A 14-yr Circum-Antarctic Iceberg Calving Dataset Derived from Continuous Satellite Observations

• Main Authors: Qi, Mengzhen, Liu, Yan, Liu, Jiping, Cheng, Xiao, Feng, Qiyang, Shen, Qiang, Yu, Zhitong
• Format: Text
• Language: English
• Published: 2021
• Subjects: Amery; Antarctic; Antarctic Peninsula; East Antarctica; The Antarctic; West Antarctica; Wilkes Land; Antarc*; Antarctica; Ice Sheet; Ice Shelves; Iceberg*
• Online Access: https://doi.org/10.5194/essd-2020-340; https://essd.copernicus.org/preprints/essd-2020-340/

Iceberg calving is the main process that facilitates the dynamic mass loss of ice sheets into the ocean, which accounts for approximately half of the net mass loss of all Antarctic ice shelves. Fine-scale calving variability observations can help reveal the involved calving mechanisms and identify the principal processes that influence how the changing climate affects the mass loss of ice sheets. Iceberg calving from specific ice shelves or regions has been monitored before, but there is still a lack of consistent, long-term and high-precision records on independent calving events for all Antarctic ice shelves. In this study, we developed a circum-Antarctic annual iceberg calving product measuring every independent calving event larger than 1 km 2 that occurred from August 2005 to August 2019. We first simulated the expansion of the coastline according to ice velocity, and then manually delineated the calved areas, which are considered to be the differences between the simulated coastline and the actual coastline derived from the corresponding satellite imagery, based on 15 years of continuous multisource optical and synthetic aperture radar images. This product provides detailed information on each calving event, including the associated year of occurrence, area, size, average thickness, mass, recurrence interval, type, and measurement uncertainties. In total, 1786 annual calving events occurred on the Antarctic ice shelves from August 2005 to August 2019. The average annual calving area was measured as 3411.4 km 2 with an uncertainty value of 17.1 km 2 , and the average calving rate was measured as 771.1 Gt/yr with an uncertainty value of 10.2 Gt/yr. The calving frequency, area, and mass fluctuated moderately during the first decade, followed by a dramatic increase from 2015/16 to 2018/19. During the dataset period, large ice shelves, such as the Ronne-Filchner, Ross and Amery Ice Shelves, advanced with low calving frequency, while small and medium-sized ice shelves retreated and calved more frequently. Iceberg calving is most prevalent in West Antarctica, followed by the Antarctic Peninsula and Wilkes Land in East Antarctica. The annual circum-Antarctic iceberg calving dataset provides consistent and precise calving observations with the longest time coverage. The dataset provides multidimensional variables for each independent calving event that can be used to study detailed spatiotemporal variations in Antarctic iceberg calving. The dataset can also be used to study ice sheet mass balance, calving mechanisms and the responses of iceberg calving to climate change. The dataset is shared via Global Change Data Repository ( href="http://www.geodoi.ac.cn/WebEn/doi.aspx?Id=1516 ), and entitled <q>Annual iceberg calving dataset of the Antarctic ice shelves (2005–2019)</q> with DOI: https://doi.org/10.3974/geodb.2020.04.09.V1 .