In this thesis results of satellite and in-situ airplane ozone data analysis are presented.rnTotal Ozone Column (TOC) from Total Ozone Mapping Spectrometer (TOMS), andrnozone enhancements sampled on the cruise flight route from Johannesburg to Viennarnby Measurement of OZone by Inservice AIrCraft (MOZAIC) at Equatorial Africa andrnNorth Africa are investigated. The work in this thesis is focused on the study of ozonerntransport during stratosphere-troposphere exchange (STE) events over intense STE areas,rnand seasonal variability of ozone over Africa. On very few occasions, at upper tropospherernEquatorial Africa ozone spikes are observed at a flying altitude of 250-200 hPa. To understandrnthe events that attribute to spiky MOZAIC ozone and relative humidity observations,rnadditional data sets from different data sources were used to examine the observedrnevents. Vertical wind fields in the regions of low Outgoing Long-wave Radiation (OLR),rnvery high latent heat and cloud liquid water content transport have indicated presencernof convection and thunderstorm events. Potential vorticity intrusion over equatorial regionrnintroduced enhanced ozone of stratospheric origin, as revealed by ERA-interim ozonerndata. Both downwelling and upwelling induced by convection and intrusion transportedrnenhanced ozone from the stratosphere all the way down to the boundary layer.rnWe have distinguished source and regions of discharge of MOZAIC ozone enhancementsrnobserved at a flying altitude of 250-200 hPa over North Africa. Different datarnsets from ECMWF-ERA-Interim are used to examine the dynamics associated with thernevents. Relative humidity from MOZAIC measurement, longitudinal cross-section of potentialrnvorticity (PV) and ozone volume mixing ratio (VMR) over the region of MOZAICrnozone enhancements confirmed that the observed enhancements are measured within lowerrnstratosphere. This is mainly due to massive shift in the tropopause level. Longitudinalrncross-section of PV, potential vorticity in isentropic surfaces (IPV) and ozone VMR revealedrnthat the first mode of transport is large scale airmass subsidence from the stratospherernover mid-latitude. Some of these events lead to cross tropopause ozone transportrnxirnto upper troposphere North Africa. The second case is subsidence at polar regions duringrnNorth hemisphere winter seasons. IPV is strongly modified as revealed by wind fields.rnIn addition zonal winds and Rossby waves, which are active during winter seasons, havernstrong contribution in modifying potential vorticity and ozone spatial and temporal distribution.rnTOC is analyzed from TOMS satellite data to study its seasonal variability over Africa.rnThe seasonal variability comparisons in the latitude regions 0-34.50 N and 0-34.50 S showrnthat ozone concentration peaks shift from April at North Africa to September near thernequator. Ozone concentration begins to raise from May to October, and decreasing afterwardsrnin the Southern part of Africa with highest peaks only between September tornOctober. This result shows that ozone concentration seasonal duration is longer in thernNorthern part of Africa than the South. Low total column ozone concentration aroundrn200 N and 200 S was observed which could be related to dynamical factors such as convectionrnwhile the seasonal variability of very high ozone VMR is related to photochemicalrnproduction