Dates

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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*

[Barnett et al., 2006]

*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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