Submitted as: model description paper 12 Jul 2021

Submitted as: model description paper | 12 Jul 2021

Review status: this preprint is currently under review for the journal GMD.

CAPS v1.0: An improved regional coupled modeling system for Arctic sea ice and climate simulation and prediction

Chao-Yuan Yang1, Jiping Liu2, and Dake Chen1 Chao-Yuan Yang et al.
  • 1School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong, China
  • 2Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, NY, USA

Abstract. The updated Coupled Arctic Prediction System (CAPS) is evaluated, which is built on new versions of Weather Research and Forecasting model (WRF), the Regional Ocean Modeling System (ROMS), the Community Ice CodE (CICE), and a data assimilation based on the Local Error Subspace Transform Kalman Filter. A set of Pan-Arctic prediction experiments with improved/changed physical parameterizations in WRF, ROMS and CICE as well as different configurations are performed for the year 2018 to assess their impacts on the predictive skill of Arctic sea ice at seasonal timescale. The key improvements of WRF, including cumulus, boundary layer, and land surface schemes, result in improved simulation in near surface air temperature and downward radiation. The major changes of ROMS, including tracer advection and vertical mixing schemes, lead to improved evolution of the predicted total ice extent (particularly correcting the late ice recovery issue in the previous CAPS), and reduced biases in sea surface temperature. The changes of CICE, that include improved ice thermodynamics and assimilation of new sea ice thickness product, have noticeable influences on the predicted ice thickness and the timing of ice recovery. Results from the prediction experiments suggest that the updated CAPS can better predict the evolution of total ice extent compared with its predecessor, though the predictions still have certain biases at the regional scale. We further show that the CAPS can remain skillful beyond the melting season, which may have potential values for stakeholders making decisions for socioeconomical activities in the Arctic.

Chao-Yuan Yang 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 gmd-2021-220', Anonymous Referee #1, 11 Aug 2021
  • RC2: 'Comment on gmd-2021-220', Anonymous Referee #2, 02 Sep 2021

Chao-Yuan Yang et al.

Chao-Yuan Yang et al.


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Short summary
We present an improved coupled modeling system for Arctic sea ice and climate prediction. We perform Arctic sea ice prediction experiments with improved/updated physical parameterizations, which show better skill in predicting sea ice state as well as atmospheric and oceanic state in the Arctic compared with its predecessor. The improved model also show extended predictive skill of Arctic sea ice after the summer season. This provides added values of this prediction system for decision-making.