Closing the Last Deglacial Global Sea Level Budget by Different Antarctic Deglaciation Models
Date
2019
Authors
Yucheng, Lin
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Abstract
Closing the Last Deglacial Global Sea Level
Budget by Different Antarctic Deglaciation Models
Abstract: The last deglacial history of the Antarctic Ice Sheet
(AIS), the world’s largest freshwater reservoir, is important
for monitoring the current AIS change and projecting the future
sea-level rise trend. However, due to the lack of direct
observational constraints on AIS last deglacial history,
currently, most of the knowledge of AIS deglaciation is from
glacial isostatic adjustment (GIA) modelling studies. Currently,
the most widely used AIS GIA models are ICE-6G_C (Argus et al.,
2014, Peltier et al., 2015), W12 (Whitehouse et al., 2012a) and
IJ05_R2 (Ivins et al., 2013). Although after combining with their
preferred Earth models, they all show good capability to predict
reasonable predictions compared to the geodetic observations
(e.g, Global Positioning System), the great differences between
their adopted deglaciation models would cause large uncertainties
in their estimations. Here we show a global sea-level budget
consistent GIA modelling approach to compare them with two
high-quality far-field sea-level datasets (H18; Hibbert et al.,
2018, L14; Lambeck et al., 2014) constructed using different
underlying philosophies to test their compatibilities with the
far-field sea-level observations. Similar to a previous study of
Lambeck et al. (2014), the global sea-level budget in this study
is defined by the global ice volume history reconstructed from
each observational datasets. From our calculation, a large ice
mass loss between 20-15 ka BP predicted by W12 is most likely to
be incorrect, since it shows large inconsistencies with both
observational datasets, suggesting that during this late glacial
period, AIS should have a stable or an advanced phase. And during
~15-11 ka BP, far-field sea-level records shows a preference with
ICE-6G_C, which is the only model with a distinct contribution to
meltwater pulse 1a and 1b, showing good consistency with the much
more dynamic cryospheric environment revealed by the new global
ice volume history reconstruced from the H18 dataset, as well as
previous GIA studies (e.g., Clark et al., 2002).
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Keywords
Glacial Isostatic Adjustment, Antarctic Ice History, Last Glaical Maximum, Missing Ice Problem
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DOI
10.25911/5e983487e7b1b