Abstract:

Antarctic ice shelves play a critical role in regulating the mass balance of the Antarctic Ice Sheet by buttressing inland ice and limiting its discharge into the surrounding oceans. Consequently, changes in ice shelf extent and thickness are important indicators of ice shelf stability and have significant implications for future sea-level rise. To investigate long-term variations in Antarctic ice shelves, optical remote sensing imagery (Landsat and MODIS) and multiple existing geospatial datasets were integrated to map Antarctic ice shelf fronts over the past four decades and quantify changes in ice shelf area. A total of 145 ice shelves were analyzed over the period 1984 to 2023. The results indicate a net loss of 76905.18 km², corresponding to 4.43% of the total ice shelf area during the study period. Among the analyzed ice shelves, 37 exhibited an overall expansion trend, including the Flichner and Brunt Stancomb ice shelves, with a cumulative area increase of 18006.25 km² (6.27%). In contrast, 108 ice shelves showed a net reduction in area, including the Ronne, Wilkins, and Crosson ice shelves, resulting in a cumulative area loss of 94911.43 km² (6.41%). To further investigate the coupled evolution of ice shelf geometry, an ice shelf thickness dataset derived from satellite altimetry observations was compiled and extended to cover 56 ice shelves during the period 1992 to 2023. Analysis of thickness changes revealed that 22 ice shelves experienced net thickening, with particularly pronounced increases observed for Publications Ice Shelf (150.2%) and Ninnis Ice Shelf (36.49%). Conversely, 34 ice shelves experienced thinning, with significant thinning observed in Crosson (33.7%), Thwaites (29.56%), and Land ice shelves (28.11%). Spatial analysis revealed pronounced regional contrasts, with ice shelves in West Antarctica exhibiting substantially greater variability in both area and thickness than those in East Antarctica. To explore the mechanisms driving ice shelf evolution, correlations were examined between observed changes in ice shelf area and thickness and potential controlling factors, including grounding discharge and iceberg calving. The results demonstrate that the relative influence of these factors varies considerably among individual ice shelves and across different regions of Antarctica, highlighting the complexity of ice shelf responses to environmental forcing. Despite the complexity and diversity of the observed ice shelf responses, a generalized classification framework comprising eight distinct change patterns was identified. 

Key words: Antarctica ice shelf, area of ice shelf, thickness of ice shelf, correlation analysis