|
|
| def growing_degree_day(
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| GDDmethod: int,
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| Tupp: float,
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| Tbase: float,
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| temp_max: float,
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| temp_min: float,
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| ):
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| """
|
| Function to calculate number of growing degree days on current day
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|
|
| <a href="https://www.fao.org/3/BR248E/br248e.pdf#page=28" target="_blank">Reference manual: growing degree day calculations</a> (pg. 19-20)
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|
|
|
|
| Arguments:
|
|
|
| GDDmethod (int): gdd calculation method
|
|
|
| Tupp (float): Upper temperature (degC) above which crop development no longer increases
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|
|
| Tbase (float): Base temperature (degC) below which growth does not progress
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|
|
| temp_max (float): Maximum tempature on current day (celcius)
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|
|
| temp_min (float): Minimum tempature on current day (celcius)
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|
|
|
|
| Returns:
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|
|
| gdd (float): Growing degree days for current day
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|
|
|
|
|
|
| """
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|
|
|
|
| if GDDmethod == 1:
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|
|
| Tmean = (temp_max + temp_min) / 2
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| Tmean = min(Tmean, Tupp)
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| Tmean = max(Tmean, Tbase)
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| gdd = Tmean - Tbase
|
| elif GDDmethod == 2:
|
|
|
| temp_max = min(temp_max, Tupp)
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| temp_max = max(temp_max, Tbase)
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|
|
| temp_min = min(temp_min, Tupp)
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| temp_min = max(temp_min, Tbase)
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|
|
| Tmean = (temp_max + temp_min) / 2
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| gdd = Tmean - Tbase
|
| elif GDDmethod == 3:
|
|
|
| temp_max = min(temp_max, Tupp)
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| temp_max = max(temp_max, Tbase)
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|
|
| temp_min = min(temp_min, Tupp)
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| Tmean = (temp_max + temp_min) / 2
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| Tmean = max(Tmean, Tbase)
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| gdd = Tmean - Tbase
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|
|
| return gdd |
