Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt
-
Published:2022-10-07
Issue:10
Volume:16
Page:4013-4032
-
ISSN:1994-0424
-
Container-title:The Cryosphere
-
language:en
-
Short-container-title:The Cryosphere
Author:
West AlexORCID, Blockley EdwardORCID, Collins Matthew
Abstract
Abstract. Arctic sea ice is declining rapidly, but predictions of
its future loss are made difficult by the large spread both in present-day
and in future sea ice area and volume; hence, there is a need to better
understand the drivers of model spread in sea ice state. Here we present a
framework for understanding differences between modelled sea ice simulations
based on attributing seasonal ice growth and melt differences. In the method
presented, the net downward surface flux is treated as the principal driver
of seasonal sea ice growth and melt. An energy balance approach is used to
estimate the pointwise effect of model differences in key Arctic climate
variables on this surface flux and hence on seasonal sea ice growth and
melt. We compare three models with very different historical sea ice
simulations: HadGEM2-ES, HadGEM3-GC3.1 and UKESM1.0. The largest driver of
differences in ice growth and melt between these models is shown to be the ice
area in summer (representing the surface albedo feedback) and the ice
thickness distribution in winter (the thickness–growth feedback).
Differences in snow and melt pond cover during the early summer exert a
smaller effect on the seasonal growth and melt, hence representing the
drivers of model differences in both this and in the sea ice volume. In
particular, the direct impacts on sea ice growth and melt of differing model
parameterisations of snow area and of melt ponds are shown to be small but
non-negligible.
Funder
Horizon 2020 Natural Environment Research Council Department for Business, Energy and Industrial Strategy, UK Government Department for Environment, Food and Rural Affairs, UK Government
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
Reference56 articles.
1. Anderson, M., Bliss, A., and Drobot, S.: Snow Melt Onset Over Arctic Sea Ice
from SMMR and SSM/I-SSMIS Brightness Temperatures, Version 3. Boulder,
Colorado USA, NASA National Snow and Ice Data Center Distributed Active
Archive Center, https://doi.org/10.5067/22NFZL42RMUO (last access: October 2015),
2001, updated 2012. 2. Barker, H. W. and Li, Z.: Improved simulation of clear-sky radiative
transfer in the CCC-GCM, J. Climate, 8, 2213–2223, 1995. 3. Bitz, C. M.: Some Aspects of Uncertainty in Predicting Sea Ice Thinning, in:
Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and
Implications, edited by: DeWeaver, E. T., Bitz, C. M., and Tremblay, L.-B., American
Geophysical Union, Washington, D.C., https://doi.org/10.1029/180GM06, 2008. 4. Bitz, C. and Lipscomb, W. H.: An energy-conserving thermodynamic model of
sea ice, J. Geophys. Res.-Oceans, 104, 15669–15677, https://doi.org/10.1029/1999JC900100, 1999. 5. Bitz, C. M. and Roe, G. H.: A Mechanism for the High Rate of Sea Ice
Thinning in the Arctic Ocean, J. Climate, 17, 3623–3632, https://doi.org/10.1175/1520-0442(2004)017<3623:AMFTHR>2.0.CO;2, 2004.
|
|