Package 'meteor'

The meteor package

Description

This pacakges contains of a number of meteorological data manipulation functions. Some of these are also available in other R packages. The context of this package is to make the functions available from dynamic simulation models of crops and crop diseases.

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Estimate hourly values from daily values

Description

Estimate hourly temperature from daily minimum and maximum temperature, or hourly relative humidity from average relative humidity and minimum and maximum temperature.

The functions require the day of the year and latitude to compute the photoperiod.

Usage

hourlyFromDailyTemp(tmin, tmax, doy, latitude)
hourlyFromDailyRelh(relh, tmin, tmax, doy, latitude)

Arguments

tmin	numeric. minimum temperature (must be in C for hourlyFromDailyRelh)
tmax	numeric. maximum temperature (must be in C for hourlyFromDailyRelh)
relh	relative humidity (percent)
doy	integer. Day of the year (between 1 and 365)
latitude	numeric. Latitude

Value

matrix

Examples

hourlyFromDailyTemp(c(20,22), c(28,34), c(150,151), 52)
hourlyFromDailyRelh(80, c(20,22), c(28,34), c(150,151), 52)

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date manipulation

Description

Helper functions for manipulation of dates, includding conversion between (day of year) (DOY) to date and back, and extraction of parts of a date.

Usage

dateFromDoy(doy, year)
doyFromDate(date)
dayFromDate(date)
monthFromDate(date)
yearFromDate(date)
isLeapYear(year)
daysInYear(year)

Arguments

doy	integer. Day of the year (1..365) or (1..366) for leap years
year	integer. Year, e.g. 1982
date	Date object or character formatted 'yyyy-mm-dd', e.g. '1982-11-23'

Value

integer or Date

Examples

doy <- 88
year <- 1970
date <- dateFromDoy(doy, year)
date
dateFromDoy(-15, 2000)
doyFromDate(date)
isLeapYear(2000)
daysInYear(2000)
daysInYear(1999)

---

Estimate the temperature during the day

Description

Estimate the mean temperature during the day (between sunrise and sunset) from daily minimum and maximum temperature.

The function requires the day of the year and latitude to compute the photoperiod.

Usage

dayTemp(tmin, tmax, doy, latitude)

Arguments

tmin	numeric. minimum temperature (any unit)
tmax	numeric. maximum temperature (any unit)
doy	integer. Day of the year (between 1 and 365)
latitude	numeric. Latitude

Value

numeric

Examples

dayTemp(c(20,22), c(28,34), c(150,151), 52)

---

Reference evapo-transpiration

Description

Functions to compute the reference evapotranspiration (ET0) from meteorological data. ET0 is a representation of the atmospheric water demand. The equations estimate the evapotranspiration rate of a short green crop (grass), completely shading the ground, of uniform height and with adequate water status in the soil profile. Actual evapotranspiration is equal reference evapotranspiration when there is ample water, but taller crops could have an evapotranspiration rate that is higher than ET0.

Usage

ET0_PenmanMonteith(temp, relh, atmp, Rn, G, ra, rs)
ET0_PriestleyTaylor(temp, relh, atmp, Rn, G)
ET0_Makkink(temp, relh, atmp, Rs)
ET0_ThornthwaiteWilmott(temp, doy, latitude)
ET0_ThornthwaiteWilmottCamargo(tmin, tmax, doy, latitude, Pereira=FALSE)

Arguments

temp	temperature (degrees C)
relh	relative humidity (percent)
atmp	air pressure (hPa
Rn	net radiation (J m-2 day-1)
Rs	incoming solar radiation (J m-2 day-1)
G	soil heat flux (J m-2 day-1)
ra	aerodynamic resistance (s m-1)
rs	surface resistance (s m-1)
doy	integer. Day of the year (between 1–365)
latitude	numeric. Latitude
tmin	numeric. minimum temperature (C)
tmax	numeric. maximum temperature (C)
Pereira	logical. If TRUE, the Pereira adjustment for photoperiod is used

