommendation currently being used.

Returns:version – Version currently being used.
Return type:int
itur.models.itu837.rainfall_probability(lat, lon)[source]

Compute the percentage probability of rain in an average year, P0, at a given location.

Parameters:
  • lat (number, sequence, or numpy.ndarray) – Latitudes of the receiver points
  • lon (number, sequence, or numpy.ndarray) – Longitudes of the receiver points
Returns:

P0 – Percentage probability of rain in an average year (%)
Return type:

numpy.ndarray

References

[1] Characteristics of precipitation for propagation modelling https://www.itu.int/rec/R-REC-P.837/en

itur.models.itu837.rainfall_rate(lat, lon, p)[source]

Compute the rainfall rate exceeded for p% of the average year at a given location.

Parameters:
  • lat (number, sequence, or numpy.ndarray) – Latitudes of the receiver points
  • lon (number, sequence, or numpy.ndarray) – Longitudes of the receiver points
  • p (number) – Percentage of time exceeded for p% of the average year
Returns:

R001 – Rainfall rate exceeded for p% of the average year
Return type:

numpy.ndarray

References

[1] Characteristics of precipitation for propagation modelling https://www.itu.int/rec/R-REC-P.837/en

itur.models.itu837.unavailability_from_rainfall_rate(lat, lon, R)[source]

Compute the percentage of time of the average year that a given rainfall rate (R) is exceeded at a given location

This method calls successively to rainfall_rate (sing bisection) with different values of p.

Note: This method cannot operate in a vectorized manner.

Parameters:
  • lat (number) – Latitude of the receiver point
  • lon (number) – Longitude of the receiver point
  • R (number, sequence, or numpy.ndarray) – Rainfall rate (mm/h)
Returns:

p – Rainfall rate exceeded for p% of the average year
Return type:

numpy.ndarray

References

[1] Characteristics of precipitation for propagation modelling https://www.itu.int/rec/R-REC-P.837/en