Ms Fortunate Nomsa Mapuka

Level of Study: 
Geography & Environmental Science
Spatial distribution of rainfall characteristics on Sub-Antarctic Marion Island

Marion Island has experienced a theatrical shift in climate since meteorological observations began in the 1950s. Recent climate changes have altered the distribution of rainfall on the Island and little research has been done on the daily spatial distribution of rainfall on the Marion Island at an island scale. This study investigated the trend in the spatial distribution and characteristics (amount, intensity, duration) of monthly rainfall on the Marion Island using five-minute rainfall data collected by the seven rainfall gauge stations located on the Island. The study also established the occurrence of intensive rainfall events using the rainfall data recorded concurrently by the rainfall gauges. Possible causes of the intensive rainfall and effects of climate change were also explored. The key findings of the study show that extreme rainfall events are still common on Marion Island as shown by the concurrent long rainfall events measuring up to 21 hours of continuous island wide intense rainfall which is associated with mid-latitudinal cyclones when the island is under pre-frontal conditions and in the warm sector of the cyclone. The annual data April 2016 to March 2017 indicate that the eastern aspect is the wettest while the western side of Marion Island is the driest. These findings will play a pivotal role in advancing further research on the island’s changing climate and designing adaptation measures to curb the effects of these changes on the Island’s ecosystem.