Value

vector with evaporation values (mm)

Author(s)

Robert Hijmans, partly based on Python evapolib by Maarten J. Waterloo http://python.hydrology-amsterdam.nl/

References

Allen, R.G., L.S. Pereira, D. Raes and M. Smith, 1998. Crop evapotranspiration. Guidelines for computing crop water requirements. FAO Irrigation and drainage paper 56. FAO - Food and Agriculture Organization of the United Nations, Rome, 1998. (http://www.fao.org/docrep/x0490e/x0490e07.htm)

Thornthwaite, C.W., 1948. An approach toward a rational classification of climate. Geogr. Rev. 38:55-94.

Willmott, C.J., Rowe, C.M. and Mintz, Y., 1985. Climatology of the terrestrial seasonal water cycle. J. Climatol. 5:589-606.

Camargo, A.P., Marin, F.R., Sentelhas, P.C. and Picini, A.G., 1999. Adjust of the Thornthwaite's method to estimate the potential evapotranspiration for arid and superhumid climates, based on daily temperature amplitude. Rev. Bras. Agrometeorol. 7(2):251-257

Pereira, A.R. and W.O. Pruitt, 2004. Adaptation of the Thornthwaite scheme for estimating daily reference evapotranspiration. Agricultural Water Management 66: 251-257

Examples

ET0_PenmanMonteith(21.67, 67, 1013, 14100000, 500000, 104, 70)
ET0_PriestleyTaylor(21.65, 67, 1013, 18200000, 600000)
ET0_Makkink(21.65, 67, 1013, 24200000)

---

Extra-terrestrial Radiation

Description

Compute incoming radiation (J day-1 m-2 ) at the top of the atmosphere and photoperiod (daylength, sunshine duration).

Usage

ExtraTerrestrialRadiation(doy, latitude, sc=1367.7, FAO=FALSE)

Arguments

doy	integer. Day of the year
latitude	numeric. Latitude
sc	numeric. The solar constant
FAO	logical. If TRUE the algorithm described by Allen et al (1998) is used. If FALSE the approach by Goudriaan and Van Laar (1995) is used

Value

matrix with incoming radiation (J/day) and

Author(s)

Robert Hijmans, based on Python meteolib by Maarten J. Waterloo and J. Delsman http://python.hydrology-amsterdam.nl/

References

Goudriaan and Van Laar, 1995.

R.G. Allen, L.S. Pereira, D. Raes and M. Smith (1998). Crop Evaporation - Guidelines for computing crop water requirements. Irrigation and drainage paper 56. FAO, Rome, Italy. https://www.fao.org/3/x0490e/x0490e07.htm

Examples

ExtraTerrestrialRadiation(50, 60)
ExtraTerrestrialRadiation(50, 60, FAO=TRUE)

---

Date manipulation

Description

Helper functions for extracting information from dates. Or to create a Date from a day number.

Usage

fromDate(x, v)
fromYear(y, v)
fromDoy(doy, y)

Arguments

x	Date or POSIX
y	integer (year)
v	character. Output variable. With fromDate it can be one of: "year", "month", "week", "day", "doy". With fromYear it can be one of "leap", "ndays", "days"
doy	integer (day of the year)

Value

integer or Date

Examples

d <- as.Date("1999-12-30") + 1:2
d
fromDate(d, "month")
fromDate(d, "doy")

fromDoy(10, 2000)

---

Read FSE formatted weather data

Description

Read or write FSE formatted weather data

Usage

readFSEwth(f)
writeFSEwth(w, country='AAA', station=1, lon=0, lat=0, elev=0,  path=".")

example_weather()

Arguments

f	character. filename
w	data.frame with daily weather data. Must include the following variables: "date", "srad", "tmin", "tmax", "wind", "prec", "vapr". The data must be sorted by date in ascending order. "date" must be a Date, the other variables must be numeric
country	character code for a country (up to three letters)
station	positive integer. Station number for the country
lon	numeric. Longitude of the weather station (not used by the models)
lat	numeric. Latitude of the weather station
elev	numeric. Elevation of the weather station
path	character. Folder where you want to write the files. It must exist

Value

readFSEwth: data.frame

writeFSEwth: character (invisibly) with the filenames

---

Generic functions

Description

These are generic functions that are declared in this package but have no implementation here.

