Tool Evapotranspiration (Grid)
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.
- Hargreaves, G.H., Samani, Z.A. (1985): Reference crop evapotranspiration from ambient air temperatures.. Paper presented in ASAE Regional Meeting, Grand Junction, Colorado. Link.
- Author: O.Conrad (c) 2015
- Menu: Climate and Weather|Evapotranspiration
Parameters
Name | Type | Identifier | Description | Constraints | |
---|---|---|---|---|---|
Input | Mean Temperature (*) | Grid, input, optional | T | [Celsius] | - |
Minimum Temperature (*) | Grid, input, optional | T_MIN | [Celsius] | - | |
Maximum Temperature (*) | Grid, input, optional | T_MAX | [Celsius] | - | |
Relative Humidity (*) | Grid, input, optional | RH | [Percent] | - | |
Solar Radiation (*) | Grid, input, optional | SR | [J/cm^2] | - | |
Wind Speed (*) | Grid, input, optional | WS | [m/s] | - | |
Air Pressure (*) | Grid, input, optional | P | [kPa] | - | |
Output | Potential Evapotranspiration | Grid, output | ET | - | - |
Options | Grid System | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
Default | Floating point | T_DEFAULT | default value if no grid has been selected | Minimum: -273.150000 Default: 10.000000 | |
Default | Floating point | T_MIN_DEFAULT | default value if no grid has been selected | Minimum: -273.150000 Default: 0.000000 | |
Default | Floating point | T_MAX_DEFAULT | default value if no grid has been selected | Minimum: -273.150000 Default: 20.000000 | |
Default | Floating point | RH_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Maximum: 100.000000 Default: 50.000000 | |
Default | Floating point | SR_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 2.000000 | |
Default | Floating point | WS_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 5.000000 | |
Default | Floating point | P_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 101.300000 | |
Method | Choice | METHOD | - | Available Choices: [0] Turc [1] Hargreave [2] Penman (simplified) [3] Penman-Monteith Default: 0 | |
Estimate Solar Radiation | Boolean | SR_EST | Estimate solar radiation from date, latitudinal position and sunshine duration as percentage of its potential maximum. | Default: 0 | |
Sunshine Duration | Floating point | SUNSHINE | Daily sunshine duration as percentage of its potential maximum. | Minimum: 0.000000 Maximum: 100.000000 Default: 50.000000 | |
Time | Choice | TIME | - | Available Choices: [0] day [1] month Default: 0 | |
Month | Choice | MONTH | - | Available Choices: [0] January [1] February [2] March [3] April [4] May [5] June [6] July [7] August [8] September [9] October [10] November [11] December Default: 2 | |
Day of Month | Integer | DAY | - | Minimum: 1 Maximum: 31 Default: 30 | |
Latitude | Floating point | LAT | [Degree] | Minimum: -90.000000 Maximum: 90.000000 Default: 53.000000 | |
(*) optional |
Command-line
Usage: saga_cmd climate_tools 8 [-T <str>] [-T_DEFAULT <double>] [-T_MIN <str>] [-T_MIN_DEFAULT <double>] [-T_MAX <str>] [-T_MAX_DEFAULT <double>] [-RH <str>] [-RH_DEFAULT <double>] [-SR <str>] [-SR_DEFAULT <double>] [-WS <str>] [-WS_DEFAULT <double>] [-P <str>] [-P_DEFAULT <double>] [-ET <str>] [-METHOD <str>] [-SR_EST <str>] [-SUNSHINE <double>] [-TIME <str>] [-MONTH <str>] [-DAY <num>] [-LAT <double>] -T:<str> Mean Temperature Grid, input, optional -T_DEFAULT:<double> Default Floating point Minimum: -273.150000 Default: 10.000000 -T_MIN:<str> Minimum Temperature Grid, input, optional -T_MIN_DEFAULT:<double> Default Floating point Minimum: -273.150000 Default: 0.000000 -T_MAX:<str> Maximum Temperature Grid, input, optional -T_MAX_DEFAULT:<double> Default Floating point Minimum: -273.150000 Default: 20.000000 -RH:<str> Relative Humidity Grid, input, optional -RH_DEFAULT:<double> Default Floating point Minimum: 0.000000 Maximum: 100.000000 Default: 50.000000 -SR:<str> Solar Radiation Grid, input, optional -SR_DEFAULT:<double> Default Floating point Minimum: 0.000000 Default: 2.000000 -WS:<str> Wind Speed Grid, input, optional -WS_DEFAULT:<double> Default Floating point Minimum: 0.000000 Default: 5.000000 -P:<str> Air Pressure Grid, input, optional -P_DEFAULT:<double> Default Floating point Minimum: 0.000000 Default: 101.300000 -ET:<str> Potential Evapotranspiration Grid, output -METHOD:<str> Method Choice Available Choices: [0] Turc [1] Hargreave [2] Penman (simplified) [3] Penman-Monteith Default: 0 -SR_EST:<str> Estimate Solar Radiation Boolean Default: 0 -SUNSHINE:<double> Sunshine Duration Floating point Minimum: 0.000000 Maximum: 100.000000 Default: 50.000000 -TIME:<str> Time Choice Available Choices: [0] day [1] month Default: 0 -MONTH:<str> Month Choice Available Choices: [0] January [1] February [2] March [3] April [4] May [5] June [6] July [7] August [8] September [9] October [10] November [11] December Default: 2 -DAY:<num> Day of Month Integer Minimum: 1 Maximum: 31 Default: 30 -LAT:<double> Latitude Floating point Minimum: -90.000000 Maximum: 90.000000 Default: 53.000000