Model output for "Observed Antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity"

The Antarctic sea ice area expanded significantly during 1979-2015. This is at odds with state-of-the-art climate models, which typically simulate a receding Antarctic sea ice cover in response to increasing greenhouse forcing. Here we investigate the hypothesis that this discrepancy between models and observations occurs due to simulation biases in the sea ice drift velocity. As a control we use the Community Earth System Model (CESM) Large Ensemble, which has 40 realizations of past and future climate change that all undergo Antarctic sea ice retreat during recent decades. We modify CESM to replace the simulated sea ice velocity field with a satellite-derived estimate of the observed sea ice motion, and we simulate 3 realizations of recent climate change.

1979-2015年间，南极海冰面积显著扩张，这与当前最先进的气候模式的模拟结果相悖——这类模式通常会模拟出南极海冰覆盖随温室强迫增强而退缩的现象。本研究旨在验证如下假说：模式与观测之间的上述差异，源于海冰漂移速度的模拟偏差。作为对照试验，我们采用社区地球系统模型（Community Earth System Model, CESM）大集合试验，该试验包含40组过去与未来气候变化的模拟集合成员，所有成员在近几十年均呈现出南极海冰退缩的特征。我们对CESM进行修改，将模式模拟的海冰速度场替换为基于卫星反演的观测海冰运动估算值，并开展了3组近几十年气候变化的模拟试验。