16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20121 Data gaps and spikes in FGM data

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20122 Data gaps dataset  Dataset is produced for both OLD and NEW (=G) versions  This dataset contains timings for both missing data intervals (gaps) and spikes  Dataset names:  Dx_CQ_FGM_GAPF for G version  Dx_CQ_FGM_GAPF_OLD for OLD version  Variables  Time tags Gap: centre time of the gap spike: removed record time  Half interval Gap: half width of the gap spike: half of the sampling interval  Source 0 = outboard sensor data missing (for gap) 1 = inboard sensor data missing (for gap) 2 = both sensors’ data missing (for gap) 3 = spike

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20123 Removing data points  Data points are removed if they appear as spikes, deviate significantly from the surrounding data points  Reasons for removing all records for the given time stamps are  data are available only from one sensor  there is a spike in one component  there is not enough data points to calculate a disturbance model  there is no SRP data

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20124 Spikes

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20125 Removing data point: normal spike  Appearance of a spike in data  This is detected using sliding window technique by comparing the value of data point with the surrounding values  Example: green – inboard, red - outboard

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20126 Removing data point: Change of SAD level  A change in the shunting of the solar power system creates small spike in magnetic field which is removed  Example: green – inboard, red - outboard

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20127 Data gaps

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20128 What is a data gap  Identification of data gap:  Statistics of data gaps

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November20129 Example: Data gaps in June 2006

16 th CAA Cross-Calibration Workshop IRAP, Toulouse, 6-9 November Example: Spikes in June 2006