Bioclimatic Variables

• Author: O.Conrad (c) 2016
• Menu: Climate and Weather | Bioclimatology

Description

This tool calculates biologically meaningful variables from monthly climate data (mean, minimum and maximum temperature and precipitation sum), as provided by climate related projects, e.g.:

• CHELSA - Climatologies at High resolution for the Earth___s Land Surface Area
• WorldClim - Global climate and weather data

It follows a short definition of the provided bioclimatic variables:

1. Annual Mean Temperature: The mean of all the monthly mean temperatures. Each monthly mean temperature is the mean of that month's maximum and minimum temperature.
2. Mean Diurnal Range: The annual mean of all the monthly diurnal temperature ranges. Each monthly diurnal range is the difference between that month's maximum and minimum temperature.
3. Isothermality: The mean diurnal range (parameter 2) divided by the annual temperature range (parameter 7).
4. Temperature Seasonality: returns either
   • the temperature coefficient of variation as the standard deviation of the monthly mean temperatures expressed as a percentage of the mean of those temperatures (i.e. the annual mean). For this calculation, the mean in degrees Kelvin is used. This avoids the possibility of having to divide by zero, but does mean that the values are usually quite small.
   • the standard deviation of the monthly mean temperatures.
5. Maximum Temperature of Warmest Period: The highest temperature of any monthly maximum temperature.
6. Minimum Temperature of Coldest Period: The lowest temperature of any monthly minimum temperature.
7. Temperature Annual Range: The difference between the Maximum Temperature of Warmest Period and the Minimum Temperature of Coldest Period.
8. Mean Temperature of Wettest Quarter: The wettest quarter of the year is determined (to the nearest month), and the mean temperature of this period is calculated.
9. Mean Temperature of Driest Quarter: The driest quarter of the year is determined (to the nearest month), and the mean temperature of this period is calculated.
10. Mean Temperature of Warmest Quarter: The warmest quarter of the year is determined (to the nearest month), and the mean temperature of this period is calculated.
11. Mean Temperature of Coldest Quarter: The coldest quarter of the year is determined (to the nearest month), and the mean temperature of this period is calculated.
12. Annual Precipitation: The sum of all the monthly precipitation estimates.
13. Precipitation of Wettest Period: The precipitation of the wettest month.
14. Precipitation of Driest Period: The precipitation of the driest month.
15. Precipitation Seasonality: The Coefficient of Variation is the standard deviation of the monthly precipitation estimates expressed as a percentage of the mean of those estimates (i.e. the annual mean).
16. Precipitation of Wettest Quarter: The wettest quarter of the year is determined (to the nearest month), and the total precipitation over this period is calculated.
17. Precipitation of Driest Quarter: The driest quarter of the year is determined (to the nearest month), and the total precipitation over this period is calculated.
18. Precipitation of Warmest Quarter: The warmest quarter of the year is determined (to the nearest month), and the total precipitation over this period is calculated.
19. Precipitation of Coldest Quarter: The coldest quarter of the year is determined (to the nearest month), and the total precipitation over this period is calculated.

The quarterly parameters are not aligned to any calendar quarters. BioClim's definition of a quarter is any consecutive 3 months. For example, the driest quarter will be the 3 consecutive months that are drier than any other set of 3 consecutive months.

References

• Jeremy van der Wal: BioClim - Bioclimatic Variables (R-Package)
• Xu, T. & Hutchinson, M. F. (2011): ANUCLIM Version 6.1. Fenner School of Environment and Society, Australian National University, Australia. User Guide.
• Xu, T. & Hutchinson, M. F. (2013): New Developments and Applications in the ANUCLIM Spatial Climatic and Bioclimatic Modelling Package. Environmental Modelling & Software Vol. 40, p.267___279. doi:10.1016/j.envsoft.2012.10.003.

Parameters

Command Line

Usage: saga_cmd climate_tools 10 [-TMEAN ] [-TMIN ] [-TMAX ] [-P ] [-BIO_01 ] [-BIO_02 ] [-BIO_03 ] [-BIO_04 ] [-BIO_05 ] [-BIO_06 ] [-BIO_07 ] [-BIO_08 ] [-BIO_09 ] [-BIO_10 ] [-BIO_11 ] [-BIO_12 ] [-BIO_13 ] [-BIO_14 ] [-BIO_15 ] [-BIO_16 ] [-BIO_17 ] [-BIO_18 ] [-BIO_19 ] [-QUARTER_COLDEST ] [-QUARTER_WARMEST ] [-QUARTER_DRIEST ] [-QUARTER_WETTEST ] [-SEASONALITY ]
  -TMEAN:          	Mean Temperature
	grid list, input
  -TMIN:           	Minimum Temperature
	grid list, input
  -TMAX:           	Maximum Temperature
	grid list, input
  -P:              	Precipitation
	grid list, input
  -BIO_01:         	Annual Mean Temperature
	grid, output
  -BIO_02:         	Mean Diurnal Range
	grid, output
  -BIO_03:         	Isothermality
	grid, output
  -BIO_04:         	Temperature Seasonality
	grid, output
  -BIO_05:         	Maximum Temperature of Warmest Month
	grid, output
  -BIO_06:         	Minimum Temperature of Coldest Month
	grid, output
  -BIO_07:         	Temperature Annual Range
	grid, output
  -BIO_08:         	Mean Temperature of Wettest Quarter
	grid, output
  -BIO_09:         	Mean Temperature of Driest Quarter
	grid, output
  -BIO_10:         	Mean Temperature of Warmest Quarter
	grid, output
  -BIO_11:         	Mean Temperature of Coldest Quarter
	grid, output
  -BIO_12:         	Annual Precipitation
	grid, output
  -BIO_13:         	Precipitation of Wettest Month
	grid, output
  -BIO_14:         	Precipitation of Driest Month
	grid, output
  -BIO_15:         	Precipitation Seasonality
	grid, output
  -BIO_16:         	Precipitation of Wettest Quarter
	grid, output
  -BIO_17:         	Precipitation of Driest Quarter
	grid, output
  -BIO_18:         	Precipitation of Warmest Quarter
	grid, output
  -BIO_19:         	Precipitation of Coldest Quarter
	grid, output
  -QUARTER_COLDEST:	Coldest Quarter
	grid, output, optional
  -QUARTER_WARMEST:	Warmest Quarter
	grid, output, optional
  -QUARTER_DRIEST: 	Driest Quarter
	grid, output, optional
  -QUARTER_WETTEST:	Wettest Quarter
	grid, output, optional
  -SEASONALITY:    	Temperature Seasonality
	choice
	Available Choices:
	[0] Coefficient of Variation
	[1] Standard Deviation
	Default: 1