Package: pyet
pyet: Estimation of Potential Evapotranspirationpyet is an open source python package for calculating reference and potential Evapotranspiration (PET) for 1D (pandas.Series)
and 3D (xarray.DataArrray) data. Currently, eighteen methods for calculating daily PET are implemented:Method namepyet functionTRHRu2Lat.El.Benchmarked?Penmanpenman✓ $^a$✓ $^{b,c}$✓ $^d$✓✓ $^d$✓ $^e$✓Penman-Monteithpm✓ $^a$✓ $^{b,c}$✓ $^d$✓✓ $^d$✓ $^e$✓ASCE-PMpm_asce✓ $^a$✓ $^{b,c}$✓ $^d$✓✓ $^d$✓ $^e$✓FAO-56pm_fao56✓ $^a$✓ $^{b,c}$✓ $^d$✓✓ $^d$✓ $^e$✓Priestley-Taylorpriestley_taylor✓✓ $^h$✓ $^h$-✓ $^h$✓ $^e$✓Kimberly-Penmankimberly_penman✓ $^a$✓ $^{b,c}$✓ $^d$✓✓ $^d$✓ $^e$-Thom-Oliverthom_oliver✓ $^a$✓ $^{b,c}$✓ $^d$✓✓ $^d$✓ $^e$-Blaney-Criddleblaney_criddle✓- $^i$- $^i$- $^i$✓-✓Hamonhamon✓---✓-✓Romanenkoromanenko✓✓----✓Linacrelinacre✓ $^j$----✓✓Haudehaude✓✓ $^k$----✓Turcturc✓✓✓---✓Jensen-Haisejensen_haise✓-✓ $^l$-✓ $^l$-✓McGuinness-Bordnemcguinness_bordne✓---✓-✓Hargreaveshargreaves✓ $^m$---✓-✓FAO-24 radiationfao_24✓✓✓✓-✓ $^e$-Abtewabtew✓-✓---✓Makkinkmakkink✓-✓--✓ $^e$✓Oudinoudin✓---✓--$^a$ $T_{max}$ and $T_{min}$ can also be provided. $^b$ $RH_{max}$ and $RH_{min}$ can also be provided. $^c$ If actual vapor pressure is provided, RH is not needed.  $^d$ 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) latitude and elevation is needed. $^e$ One must provide either the atmospheric pressure or elevation. $^f$ The PM method can be used to estimate potential crop evapotranspiration, if leaf area index or crop height data is available. $^g$ The effect of $CO_2$ on stomatal resistance can be included using the formulation of Yang et al. 2019.  $^h$ If net radiation is provided, RH and Lat are not needed. $^i$ If method==2, $u_2$, $RH_{min}$ and sunshine hours are required. $^j$ Additional input of $T_{max}$ and $T_{min}$, or $T_{dew}$. $^k$ Input can be $RH$ or actual vapor pressure. $^l$ If method==1, latitude is needed instead of $R_s$. $^m$ $T_{max}$ and $T_{min}$ also needed.Examples and DocumentationExamples of usingpyetcan be found in the example folder:Example 1: Estimating PET using pandas.SeriesExample 2: Estimating PET using xarray.DataArrayExample 3: Benchmarking Makkink
againstKNMI dataExample 4: Benchmarking FAO56
againstCoAgMET dataExample 5: Calibrating the Romanenko and Abtew method against the PM-FAO56Example 6: Worked examples for estimating meteorological
variables and potential evapotranspiration after McMahon et al., 2013Example 7: Example for estimating potential evapotranspiration under
warming and elevated $CO_2$ concentrations following Yang et al., (2019)Example 8: Determining the crop coefficient function with PythonDocumentation is hosted onReadTheDocs.After defining the input data, evapotranspiration is estimated using only one
line of python code:>>> pyet.pm_fao56(tmean, wind, rn=rn, tmax=tmax, tmin=tmin, rh=rh, elevation=elevation)We support Python >= 3.8.BenchmarkingMost of the methods implemented inpyetare benchmarked against literature values from theFAO Irrigation and
drainage paper 56,McMahon et al., 2013 (supplementary)andSchrödter, 1985. In addition, two comparative analysis between daily PE estimated withpyetand other organizations is
made:pyet.pm_fao56against daily PET estimated with ASCE Penman-Monteith fromCoAgMET(
Colorado State University),pyet.makkinkagainst daily PET estimated with Makkink from The Royal Netherlands Meteorological
Institute (KNMI).DimensionsAs of version v1.2.,pyetis compatible with both Pandas.Series and xarray.DataArray, which means you can now estimate
potential evapotranspiration for both point and gridded data.Bug reports and Questionspyet is in active development, and bug reports are welcome asGitHub
Issues.
General questions or discussions are possible throughGitHub Discussions.InstallationThepyetpackage is available from the Pypi package index and can be installed
as follows::>>> pip install pyetTo install in developer mode, use the following syntax:>>> pip install -e .CitingIf you usepyetin one of your studies, please cite thepyetEGU abstract:Vremec, M. and Collenteur, R.:pyet- a Python package to estimate potential and reference evapotranspiration, EGU
General Assembly 2021, online, 19–30 Apr 2021, EGU21-15008,https://doi.org/10.5194/egusphere-egu21-15008, 2021.@inproceedings{vremec2021pyet,
  title={PyEt-a Python package to estimate potential and reference evapotranspiration},
  author={Vremec, Matev{\v{z}} and Collenteur, Raoul},
  booktitle={EGU General Assembly Conference Abstracts},
  pages={EGU21--15008},
  year={2021},
  doi={https://doi.org/10.5194/egusphere-egu21-15008}
}