In 2013 McMahon TA, Peel MC, Lowe L, Srikanthan R & McVicar TR published Estimating actual, potential, reference crop and pan evaporation using standard meteorological data: a pragmatic synthesis in Hydrology and Earth Systems Sciences. The paper and Supplementary Material can be downloaded free of charge from HESS.
In the supplementary material the the Morton models are described in section S7, section S20 is a listing of Fortran code to run Morton's WREVAP program and section S21 provides some worked examples from the WREVAP program.
On this website we provide:
A listing of corrections made to the Paper since publication,
A listing of corrections made to the Fortran code since publication,
An up-to-date version of the Morton Fortran code to download
Corrected version of the published Morton Fortran code and executable
This version uses constant values of fZ = 29.2, b1 = 13.4 and b2 = 1.13 that were re-calibrated to achieve a Priestley-Taylor coefficient of 1.26, rather the original values used by Morton that gave a Priestley-Taylor coefficient of 1.32
More recent corrected version of the Morton Fortran code and executable that allows either set of constants to be used
Run the code and input ETpaper.par to use constant values fZ = 29.2, b1 = 13.4 and b2 = 1.13 that were re-calibrated to achieve a Priestley-Taylor coefficient of 1.26 (not original Morton)
Run the code and input ETpaper2.par to use constant values fZ = 28.0, b1 = 14.0 and b2 = 1.2 that achieve a Priestley-Taylor coefficient of 1.32 (original Morton)
See this report for details about the two sets of constant values
We recommend downloading the files from the links above by saving the content of the link to your system (eg: right-click and select Save Link As).
To use the .exe file, follow the readme instructions for formatting input files to run the program. Example input files are ETpaper.par, melbourne.dat, thomsonReservoir.dat and thomsonReservoirVD.dat.
The complete reference to cite when using this code is :
McMahon TA, Peel MC, Lowe L, Srikanthan R & McVicar TR (2013) Estimating actual, potential, reference crop and pan evaporation using standard meteorological data: a pragmatic synthesis. Hydrology and Earth System Sciences, 17, 1331–1363.
| Date | Error | Solution | Thanks |
|---|---|---|---|
| 4/2014 | Throughout the paper the author Stricker was misspelt as Strickler | ||
| 4/2018 | Equation 6: EPT=αPT[Δ/(Δ+γ)Rn/λ-G/λ] | Should be EPT=αPTΔ/(Δ+γ)[Rn/λ-G/λ] | Wouter Knoben |
| 4/2018 | In equation 14, va* | Should be vw* | |
| 4/2018 | Supplementary Material Page 47, 2nd line after heading Granger-Gray model | Delete “following Granger (1998)” | |
| 4/2018 | Supplementary Material Page 85, Equation S19.109 | Requires correction following Equation 6. This also applies to the equation used in the calculation of EPT although the estimate of EPT does not change because G is assumed to be 0. | |
| 4/2018 | Supplementary Material Page 139, reference to Winter, T.C. and Rosenberry, D.O. | Should read ‘Winter, T.C., Rosenberry, D.O. and Sturrock, A.M.’ | |
| 8/2019 | Supplementary Material Page 31, Equation S5.1 | Missing 86400 should be applied to the second term in the numerator to convert the value from mm/s to mm/day. '+86400ρaca' | Shaochun Huang |
Yes! Please use the code and cite "McMahon et al (2013)" and the reference above. If you adapt or modify the code, cite "Adpated from McMahon et al (2013)" and the reference above.
Hydrology and Earth Systems Sciences is published under a Creative Commons Attribution 3.0 Unported License. This means you are free to use and adapt the code so long as you abide by the terms of the License (acknowledge the original source).
| Date | Error/Problem | Solution | Thanks |
|---|---|---|---|
| 10/07/2013 | Input data length: the variable nmx was set to 360, which meant only 29 years of input data could be run | nmx is now set to 1212 to allow 100 years of input data | Alice Drummond |
| 18/07/2013 | Subroutine deepLakeVD: slightly different values for the same data with different record lengths | The parameter k should have been an array as it depends on the lake depth. The array ka with dimension nmx has replaced k in the subroutine deepLakeVD | Alice Drummond |
| 18/11/2014 | Definition of Pi: was 3.14159254, which is incorrect | Pi is now set to 3.141592654 | Andrew Reeve |
| 16/07/2015 | Typo in code: line 489, should have been “rh” instead of “td” | corrected | Nelson (Ning) Ma & Jarrah Muller |
| 30/07/2021 | The published code uses constant values that gives a Priestley-Taylor coefficient of 1.26, rather than 1.32 as originally used by Morton | Updated version of the code and executable to allow either set of constant values for Priestley-Taylor coefficient | Ted Lewis for pointing this out & Rory Nathan for the updated code and executable |
Danlu Guo (danlu.guo@adelaide.edu.au) & Seth Westra created and maintain an R package Evapotranspiration that includes an R implementation of Morton's WREVAP program among many other methods.