Parameters for the modified Penman (Penman/Monteith) Formula

Besides time-depended climatic parameters

the modified Penman (Penman/Monteith) formula applies the following time-independent station-related physical parameters:

Table StData_db - physical parameters applied in Jordan

Code DESCRIPTION unit minimum maximum
Latitude_decimal Latitude Decimal degrees 29.379 32.683
Altitude_m Altitude m -285 1350
S_Wave_a Short Wave fraction
of extraterrestrial radiation (Ra)
on overcast days
- 0.25 0.25
S_Wave_b Short Wave fraction
of radiation on clear days
- fraction on overcast days
- 0.5 0.5
Albedo_alpha Albedo - 0.23 0.23
L_Wave_Rad_a Coefficient a
(for calculation of longwave fraction
out of daily sunshine)
- 0.9 0.9
L_Wave_Rad_b Coefficient b
(for calculation of longwave fraction
out of daily sunshine)
- 0.1 0.1
L_Wave_al Long Wave correlation coefficient - 0.34 0.34
L_Wave_bl Long Wave correlation coefficient - -0.139 -0.139
Instr_height_wind_cm Instrument height -
wind run
cm 200 1000
Instr_height_tempr_cm Instrument height -
thermometres
cm 190 200
Cropheight_cm height of reference crop cm 12 12