Evaluation of ocean dimethylsulfide concentration and emission in CMIP6 models
Evaluation of ocean dimethylsulfide concentration and emission in CMIP6 models
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DOI：
10.5194/bg-18-3823-2021
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发表时间：
2021-06-29
期刊：
影响因子：
4.9
通讯作者：
Seferian, Roland
中科院分区：
文献类型：
--
作者：
Bock, Josue;Michou, Martine;Seferian, Roland
使用耦合模型比较项目 6 (CMIP6) 模拟，分析了最近（1980-2009 年）和未来四个地球系统模型（ESM：CNRM-ESM2-1、MIROC-ES2L、NorESM2-LM 和 UKESM1-0-LL）表面海洋二甲硫醚 (DMS) 浓度和进入大气的通量的特征和趋势。历史模拟中的 DMS 浓度系统地低估了最广泛使用的观测气候学，但与最近两个基于观测的数据集相比更为有利。这些模型更好地再现了中高纬度地区以及极地和西风带海洋生物群落的观测结果。由此产生的当代全球海洋 DMS 排放的多模型估计为 16-24 Tg S yr(-1)，比观测得出的 16 至 28 Tg S yr(-1) 范围窄。四个模型对 1980 年以来全球 DMS 通量趋势的符号不一致，其中两个模型显示增加，两个模型显示减少。在全球范围内，这些趋势主要由所有模型中表面 DMS 浓度的变化主导，无论使用的海气通量参数如何。反过来，三个模型一致表明 DMS 浓度的变化与海洋生产力的变化相关；然而，海洋生产力在当前一代 ESM 中受到的限制很弱，从而限制了这种关系的预测能力。相比之下，极地纬度的所有模型都达成了共识，即增加的趋势主要是由海冰范围的消退驱动的。然而，1980 年至 2014 年期间，模型之间这种趋势的幅度相差 3 倍，从 2.9 到 9.2 Gg S 十年(-1)，处于最近卫星分析的低端。21 世纪的气候预测中也发现了类似的增长趋势。
Characteristics and trends of surface ocean dimethylsulfide (DMS) concentrations and fluxes into the atmosphere of four Earth system models (ESMs: CNRM-ESM2-1, MIROC-ES2L, NorESM2-LM, and UKESM1-0-LL) are analysed over the recent past (1980-2009) and into the future, using Coupled Model Intercomparison Project 6 (CMIP6) simulations. The DMS concentrations in historical simulations systematically underestimate the most widely used observed climatology but compare more favourably against two recent observation-based datasets. The models better reproduce observations in mid to high latitudes, as well as in polar and westerlies marine biomes. The resulting multi-model estimate of contemporary global ocean DMS emissions is 16-24 Tg S yr(-1), which is narrower than the observational-derived range of 16 to 28 Tg S yr(-1). The four models disagree on the sign of the trend of the global DMS flux from 1980 onwards, with two models showing an increase and two models a decrease. At the global scale, these trends are dominated by changes in surface DMS concentrations in all models, irrespective of the air-sea flux parameterisation used. In turn, three models consistently show that changes in DMS concentrations are correlated with changes in marine productivity; however, marine productivity is poorly constrained in the current generation of ESMs, thus limiting the predictive ability of this relationship. In contrast, a consensus is found among all models over polar latitudes where an increasing trend is predominantly driven by the retreating sea-ice extent. However, the magnitude of this trend between models differs by a factor of 3, from 2.9 to 9.2 Gg S decade(-1) over the period 1980-2014, which is at the low end of a recent satellite-derived analysis Similar increasing trends are found in climate projections over the 21st century.