The Totten Glacier, located in the East Antarctica Ice Sheet, is a significant contributor to global sea-level rise. However, the mechanisms through which offshore ocean heat reaches the glacier’s ice shelf cavity remain largely unknown. In a recent study, a multinational team of researchers has shed light on the physical processes that control the melting rate of the Totten Glacier. By providing additional insights into the pathways of warm water reaching the ice shelf, their findings contribute to a better understanding of the impact of climate change on the region.
One of the most alarming consequences of global warming is the rise in sea level due to the melting of polar ice. Polar researchers have been working diligently to raise awareness of this imminent threat. To assess the risks associated with melting ice, scientists rely on sampling remote areas of the Arctic and Antarctic continental shelves. By modeling and understanding the processes driving ice melting in these regions, they can estimate the amount of meltwater that will eventually flow into the ocean over time.
The East Antarctic Ice Sheet, which encompasses the Totten Glacier, is a significant contributor to global sea-level rise, alongside the extensively studied West Antarctic region. The Totten Glacier lies below the ocean’s surface and contains enough ice to potentially raise global sea levels by more than 3.5 meters. However, due to thick sea ice cover in the Totten embayment, sampling and observing the continental shelf near the glacier has been challenging. Consequently, little is known about how offshore ocean heat reaches the ice shelf cavity beneath the Totten Glacier.
A team of researchers led by Assistant Professor Daisuke Hirano from the National Institute of Polar Research (NIPR) in Japan undertook a study to fill this crucial knowledge gap. The researchers used a variety of techniques over several years to gather data from the Totten embayment. This included helicopter-based measurements, comprehensive scans of the ocean floor’s topography (bathymetry), and sea water sampling. By combining this data with existing measurements, the team developed a model to describe the interactions between the ocean and the Totten Ice Shelf.
Through observations and numerical simulations, the researchers uncovered essential details about how warm offshore-origin Circumpolar Deep Water interacts with the Totten Ice Shelf, accelerating melting processes. They discovered that a chain of cyclonic eddy currents brings warm water from offshore towards the continental shelf break. This warm water then enters a broad depression on the inner side of the break and circulates within it until it reaches the cavity of the Totten Ice Shelf. This circulation is facilitated by two large, deep glacial troughs.
The inflow and subsequent mixing of warm water in the Totten Ice Shelf cavity leads to basal meltwater, which ultimately exits through the glacier’s western ice front. Assistant Professor Hirano highlights the importance of bathymetry and regional circulation in regulating ocean heat transport towards the ice shelf cavity. The findings of this study provide valuable insights into the physical processes controlling the Totten Glacier’s melt rate. This knowledge can contribute to more accurate predictions about the future state of the East Antarctic region in the face of climate change.
Understanding the pathways through which warm water reaches the Totten Glacier’s ice shelf is crucial for predicting its future behavior and the resulting impact on global sea levels. The research conducted by Assistant Professor Hirano and his team fills a significant knowledge gap and reveals the importance of bathymetry and regional circulation in the melting processes. Long-term monitoring will be necessary to fully comprehend the sensitivity of the Totten Glacier and its potential contribution to sea-level rise. Ultimately, this research enhances our understanding of the larger picture of how Antarctic ice loss driven by oceanic factors affects our planet.
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