ETo Calculation - Revision history

Agrineer at 18:01, 4 May 2026

2026-05-04T18:01:00Z

← Older revision		Revision as of 11:01, 4 May 2026
Line 42:		Line 42:
	\|-		\|-
	\|<math>\Delta</math>		\|<math>\Delta</math>
	\|saturation slope vapour pressure curve at <math>T_{hr}~[kPa~°C^{-1}]</math> (Equation 13),		\|saturation slope vapour pressure curve at <math>T_{hr}~[kPa~^{o}C^{-1}]</math> (Equation 13),
	\|-		\|-
	\|<math>\gamma</math>		\|<math>\gamma</math>
	\|psychrometric constant <math>[kPa~°C^{-1}] </math>(Equation 8),		\|psychrometric constant <math>[kPa~^{o}C^{-1}] </math>(Equation 8),
	\|-		\|-
	\|<math>e^o(T_{hr})</math>		\|<math>e^o(T_{hr})</math>

Agrineer at 18:00, 4 May 2026

2026-05-04T18:00:01Z

← Older revision		Revision as of 11:00, 4 May 2026
Line 39:		Line 39:
	\|-		\|-
	\|<math>T_{hr}</math>		\|<math>T_{hr}</math>
	\|mean hourly air temperature at 2 meter height <math>[°C]</math>,		\|mean hourly air temperature at 2 meter height <math>[^{o}C]</math>,
	\|-		\|-
	\|<math>\Delta</math>		\|<math>\Delta</math>

Agrineer: Agrineer moved page WRF ETo Calculation to ETo Calculation without leaving a redirect

2019-01-16T18:13:31Z

Agrineer moved page WRF ETo Calculation to ETo Calculation without leaving a redirect

← Older revision	Revision as of 11:13, 16 January 2019
(No difference)

Agrineer at 02:22, 11 December 2018

2018-12-11T02:22:08Z

← Older revision		Revision as of 19:22, 10 December 2018
Line 15:		Line 15:
	- eto.py - Calculates standard evapotranspiration (ETo) using Weather, Research, and Forecasting (WRF) model data as input, accumulated hourly per day.		- eto.py - Calculates standard evapotranspiration (ETo) using Weather, Research, and Forecasting (WRF) model data as input, accumulated hourly per day.

	- merge.py - Selectively reads WRF meta and data variables (lat, long, min/max temp, rain) used for ETo calculation in "eto.py" class, then merges these variables with the output ETo data, to be used as input to the SME package.		- merge.py - Selectively reads WRF meta and data variables (lat, long, min/max temp, rain) used for ETo calculation in "eto.py" class, then merges these variables with the output ETo data, to be used as input for the SME package.

	Data generated daily by Agrineer.org are produced by "merge.py" and serve as input for the SME application. Zipped versions of the daily runs can be found here [https://www.agrineer.org/downloads/sectors.php here].		Data generated daily by Agrineer.org are produced by "merge.py" and serve as input for the SME application. Zipped versions of the daily runs can be found here [https://www.agrineer.org/downloads/sectors.php here].

Agrineer at 02:17, 11 December 2018

2018-12-11T02:17:55Z

← Older revision		Revision as of 19:17, 10 December 2018
Line 39:		Line 39:
	\|-		\|-
	\|<math>T_{hr}</math>		\|<math>T_{hr}</math>
	\|mean hourly air temperature <math>[°C]</math>,		\|mean hourly air temperature at 2 meter height <math>[°C]</math>,
	\|-		\|-
	\|<math>\Delta</math>		\|<math>\Delta</math>
Line 54:		Line 54:
	\|-		\|-
	\|<math>u_2</math>		\|<math>u_2</math>
	\|average hourly wind speed <math>[m~s^{-1}]</math>.		\|average hourly wind speed at 2 meter height <math>[m~s^{-1}]</math>.
	\|}		\|}

Agrineer at 01:54, 11 December 2018

2018-12-11T01:54:31Z

← Older revision		Revision as of 18:54, 10 December 2018
Line 21:		Line 21:
	These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).		These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).

	~~<math>\alpha</math>~~		The FAO Penman-Monteith equation for hourly time steps is given below. Equation numbers refer to [http://www.fao.org/docrep/X0490E/x0490e08.htm FAO paper #56, Chapter 4]:
	The FAO Penman-Monteith equation for hourly time steps is:

	<math> ~~ETo~~ = ~~a/b~~ </math>		<math>ET_o=\frac{0.408\Delta(R_n-G)+\gamma\frac{37}{T_{hr}+273}u_2(e^o(T_{hr})-e_a)}{\Delta+\gamma(1+0.34u_2)}</math> (Equation 53)

	~~(53)~~		where:

	~~where~~		{\|
			\|-
	~~ETo~~ reference evapotranspiration [mm hour-1],		\|<math>ET_o</math>
	Rn net radiation at the grass surface [MJ m-2 hour-1] (Equation 40),		\|reference evapotranspiration <math>[mm~hour^{-1}]</math>,
	G soil heat flux density [MJ m-2 hour-1] (Equations 45 and 46),		\|-
	~~Thr~~ mean hourly air temperature [°C],		\|<math>R_n</math>
	D saturation slope vapour pressure curve at ~~Thr~~ [kPa °C-1] (Equation 13),		\|net radiation at the grass surface <math>[MJ~m^{-2}~hour^{-1}]</math> (Equation 40),
	g psychrometric constant [kPa °C-1] (Equation 8),		\|-
	e°(~~Thr~~) saturation vapour pressure at air temperature ~~Thr~~ [kPa] (Equation 11),		\|<math>G</math>
	ea average hourly actual vapour pressure [kPa] (Equation 54),		\|soil heat flux density <math>[MJ~m^{-2}~hour^{-1}] </math>(Equations 45 and 46),
	u2 average hourly wind speed [m s-1].		\|-
			\|<math>T_{hr}</math>
			\|mean hourly air temperature <math>[°C]</math>,
			\|-
			\|<math>\Delta</math>
			\|saturation slope vapour pressure curve at <math>T_{hr}~[kPa~°C^{-1}]</math> (Equation 13),
			\|-
			\|<math>\gamma</math>
			\|psychrometric constant <math>[kPa~°C^{-1}] </math>(Equation 8),
			\|-
			\|<math>e^o(T_{hr})</math>
			\|saturation vapour pressure at air temperature <math>T_{hr}~[kPa] </math> (Equation 11),
			\|-
			\|<math>e_a</math>
			\|average hourly actual vapour pressure <math>[kPa]</math> (Equation 54),
			\|-
			\|<math>u_2</math>
			\|average hourly wind speed <math>[m~s^{-1}]</math>.
			\|}

