Implementation and evaluation of the GEOS-Chem chemistry module version 13.1.2 within the Community Earth System Model v2.1
Implementation and evaluation of the GEOS-Chem chemistry module version 13.1.2 within the Community Earth System Model v2.1
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DOI：
10.5194/gmd-15-8669-2022
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发表时间：
2022-11-30
影响因子：
5.1
通讯作者：
Jacob, Daniel J.
中科院分区：
文献类型：
--
作者：
Fritz, Thibaud M.;Eastham, Sebastian D.;Jacob, Daniel J.
我们实现了地球观测系统化学模块作为社区地球系统模型（CESM）第2版的化学机制。我们的实施允许国家的科学GEOS-Chem化学模块与相同的排放，气象和气候反馈CESM内的CAM-Chem化学模块。我们使用耦合接口，使GEOS-Chem在CESM内几乎不发生变化地运行。气溶胶在GEOS-Chem批量表示和CESM模态气溶胶模型（MAM 4）的尺寸分辨表示之间的每个时间步长进行转换。地球观测系统-化学中干沉积计算所需的土地类型信息通过耦合器传送，从而允许在线陆地-大气相互作用。用Neu和Prather方案取代了GEOS-Chem中的湿扫气，并为CESM中的CAM-Chem和GEOS-Chem开发了一种共同的排放方法。我们比较了嵌入CESM（C-GC）的GEOS-Chem与现有CAM-chem化学选项（C-CC）在2016年用于模拟大气化学时的对比情况，具有相同的气象和排放。我们比较了两个模拟之间的大气成分和沉积趋势，并评估C-GC和它作为一个独立的化学传输模型在GEOS-Chem高性能配置（S-GC）之间的剩余差异。我们发现，平流层臭氧同意之间的三个模式，在臭氧层的核心的差异小于10%，但对流层中的臭氧通常是较低的C-GC比在C-CC或S-GC。这可能是由于对流层中溴的浓度更高，尽管其他因素，如水蒸气，可能会在更大或更小的程度上取决于该区域。对流层臭氧的这种差异是不均匀的，与S-GC相比，南半球C-GC中的对流层臭氧低30%，但在北方半球在10%以内。这表明人为排放的影响存在差异。在热带低海拔地区，C-GC中的气溶胶浓度与S-GC中的气溶胶浓度一致，但由于对流清除代表性的差异，对流层上部的气溶胶浓度要高出100%以上。我们还发现，水蒸气浓度之间的独立和CESM实施的版本的GEOS-Chem的显着变化，CESM中的模拟水文循环偏离源美国宇航局现代回顾分析研究和应用（版本2; MERRA-2）再分析气象学，这是直接用于GEOS-Chem化学传输模型（CTM）。我们将GEOS-Chem作为CESM中的一个化学选项（包括完整的化学-气候反馈）的实施是公开的，并正在考虑将其纳入CESM主代码库。这项工作是多尺度化学和气溶胶基础设施（MUSICA）项目的重要一步，使两个大气研究人员社区（CESM和GEOS-Chem）能够通过共同的建模框架分享专业知识，从而加速大气科学的进步。
We implement the GEOS-Chem chemistry module as a chemical mechanism in version 2 of the Community Earth System Model (CESM). Our implementation allows the state-of-the-science GEOS-Chem chemistry module to be used with identical emissions, meteorology, and climate feedbacks as the CAM-chem chemistry module within CESM. We use coupling interfaces to allow GEOS-Chem to operate almost unchanged within CESM. Aerosols are converted at each time step between the GEOS-Chem bulk representation and the size-resolved representation of CESM's Modal Aerosol Model (MAM4). Land-type information needed for dry-deposition calculations in GEOS-Chem is communicated through a coupler, allowing online land-atmosphere interactions. Wet scavenging in GEOS-Chem is replaced with the Neu and Prather scheme, and a common emissions approach is developed for both CAM-chem and GEOS-Chem in CESM. We compare how GEOS-Chem embedded in CESM (C-GC) compares to the existing CAM-chem chemistry option (C-CC) when used to simulate atmospheric chemistry in 2016, with identical meteorology and emissions. We compare the atmospheric composition and deposition tendencies between the two simulations and evaluate the residual differences between C-GC and its use as a stand-alone chemistry transport model in the GEOS-Chem High Performance configuration (S-GC). We find that stratospheric ozone agrees well between the three models, with differences of less than 10 % in the core of the ozone layer, but that ozone in the troposphere is generally lower in C-GC than in either C-CC or S-GC. This is likely due to greater tropospheric concentrations of bromine, although other factors such as water vapor may contribute to lesser or greater extents depending on the region. This difference in tropospheric ozone is not uniform, with tropospheric ozone in C-GC being 30 % lower in the Southern Hemisphere when compared with S-GC but within 10 % in the Northern Hemisphere. This suggests differences in the effects of anthropogenic emissions. Aerosol concentrations in C-GC agree with those in S-GC at low altitudes in the tropics but are over 100 % greater in the upper troposphere due to differences in the representation of convective scavenging. We also find that water vapor concentrations vary substantially between the stand-alone and CESM-implemented version of GEOS-Chem, as the simulated hydrological cycle in CESM diverges from that represented in the source NASA Modern-Era Retrospective analysis for Research and Applications (Version 2; MERRA-2) reanalysis meteorology which is used directly in the GEOS-Chem chemistry transport model (CTM). Our implementation of GEOS-Chem as a chemistry option in CESM (including full chemistry-climate feedback) is publicly available and is being considered for inclusion in the CESM main code repository. This work is a significant step in the MUlti-Scale Infrastructure for Chemistry and Aerosols (MUSICA) project, enabling two communities of atmospheric researchers (CESM and GEOS-Chem) to share expertise through a common modeling framework, thereby accelerating progress in atmospheric science.