reducer.sd.forbid-nulls is available since version 1.0.11.
reducer.sd.forbid-nulls function outputs for each tick the standard deviation of the values of Geo Time Series™ which are in the same equivalence class.
It operates on LONG and DOUBLE.
The location and elevation returned are the first encountered.
This reducer takes an additional boolean parameter to choose if Bessel correction should be applied.
It will return null for any tick where one or more GTS have null values.