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Definitions of statistically downscaled climate indices

There are 49 statistically downscaled climate indices

Index Definition Unit
Hot days (Tmax > 25°C)

Number of days with maximum temperature above 25°C

Days
Hot days (Tmax > 30°C)

Number of days with maximum temperature above 30°C

Days
Hot days (Tmax > 33°C)

Number of days with maximum temperature above 33°C

Days
Hot days (Tmax > 35°C)

Number of days with maximum temperature above 35°C

Days
Hot days (Tmax > 37°C)

Number of days with maximum temperature above 37°C

Days
Hot nights (Tmin > 18°C)

Number of days with minimum temperature above 18°C

Days
Hot nights (Tmin > 20°C)

Number of days with minimum temperature above 20°C

Days
Hot nights (Tmin > 22°C)

Number of days with minimum temperature above 22°C

Days
Hot nights (Tmin > 25°C)

Number of days with minimum temperature above 25°C

Days
Cold days (Tmin < -15°C)

Number of days with minimum temperature below -15°C

Days
Cold days (Tmin < -20°C)

Number of days with minimum temperature below -20°C

Days
Cold days (Tmin < -25°C)

Number of days with minimum temperature below -25°C

Days
Cold days (Tmin < -30°C)

Number of days with minimum temperature below -30°C

Days
Hot spell days (Tmax consecutive 3 day > 25°C)

The total number of days with a maximum temperature above 25°C during a hot spell. A hot spell is defined as 3 or more consecutive hot days.

Days
Hot spell days (Tmax consecutive 3 day > 30°C)

The total number of days with a maximum temperature above 30°C during a hot spell. A hot spell is defined as 3 or more consecutive hot days.

Days
Hot spell days (Tmax consecutive 3 day > 33°C)

The total number of days with a maximum temperature above 33°C during a hot spell. A hot spell is defined as 3 or more consecutive hot days.

Days
Hot spell days (Tmax consecutive 3 day > 35°C)

The total number of days with a maximum temperature above 35°C during a hot spell. A hot spell is defined as 3 or more consecutive hot days.

Days
Hot spell days (Tmax consecutive 3 day > 37°C)

The total number of days with a maximum temperature above 37°C during a hot spell. A hot spell is defined as 3 or more consecutive hot days.

Days
Longest hot spell days (where Tmax > 25°C)

The number of days of the longest hot spell where the maximum temperature was consecutively above 25°C.

Days
Longest hot spell days (where Tmax > 30°C)

The number of days of the longest hot spell where the maximum temperature was consecutively above 30°C.

Days
Longest hot spell days (where Tmax > 33°C)

The number of days of the longest hot spell where the maximum temperature was consecutively above 33°C.

Days
Longest hot spell days (where Tmax > 35°C)

The number of days of the longest hot spell where the maximum temperature was consecutively above 35°C.

Days
Longest hot spell days (where Tmax > 37°C)

The number of days of the longest hot spell where the maximum temperature was consecutively above 37°C.

Days
Longest hot spell nights (where Tmin > 18°C)

The number of days of the longest hot spell where the minimum temperature was consecutively above 18°C.

Days
Longest hot spell nights (where Tmin > 20°C)

The number of days of the longest hot spell where the minimum temperature was consecutively above 20°C.

Days
Longest hot spell nights (where Tmin > 22°C)

The number of days of the longest hot spell where the minimum temperature was consecutively above 22°C.

Days
Longest hot spell nights (where Tmin > 25°C)

The number of days of the longest hot spell where the minimum temperature was consecutively above 25°C.

Days
Hot day and night

The number of days with a maximum temperature above 30°C and a minimum temperature above 20°C in the same day.

Days
Frost free days

The period between the last observed occurrence of frost (minimum temperature below 0°C) in the spring and the first observed occurrence of frost in the autumn

Days
Killing frost free days

The period between the last observed occurrence of killing frost (minimum temperature below -2°C) in the spring and the first observed occurrence of killing frost in the autumn

Days
Heating degree days

The number of degrees Celsius that a day’s average temperature is below 18°C, accumulated over the heating season

°C-day
Cooling degree days

The number of degrees Celsius that a day’s average temperature is above 18°C, accumulated over the cooling season

°C-day
Number of days with precipitation > 1mm

Number of days with precipitation > 1mm /day

Days
Number of days with precipitation ≥ 10mm

Number of days with precipitation ≥ 10mm/day

Days
Cool season annual one-day maximum precipitation

The maximum precipitation in one day per annual cool season.

