Inferring Holocene precipitation in west central Greenland using the Unscented Transform

• Main Author: Downs, Jake
• Format: Text
• Language: unknown
• Published: ScholarWorks at University of Montana 2019
• Subjects: Greenland; Ice Sheet
• Online Access: https://scholarworks.umt.edu/mathcolloquia/580

We investigate changing precipitation patterns in Greenland during a period of elevated temperatures called the Holocene thermal maximum (~10,000 - 6,000 years ago), exploiting a new chronology of ice sheet extent through the Holocene and an inverse modeling approach based on the unscented transform (UT) . The UT is applied to estimate changes in annual precipitation in order to reduce the misfit between modeled and observed ice sheet margin positions. We discuss the basic theory of the UT and show how it can be applied to the problem of time dependent data assimilation. Our results indicate that Holocene warming coincided with elevated precipitation, without which modeled retreat in west Greenland is more rapid than suggested by observations. This result highlights the important role that changing precipitation patterns had in controlling ice sheet extent during the Holocene.