Modeling Ocean Wave Transfer to Ross Ice Shelf Flexure

Abstract

The Ross Ice Shelf (RIS) is the world's largest ice shelf. It is hundreds of meters thick, with width and length many hundreds of kilometers and covering the majority of the Ross Sea bay (Figure 1a). Two sets of seminal experiments have been made on the RIS over the past two decades to measure its vibrational response to ocean surface wave forcing, ranging from swell (roughly frequencies 0.03-0.1 Hz or periods 10-30 s) to infragravity (IG) waves (0.003-0.02 Hz or 50-300 s) to very long period waves including tsunamis (0.001-0.003 Hz or 300-1,000 s). Interest in ocean wave-ice shelf interactions derives from a series of classic theoretical studies that argue wave-induced flexure of ice shelves (and ice tongues) has the capacity to create or enhance near-shelffront ice fractures, crevasses and rifts, and

A thin-plate approximation for ocean wave interactions with an ice shelf

“…In particular, flexural-gravity waves at periods in the swell regime are amplified by crevasses in ice shelves (Bennetts et al. 2022), and, thus, our findings highlight a potential, additional role of water–ice coupling and extensional waves in these amplifications. Further, the thin-plate model presented could be extended to study whether periodic thickness variations in the ice shelf block ocean wave energy propagation through the shelf (Freed-Brown et al.…”

“…However, swell amplitudes are typically much greater than infragravity wave amplitudes, such that the benchmark model predicts they create strains of comparable magnitude (Bennetts, Liang & Pitt 2022). In particular, flexural-gravity waves at periods in the swell regime are amplified by crevasses in ice shelves (Bennetts et al 2022), and, thus, our findings highlight a potential, additional role of water-ice coupling and extensional waves in these amplifications. Further, the thin-plate model presented could be extended to study whether periodic thickness variations in the ice shelf block ocean wave energy propagation through the shelf (Freed-Brown et al 2012;Nekrasov & MacAyeal 2023).…”

“…The strain magnitudes presented in § 6 are one to two orders of magnitude smaller for wave periods in the swell regime than in the infragravity wave regime. However, swell amplitudes are typically much greater than infragravity wave amplitudes, such that the benchmark model predicts they create strains of comparable magnitude (Bennetts, Liang & Pitt 2022). In particular, flexural-gravity waves at periods in the swell regime are amplified by crevasses in ice shelves (Bennetts et al.…”

Closing the loops on Southern Ocean dynamics: From the circumpolar current to ice shelves and from bottom mixing to surface waves

“…Ice shelf flexure has been detected in response to swell ( § 5.1), as well as tides ( § 5.2), infragravity waves and tsunamis (Bromirski et al, 2010;Brunt et al, 2011;Padman et al, 2018). Flexure due to swell is greatest in the outer shelf margins (Chen et al, 2018;Bennetts, Liang, & Pitt, 2022) and during summer when the sea ice barrier is at its weakest or absent (Massom et al, 2018;Chen et al, 2019). Swellinduced shelf stresses peak at crevasses (Bennetts, Liang, & Pitt, 2022), and they have been associated with crevasse and rift propagation (Banwell et al, 2017;Lipovsky, 2018), iceberg calving (MacAyeal et al, 2006;Cathles IV et al, 2009) and triggering catastrophic ice shelf disintegration events (Massom et al, 2018).…”

Time Domain Vibration Analysis of an Ice Shelf

“…Observation using a satellite radar altimeter for 18 years has shown that losses in the West Antarctic increased by approximately 70% in the past decade [4]. Strong evidence suggests that ocean waves contribute to the calving process of the ice shelf [5][6][7][8]. Seismic instruments have measured the impact of ocean swells on the Ross Ice Shelf in Antarctica, which causes it to vibrate [2,[9][10][11].…”