6 merge requests!319add all changes of dev into release v1.4.0 branch,!318Resolve "release v1.4.0",!317enabled window_lead_time=1,!297Resolve "BUG: data handler fails if no chem variable is used",!295Resolve "data handler FIR filter",!259Draft: Resolve "WRF-Datahandler should inherit from SingleStationDatahandler"
