A Joint Soil‐Vegetation‐Atmospheric Modeling Procedure of Water Isotopologues: Implementation and Application to Different Climate Zones With WRF‐Hydro‐Iso
A Joint Soil‐Vegetation‐Atmospheric Modeling Procedure of Water Isotopologues: Implementation and Application to Different Climate Zones With WRF‐Hydro‐Iso
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DOI：
10.1029/2021ms002562
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发表时间：
2021-09
影响因子：
6.8
通讯作者：
J. Arnault;G. Jung;B. Haese;B. Fersch;Thomas Rummler;Jianhui Wei;Zhenyu Zhang;H. Kunstmann
中科院分区：
文献类型：
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作者：
J. Arnault;G. Jung;B. Haese;B. Fersch;Thomas Rummler;Jianhui Wei;Zhenyu Zhang;H. Kunstmann
水同位素作为地球上水文循环的天然示踪剂，提供了一种独特的方法来评估气候模型在描述真实的大气-陆地水路径方面的技能。这项研究介绍了最新发展的WRF-HYDRO-ISO，它是大气-水文WRF-HYDRO耦合模型的一个版本，该模型增强了对水的同位素运动的土壤-植被-大气联合描述。它允许考虑大气、地表和次表层中水相变化过程中的同位素分馏过程。为了验证，在目前的气候条件下，WRF-Hydro-iso被应用于两个不同的气候带，即欧洲和南部非洲。每种情况都用一个采用5公里网格间距的区域和一个采用500米网格间距的陆面子网格来模拟，以表示横向陆地水流。使用ERA5再分析作为驱动数据，模拟了2003-2012年的10年切片。同位素变量的边界条件是用共同体地球系统模式版本1进行的10年模拟的平均值规定的。WRF-HYDRO-ISO真实地再现了来自全球降水同位素网络的同位素浓度δPO18和δPH2的气候变化。敏感性分析发现，地表蒸发分馏增加了根际土壤水分中的同位素浓度，略有降低降水中的同位素浓度。侧向陆地水流通过蒸发-蒸腾分配的变化对这些同位素浓度的影响很小。
Water isotopologues, as natural tracers of the hydrological cycle on Earth, provide a unique way to assess the skill of climate models in representing realistic atmospheric‐terrestrial water pathways. This study presents the newly developed WRF‐Hydro‐iso, which is a version of the coupled atmospheric‐hydrological WRF‐Hydro model enhanced with a joint soil‐vegetation‐atmospheric description of water isotopologue motions. It allows the consideration of isotopic fractionation processes during water phase changes in the atmosphere, the land surface, and the subsurface. For validation, WRF‐Hydro‐iso is applied to two different climate zones, namely Europe and Southern Africa under the present climate conditions. Each case is modeled with a domain employing a 5 km grid‐spacing coupled with a terrestrial subgrid employing a 500 m grid‐spacing in order to represent lateral terrestrial water flow. A 10‐year slice is simulated for 2003–2012, using ERA5 reanalyses as driving data. The boundary condition of isotopic variables is prescribed with mean values from a 10‐year simulation with the Community Earth System Model Version 1. WRF‐Hydro‐iso realistically reproduces the climatological variations of the isotopic concentrations δPO18 and δPH2 from the Global Network of Isotopes in Precipitation. In a sensitivity analysis, it is found that land surface evaporation fractionation increases the isotopic concentrations in the rootzone soil moisture and slightly decreases the isotopic concentrations in precipitation. Lateral terrestrial water flow minorly affects these isotopic concentrations through changes in evaporation‐transpiration partitioning.