---

Globe temperature

Description

Globe temperatures (Tg, Tnwb, WBGT).

The can be computed for either a data.frame or a SpatRasterDataset. These must have variables "temp" (C), "rhum" (%), "wind" (m s-1), and "srad" (J s-1 m-2). The data.frame must also have a variable "date".

Usage

## S4 method for signature 'data.frame'
Tg(x, latitude)
## S4 method for signature 'SpatRasterDataset'
Tg(x, filename="", overwrite=FALSE, ...)

## S4 method for signature 'data.frame'
Tnwb(x, latitude, kelvin=FALSE)
## S4 method for signature 'SpatRasterDataset'
Tnwb(x, kelvin=FALSE, filename="", overwrite=FALSE, ...)

## S4 method for signature 'data.frame'
WBGT(x, latitude, kelvin=FALSE)
## S4 method for signature 'SpatRasterDataset'
WBGT(x, kelvin=FALSE, mask=NULL, filename="", overwrite=FALSE, ...)

Arguments

x	data.frame or SpatRasterDataset
latitude	numeric
filename	character. Output filename
overwrite	logical. If TRUE, filename is overwritten
...	additional arguments for writing files as in writeRaster
kelvin	logical. Set to TRUE of the units of temperature are in Kelvin
mask	NULL of SpatRaster. if a SpatRaster is used, it should have one layer. No computations are done for cells that are NA, and these are set to NA in the output

Value

numeric or SpatRaster

Examples

wd <- data.frame(date=as.Date("2003-08-28") + 1:3, 
		temp=c(19.1, 20.6, 19.4), 
		rhum=c(66,71,73), 
		wind=c(3.3, 1.9, 1.1), 
		srad=c(168, 178, 125))
Tg(wd, 40.96) 

Tnwb(wd, 40.96) 

WBGT(wd, 40.96) 


library(terra)
r <- rast(ncol=2, nrow=2, nlyr=1)
temp <- setValues(r, 21:24)
time(temp) <- as.Date("2000-01-01")
rhum <- setValues(r, 81:84)
wind <- setValues(r, 9:12)
srad <- setValues(r, 100:103)
s <- sds(list(temp=temp, rhum=rhum, wind=wind, srad=srad))

x <- Tg(s)
y <- WBGT(s)

---

photoperiod

Description

Compute photoperiod (daylength, sunshine duration) at a given latitude and day of the year.

Usage

## S4 method for signature 'Date'
photoperiod(x, latitude)

## S4 method for signature 'data.frame'
photoperiod(x)

## S4 method for signature 'SpatRaster'
photoperiod(x, filename="", overwrite=FALSE, ...)

Arguments

x	Date, integer (day of the year), or data.frame (with variables "date" and "latitude", or SpatRaster
latitude	numeric. Latitude
filename	character. Output filename
overwrite	logical. If TRUE, filename is overwritten
...	additional arguments for writing files as in writeRaster

Value

double. Photoperiod in hours

References

Forsythe, W.C., E.J. Rykiel Jr., R.S. Stahl, H. Wu, R.M. Schoolfield, 1995. A model comparison for photoperiod as a function of latitude and day of the year. Ecological Modeling 80: 87-95.

Examples

photoperiod(50, 52)
photoperiod(50, 5)
photoperiod(180, 55)

p <- photoperiod(1:365, 52)
d <- dateFromDoy(1:365, 2001)
plot(d, p)

---

Global weather data estimated from satellite data and models.

