Variation of total Ozone during 24 August 2005 magnetic storm: a case study

Abstract

This paper presents the longitudinal distribution of total ozone along several latitudinal circles from both hemispheres during a strong geomagnetic storm that occurred on 24 August 2005 after a solar proton event (the maximum flux of protons with energy > 10 MeV was 1.70 × 107 protons cm−2 ·day−1 ·sr−1 on 23 August). For that, we use average daily values of total ozone observations (=column ozone amount) in Dobson units for the period 18-25 August 2005 (obtained from the Total Ozone Mapping Spectrometer, TOMS). The considered storm occurred after a relatively quiet geomagnetic period and it is not superposed by another perturbation, which permit us to identify clearly the effects of the geomagnetic storm on total ozone. The results show statistically significant decreases in ozone along the latitudinal circles 70˚N and 70˚S (summer and winter), no statistically significant effects at middle latitudes (40˚S) and sparse statistically significant increases at low latitudes (20˚S). The role of some mechanisms to explain the features observed is considered.