ck_branas: Branas Hydrothermal Index

In climatekit: Unified Climate Indices for Temperature, Precipitation, and Drought

Branas Hydrothermal Index

Description

The Branas index combines temperature and precipitation during the growing season to estimate disease pressure (especially downy mildew) in vineyards. It is the sum of (monthly mean temperature) times (monthly precipitation total) over the five months of the growing season: April-August in the Northern Hemisphere; October-February in the Southern Hemisphere. The Southern Hemisphere season spans two calendar years and is reported under the year in which it starts.

Usage

ck_branas(precip, tavg, dates, lat = 50)

Arguments

precip	Numeric vector of daily precipitation (mm).
tavg	Numeric vector of daily mean temperatures (degrees C).
dates	Date vector of the same length as precip.
lat	Numeric. Latitude in decimal degrees, used to select the hemisphere convention. Default 50 (Northern Hemisphere).

Value

A data frame with columns period, value, index, and unit.

References

Branas, J., Bernon, G., & Levadoux, L. (1946). Elements de viticulture generale.

Examples

dates <- seq(as.Date("2024-04-01"), as.Date("2024-08-31"), by = "day")
set.seed(42)
tavg <- rnorm(length(dates), mean = 12, sd = 3)
precip <- rgamma(length(dates), shape = 0.5, rate = 0.2)
ck_branas(precip, tavg, dates)

climatekit documentation built on May 9, 2026, 5:08 p.m.