Agrineer at 23:18, 10 December 2018

2018-12-10T23:18:53Z

← Older revision		Revision as of 16:18, 10 December 2018
Line 20:		Line 20:

	These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).		These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).

			<math>\alpha</math>
			The FAO Penman-Monteith equation for hourly time steps is:

			<math> ETo = a/b </math>

			(53)

			where

			ETo reference evapotranspiration [mm hour-1],
			Rn net radiation at the grass surface [MJ m-2 hour-1] (Equation 40),
			G soil heat flux density [MJ m-2 hour-1] (Equations 45 and 46),
			Thr mean hourly air temperature [°C],
			D saturation slope vapour pressure curve at Thr [kPa °C-1] (Equation 13),
			g psychrometric constant [kPa °C-1] (Equation 8),
			e°(Thr) saturation vapour pressure at air temperature Thr [kPa] (Equation 11),
			ea average hourly actual vapour pressure [kPa] (Equation 54),
			u2 average hourly wind speed [m s-1].

Agrineer at 21:04, 23 September 2018

2018-09-23T21:04:18Z

← Older revision		Revision as of 14:04, 23 September 2018
Line 17:		Line 17:
	- merge.py - Selectively reads WRF meta and data variables (lat, long, min/max temp, rain) used for ETo calculation in "eto.py" class, then merges these variables with the output ETo data, to be used as input to the SME package.		- merge.py - Selectively reads WRF meta and data variables (lat, long, min/max temp, rain) used for ETo calculation in "eto.py" class, then merges these variables with the output ETo data, to be used as input to the SME package.

	Data produced by "merge.py" ~~are archived~~ as input for the SME application [https://www.agrineer.org/downloads/sectors.php here].		Data generated daily by Agrineer.org are produced by "merge.py" and serve as input for the SME application. Zipped versions of the daily runs can be found here [https://www.agrineer.org/downloads/sectors.php here].

	These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).		These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).

Agrineer at 18:02, 23 September 2018

2018-09-23T18:02:43Z

← Older revision		Revision as of 11:02, 23 September 2018
Line 1:		Line 1:

	This package calculates standard evapotranspiration data, ETo, and merges it into a netCDF file along with WRF precipitation, and temperature data.		This package calculates standard evapotranspiration data, ETo, for a given sector and merges it into a netCDF file along with WRF precipitation, and temperature data. Refer to [[WRF Hindcast]] for more information on sectors.

	The merged file is used as input data for the [[Soil Moisture Estimator]] (SME) application.		The merged file is used as input data for the [[Soil Moisture Estimator]] (SME) application.

	A GUI implementation of the SME is on the Agrineer.org [https://agrineer.org/sme/sme.php website]		A GUI implementation of the SME is on the Agrineer.org [https://agrineer.org/sme/sme.php website]
	and currently covers about half of the western United States, with a ~3km pixel resolution.		and currently covers about half of the western United States, with a ~3km pixel resolution.
			You can go [https://gitlab.com/agrineer/sme here] to download a command-line version of the SME software.

	This package was developed using GNU/Linux Mint 17, but other		This package was developed using GNU/Linux Mint 17, but other
Line 19:		Line 20:

	These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).		These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).

	~~You can go [https://gitlab.com/agrineer/eto here] to download the software.~~

Agrineer at 17:51, 23 September 2018

2018-09-23T17:51:37Z

@@ Line 2: / Line 2: @@
 This package calculates standard evapotranspiration data, ETo, and merges it into a netCDF file along with WRF precipitation, and temperature data.
-The merged file is used as input data for the
+The merged file is used as input data for the [[Soil Moisture Estimator]] (SME) application.
 A GUI implementation of the SME is on the Agrineer.org [https://agrineer.org/sme/sme.php website]
-and covers about half of the western United States, with a ~3km pixel resolution.
+and currently covers about half of the western United States, with a ~3km pixel resolution.
 This package was developed using GNU/Linux Mint 17, but other
@@ Line 19: / Line 16: @@
 - merge.py - Selectively reads WRF meta and data variables (lat, long, min/max temp, rain) used for ETo calculation in "eto.py" class, then merges these variables with the output ETo data, to be used as input to the SME package.
-Data produced by "merge.py" are archived as input for the SME application [here](https://www.agrineer.org/downloads/sectors.php).
+Data produced by "merge.py" are archived as input for the SME application [https://www.agrineer.org/downloads/sectors.php here].
 These programs are provided for review purposes on the data flow. They show how the ETo is calculated and merged with other data. They are made available in case you want to modify and run your own WRF/Eto runs. You can find WRF input namelist files for each sector used [here](https://www.agrineer.org/downloads/sectors.php).
+You can go [https://gitlab.com/agrineer/eto here] to download the software.