Tool Name	Evapotranspiration (Table)
Tool ID	6
Library ID	climate_tools
Version	1.0
Author(s)	O.Conrad (c) 2011

Description

Estimation of daily potential evapotranspiration from weather data with different methods. Besides mean daily temperature it depends on the chosen method which additional data has to be provided. In order to estimate extraterrestrial net radiation some of the methods need to know the location's geographic latitude and the date's Julian day number.

References

Allen, R.G., Pereira, L.S., Raes, D., Smith, M. (1998): Crop evapotranspiration - Guidelines for computing crop water requirements. FAO Irrigation and drainage paper 56. Link

Ambikadevi, K.M. (2004): Simulation of Evapotranspiration and Rainfall-runoff for the Stillwater River Watershed in Central Massachusetts. Environmental & Water Resources Engineering Masters Projects, University of Massachusetts, Amherst. Link

DVWK (1996): Ermittlung der Verdunstung von Land- u. Wasserflaechen. Merkblaetter 238/1996.

Hargreaves, G.H., Samani, Z.A. (1985): Reference crop evapotranspiration from ambient air temperatures. Paper presented in ASAE Regional Meeting, Grand Junction, Colorado. Link

Parameters

Name	Type	Identifier	Description	Constraints
Input
Data	table, input	TABLE
Output
Results	table, output, optional	RESULT
Options
Mean Temperature	table field	T	[°C]
Minimum Temperature	table field	T_MIN	[°C]
Maximum Temperature	table field	T_MAX	[°C]
Relative Humidity	table field	RH	[%]
Solar Radiation	table field	SR	daily sum of global horizontal irradiance [J/cm²]
Wind Speed	table field	WS	daily mean of wind speed at 2m above ground [m/s]
Air Pressure	table field	P	[kPa]
Date	table field	DATE
Evapotranspiration	table field	ET
Latitude	floating point number	LAT		Minimum: -90.000000 Maximum: 90.000000 Default: 53.000000
Method	choice	METHOD		Available Choices: [0] Turc [1] Hargreave [2] Penman (simplified) [3] Penman-Monteith Default: 0