Part IV: Radiometeorological data
TABLE IV-1 – Statistics of yearly and monthly rain intensity+
Station number
______
RG site name
RG country(1)
RG latitude (–90..+90) (degrees)
RG longitude (0..360) (degrees) E
RG altitude amsl hg (m)
____________________
__
_______
_______
____
Measurement: Experiment No.
___
Rain gauge type
RG resolution (mm/h)
RG integration time (s)
RG accumulation per tip (mm/tip)
RG aperture (cm2)
__________
_______
____
_____
_____
Start date (yyyy.mm.dd)
End date (yyyy.mm.dd)
________
________
Table a (6) (7):
R: Yearly/monthly rain rate exceeded for 0.001%, 0.002%, 0.003%, 0.005%, 0.01%, 0.02%, 0.03%, 0.05%, 0.1%, 0.2%, 0.3%, 0.5%, 1%, 2%, 3%, 5% and 10% of the measurement period - R (mm/h) (8)
Rwm: Rain rate exceeded for percentage of worst month - Rwm (mm/h) (9)
Rt: Yearly/monthly total accumulation of rain during the measurement period Rt (mm)
_______________
+ In addition to the tables provided in this document the submitter is requested to provide the data files according to the instructions available on ITU-R SG 3 Web page: Study Group 3 databanks -
DBSG3.
Period of year
dt (3)
dg
(4)
(5)
p0
(days)
(days)
(%)
R 0.001(10)
(mm/h)
R
0.002(10)
(mm/h)
R
0.003(10)
(mm/h)
R
0.005(10)
(mm/h)
R
0.01(10)
(mm/h)
R
0.02(10)
(mm/h)
R
0.03(10)
(mm/h)
R
0.05(10)
(mm/h)
R
0.1(10)
(mm/h)
R
0.2(10)
(mm/h)
R
0.3(10)
(mm/h)
R
0.5(10)
(mm/h)
R
1(10)
(mm/h)
R
2(10)
(mm/h)
R
3(10)
(mm/h)
R
5(10)
(mm/h)
R
10(10)
(mm/h)
Rt
(mm)
Snow included (11)
RG up-time(12) (%)
Year
Worst
month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Comments (12):
References (13):
Instructions, definitions and notes:
(1) Use ISO 3166-1 alpha-2 country codes.
(2) This was referring to Rec. ITU-R P.837-1 (in the current version, these zones do not exist anymore).
(3) The total period of the measurements, dt, (in days) is defined by the start and the end dates of the experiment.
For months, the total period of the measurements in month N, is defined as the total number of days of month N between the start and the end dates of the experiment.
(e.g. for For example, for an experiment starting on 2001/1/1 and ending 2002/12/31 the total period of the measurements in month 4, is 60 days). In another case for an
experiment starting on 2002/1/1 and ending 2004/12/31 (leap year in 2004) the total period of the measurements in month 2, is 85 days.
(4) The duration of valid rain gauge data, dg, is the total time of valid rain gauge measurements during the total period of the measurements, expressed in days as a real number. (e.g.
339.888 days for a year).
The duration of valid rain gauge data in month N, is the total time of valid rain measurements in month N during the total period of the measurements in month N, expressed in
days as a real number.
For example an experiment starting on 2001/1/1 and ending on 2002/12/31, with an amount of valid data in the months of April during this period corresponding to 98.15 % of
the total period of measurements in April, dt equals 60 days, the concurrent duration parameter dc, shall indicate = 58.890 days.
(5) The threshold values of 0.25 mm/h for p0 has been derived from the sensitivity of commonly used tipping bucket rain gauges.
(6) It is requested to provide distributions of measurement periods lasting at least one year or multiple complete years.
In the case where the measurement period includes multiple years, it is requested to provide the distributions of individual years ( 12 consecutive months) and the distribution of
the complete measurement period (multiple of 12 months).
(7) Submissions should comply with the acceptance criteria specified in Rec. ITU-R P.311.
(8) The yearly exceedance percentage shall be calculated as the ratio between the exceedance time and the total amount of time during the which the experiment was performed from
the start of the experiment to its end, dt (3).
For example, in an experiment starting on 2001/1/1 and ending on 2001/12/31 (i.e. dt=365 days) with an exceedance time of 63072 s, the exceedance percentage shall be the ratio
between 63072 s and 365 x 24 x 3600 s (i.e. 0.2 %).
The monthly exceedance percentage shall be calculated as the ratio between the exceedance time during the month and the total amount of time in the during the which the
experiment was performed from the start of the experiment to its end, dt (3).
For example in an experiment starting on 2001/1/1 and ending on 2002/12/31 with an exceedance time of 10000 s in the months of April (in this case dt is equal to 60 days ), the
exceedance percentage in the month of April shall be the ratio between 10368 s and 60 x 24 x 3600 s (i.e. 0.2 %).
Whatever the period of the measurement, the experimenter shall not normalise using the total duration of valid rain gauge data, dg (4).
(9) The worst month concept is defined in Rec. ITU-R P.581.
(10) For versions of this table published before 2014, this parameter was defined as “percentage of time”.
(11) In geographic locations where precipitation in the form of ice or snow may occur, an explanation should be given as to when and how long these conditions prevail and how the
rain gauge data is treated during these intervals.
The occurrence of snow is to be indicated as follows: 0: No snow, 1: Snow eliminated from statistics, 2: Equivalent water content of snow was included in the measurements, 3:
Other (explain under Comments).
(12) If outages occurred in the measurement of rain, explain under ‘Comments’ whether rainfall occurred during the outage or not.
(13) This field should indicate the reference documents that provide the detailed description of the experiment.
These documents shall be available to study group participants (e.g. input document for SG3, journal or international conference).