mm/day
Warm season annual one-day maximum precipitation

The maximum precipitation in one day per annual warm season.

mm/day
Overwintering annual one-day maximum precipitation

The maximum precipitation in one day per annual overwintering.

mm/day
Cool season annual ten-day maximum precipitation

The maximum precipitation accumulated over ten days per annual cool season.

mm/10d
Warm season annual ten-day maximum precipitation

The maximum precipitation accumulated over ten days per annual warm season.

mm/10d
Overwintering annual ten-day maximum precipitation

The maximum precipitation accumulated over ten days per annual overwintering.

mm/10d
Length of growing season for cool season crops

The number of days between the cool season’s start and end dates:

Start: When the weighted 5 day mean temperature ≥ 5°C has been reached for five consecutive days in first half of the year.

End: When the weighted 5 day mean daily maximum temperature ≥ 30°C has been reached for five consecutive days in July or August, or August 31, whichever occurs earlier.

Days
Length of growing season for warm season crops

The number of days between the warm season’s start and end dates:

Start: When the weighted 5 day mean temperature ≥ 10°C has been reached for five consecutive days in first half of the year.

End: When the weighted 5 day mean temperature has dropped and stayed below 10°C in second half of the year.

Days
Length of growing season for overwintering crops

The number of days between the overwintering start and end dates:

Start: When the weighted 5 day mean temperature ≥ 5°C has been reached for five consecutive days in first half of the year.

End: When the weighted 5 day mean temperature has dropped and stayed below 5°C in second half of the year.

Days
Cool season crop heat units

The accumulated daily Crop Heat Units (CHU) within the cool growing season.

Daily CHU = (Ymax + Ymin)/2
where Ymax = 3.33(Tmax - 10) - 0.084(Tmax - 10)2 for
Tmax ≥ 10°C, and Ymin = 95(Tmin - 4.4) for Tmin ≥ 4.4°C

Heat unit
Warm season crop heat units

The accumulated daily Crop Heat Units (CHU) within the warm growing season.

Daily CHU = (Ymax + Ymin)/2
where Ymax = 3.33(Tmax - 10) - 0.084(Tmax - 10)2 for
Tmax ≥ 10°C, and Ymin = 95(Tmin - 4.4) for Tmin ≥ 4.4°C

Heat unit
Overwintering crop heat units

The accumulated daily Crop Heat Units (CHU) within the overwintering season.

Daily CHU = (Ymax + Ymin)/2
where Ymax = 3.33(Tmax - 10) - 0.084(Tmax - 10)2 for
Tmax ≥ 10°C, and Ymin = 95(Tmin - 4.4) for Tmin ≥ 4.4°C

Heat unit
Cool season effective growing degree days

The accumulated daily growing degree days (GDD) values within the cool growing season multiplied by a day length factor (DLF) that equals 1.0 when the latitude (LAT) is below 49°N and 1.18 higher than 61°N. DLF = -19.3257 + 1.158643(LAT) - 0.022107689(LAT)2 + 0.0001413685(LAT)3

Daily growing degree days (GDD): GDD= Tmax+ Tmin2- CTmin if Tmax +Tmin 2CTmi n

CTmin: 5°C for cool season crops

°C-day
Warm season effective growing degree days

The accumulated daily growing degree days (GDD) values within the warm growing season multiplied by a day length factor (DLF) that equals 1.0 when the latitude (LAT) is below 49°N and 1.18 higher than 61°N. DLF = -19.3257 + 1.158643(LAT) - 0.022107689(LAT)2 + 0.0001413685(LAT)3

Daily growing degree days (GDD): GDD= Tmax+ Tmin2- CTmin if Tmax +Tmin 2CTmi n

CTmin: 10°C for warm season crops

°C-day
Overwintering effective growing degree days

The accumulated daily growing degree days (GDD) values within the overwintering growing season multiplied by a day length factor (DLF) that equals 1.0 when the latitude (LAT) is below 49°N and 1.18 higher than 61°N. DLF = -19.3257 + 1.158643(LAT) - 0.022107689(LAT)2 + 0.0001413685(LAT)3

Daily growing degree days (GDD): GDD= Tmax+ Tmin2- CTmin if Tmax +Tmin 2CTmi n

CTmin: 5°C for overwintering crops

°C-day
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