Preprints
https://doi.org/10.5194/tc-2022-52
https://doi.org/10.5194/tc-2022-52
 
10 Mar 2022
10 Mar 2022
Status: a revised version of this preprint is currently under review for the journal TC.

Antarctic surface climate and surface mass balance in the Community Earth System Model version 2 (1850–2100)

Devon Dunmire, Jan T. M. Lenaerts, Rajashree Tri Datta, and Tessa Gorte Devon Dunmire et al.
  • Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, USA

Abstract. Antarctic Ice Sheet (AIS) mass loss can be mitigated by an increase in surface mass balance (SMB) which is impacted by the ice sheet's surface climate. Because of Antarctica’s remoteness, in-situ observations of its surface climate are spatially and temporally sparse, limiting our understanding of how the surface climate, and therefore SMB, are changing. To that end, Earth System Models (ESMs) fill an important gap, allowing us to explore components of the AIS climate system, both historically and under future climate change scenarios. Here, we present and analyze output of the most recent version of the National Center for Atmospheric Research’s ESM: the Community Earth System Model version 2 (CESM2). We compare AIS surface climate and SMB as simulated by CESM2 with regional climate models and observations. We find that CESM2 substantially better represents AIS near-surface temperature, wind speed, and surface melt compared with its predecessor, CESM1, which is likely a result of the inclusion of new cloud microphysical parameterizations and changes made to the snow model. However, CESM2 SMB is shown to be biased high, particularly because of excessive precipitation. ESMs such as CESM2 are used as forcing for ice sheet models, which provide estimates and projections of ice sheet contribution to sea level rise. Thus, it is important to fully understand the limitations and biases of this climate model forcing. This study provides a comprehensive analysis of the strengths and weaknesses of CESM2 representation of AIS surface climate, which will be especially useful in preparation for CESM3, which plans to incorporate a coupled Antarctic Ice Sheet that interacts with the ocean and atmosphere.

Devon Dunmire et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2022-52', Christoph Kittel, 31 Mar 2022
    • AC1: 'Reply on RC1', Devon Dunmire, 17 May 2022
  • RC2: 'Comment on tc-2022-52', Anonymous Referee #2, 06 Apr 2022
    • AC2: 'Reply on RC2', Devon Dunmire, 17 May 2022

Devon Dunmire et al.

Devon Dunmire et al.

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Latest update: 30 Jun 2022
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Short summary
Earth System Models (ESMs) are used to model the climate system and the interactions of its components (i.e. atmosphere, ocean, etc.) both historically and into the future under different assumptions of human activity. The representation of Antarctica in ESMs is important because it can inform projections of the ice sheet's contribution to sea level rise. Here, we compare output of Antarctica's surface climate from an ESM with observations to understand strengths and weaknesses within the model.