% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/agroclimatic.R
\name{ck_branas}
\alias{ck_branas}
\title{Branas Hydrothermal Index}
\usage{
ck_branas(precip, tavg, dates, lat = 50)
}
\arguments{
\item{precip}{Numeric vector of daily precipitation (mm).}

\item{tavg}{Numeric vector of daily mean temperatures (degrees C).}

\item{dates}{Date vector of the same length as \code{precip}.}

\item{lat}{Numeric. Latitude in decimal degrees, used to select the
hemisphere convention. Default 50 (Northern Hemisphere).}
}
\value{
A data frame with columns \code{period}, \code{value}, \code{index}, and \code{unit}.
}
\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.
}
\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)
}
\references{
Branas, J., Bernon, G., & Levadoux, L. (1946).
Elements de viticulture generale.
}
