我写了一个函数来计算作物生长阶段的时间(成长度日)。作为背景,在种植作物后,它在累积某些热量单位后从一个阶段移动到另一个阶段。对于例如对于给定的植物日,作物需要300°C,500°C,600°C的累积热量单位分别达到第1阶段,第2阶段和第3阶段。
此函数采用温度矢量temp.vec
,plant.date
,这基本上是您想要开始计算累积热量单位,基准温度,最佳温度和临界温度的一天。
set.seed(123)
sample.temp <- data.frame(day = 1:365,tmean = c(sample(25:32,365, replace = T)))
gdd.func <- function(temp.vec,plant.date,t.base,t.opt,t.cri){
x <- temp.vec[temp.vec > plant.date]
fT <- ifelse(x >= t.base & x <= t.opt,(x - t.base)/(t.opt - t.base),
ifelse(t.opt <= x & x <= t.cri,(t.cri - x)/(t.cri - t.opt),0))
Te <- t.base + fT*(t.opt - t.base)
thermal.units <- Te - t.base
day.stage1 <- which.max(cumsum(thermal.units) >= 300) # this will give me the day when cumulative accumulation of thermal units crossed 300 heat units
# once growth stage 1 is reached, t.base,t.opt and t.cri are updated
t.base <- t.base - 2
t.opt <- t.opt - 2
t.cri <- t.cri - 2
fT[(day.stage1 + 1):length(fT)] <- ifelse(x[(day.stage1 + 1):length(fT)] >= t.base & x[(day.stage1 + 1):length(fT)] <= t.opt,(x[(day.stage1 + 1):length(fT)] - t.base)/(t.opt - t.base), ifelse(t.opt <= x[(day.stage1 + 1):length(fT)] & x[(day.stage1 + 1):length(fT)] <= t.cri,(t.cri - x[(day.stage1 + 1):length(fT)])/(t.cri - t.opt),0))
Te[(day.stage1 + 1):length(Te)] <- t.base + fT[(day.stage1 + 1):length(fT)]*(t.opt - t.base)
thermal.units[(day.stage1 + 1):length(Te)] <- Te[(day.stage1 + 1):length(Te)] - t.base
day.stage2 <- which.max(cumsum(thermal.units) >= 500)
# once growth stage 2 is reached, t.base,t.opt and t.cri are updated again
t.base <- t.base - 1
t.opt <- t.opt - 1
t.cri <- t.opt - 1
fT[(day.stage2 + 1):length(fT)] <- ifelse(x[(day.stage2 + 1):length(fT)] >= t.base & x[(day.stage2 + 1):length(fT)] <= t.opt,(x[(day.stage2 + 1):length(fT)] - t.base)/(t.opt - t.base), ifelse(t.opt <= x[(day.stage2 + 1):length(fT)] & x[(day.stage2 + 1):length(fT)] <= t.cri,(t.cri - x[(day.stage2 + 1):length(fT)])/(t.cri - t.opt),0))
Te[(day.stage2 + 1):length(Te)] <- t.base + fT[(day.stage2 + 1):length(fT)]*(t.opt - t.base)
thermal.units[(day.stage2 + 1):length(Te)] <- Te[(day.stage2 + 1):length(Te)] - t.base
day.stage3 <- which.max(cumsum(thermal.units) >= 600)
list(day.stage1,day.stage2,day.stage3)
}
进行试运行
t.base <- 24
t.opt <- 32
t.cri <- 36
plant.dates <- gdd.func(temp.vec = sample.temp$tmean,plant.date = 10,t.base,t.opt,t.cri)
unlist(plant.dates)
# [1] 66 117 144
输出是三天的向量,它给出plant.date
10的stage1,stage2和stage3的出现。
我的问题是,是否要在多个位置和年份内为多个plant.date
运行上述功能。对于例如想象一下这个数据:
sample.data <- data.frame(id1 = rep(1:20, each = 730*36), year = rep(rep(1980:2015, each = 365*2), times = 20),day = rep(rep(1:730, times = 36), times = 20), tmean = sample(25:32,20*730*36,replace = T))
head(sample.data)
id1 year day tmean
1 1 1980 1 26
2 1 1980 2 32
3 1 1980 3 25
4 1 1980 4 26
5 1 1980 5 28
6 1 1980 6 28
数据由20个位置组成,每个位置有36年的数据。每年有730天(365 * 2)和每天的平均温度。
我有三个plant.date
。
plant.vec <- c(250,290,302)
我想选择每个种植日,并为我的每个位置X年组合生成三个生长阶段
for(p in seq_along(plant.vec))
plant.date <- plant.vec[p]
sample.data %>% group_by(id1,year) %>% # how to insert my gdd.func here so that it runs for each id1 and year combination)
谢谢
答案 0 :(得分:1)
这有帮助吗?
library(dplyr)
plant.vec <- c(10, 20, 30)
final_lst <- lapply(plant.vec, function(x)
sample.data %>%
group_by(id1,year) %>%
summarise(plant.dates = paste(gdd.func(temp.vec = tmean, plant.date = x, t.base, t.opt, t.cri), collapse=",")))