Supporting Information for “Arctic

Amplification: a Rapid Response to Radiative

Forcing”

Michael Previdi1*, Tyler P. Janoski1,2, Gabriel Chiodo3,4, Karen L. Smith1,5,

Lorenzo M. Polvani1,2,4

1Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.

2Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027,

USA.

3Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology Zurich,

8092 Zurich, Switzerland.

4Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY

10027, USA.

5Department of Physical and Environmental Sciences, University of Toronto Scarborough,

Toronto, Ontario, Canada M1C 1A4.

*e-mail: mprevidi@ldeo.columbia.edu

Contents of this file:

Figures S1-S3

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Figure S1. Multimodel mean surface air temperature (SAT) response (in K)

averaged over the first 3 months (January-March) of the CMIP5 simulations.

Figure S2. Annual mean stratosphere-adjusted radiative forcing (in W m-2) from 4

CO2 as computed by PORT.

Figure S3. Anomalous (i.e., Arctic minus global) warming contributions from feedbacks

and energy transport responses for (a) the first 3 months (January-March), (b) the first

year, and (c) the last 30 years of the CMIP5 simulations. Colored circles represent

individual models, and horizontal bars are the multimodel means.

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Figure S1.

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Figure S2.

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Figure S3.

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