Useful Calculated Inputs for Weather Stations

Growing Degree Days (Deg C)

Determines amount of time crop experiences in defined temperature range, used in growth and pest models

Dim currentDate As Date = Inputs.Daily Max Temp.LogTime
Dim Temp As Decimal = (Inputs.<Daily Max Temp>.Value + Inputs.<Daily Min Temp>.Value) / 2 - 10

If currentDate.Month >= 10 OrElse currentDate.Month <= 4 Then
If Temp >= 0 Then
If currentDate.Month = 10 AndAlso currentDate.Day = 1 OrElse Not PreviousValue.HasValue Then
Return Temp
Else
Return Temp + PreviousValue
End If
End If
End If
Return Nothing

Growing Season Rainfall

Returns cumulative rainfall within a defined "growing season"

Dim fromDate = New Date(2017, 1, 1)
Dim toDate = New Date(2018, 1, 1)
Dim rain = Inputs.<Rain mm>.Value

If rain.LogTime >= fromDate AndAlso rain.LogTime < toDate Then
  Return rain.Value + If(PreviousValue.HasValue, PreviousValue.Value, 0)
Else
  Return 0
End If

Delta-T °C

Returns difference between wet-bulb and dry-bulb temperatures, determines efficacy of inputs applied by spraying

Return (Inputs.<Temperature>.Value) - (Inputs.<Temperature>.Value * System.Math.ATAN(0.151977*(Inputs.<Relative Humidity>.Value+8.313659)^0.5)+ System.Math.ATAN(Inputs.<Temperature>.Value+Inputs.<Relative Humidity>.Value)- System.Math.ATAN(Inputs.<Relative Humidity>.Value-1.676331)+0.00391838*(Inputs.<Relative Humidity>.Value)^1.5 * System.Math.ATAN(0.023101*Inputs.<Relative Humidity>.Value)-4.686035)

Fire Danger Index (McArthur Grassland MK4)

Returns the Fire Danger Index used to inform when fire-risk activities such as grain harvesting can occur

Return 2*(System.Math.Exp((5.01*System.Math.Log(100+0.001))-23.6+(.0281*Inputs.<Temperature>.Value)-(.226*(System.Math.Sqrt((Inputs.<Relative Humidity>.Value))))+(.633*(System.Math.Sqrt(Inputs.<Wind Speed>.Value)))))