pyet - Estimation of Potential Evapotranspiration

pyet is an open source Python package for the estimation of reference and potential evapotranspiration (PET) from time series data (Pandas) and gridded data (Xarray). This allows users to estimate potential evapotranspiration and calibrate the models with just a few lines of python code.

Getting started

User guide on the basic concepts of Pastas.

Examples

Examples of pyet usage.

Code Reference

pyet code reference.

Publications

Overview of publications that use pyet

References

References used in the package.

Currently, 18 methods are implemented for calculating daily PET

PET Calculation Methods

Method name	pyet function	T	RH	R	u2	Lat.	El.	Benchmarked?
Penman	penman	✓ [1]	✓ [2]	✓ [3]	✓	✓ [3]	✓ [4]	✓
Penman-Monteith	pm	✓ [1]	✓ [2]	✓ [3]	✓	✓ [3]	✓ [4]	✓
ASCE-PM	pm_asce	✓ [1]	✓ [2]	✓ [3]	✓	✓ [3]	✓ [4]	✓
FAO-56	pm_fao56	✓ [1]	✓ [2]	✓ [3]	✓	✓ [3]	✓ [4]	✓
Priestley-Taylor	priestley_taylor	✓	✓ [5]	✓ [5]		✓ [5]	✓ [4]	✓
Kimberly-Penman	kimberly_penman	✓ [1]	✓ [2]	✓ [3]	✓	✓ [3]	✓ [4]
Thom-Oliver	thom_oliver	✓ [1]	✓ [2]	✓ [3]	✓	✓ [3]	✓ [4]
Blaney-Criddle	blaney_criddle	✓	[6]	[6]	[6]	✓		✓
Hamon	hamon	✓				✓		✓
Romanenko	romanenko	✓	✓					✓
Linacre	linacre	✓ [7]					✓	✓
Haude	haude	✓	✓ [8]					✓
Turc	turc	✓	✓	✓				✓
Jensen-Haise	jensen_haise	✓		✓ [9]		✓ [9]		✓
McGuinness-Bordne	mcguinness_bordne	✓				✓		✓
Hargreaves	hargreaves	✓ [10]				✓		✓
FAO-24 radiation	fao_24	✓	✓	✓	✓		✓ [4]
Abtew	abtew	✓		✓				✓
Makkink	makkink	✓		✓			✓ [4]	✓
Oudin	oudin	✓				✓

Footnotes

[1]

T_max and T_min can also be provided.

[2]

RH_max and RH_min can also be provided. If actual vapor pressure is provided, RH is not needed.

[3]

Input for radiation can be (1) Net radiation, (2) solar radiation, or (3) sunshine hours. If (1), then latitude is not needed. If (1, 3) then latitude and elevation are needed.

[4]

One must provide either the atmospheric pressure or elevation.

[5]

If net radiation is provided, RH and Lat are not needed.

[6]

If method==2, u2, RH_min, and sunshine hours are required.

[7]

Additional input of Tmax and Tmin, or Tdew.

[8]

Input can be RH or actual vapor pressure.

[9]

If method==1, latitude is needed instead of Rs.

[10]

Tmax and Tmin also needed.

Using pyet? Show your support by citing us!

If you find pyet useful and use it in your research or project, we kindly ask you to cite the pyet preprint published in Hydrology and Earth System Sciences (HESS) as follows:

• Vremec, M., Collenteur, R. A., and Birk, S.: Technical note: Improved handling of potential

  evapotranspiration in hydrological studies with PyEt, Hydrol. Earth Syst. Sci. Discuss. [preprint], https://doi.org/10.5194/hess-2022-417, 2023.