warsa.evapotranspiration package

Submodules

warsa.evapotranspiration.penman_monteith module

actual_vapour_pressure(**args)

page 37 , 38 , 39

Parameters:args (float) – tmax : maximum air temperature [C] tmin : minimum air temperature [C] tdew : dewpoint temperature [C] twet : wet bulb temperature temperature [C] tdry : dry bulb temperature temperature [C] apsy : coefficient depending on the type of ventilation of the wet bulb rhmax : maximum relative humidity [%] rhmin : minimum relative humidity [%] rhmean : mean relative humidity [%] z : elevation above sea level [m]
Returns:
Return type:
atmospheric_pressure(z)

Calculates the atmospheric pressure in kpa as a function of the elevation above the sea level.

The atmospheric pressure, P, is the pressure exerted by the weight of the earth’s atmosphere. Evaporation at high altitudes is promoted due to low atmospheric pressure as expressed in the psychrometric constant. The effect is, however, small and in the calculation procedures, the average value for a LOCATION is sufficient. A simplification of the ideal gas law, assuming 20 C for a standard atmosphere, can be employed to calculate P (FAO56)

Parameters:z – elevation above sea level [m]
Returns:atmospheric pressure [kPa]
psychrometric_constant(p, a_psy=0.000665)
Parameters:
  • p – atmospheric pressure [kPa]
  • a_psy – coefficient depending on the type of the ventilation of the bulb [1/C] Examples: a_psy = 0.000665 (default) a_psy = 0.000662 for ventilated (Asmann type) psychrometers, with an air movement of some 5 m/s a_psy = 0.000800 for natural ventilated psychrometers (about 1 m/s) a_psy = 0.001200 for non-ventilated psychrometers installed indoors
Returns:

psychrometric constant[]
reference_evapotranspiration(lat, z, albedo, day, n, u2, g=0.0, tmin=None, tmax=None, t=None, rhmin=None, rhmax=None, rh=None)
Parameters:
  • lat –
  • z –
  • albedo –
  • day –
  • n –
  • u2 –
  • g –
  • tmin –
  • tmax –
  • t –
  • rhmin –
  • rhmax –
  • rh –
Returns:
Return type:
saturation_vapour_pressure(t)
Parameters:t – temperature [C]
Returns:saturation vapour pressure
slope_of_saturation_vapour_pressure_curve(t)
Parameters:t –
Returns:
Return type:

warsa.evapotranspiration.pet_haude module

pet_haude(df, temp_col, hum_col, monthly_factor=None)
Parameters:
  • df – pandas DataFrame with with at least two columns: - temperature in °C - relative air humidity in percentage both at 2 pm
  • temp_col – name of the column containing temperature values
  • hum_col – name of the column containing relative air humidity values
  • monthly_factor – correction factor for each month (default to Germany)
Returns:

Module contents