Total ozone decrease in the Arctic after REP events

Eight periods of relativistic electron precipitation (REP) with electron en ergies of more than 300 kev re identified from VLF data (10-14 kHz) monitor ed along the Aldra (Norway)- Apatity (Kola peninsula) radio trace..:In thes e cases, anomalous ionization below 55-50 km occurred without disturbing th e higher layers of the ionosphere. The daily total ozone values in Murmansk for six days before and six days after the REP events are compared. In sev en of eight events a decrease in the total ozone of about 20 DU is observed : In one event of 25 March, 1986, the mean total ozone value for six days b efore the REP is bigger than that for six days after, but this a case of an extremely high ozone increase (144 DU during the six days). However, on da ys 3 and 4 there was a minimum of about 47 DU with regard to REP days, so , this case also confirms the:concept of the ozone decrease after REP. The di fference between mean ozone values for periods six days before and six days after the REPs was found also for 25 points in Arctic on TOMS data, The di fference was negative only in Murmansk longitudinal sector. Along the merid ian of the trace it was negative at high latitudes in both hemispheres and was near zero at low latitudes.