SUDDEN ENHANCEMENTS OF ATMOSPHERICS - SEA Month: DECEMBER YEAR: 2017 Observing Station: OBSERVATORY U P I C E CZECH REPUBLIC Lat.: 50 30 26.6 N Sea level: 416 m Long.: 16 00 43.5 E Frequency: 27 kHz Band pass: 308 Hz a 3 dB Chart speed: 3.4 cm/H Recorder time constant: 27 sec Date Start End Max. Imp. Def. Dur. Type REMARKS UT UT UT SEA min. 15 0847 0921 0856 1 2 34 3 27 1448 1512 1453 1 2 24 5 Evaluated by J.Klimes