North Atlantic natural variability modulates emergence of widespread Greenland melt in a warming climate

• Published in: Geophysical Research Letters
• Main Authors: Hahn, Lily, Ummenhofer, Caroline C., Kwon, Young-Oh
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons 2018
• Subjects: Greenland; North Atlantic; North Atlantic oscillation
• Online Access: https://hdl.handle.net/1912/10638

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 9171-9178, doi:10.1029/2018GL079682. Record‐breaking melt over Greenland in recent decades is linked not only to climate change but also to natural variability, including persistent atmospheric high‐pressure conditions in the negative phase of the North Atlantic Oscillation and warm North Atlantic Ocean temperatures during the positive phase of the Atlantic Multidecadal Oscillation. However, the relative importance of natural variability for Greenland melt under varying degrees of greenhouse forcing is still unclear. Using reanalysis data and a large ensemble of climate model simulations, we find that a negative North Atlantic Oscillation and positive Atlantic Multidecadal Oscillation consistently promote heightened summer melt under various forcing conditions. Moreover, timing of widespread 21st century Greenland melt varies considerably between ensemble members due to different phasing of these modes of natural variability. These results indicate the importance of natural modes of variability across a range of external forcing conditions for interannual melt variability and the emergence of widespread Greenland melt. U.S. National Science Foundation Grant Number: ANS‐1736738; Woods Hole Oceanographic Institution Summer Student Fellow program Grant Number: AGS‐1355339 2019-03-10