method_Ribes | R Documentation |
The method Ribes uva-crispa
is based on leaf-out of gooseberry (Janssen 2009).
It was developed by the Germany's National Meteorological Service
(Deutscher Wetterdienst, DWD) and is more robust against early starts than
common simple meteorological procedures.
starting from 18th February sum all day degrees above 0 °C (daily average air temperature). Vegetetaion period starts at the day when 164 is crossed.
# start day: February 18th == 49 doy # only Tavg over 0°C are summed df[df$DOY < 49 | df$Tavg < 0, 'Tavg'] <- 0 # find day where cum day degrees cross 164 start <- tapply(df$Tavg, df$year, FUN=function(x){ x <- cumsum(x) min(which(x > 164)) })
Janssen, W. (2009) Definition des Vegetationsanfanges. Internal Report, Deutscher Wetterdienst, Abteilung Agrarmeteorologie.
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