This function calculates the 19 standard bioclimatic variables derived from monthly temperature and precipitation data. Bioclimatic variables are often used in ecological modeling and species distribution modeling to capture biologically meaningful patterns in climate data, including annual trends, seasonality, and extreme environmental factors.
The bioclimatic variables represent metrics such as the annual mean temperature, temperature seasonality, and precipitation patterns (e.g., wettest or driest quarter). These metrics help to model species distributions and analyze ecological dynamics.
The bioclimatic variables 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
These variables are computed using temperature and precipitation data in a standard format, and are critical for understanding species habitats and the effects of climate on ecosystems.
This work is derived from the dismo R package.
Arguments
- data
A data frame containing monthly climate data. The data frame must include:
year: The year for each set of monthly data.
ppt: Monthly precipitation values (in mm).
tmin: Monthly minimum temperature values (in degrees Celsius).
tmax: Monthly maximum temperature values (in degrees Celsius).
The data should contain 12 rows (one for each month from January to December) per year, with the columns sorted in the order of year, ppt, tmin, and tmax.
Value
A data frame with 19 columns representing the bioclimatic variables (BIO1 to BIO19) and an additional column for the year. The output data frame provides one row per year, with each column corresponding to one of the bioclimatic variables described above.
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