Evaluating the Model Representation of Asian Summer Monsoon Upper Troposphere and Lower Stratosphere Transport and Composition Using Airborne In Situ Observations
Evaluating the Model Representation of Asian Summer Monsoon Upper Troposphere and Lower Stratosphere Transport and Composition Using Airborne In Situ Observations
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DOI：
10.1029/2023jd039756
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发表时间：
2024-02-28
影响因子：
4.4
通讯作者：
Ravegnani，Fabrizio
中科院分区：
文献类型：
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作者：
Smith，Warren P.;Pan，Laura L.;Ravegnani，Fabrizio
化学气候模型 (CCM) 是描述和预测大气成分和化学在地球气候系统中的作用的重要工具。本研究展示了利用机载原位观测来诊断 CCM 的化学成分和传输的表征。提出了使用动态和化学坐标的基于过程的诊断，最大限度地减少了机载原位测量和 CCM 网格点之间的空间和时间采样差异。所选择的过程是亚洲夏季季风（ASM）的化学影响，其中深层对流作为表面排放到达对流层上层和平流层下层（UTLS）的快速传输路径。我们使用一组来自南亚的机载观测结果检查了两种 CCM 配置，以了解它们对 ASM UTLS 的表示。诊断显示模型在表示整个对流层和平流层下部的对流层示踪剂分布方面具有良好的性能，并且当化学损失主要由光解作用时，可以很好地表示平流层下部的化学老化。已确定的模型局限性包括对对流层寿命足够短的物种使用区域平均摩尔分数边界条件，这可能会掩盖增强的区域排放源。总体而言，诊断结果强调了当前一代模型通过 ASM 机制表示污染从边界层到平流层传输的能力，并证明了机载原位观测在表征这种表示方面的优势。
Chemistry Climate Models (CCMs) are essential tools for characterizing and predicting the role of atmospheric composition and chemistry in Earth's climate system. This study demonstrates the use of airborne in situ observations to diagnose the representation of chemical composition and transport by CCMs. Process‐based diagnostics using dynamical and chemical coordinates are presented which minimize the spatial and temporal sampling differences between airborne in situ measurements and CCM grid points. The chosen process is the chemical impact of the Asian summer monsoon (ASM), where deep convection serves as a rapid transport pathway for surface emissions to reach the upper troposphere and lower stratosphere (UTLS). We examine two CCM configurations for their representation of the ASM UTLS using a set of airborne observations from south Asia. The diagnostics reveal good model performance at representing tropospheric tracer distribution throughout the troposphere and lower stratosphere, and excellent representation of chemical aging in the lower stratosphere when chemical loss is dominated by photolysis. Identified model limitations include the use of zonally averaged mole fraction boundary conditions for species with sufficiently short tropospheric lifetimes, which may obscure enhanced regional emissions sources. Overall, the diagnostics underscore the skill of current‐generation models at representing pollution transport from the boundary layer to the stratosphere via the ASM mechanism, and demonstrate the strength of airborne in situ observations toward characterizing this representation.