Agroclimatic indicators

GrowingDegreeDays: averaging-method GDD with optional horizontal cutoff (McMaster and Wilhelm 1997). ChillAccumulation: chill hours (0 to 7.2 C) and Utah chill units (Richardson et al. 1974). LaiFromSavi: METRIC leaf area index. RainfallAdequacy: precipitation over crop evapotranspiration and per-period deficits. GrowingSeasonLength: ETCCDI GSL. ColdSpellDuration: ETCCDI CSDI. Identical to the Python arm morie.fn.agroclim.

Usage

GrowingDegreeDays(tmax, tmin, base = 10, upper = NULL)

ChillAccumulation(hourly_temp)

LaiFromSavi(savi, cap = 6)

RainfallAdequacy(precip, et0, kc = 1)

GrowingSeasonLength(tmean, threshold = 5, span = 6, midyear = 181)

ColdSpellDuration(tmin, threshold, span = 6)

Arguments

tmax, tmin

Daily maximum and minimum temperatures.

base, upper

Base and upper thresholds.

hourly_temp

Hourly temperatures.

savi

Soil-adjusted vegetation index values.

cap

Maximum LAI.

precip, et0

Precipitation and reference evapotranspiration.

kc

Crop coefficient(s).

tmean

Daily mean temperatures for one year.

threshold

Temperature threshold (scalar or per day).

span

Minimum run length.

midyear

0-based day index after which the season may end.

Value

Numeric or list.

References

McMaster, G. S. and Wilhelm, W. W. (1997). Growing degree-days: one equation, two interpretations. Agricultural and Forest Meteorology 87, 291-300.

Richardson, E. A., Seeley, S. D. and Walker, D. R. (1974). A model for estimating the completion of rest for Redhaven and Elberta peach trees. HortScience 9, 331-332.

Zhang, X. et al. (2011). Indices for monitoring changes in extremes based on daily temperature and precipitation data. WIREs Climate Change 2, 851-870.

Examples

GrowingDegreeDays(c(25, 32, 12), c(11, 20, 4), base = 10, upper = 30)$total
#> [1] 24
ChillAccumulation(c(-1, 2, 5, 8, 10, 14, 17, 20))$utah_units
#> [1] 1.5
GrowingSeasonLength(c(rep(0, 100), rep(10, 150), rep(0, 115)))
#> [1] 150