USIDS Codes

Type of ionospheric phenomena observed, and importance with appropriate times.

Example:

Definition of symbols:

  • USIDS comes from radio Sudden IonosphericDisturbance, code S

  • I I I I I = station indicator

  • Y = last digit of year
  • MM = month of year, 01 = January, 02 = February, etc.
  • DD = UT day of month

  • a = type of phenomena
    • 0 = sudden frequency deviation (SFD)
    • 1 = short wave fade-out with sudden drop out (typical S-SWF)
    • 2 = short wave fade-out with slow drop out - 5 to 15 minutes with gradual recovery
    • (slow S-SWF)
    • 3 = short wave fade-out with fade irregular in drop out and recovery (G-SWF)
    • 4 = sudden enhancement of atmospherics (SEA)
    • 5 = sudden phase anomaly-phase advance (SPA)
    • 6 = sudden cosmic noise absorption (SCNA)
    • 7 = sudden enhancement of signal .15 to 200 KHz (SES)
    • 8 = sudden phase anomaly-phase retardation (SPA)

Note: To report SPA by degrees, use code UABSE.

  • HHmm = UT hour and minute of beginning of phenomena

  • c = importance of phenomena
    • 0 = importance 1-
    • 1 = importance 1
    • 2 = importance 2
    • 3 = importance 3
    • 7 = importance 1+
    • 8 = importance 2+
    • 9 = importance 3+
  • HHmm = UT hour and minute of maximum of phenomena

  • d = recording definitiveness and time qualifier

  • HHmm = UT hour and minute of end time of phenomena

Note: / is to be used for data not available.