Relation Between Arctic Moisture Flux and Tropical Temperature Biases in CMIP5 Simulations and Its Fingerprint in RCP8.5 Projections
Relation Between Arctic Moisture Flux and Tropical Temperature Biases in CMIP5 Simulations and Its Fingerprint in RCP8.5 Projections
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DOI：
10.1029/2018gl080562
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
Sukyoung Lee;C. Woods;R. Caballero
中科院分区：
文献类型：
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作者：
Sukyoung Lee;C. Woods;R. Caballero
在过去的几十年里，北极水分入侵在北极变暖方面发挥了重要作用。先前的一项研究发现，耦合模型相互比较项目第5阶段（CMIP 5）模型在70°N的水分通量中表现出较大的区域偏差。这里表明，系统的水分通量的误报是与模式的纬向波数k = 2的贡献和低估的k = 1的贡献通量的高估。热带对流层上层温度较暖且热带表面温度类似厄尔尼诺的模式往往模拟出较强的k = 2通量，而k = 1通量与热带对流层上层温度无关，与类似拉尼娜的表面温度相关。该模型还高估了瞬态涡动水分通量，而低估了稳态涡动通量。此外，代表性浓度路径8.5（RCP8.5）模拟中的未来预测显示，水分通量的趋势与历史模拟中的偏差一致，这表明这些CMIP5预测反映了导致模型偏差的相同误差。
Arctic moisture intrusions have played an important role in warming the Arctic over the past few decades. A prior study found that Coupled Model Intercomparison Project Phase 5 (CMIP5) models exhibit large regional biases in the moisture flux across 70°N. It is shown here that the systematic misrepresentation of the moisture flux is related to the models' overprediction of zonal wavenumber k = 2 contribution and underprediction of k = 1 contribution to the flux. Models with a warmer tropical upper troposphere and El‐Niño‐like tropical surface temperature tend to simulate stronger k = 2 flux, while k = 1 flux is uncorrelated with tropical upper tropospheric temperature and is associated with La‐Niña‐like surface temperature. The models also overpredict the transient eddy moisture flux while underpredicting the stationary eddy flux. Moreover, future projections in Representative Concentration Pathway 8.5 (RCP8.5) simulations show trends in moisture flux that is consistent with biases in historical simulations, suggesting that these CMIP5 projections reflect the same error(s) that cause the model biases.