Скачать или смотреть Sea Level Rise Seminar, 2025-06-24: Caitlin Locke

Sea Level Rise Seminar
Tuesday June 24, 2025
Speaker: Caitlin Locke (Lamont-Doherty Earth Observatory)

Title: Novel Record of Intermittent Grounding of the Venable Ice Shelf since 1935 from Operation IceBridge Airborne-Gravity-Derived Bathymetry and Landsat Imagery

Abstract: Future projections and past reconstructions of Antarctic Ice Sheet stability and sea-level rise depend on knowledge of continental shelf bathymetry, which controls water circulation under floating ice and interactions between the ice shelf and seafloor. In the Bellingshausen Sea Sector, bathymetry beneath the Venable Ice Shelf is not well known because ice-covered waters limit ship-based multibeam echo sounding and satellite mapping. We present a bathymetry model of the Venable Ice Shelf from an inversion of airborne gravity data. The new model reveals troughs up to ~1.6 km deeper than previously mapped, providing pathways for warm Circumpolar Deep Water to access the grounding line. A bathymetric high beneath the western Venable Ice Shelf is identified as a former pinning point. From crevasse patterns in Landsat satellite imagery, we infer intermittent grounding of the ice shelf on this high since ~1935, and we interpret these patterns as evidence of mid-twentieth century ice-shelf thinning, in addition to a regrounding between 1970 and 1988, extending the ice-shelf thickness record beyond the satellite era.