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Calculate the Bioclimatic Variables

Source: R/qbms.R
calc_biovars.Rd

Bioclimatic variables are derived from the monthly temperature and rainfall values in order to generate more biologically meaningful variables. These are often used in species distribution modeling and related ecological modeling techniques. The bioclimatic variables represent annual trends (e.g., mean annual temperature, annual precipitation) seasonality (e.g., annual range in temperature and precipitation) and extreme or limiting environmental factors (e.g., temperature of the coldest and warmest month, and precipitation of the wet and dry quarters). A quarter is a period of three months (1/4 of the year).

They are coded as follows:

  • BIO1 = Annual Mean Temperature

  • BIO2 = Mean Diurnal Range (Mean of monthly (max temp - min temp))

  • BIO3 = Isothermality (BIO2/BIO7) (* 100)

  • BIO4 = Temperature Seasonality (standard deviation *100)

  • BIO5 = Max Temperature of Warmest Month

  • BIO6 = Min Temperature of Coldest Month

  • BIO7 = Temperature Annual Range (BIO5-BIO6)

  • BIO8 = Mean Temperature of Wettest Quarter

  • BIO9 = Mean Temperature of Driest Quarter

  • BIO10 = Mean Temperature of Warmest Quarter

  • BIO11 = Mean Temperature of Coldest Quarter

  • BIO12 = Annual Precipitation

  • BIO13 = Precipitation of Wettest Month

  • BIO14 = Precipitation of Driest Month

  • BIO15 = Precipitation Seasonality (Coefficient of Variation)

  • BIO16 = Precipitation of Wettest Quarter

  • BIO17 = Precipitation of Driest Quarter

  • BIO18 = Precipitation of Warmest Quarter

  • BIO19 = Precipitation of Coldest Quarter

This work is derivative from the dismo R package

Usage

calc_biovars(data)

Arguments

data

Data.frame has 4 mandatory columns (year, ppt, tmin, and tmax), and 12 rows (months) for each year sorted from Jan to Dec.

Value

Data.frame has 19 columns for "bioclim" variables (bio1-bio19) and last column for year (you will get one row per year).

References

Nix, 1986. A biogeographic analysis of Australian elapid snakes. In: R. Longmore (ed.). Atlas of elapid snakes of Australia. Australian Flora and Fauna Series 7. Australian Government Publishing Service, Canberra.

Author

Khaled Al-Shamaa, k.el-shamaa@cgiar.org

Robert Hijmans, Museum of Vertebrate Zoology, UC Berkeley