diagwl {climatol}

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=NULL, p3line=FALSE, ...)

Arguments

dat

Data frame with the required climatic data (see details).

cols

Columns containing dates and daily data of precipitation and extreme temperatures. Set to NULL if a monthly climate summary is provided.

format

Format of the dates if data are provided in 4 columns ['%Y-%m-%d'].

yeari, yearf

Initial and final years of the period to use. (Defaults to the period contained in dat, but if it contains a climate summary, then the parameter per should be supplied (see below).

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? NULL by default, to be detected from warm season. Set to TRUE or FALSE to force southern or northern hemisphere.

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 must be in the 12 first columns (any additional trailing columns will be disregarded) and four rows, in the following order:

Row 1:

Mean total precipitation

Row 2:

Mean maximum daily temperature

Row 3:

Mean minimum daily temperature

Row 4:

Absolute minimum daily temperature

This last row is used only to determine the probable frost months (when absolute monthly minimums are equal or lower than 0 C).

Alternatively, if series of 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.)

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 month names in English or Spanish respectively.

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, mlab="en")

## idem limiting the period to calculate monthly values:
diagwl(p064.df, yearf=1990, stname="Cold Place", alt=100, mlab="en")