A Simple Model for Deglacial Meltwater Pulses

• Main Authors: Robel, Alexander A., Tsai, Victor C.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2018
• Subjects: sea level; meltwater; ice sheet; instability; Arctic; Ice Sheet
• Online Access: https://doi.org/10.1029/2018GL080884

Evidence from radiocarbon dating and complex ice sheet modeling suggests that the fastest rate of sea level rise in Earth's recent history coincided with collapse of the ice saddle between the Laurentide and Cordilleran ice sheets during the last deglaciation. In this study, we derive a simple, twoâ€equation model of two ice sheets intersecting in an ice saddle. We show that two conditions are necessary for producing the acceleration in ice sheet melt associated with meltwater pulses: the positive heightâ€mass balance feedback and an ice saddle geometry. The amplitude and timing of meltwater pulses is sensitively dependent on the rate of climate warming during deglaciation and the relative size of ice sheets undergoing deglaciation. We discuss how simulations of meltwater pulses can be improved and the prospect for meltwater pulses under continued climate warming. © 2018 American Geophysical Union. Received 11 OCT 2018; Accepted 14 OCT 2018; Accepted article online 18 OCT 2018; Published online 4 NOV 2018. A simple numerical implementation of the mathematical model described in this study is available as a public repository on GitHub: https://github.com/aarobel/. This work was primarily supported by the NSF Arctic Natural Sciences Program (Grant OPP 1735715). AAR was also supported by the NOAA Climate and Global Change Postdoctoral Fellowship and the Caltech Stanback Postdoctoral Fellowship during an early phase of this project. Thanks to Lev Tarasov for providing the output from his observationally-constrained Laurentide Ice Sheet model. Published - Robel_et_al-2018-Geophysical_Research_Letters.pdf Submitted - RobelTsai_MWP_EarthArxiv_postprint.pdf Supplemental Material - 2018gl080884-sup-0001-text_si-s01_aa.pdf