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

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

References

Allen 2005 ASCE

Examples

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
Loading required package: sp
Loading required package: rgdal
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 2, 2019, 2:17 a.m.