diagwl: Walter & Lieth climatic diagram

In climatol: Climate Tools (Series Homogenization and Derived Products)

Walter & Lieth climatic diagram

Description

Plot a Walter & Lieth climatic diagram of a station.

Usage

diagwl(dat, cols=1:6, format='%Y-%m-%d', yeari=NA, yearf=NA,
stname='', alt=NA, per='', mlab='', shem=FALSE, p3line=FALSE, ...)

Arguments

dat	Data frame with the required climatic data (see details).
cols	Columns containing the needed data.
format	Format of the dates if data are provided in 4 columns ['%Y-%m-%d'].
yeari, yearf	If dat is a file name, initial and final years of the period to use (defaults to the period contained in the data file).
stname	Name of the climatological station.
alt	Elevation (altitude) of the climatological station.
per	If data is a data frame with already calculated climate averages, the original period of the data.
mlab	Vector of 12 monthly labels for the X axis (see the details).
shem	Southern hemisphere? (FALSE by default.)
p3line	Draw a supplementary precipitation line referenced to three times the temperature? (FALSE by default.)
...	Other optional graphic parameters.

Details

The data frame can contain daily data of precipitation and extreme temperatures or 12 columns with pre-calculated monthly climate parameters.

In the latter case the monthly values from January to December occupy the 12 first columns (additional columns may be present, although they will be disregarded) and four rows, in the following order:

Row 1:

Mean precipitation

Row 2:

Mean maximum daily temperature

Row 3:

Mean minimum daily temperature

Row 4:

Absolute monthly minimum temperature

This last row is only used to determine the probable frost months (when absolute monthly minimums are equal or lower than 0 C). It is very important to set cols=NULL in this case.

Alternatively, if daily data of precipitation and extreme temperatures are provided, dates can be given in three separate columns (year, month, day) or in a single column with the specified format ('%Y-%m-%d' by default).

cols indicate in which columns are located the dates and climatic data. By default they are expected in columns 1 to 3 for year, month and day, and columns 4 to 6 for precipitation, maximum and minimum temperature respectively. (Remember to set cols=NULL if you provide pre-calculated monthly climatic parameters.)

mlab is the vector for the 12 monthly labels, but it may be set to just 'en' or 'es' to use the first letter of the month names in English or Spanish respectively.

For stations located in the southern hemisphere it is useful to set shem=TRUE, in order to keep the summer period in the central zone of the graphic (the diagram will begin the plot with the July data).

As described by Walter and Lieth, when monthly precipitation is greater than 100 mm, the scale is increased from 2 mm/C to 20 mm/C to avoid too high diagrams in very wet locations. This change is indicated by a black horizontal line, and the graph over it is filled in solid blue.

When the precipitation graph lies under the temperature graph (P < 2T) we have an arid period (filled in dotted red vertical lines). Otherwise the period is considered wet (filled in blue lines), unless p3line=TRUE, that draws a precipitation black line with a scale P = 3T; in this case the period in which 3T > P > 2T is considered semi-arid. (Parameter p3line was suggested by Bogdan Rosca.)

Daily maximum average temperature of the hottest month and daily minimum average temperature of the coldest month are frequently used in vegetation studies, and are labeled in black at the left margin of the diagram.

References

Walter H & Lieth H (1960): Klimadiagramm Weltatlas. G. Fischer, Jena.

Examples

data(climatol_data)

## from pre-calculated monthly climatic data:
diagwl(datcli,cols=NULL,est="My Airport",alt=100,per="1961-90",mlab="en")

## from daily series of precipitation and extreme temperatures:
diagwl(p064.df, stname="Cold Place", alt=100, per="1961-1990", mlab="en")

climatol documentation built on April 20, 2023, 5:08 p.m.