Description

This functions returns a data.frame with weather data from the NASA POWER database. It has the date, incoming solar radiation (srad, kJ m-2 day-1), minimum temperature (tmin, degrees C) and maximum temperature (tmax, degrees C), vapor pressure (vapr, Pa), precipitation (prec, mm), and windspeed (wind, m/s)

The data are from 1983-01-01 to 2016-12-31

Missing values for radiation (Jan to June 1983 and ...) and a few inbetween were replaced by the long term averages.

There are no precipitation values before 1997-01-01. Missing values for precipitaion after that date were estimated as the long term average (i.e., not a particularly good method).

The data are at 1 degree spatial resolution. That is, they are the average for a large grid cell.

These are estimates. They can give a good general impression, but they are not ground observations.

Data are downloaded as-needed by tile. By default to folder called "power" in your working directory.

Usage

power_weather(lon, lat, folder=file.path(getwd(), 'power'), tiles=FALSE, ...)

Arguments

lon	numeric
lat	numeric
folder	character
tiles	logical. Download by tile?
...	additional arguments

Value

data.frame

Examples

## Not run: 
w <- power_weather(5, 50)
w$srad <- w$srad * 1000
wth <- subset(w, date > as.Date('2012-01-01'))
head(wth)

## End(Not run)

---

pwc

Description

pwc

Usage

## S4 method for signature 'numeric'
pwc(x, input="wbgt", adjust=TRUE)

## S4 method for signature 'SpatRaster'
pwc(x, input="wbgt", adjust=TRUE, filename="", overwrite=FALSE, ...)

Arguments

x	numeric or SpatRaster
input	character. One of "wbgt" or "utci"
adjust	logical. If TRUE, the Smallcombe et al. (2022) adjustment for a 7-hour workday is used
filename	character. Output filename
overwrite	logical. If TRUE, filename is overwritten
...	additional arguments for writing files as in writeRaster

Value

numeric or SpatRaster

References

Smallcombe et al.. 2022

Foster et al., 2022

Examples

pwc(25)

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utci

Description

utci

Usage

## S4 method for signature 'data.frame'
utci(x)

Arguments

x	data.frame

Value

numeric or SpatRaster

Examples

d <- data.frame(temp=20, rhum=80, tglb=22, wind=10)
utci(d)

---

Vapor pressure

Description

Functions to compute the saturated vapor pressure (SVP), actual vapor pressure (VP), and vapor pressure deficit (VPD) in Pascal or the dew-point temperature in C.

For temperature < 0C the saturation vapour pressure equation for ice is used according to Goff and Gratch (1946), whereas for temperature >=0C that of Goff (1957) is used.

Usage

SVP(temp)
VP(temp, relh)
VPD(temp, relh)
tDew(temp, relh)

Arguments

temp	numeric. Temperature in degrees C
relh	relative humidity (percent)

Value

numeric vector (Pascal).

Author(s)

Robert Hijmans, partly based on Python meteolib by Maarten J. Waterloo and J. Delsman http://python.hydrology-amsterdam.nl/

References

Goff, J.A.,and S. Gratch, 1946. Low-pressure properties of water from -160 to 212 F. Transactions of the American society of heating and ventilating engineers, p. 95-122, presented at the 52nd annual meeting of the American society of heating and ventilating engineers, New York, USA.

Goff, J. A. 1957. Saturation pressure of water on the new Kelvin temperature scale, Transactions of the American society of heating and ventilating engineers, pp 347-354, presented at the semi-annual meeting of the American society of heating and ventilating engineers, Murray Bay, Quebec, Canada.

Examples

temperature <- seq(-10,30,10)
SVP(temperature)
VP(temperature, 60)
VPD(temperature, 60)
tDew(temperature, 60)

---

Weather class

Description

Weather data

Objects from the Class

Objects can be created by calls of the form new("Weather", ...), or with the helper functions such as weather.

Slots

Slots of Weather objects

data:

data.frame with the weather data

ID:

character

name:

character

country:

character

longitude:

numeric

latitude:

numeric

elevation:

numeric

Examples

showClass("Weather")

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