WeatherData: Weather Data Object

In growR: Implementation of the Vegetation Model ModVege

Weather Data Object

Description

Data structure containing weather data for a given site for several years.

Details

All fields representing weather variables are vectors of length 365 times N, where N is the number of years for which weather data is stored. In other words, every variable has one value for each of the 365 of each of the N years.

Weather inputs

The weather input file should be organized as space separated columns with a year column and at least the following parameters as headers (further columns are ignored):

• DOY day of year in given year

• Ta average temperature of given day (Celsius).

• precip precipitation in millimeter per day.

• PAR photosynthetically active radiation in MJ/m^2^. Can be calculated from average sunlight irradiance SRad in J/s/m^2^ as: PAR = SRad * 0.47 * 24 * 60 * 60 / 1e6

• ET0 evapotranspiration in mm.

These parameters are stored in this object in the respective PARAM_vec fields.

Snow model

The precipitation and temperature inputs are used in order to estimate the snow cover for each day by use of a snow model. The employed model is as formulated by Kokkonen et al. 2006 and makes use of parameters from Rango and Martinec, 1995.

Public fields

weather_file

Name of provided weather data file.

years

numeric Integer representation of the contained years.

vec_size

Length of the PARAM_vec vectors, which is equal to number of contained years times 365.

year_vec

Vector of length vec_size, holding the year for the respective index.

W

A list generated by get_weather_for_year() which contains weather data only for a given year. The keys in the list are:

• aCO2 (atmospheric CO2 concentration in ppm)

• year

• DOY

• Ta

• Ta_sm (smoothed daily average temperature)

• PAR

• PP

• PET

• liquidP

• melt

• snow

• ndays (number of days in this year)

Methods

Public methods

• WeatherData$new()

• WeatherData$read_weather()

• WeatherData$ensure_file_integrity()

• WeatherData$calculate_day_length()

• WeatherData$get_weather_for_year()

• WeatherData$clone()

---

Method new()

Create a new WeatherData object.

Usage

WeatherData$new(weather_file = NULL, years = NULL)

Arguments

weather_file

string Path to file containing the weather data to be read.

years

numeric Vector of years for which the weather is to be extracted.

---

Method read_weather()

Read weather data from supplied weather_file.

Usage

WeatherData$read_weather(weather_file, years = NULL)

Arguments

weather_file

Path to or name of file containing weather data.

years

Years for which the weather is to be extracted. Default (NULL) is to read in all found years.

---

Method ensure_file_integrity()

Check if supplied input file is formatted correctly.

Check if required column names are present and fix NA entries.

Usage

WeatherData$ensure_file_integrity(weather)

Arguments

weather

data.table of the read input file with header = TRUE.

---

Method calculate_day_length()

Calculate the expected length of day based on a site's geographical latitude.

Usage

WeatherData$calculate_day_length(latitude)

Arguments

latitude

numeric; geographical latitude in degrees.

---

Method get_weather_for_year()

Extract state variables to the weather data for given year and return them as a list.

Usage

WeatherData$get_weather_for_year(year)

Arguments

year

integer Year for which to extract weather data.

Returns

W List containing the keys aCO2, year, DOY, Ta, Ta_sm, PAR, PP, PET, liquidP, melt, snow, ndays.

---

Method clone()

The objects of this class are cloneable with this method.

Usage

WeatherData$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

References

\insertRef

rango1995RevisitingDegreeDayMethodgrowR

\insertRef

kokkonen2006ConstructionDegreedaySnowgrowR

See Also

WeatherData⁠$read_weather()⁠

growR documentation built on May 29, 2024, 9:12 a.m.