Duan Xianzhe, Sun Haoran, Li Nan, Dou Jiale
School of Resource &Environment and Safety Engineering, University of South China, Hengyang, 421001, China.
Hunan Key Laboratory of the Rare Metal Minerals Exploitation and Geological Disposal of Wastes, Hengyang, 421001, China.
Carbon Balance Manag. 2025 Aug 20;20(1):32. doi: 10.1186/s13021-025-00320-5.
As the global greenhouse effect intensifies, the emission and balance of greenhouse gases, particularly carbon dioxide (CO), have become crucial for achieving global carbon neutrality. Volcanic geothermal regions, as major natural sources of carbon emissions, release substantial volume of greenhouse gases into the atmosphere in various ways including volcanic eruptions, soil microseepages, vents, and hot springs. Among these, soil microseepages are particularly important due to their widespread and persistent nature. However, the geochemical dynamics of CO release from soil microseepage in volcanic regions remain poorly understood. In this study, we propose a novel CO release model employing computational fluid dynamics (CFD) to model CO emissions from soil microseepage in volcanic regions. Our results provide important insights as follows: (1) Low porosity in subsurface strata inhibits CO penetration, while well-developed underground cracks and channels enhance release rates. (2) Favorable gas pathways enable CO to penetrate dense layers, and migrate upward, with migration patterns influenced by gas source pressure, temperature, and soil permeability. Slowing vertical migration increases horizontal diffusion and expands the effective surface release area. (3) Surface release is also influenced by external factors like wind speed, though these do not significantly affect underground seepage. (4) To improve the accuracy of CO flux measurements using the closed chamber method, it is recommended to reverse the initial slope of the CO concentration-time curve. This study provides critical data to enhance global carbon budget assessments and support efforts towards carbon neutrality.
随着全球温室效应加剧，温室气体的排放与平衡，尤其是二氧化碳（CO），对于实现全球碳中和至关重要。火山地热区域作为碳排放的主要天然来源，通过火山喷发、土壤微渗漏、喷口和温泉等多种方式向大气中释放大量温室气体。其中，土壤微渗漏因其广泛且持续的特性尤为重要。然而，火山区域土壤微渗漏中CO释放的地球化学动力学仍知之甚少。在本研究中，我们提出了一种新颖的CO释放模型，采用计算流体动力学（CFD）对火山区域土壤微渗漏中的CO排放进行建模。我们的结果提供了以下重要见解：（1）地下地层的低孔隙率抑制CO渗透，而发育良好的地下裂缝和通道则提高释放速率。（2）有利的气体通道使CO能够穿透致密层并向上迁移，迁移模式受气源压力、温度和土壤渗透率影响。垂直迁移减缓会增加水平扩散并扩大有效地表释放面积。（3）地表释放也受风速等外部因素影响，不过这些因素对地下渗漏影响不大。（4）为提高使用密闭箱法测量CO通量的准确性，建议反转CO浓度 - 时间曲线的初始斜率。本研究提供了关键数据，以加强全球碳预算评估并支持碳中和努力。
