Dates refer to the first/last occurrence of a phenomenon in a given period of time.
Indicator |
Metric |
Start Growing Season |
first day when five consecutive days Tavg > Tc* [Barnett et al., 2006] |
Start of Field Operations |
first day when ∑Tavg > ∑Tavg(c) oC-days* [Barnett et al., 2006] |
End of Field Capacity |
last day when SMD < SWCFC - 5 mm* (before date of max SMD) [Barnett et al., 2006] |
Last Air Frost (Spring) |
last day when Tmin < 0.0 oC* [Barnett et al., 2006] |
Last Grass Frost (Spring) |
last day when Tmin < Tc oC* [Barnett et al., 2006] |
Summer moisture deficit (date) |
day when SMD is at maximum [Barnett et al., 2006] |
Wettest Week |
mid week date when maximum value of ∑P (seven days) occurs [Barnett et al., 2006] |
First Grass Frost (Autumn) |
first day when Tmin < Tc oC* [Barnett et al., 2006] |
First Air Frost (Autumn) |
first day when Tmin < 0.0 oC* |
Return to Field Capacity |
first day when SMD > SWCFC - 5 mm (after date of max SMD) [Barnett et al., 2006] |
End Growing Season |
day when five consecutive days Tavg < Tc oC* |
*Starting from January 1st in the Northern hemisphere and from July 1st in the Southern hemisphere.
Tavg (oC): average air temperature
∑Tavg (oC-days): sum of Tavg > 0 °C
∑Tavg(c) (oC-days): critical ∑Tavg (e.g. 200 oC-days)
Tc (oC): critical air temperature (e.g. 5.6 oC)
Tmin (oC): minimum air temperature
P (mm): precipitation
∑P (mm): sum of precipitation above a minimum threshold (e.g. 0.2 mm)
SMD (mm): summer moisture deficit (minimum soil water content) (see Water balance)
SWCFC (mm): soil water content at field capacity (see Water balance)
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