Analysis of Extreme Precipitation Conditions near the Wilkes and Adelie Lands in Antarctica

Sea level rise affects many coastal cities and ecosystems. Over the last four decades, the rate of ice mass loss in Antarctica (from the flow of glaciers into the ocean) has accelerated, contributing a total of 14 mm to sea level rise (Rignot et al., 2019). In order to prepare for future sea level rise, it is important to understand the changes in the earth's cryosphere, especially the extensive ice sheets in Greenland and Antarctica. On the Antarctic continent, mass is accumulated mainly through snowfall, and extreme precipitation events contribute a significant portion of the total snowfall each year (Turner et al., 2018). A potential source of precipitation extremes are atmospheric rivers (ARs), which are long, thin channels of moisture transport. In regions such as the Dronning Maud Land and the Antarctic Peninsula, extreme precipitation events have been attributed to ARs (Gorodetskaya et al., 2014, Bozkurt et al., 2018). More research is needed to understand their impact on extreme precipitation in Antarctica. In particular, some possible precipitation trends have been observed in the Wilkes and Adelie Lands (Tang et al., 2018, Lenaerts et al., 2012), however, the impact of ARs on extreme precipitation patterns in this region has received little attention.

For this work, we compare the characteristics of extreme precipitation events and landfalling AR events in the the Wilkes and Adelie Lands between 1979 and 2019, using ERA-Interim reanalysis data and the Tracking Atmospheric Rivers Globally as Elongated Targets (tARget) algorithm (Guan et al., 2019). Composite analysis shows significant differences but also noteworthy similarities between the conditions of extreme precipitation events and AR events. Future work would explore in more detail the patterns found here in order to improve understanding and prediction of AR-caused extreme precipitation in Antarctica.