# hourlyET: Calculates ET using Penman Monteith hourly formula In water: Actual Evapotranspiration with Energy Balance Models

## Description

Calculates ET using Penman Monteith hourly formula

## Usage

 ```1 2``` ```hourlyET(WeatherStation, hours, DOY, long.z = WeatherStation\$long, ET.instantaneous = FALSE, ET = "ETr", height = 2, lat, long, elev) ```

## Arguments

 `WeatherStation` a data frame with all the needed fields (see example) `hours` time of the day in hours in 24hs format `DOY` day of year `long.z` longitude for local time `ET.instantaneous` Logical. True if you want to calculate instantaneous ET instead of hourly ET. See Details. `ET` "ETo" for short crops, similar to clipped, cool-season grass; or "ETr" for tall crops, similar to 0.5 m tall full-cover alfalfa. `height` weather station sensors height in meters `lat` latitude of weather station in decimal degrees. Negative values for south latitude `long` longitude of weather station in decimal degrees. Negative values for west longitude `elev` elevation of weather station in meters

## Details

The only difference on instantaneous ET is how the hour is interpreted. On FALSE, and for example at 11:00, ET is calculated between 10:00 and 11:00, on TRUE Et is calculated at 11:00 hs.

## Value

ET hourly in mm.h-1

## Author(s)

Guillermo Federico Olmedo

Allen 2005 ASCE

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```WeatherStation <- data.frame(wind=4.72, RH=59, temp=24.3, radiation=675, height=2.2, lat=-35.37, long=71.5946, elev=124) hourlyET(WeatherStation, hours=10.5, DOY=363, long.z=71.635) ```

### Example output

```Loading required package: raster
rgdal: version: 1.2-10, (SVN revision 673)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 1.10.1, released 2013/08/26
Path to GDAL shared files: /usr/share/gdal/1.10
Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
Path to PROJ.4 shared files: (autodetected)
WARNING: no proj_defs.dat in PROJ.4 shared files
Linking to sp version: 1.2-3
[1] 0.6372407
```

water documentation built on May 29, 2017, 5:55 p.m.