Evaluation of Arctic Sea Ice Drift and its Relationship with Near-surface Wind and Ocean Current in Nine CMIP6 Models from China

Abstract

The simulated Arctic sea ice drift and its relationship with the near-surface wind and surface ocean current during 1979–2014 in nine models from China that participated in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) are examined by comparison with observational and reanalysis datasets. Most of the models reasonably represent the Beaufort Gyre (BG) and Transpolar Drift Stream (TDS) in the spatial patterns of their long-term mean sea ice drift, while the detailed location, extent, and strength of the BG and TDS vary among the models. About two-thirds of the models agree with the observation/reanalysis in the sense that the sea ice drift pattern is consistent with the near-surface wind pattern. About the same proportion of models shows that the sea ice drift pattern is consistent with the surface ocean current pattern. In the observation/reanalysis, however, the sea ice drift pattern does not match well with the surface ocean current pattern. All nine models missed the observational widespread sea ice drift speed acceleration across the Arctic. For the Arctic basin-wide spatial average, five of the nine models overestimate the Arctic long-term (1979–2014) mean sea ice drift speed in all months. Only FGOALS-g3 captures a significant sea ice drift speed increase from 1979 to 2014 both in spring and autumn. The increases are weaker than those in the observation. This evaluation helps assess the performance of the Arctic sea ice drift simulations in these CMIP6 models from China.

摘 要

本文利用北极观测与再分析数据评估了9个参与耦合模式比较计划第六阶段(CMIP6)的中国模式模拟的1979-2014年北极海冰漂移及其与近地表风和表层洋流的关系。评估结果显示:大多数模式模拟的平均海冰漂移空间分布能较好地再现波弗特环流和穿极流,但这两种大尺度海冰漂移模态的具体位置、范围和强度在不同的模式中有所差异。约2/3的模式模拟的海冰漂移空间分布与近地表风场空间分布一致,这与观测和再分析资料中的结果一致。约2/3的模式模拟的海冰漂移空间分布与表层洋流空间分布一致。但观测与再分析资料中两者的空间分布并不一致。9个模式均未能模拟出观测数据所展现的北极大部分区域海冰漂移速度的显着增加趋势。对于北极海盆范围内的区域平均值,5个模式高估了所有月份北极海冰的长期平均(1979-2014)漂移速度。9个模式中只有 FGOALS-g3 模式模拟出了1979 -2014年春季和秋季北极海冰漂移速度的显着增加趋势,但该趋势小于观测中的趋势。本研究有助于评估参与CMIP6的中国模式模拟北极海冰漂移的性能。