Simulated stable water isotopes during the mid-Holocene and pre-industrial periods using AWI-ESM-2.1-wiso

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscientific Model Development Pub Date : 2023-09-08 DOI:10.5194/gmd-16-5153-2023

Xiaoxu Shi, A. Cauquoin, Gerrit Lohmann, L. Jonkers, Qian Wang, Hu Yang, Yuchen Sun, Martin Werner

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引用次数: 0

Abstract

Abstract. Numerical simulations employing prognostic stable water isotopes can not only facilitate our understanding of hydrological processes and climate change but also allow for a direct comparison between isotope signals obtained from models and various archives. In the current work, we describe the performance and explore the potential of a new version of the Earth system model AWI-ESM (Alfred Wegener Institute Earth System Model), labeled AWI-ESM-2.1-wiso, in which we incorporated three isotope tracers into all relevant components of the water cycle. We present here the results of pre-industrial (PI) and mid-Holocene (MH) simulations. The model reproduces the observed PI isotope compositions in both precipitation and seawater well and captures their major differences from the MH conditions. The simulated relationship between the isotope composition in precipitation (δ18Op) and surface air temperature is very similar between the PI and MH conditions, and it is largely consistent with modern observations despite some regional model biases. The ratio of the MH–PI difference in δ18Op to the MH–PI difference in surface air temperature is comparable to proxy records over Greenland and Antarctica only when summertime air temperature is considered. An amount effect is evident over the North African monsoon domain, where a negative correlation between δ18Op and the amount of precipitation is simulated. As an example of model applications, we studied the onset and withdrawal date of the MH West African summer monsoon (WASM) using daily variables. We find that defining the WASM onset based on precipitation alone may yield erroneous results due to the substantial daily variations in precipitation, which may obscure the distinction between pre-monsoon and monsoon seasons. Combining precipitation and isotope indicators, we suggest in this work a novel method for identifying the commencement of the WASM. Moreover, we do not find an obvious difference between the MH and PI periods in terms of the mean onset of the WASM. However, an advancement in the WASM withdrawal is found in the MH compared to the PI period due to an earlier decline in insolation over the northern location of Intertropical Convergence Zone (ITCZ).

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使用AWI-ESM-2.1-wiso模拟全新世中期和工业化前时期的稳定水同位素

摘要采用预测稳定水同位素的数值模拟不仅有助于我们理解水文过程和气候变化，还可以直接比较从模型和各种档案中获得的同位素信号。在目前的工作中，我们描述了新版地球系统模型AWI-ESM（阿尔弗雷德·韦格纳研究所地球系统模型）的性能并探索了其潜力，该模型被标记为AWI-ESM-2.1-wiso，其中我们将三种同位素示踪剂纳入了水循环的所有相关组成部分。我们在这里展示了工业化前（PI）和全新世中期（MH）模拟的结果。该模型再现了在降水和海水井中观察到的PI同位素组成，并捕捉到了它们与MH条件的主要差异。在PI和MH条件下，降水中同位素组成（δ18Op）和地表气温之间的模拟关系非常相似，尽管存在一些区域模型偏差，但它与现代观测结果基本一致。只有在考虑夏季气温的情况下，δ18Op中的MH–PI差异与地表气温中的MH-PI差异之比才能与格陵兰岛和南极洲的代理记录相比较。数量效应在北非季风区很明显，在那里模拟了δ18Op与降水量之间的负相关性。作为模型应用的一个例子，我们使用日变量研究了MH西非夏季风（WASM）的开始和结束日期。我们发现，由于降水量的巨大日变化，仅根据降水量来定义WASM发作可能会产生错误的结果，这可能会混淆季风前季节和季风季节之间的区别。结合降水和同位素指标，我们在这项工作中提出了一种新的方法来识别WASM的开始。此外，就WASM的平均发作而言，我们没有发现MH和PI周期之间的明显差异。然而，与PI期相比，由于热带辐合带（ITCZ）北部位置的日照减少较早，MH期的WASM消退有所增加。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geoscientific Model Development GEOSCIENCES, MULTIDISCIPLINARY-

CiteScore

8.60

自引率

9.80%

发文量

352

审稿时长

6-12 weeks

期刊介绍： Geoscientific Model Development (GMD) is an international scientific journal dedicated to the publication and public discussion of the description, development, and evaluation of numerical models of the Earth system and its components. The following manuscript types can be considered for peer-reviewed publication: * geoscientific model descriptions, from statistical models to box models to GCMs; * development and technical papers, describing developments such as new parameterizations or technical aspects of running models such as the reproducibility of results; * new methods for assessment of models, including work on developing new metrics for assessing model performance and novel ways of comparing model results with observational data; * papers describing new standard experiments for assessing model performance or novel ways of comparing model results with observational data; * model experiment descriptions, including experimental details and project protocols; * full evaluations of previously published models.